content · 2018-01-11 · t8 leonardelli, sonia chromosomal alterations predispose to the...

1st ESSEN TRANSLATONAL ONCOLOGY SYMPOSIUM, JANUARY 12th, 2018 - 1 -

CONTENT

TALKS IN ALPHABETICAL ORDER ............................................................................................................................. 2

POSTERS IN ALPHABETICAL ORDER ......................................................................................................................... 3

ABSTRACTS FOR TALKS T1 – T19 ............................................................................................................................. 2

ABSTRACTS FOR POSTERS P1 – P79....................................................................................................................... 23

FLOOR PLAN ........................................................................................................................................................ 102

INDEX PRESENTERS AND POSTERS ...................................................................................................................... 104

Editorial Responsibility: Sabine Kaul DKTK Administrative Coordinator [email protected]

Edited by: German Cancer Consortium (DKTK) German Cancer Research Center (DKFZ) DKTK Partner Site Essen/Düsseldorf University Hospital Essen Hufelandstrasse 55 47147 Essen The texts originate from the individual research groups.


INDEX TALKS AND POSTERS

TALKS IN ALPHABETICAL ORDER

PRESENTER TITLE TALK NBR.

Adamczyk, Alexandra Homing to suppress – the role of GPR15 on Treg trafficking during colon cancer

T11

Ahmadov, Ulvi The Onco-LincRNA HOTAIRM1 in glioblastoma T2

Fleischhauer, Katharina NGS-based characterization of HLA immune escape by leukemia after immunotherapy

T10

Glas, Martin PriCoTTF: A phase I/II single-arm trial of Tumor Treating Fields prior and concomitant with radiotherapy and temozolomide in newly diagnosed glioblastoma

T13

Glas, Martin Randomized trial of radiotherapy with protons vs. conventional radiotherapy with photons for patients with WHO grade II-III glioma (GliProPh)

T13

Grunewald, Susanne Retrograde translation in a BLU-285-resistant PDGFRA-D842V mutant GIST

T18

Hanoun, Maher Dissecting the architecture of the human bone marrow niche in acute myeloid leukemia

T1

Hauer, Julia Targeting of MYC downstream pathways in pediatric refractory T-ALL

T16

Kebir, Sied Olfactory Function as Independent Prognostic Factor in glioblastoma Multiforme

T8

Leonardelli, Sonia Chromosomal alterations predispose to the development of immunotherapy resistance

T7

Matschke, Johann Role of metabolic adaptations for survival and radiation resistance of hypoxic or chronic cycling anoxia/reoxigenation adapted cancer cells

T3

Picard, Daniel Proteogenomics discriminates pediatric and adult pilocytic astrocytoma into three distinct biological entities

T5

Pylaeva, Ekaterina Type I interferon-mediated neutrophil activation during tumorigenesis may contribute to infectious complications

T12

Reis, Henning Molecular mechanisms in urachal cancer: potential targets for therapeutic intervention

T19

Remke, Marc Proteogenomics and high-throughput drug screening for novel brain tumor therapies – it takes two to tango

T15

Ritter, Cathrin Merkel cell carcinoma derived miR-375 reprograms fibroblasts into MCC associated fibroblasts

T9

Schulze-Schleithoff, Stefanie

Treatment of sarcomas at West German Proton Therapy Center Essen (WPE)

T14

Stang, Andreas The incidence of Merkel cell carcinoma: A comprehensive international assessment

T6

Varaljai, Renata Application of circulating cell-free tumor DNA (ctDNA) profiles for monitoring metastatic melanoma progression under therapy

T4

Zegar, Tim Functional characterization of epigenetic targeting with dual active BET/HDAC-inhibitors in model systems of pancreatic cancer

T17


POSTERS IN ALPHABETICAL ORDER

PRESENTER TITLE POSTER

NBR. Al-Matary, Yahya AML–associated mesenchymal stromal cells (AMSCs) support

the growth of leukemia cells in vivo and in vitro P6

Bartl, Jasmin Targeting the long non-coding RNA HHIP-AS1 in sonic hedgehog driven brain tumors

P2

Batzke, Katharina The Role of Gal-1 in modulating radioresistance of neuroblastoma cell lines

P79

Bäumer, Christian Medical physics research in proton therapy centers: combining DKTK activities with European collaborations

P26

Blümel, Lena TARGETING PRIMARY CILIOGENESIS IN ATYPICAL TERATOID/RHABDOID TUMORS

P54

Borchert, Sabrina BRCAness phenotype is common in MPM and is associated with response to olaparib in vitro

P43

Bordbari, Sharareh The regulatory effect of Type I IFNs on neutrophil angiogenic capability in tumor microenvironment

P39

Bruderek, Kirsten Clinical relevance and suppressive capacity of human MDSC subsets

P18

Carpinteiro, Alexander Role of sphingolipid signaling/metabolism in hematopoietic stem and progenitor cell (HSPC) mobilization

P33

Chauvistré, Heike Phenotypic modulation as a new therapeutic strategy in melanoma

P51

Dierichs, Laura Characterization and Epigenetic Targeting of Acquired Therapy Resistance in Pancreatic Cancer

P7

Dobersalske, Celia Profiling cell types in glioblastoma using transcriptomes P4

Dorsch, Madeleine Multiplexed in vivo small molecule screening for immediate drug repositioning reveals novel therapeutic targets in metastatic pancreatic cancer

P64

Falkenhorst, Johanna DKTK MASTER Essen – A single center experience P40

Farsijani, Navid Genome-wide mutational analysis of Hodgkin lymphoma P44

Frank, Daria The Role of Gfi1 in Genome Stability P42

Franken, André CTCs from Leukapheresis Products Can Be Isolated by Parsortix System for Subsequent Culture

P70

Frisch, Sabine Proton beam therapy for CNS tumors at the West German Proton Therapy Centre Essen (WPE) – Early experiences and future perspectives

P11

Glas, Martin Longitudinal heterogeneity in glioblastoma – moving targets in recurrent versus primary tumors.

P55

Göthert, Joachim Potent anti-leukemic activity of a specific cyclin-dependent kinase 9 inhibitor in mouse models of chronic lymphocytic leukemia

P23

Göthert, Joachim Pharmacologic LSD1 inhibition perturbs terminal human granulopoiesis while preserving monopoiesis

P24

Gravemeyer, Jan A comparative Analysis of merkel cell carcinoma cell lines by means of differential methylation

P66

Hamacher, Rainer PD-L1 inhibition – a new therapeutic opportunity in cutaneous angiosarcoma?

P16



NBR. Hegedüs, Luca Molecularly targeted treatment of novel malignant pleural

effusion derived cell models P9

Hetkamp, Philipp Ga-PSMA PET/CT mapping of early biochemical recurrence after primary surgery in 270 patients: Impact on Salvage Radiotherapy Planning

P3

Hönes, Judith The role and influence of ecto-5´-nucleotidase (CD73) and the programmed cell death receptor (PD-1) in tumor microenvironment and progression in a PTC mouse model

P31

Honisch, Ellen TruRisk® gene panel analysis in familial breast and ovarian cancer patients

P22

Kahlert, Ulf Prevailing starvation resistance by glutaminase inhibition P50

Kalmbach, Sophie Identification of novel targets for rational chemoradiotherapy strategies in non-small-cell lung cancer

P13

Kess, Knud Identification of compounds inducing differentiation in solid tumors using a novel cell-based screening system.

P58

Ketzer, Julia HUSARC – the Human Sarcoma Model Initiative P8

Kitanovski, Simo HTSeq analyses of genetic diversity of cellular repertoires in oncological contexts

P46

Kumar Patnana, Pradeep Role of GFI1 in Acute myeloid leukemia (AML) and the functional role in metabolic regulation

P68

Lahner, Harald Onset and progression of bone metastases in neuroendocrine tumors

P59

Lahner, Harald Impact of STZ based chemotherapy versus targeted therapy for outcome of pancreatic neuroendocrine tumors

P60

Lahner, Harald Everolimus in Neuroendocrine Tumors of the Gastrointestinal Tract and Unknown Primary

P61

Lampignano, Rita Enrichment, isolation and PIK3CA mutational analysis of patient-matched

P52

Langini, Maike The role of RMST, a functional long-noncoding RNA, in Glioblastoma

P45

Mairinger, Elena Searching predictive biomarkers for ovarian cancer – establishment of a new mRNA-based scoring system

P34

Mairinger, Fabian Inhibition of MDM2 via Nutlin-3A – A Potential Therapeutic Approach for Pleural Mesotheliomas with MDM2-Induced Inactivation of P53

P14

Marquardt, Viktoria Identification of a selective histone deacetylase inhibitor for MYC-driven medulloblastoma by high-throughput drug screening

P15

Mergener, Svenja Effects of pharmacological compounds in patient derived cell culture models

P76

Michel, Lars The Role of Programmed Death 1 in Myocardial Injury P53

Möller, Lars A 6 bp in frame germline deletion in exon 7 of RET leads to increased RET phosphorylation, ERK activation and MEN2A

P72



NBR. Möller, Lars ALK activation promotes an aggressive thyroid carcinoma in

mice,resembling human poorly differentiated carcinoma (PDTC)

P73

Möller, Lars Targeted next-generation sequencing for TP53, RAS, BRAF, ALK and NF1 mutations in anaplastic thyroid cancer

P74

Möller, Lars Thyroxine promotes tumor growth in an orthotopic lung cancer mouse model

P75

Mrotzek, Simone Presentation of acute coronary syndromes in cancer patients P65

Mühlenberg, Thomas Academic drug development in genomically well-defined cancer models using drug-screens and rational design approaches

P77

Muminova, Shakhlo Application of unaltered and genetically modified natural killer (NK) cells for cancer therapy

P69

Naskou, Johanna Loss of EZH2 increases therapy resistance to combinational treatment with carboplatin and Taxol in ovarian cancer

P19

Neander, Christian Influence of Trametinib on Tumor-Associated Macrophages in Pancreatic Ductal Adenocarcinoma

P57

Neubauer, Hans CTCEndo: Endocrine Resistance in breast cancer circulating tumor cells

P67

Nothdurft, Silke Identification of novel metastasis-modulating factors in non-small-cell lung cancer

P56

Pastille, Eva Intestinal helminth infection drives carcinogenesis in colitis-associated colon cancer

P12

Pauck, David High-throughput drug screening reveals novel therapeutic vulnerabilities of ependymomas.

P32

Piras-Straub, Katja Antiviral HCV therapy with sofosbuvir reduces HCC recurrence by inhibition of hepatocyte proliferation

P37

Piras-Straub, Katja HCC progression is fostered by an allele specific impairment of TRAIL expression

P38

Qin, Nan Comparative and functional analysis of MYC-dependent secretome perturbations in medulloblastoma

P48

Rudner, Justine ABT263 overcomes hypoxia-mediated resistance to radiotherapy

P78

Schaefer, Christiane Identification of novel therapeutic targets in Ewing sarcoma utilizing innovative pooled screening approach in a tumorcell-specific environment.

P71

Scheffler, Björn Clonally expanding temozolomide-resistant tumor cells in recurrent glioblastoma.

P17

Schmeller, Jan Immunohistochemically detectable metallothionein expression in malignant pleural mesotheliomas is strongly associated with early failure to platin-based chemotherapy

P25

Schulte, Marc Effects of Protein Kinase C Iota (PRKCI) expression on the development of metastases and /or recurrent tumors.

P30



NBR.

Shannan, Batool Melanoma cross-resistance between BRAFV600E inhibition and radiotherapy depends on therapy timing

P35

Si, Yu Spatial profiling of neutrophils and T cells in the human head and neck cancer microenvironment

P49

Spassova, Ivelina Fibroblast plasticity and heterogeneity in skin cancer P5

Stang, Andreas Incidence rates of testicular cancer according to the updated WHO classification of testicular cancer, North Rhine-Westphalia, Germany 2008-2013

P28

Stang, Andreas Skin cancer rates in North Rhine-Westphalia, Germany before and after the introduction of the nationwide skin cancer screening program (2000-2015)

P29

Stefanski, Anja Quantitative Proteomics – a versatile tool for translational cancer research

P20

Stockhammer, Paul The role of TGF-β in malignant pleural mesothelioma progression

P47

Trajkovic-Arsic, Marija Unrevealing the metabolic subtypes in pancreatic cancer P1

Unger, Nicole Endocrine disorders in adult survivors of childhood cancer P41

Vogel, Felix Epigenetic modulation of cell metabolism and its effects on cell survival in melanoma

P62

Weniger, Marc Human CD30+ B cells represent unique B-cell subsets related to Hodgkin lymphoma cells

P10

Wessolly, Michael Processing escapes, a new resistance mechanism in immune therapy

P63

Willibald, Marina PGRMC1 Promotes Tumour Progression of Breast Cancer through Upregulation of ERα Expression

P27

Zhao, Fang Evolution of melanoma cross-resistance to CD8+ T cells and MAPK inhibition in the course of BRAFi treatment

P21


ABSTRACTS FOR TALKS T1 – T19


EXPLOITATION OF ONCOGENIC MECHANISMS

PRECLINICAL MODELS

Dissecting the architecture of the human bone marrow niche in acute myeloid leukemia

Yiyang Chen, Yasmin Zaun, Lucas Arnold, Kerstin Weissenfels, Kurt Werner Schmid, Ludger Klein-Hitpass, Anthony Squire, Ulrich Dührsen, Stefanie Bertram, Maher Hanoun

Introduction: Acute myeloid leukemia (AML) is an aggressive hematological malignancy which is characterized by a high relapse rate, suggesting that leukemic stem cells escape chemotherapeutic treatment. Only recently we got an impressive insight how the bone marrow niche regulates the integrity and function of hematopoietic stem cells (HSC). Particularly mesenchymal stem and progenitor cells (MSPCs), osteolineage cells as well as adrenergic signals released to the bone marrow are crucial components of the HSC niche. Our group has recently shown in a murine AML model how leukemia infiltration alters the microenvironment to reinforce malignancy at the expense of HSCs. However, so far there is no grasp of the bone marrow niche in AML patients.

Materials and Methods: For the characterization of the human bone marrow architecture we performed different immunohistochemical stainings to specifically identify MSPCs, osteoblasts, reticulin+ fibers and endothelial cells which have been automatically quantified with an Image J-based software and compared the results to non-leukemic donors. Next to morphological studies we assessed the global gene expression profile of MSPCs by microarray analyses of freshly FACS sorted MSPCs. These results were finally correlated to clinical features.

Results and Conclusion: Preliminary analyses so far reveal a significant increase in the number of bone marrow MSPCs compared to non-leukemic donors. These harbor an aberrant gene expression profile with skewed HSC and niche capacities. These findings finally allowed us to detect new prognostic markers that predict clinical outcome. These results might open the window for new niche-targeted therapies to eradicate leukemic stem cells and eventually decrease the high relapse rate in AML.

For further information please contact: Maher Hanoun ([email protected])

Department of Hematology

Seminar Room 0.019 TALK Nbr.

T1



PRECLINICAL MODELS

The Onco-LincRNA HOTAIRM1 in Glioblastoma

Ulvi Ahmadov, Daniel Picard, Patrick Roth, Nan Qin, David Pauck, Maike Langini, Manuela Silginer, Kai Stühler, Michael Weller, Guido Reifenberger, Marc Remke

Introduction: Glioblastoma (GBM) is the most common malignant brain tumor in adults and the prognosis of glioblastoma patients remains poor despite aggressive therapies with a Median overall survival around 15 months and a five-year survival rate less than 10%. GBMs are invasive and have a diffuse growth pattern with ill-defined borders causing surgical incurability of the disease. The vast majority of GBMs demonstrate resistance to radiation and chemotherapeutic agents either upfront or during the course of treatment. Long non-coding RNAs (lncRNA) are transcripts longer than 200 base pairs that do not code for proteins. Although we have typically only studied protein coding genes, long non-coding genes are more abundant in the genome and we currently know the function of only a small fraction of these. Nevertheless, lncRNAs have been found to play important roles in all aspects of cell biology, including stemness, regulation of gene expression, and regulation of protein synthesis.

Materials and Methods: Using a bioinformatic approach, we identified a total of 2,857 lncRNAs on the Affymetrix U133 Plus 2 array to re-analyze published gene expression datasets where we specifically focused on lncRNAs associated with a more aggressive clinical behavior of GBM. HOXA transcript antisense RNA myeloid-specific 1 (HOTAIRM1) was one of the most differently expressed lncRNAs clearly up-regulated in short-term survivors and this observation was corroborated in two independent, non-overlapping gene expression datasets (p<0.006). Using both transient and stable knockdown models we did RNA-Seq and Proteomics analysis. Following, we did onco-phenotyping, metabolic analysis by using TCA cycle analysis, Seahorse analysis, Mitochondrial and ROS staining approaches to characterize our onco-lncRNA in GBM.

Results: Upon knockdown of HOTAIRM1 in both transient and stable models, we observed a decrease in cell viability, migration and colony formation. We also performed RNA-Seq, proteomic and metabolite profiling of control and knockdown stable cell lines and, upon Gene Set Enrichment Analysis, discovered that metabolism was the most differentially regulated pathway, a finding that was supported by the metabolite data. Seahorse Mitostress assay also suggested impaired function of TCA cycle, which was supported by Mitotracker mitochondrial staining as well. MitoSOX and HEt staining of ROS production further supported mitochondrial dysfunction.

Conclusion:Therefore, we show that HOTAIRM1 expression is correlated with an aggressive phenotype and propose that a subset of GBMs could be susceptible to a novel therapeutics not previously used in GBM.

For further information please contact: Ulvi Ahmadov ([email protected]) DKTK Pediatric Neuro-Oncogenomics


T2


EXPLOITATION OF ONCOGENIC MECHANISMS PRECLINICAL MODELS

Role of metabolic adaptations for survival and radiation resistance of hypoxic or chronic cycling anoxia/reoxigenation adapted cancer cells

Matschke J, Shlomi T, Klein-Hitpass L, Jendrossek V

Introduction: Hypoxia-mediated resistance of solid tumors to ionizing radiation is a major obstacle to successful radiotherapy. We showed previously that chronic cycling hypoxia drives the evolution of anoxia/reoxygenation-tolerant (ART) cancer cells with increased resistance to ionizing radiation. Radiation resistance of ART cancer cells was associated with complex metabolic reprogramming 1, 2. Aim of the present study was to gain a more comprehensive understanding of the metabolic adaptation of cancer cells and to systematically explore opportunities for targeted pharmacologic intervention based on their suspected specific metabolic needs upon irradiation.

Materials and Methods: We compared gene expression profiles of ART and control cancer cells by microarray analysis and validated genes of interest by qRT-PCR. We used LC-MS high-throughput metabolomics, metabolic flux analyses, nutrient deprivation and drugs interfering with metabolism to characterize the cellular metabolic state.

Results: Our microarray data indicated changes in major metabolic pathways after chronic cycling hypoxia selection. Furthermore, tolerance to severe hypoxia was associated with the formation of enlarged mitochondria in ART NCI-H460 cells. The analysis of metabolic alterations in irradiated cancer cells by LC-MS high-throughput metabolome analysis demonstrated a high and time-dependent need of irradiated cancer cells in central metabolism.

Conclusion: Specific metabolic requirements under stress conditions such as severe hypoxia or irradiation render cancer cells vulnerable to metabolic inhibitors alone and in combination with ionizing radiation in a context and cell type-dependent manner. 1 Matschke et al., Antioxid Redox Signal 2016,25:89-107, 2 Matschke et al., Radiat Oncol 2016,11(1):75

For further information please contact: Johann Matschke ([email protected])

Institute of Cell Biology (Cancer Research)


T3


MOLECULAR DIAGNOSTICS, EARLY DETECTION AND BIOMARKER DEVELOPMENT

PRECLINICAL MODELS

Application of circulating cell-free tumor DNA (ctDNA) profiles for monitoring metastatic melanoma progression under therapy

Renáta Váraljai, Nils von Neuhoff, Antje Sucker, Julia Newton-Bishop, Dirk Schadendorf, Alexander Rösch

Introduction: Precision oncology is particularly seeking for novel disease and therapy monitoring technologies that are non-invasive and highly sensitive. Specifically, our project aims to establish blood-based assays that allow quantitative detection of ctDNA as a biomarker that corresponds to the tumor load in patients. ctDNA fragments are released from all parts of the tumors by apoptosis and necrosis, thus, it reflects the full spectrum of specific mutations of a systemically progressed tumor.

Materials and Methods: With droplet digital PCR approach, we have analyzed 545 plasma samples from 77 stage III and IV melanoma patients with the BRAFV600E mutation, with mutations at the Q61 codon of the NRAS gene, and mutations in the promoter region of TERT gene. The patients received either MAPK-targeted treatment or immune checkpoint blockade. Additionally, plasma samples from 90 healthy donors were analyzed to test the positive and negative predictive values of our assays.

Results: ROC analyses showed over 90% AUC for all our assays. Our analyses revealed that increasing ctDNA levels were associated with disease progression with p<0.05. We evaluated our ctDNA assays with bio-statistical methods, where ctDNA levels were correlated with treatment response and progression free survival. ctDNA levels during therapy corresponded to the radiologic tumor load from CT and MRI scans. Moreover, ctDNA levels often indicated disease progression earlier than the routine radiological scans.

Conclusion: In brief, our results show the potential role of ctDNA measurement as a sensitive monitoring tool for the early assessment of disease progression and therapeutic response/resistance in melanoma patients.

For further information please contact: Renata Varaljai ([email protected])

Department of Dermatology


T4



EX VIVO STUDIES / CORRELATIVE SCIENCE

Proteogenomics discriminates pediatric and adult pilocytic astrocytoma into three distinct biological entities

Daniel Picard, Jörg Felsberg, Maike Langini, David Pauck, Viktoria Marquardt, Frauke Meyer, Anja Stefanski, Kai Stühler, Arndt Borkhardt, Guido Reifenberger, Cláudia Faria and Marc Remke

Introduction: Pilocytic astrocytoma (PA) is the most common low-grade brain tumor in childhood. Aberrant MAPK signaling typically mediated by BRAF alterations drives PA formation. While five-year overall survival rates exceed 95%, incompletely resected tumors recur frequently despite treatment. We used a proteogenomics approach to discern the biological heterogeneity of PA to improve classification of this tumor entity and identify novel therapeutic targets.

Materials and Methods: Our proteogenomics approach utilizes RNA sequencing (RNAseq) and LC/MS-based proteomic profiling and we determine the biological heterogeneity of PA using Similarity Fusion Network (SNF). Integrative genomics dissects aberrant pathway activation in biological subgroups. Lastly, we utilize a drug screening pipeline to evaluate conventional and phase III/IV clinical trial drugs in PA culture models.

Results: PAs segregate into three groups with distinct clinical and molecular features. Age and tumor location were significantly associated with the SNF groups. BRAF fusions were only observed in Groups 1 and 2, which are generally expected to occur in over 50% of PA. Pathway enrichment analyses revealed genesets involved in primary ciliogenesis in Group 3, while immune response signatures, many SYK-related, were associated with Group 1. Corroborating our analyses, the SYK inhibitor R788 was specifically active in Group 1 PA, and less active in other brain tumors models (n=27).

Conclusion: In all, our proteogenomic approach reveals important biological heterogeneity with novel therapeutic targets emerging in PA. These biological insights may improve biological classification and reveal novel therapeutic targets specifically useful for non-resectable tumors with high risk of progressive disease.

For further information please contact: Daniel Picard ([email protected])

DKTK Pediatric Neuro-Oncogenomics


T5



CLINICAL STUDIES

The incidence of Merkel cell carcinoma: A comprehensive international assessment

Andreas Stang, Jürgen C. Becker, Paul Nghiem, Jacques Ferlay

Introduction: Most reports of Merkel cell carcinoma (MCC) epidemiology are confined to single countries. Due to different methodologies, the comparison of these reports is difficult. The aim of this study is to provide worldwide, population-based incidence rates for MCC.

Materials and Methods: We included 11576 cases from 20 countries for the time trend analysis (1990-2007) and 11028 cases (2·5 billion person-years) from 21 countries for the period 2003-2007 extracted from Cancer Incidence in Five Continents. We computed age-standardized incidence rates (World Standard population) per million person years and sex ratios of these rates together with 95% confidence intervals. We estimated annual percentage changes (EAPC) of the incidence and studied the association between geographic latitude and MCC incidence among Non-Hispanic whites. We examined the body site distribution of MCC.

Results: In the majority of populations, the incidence has increased over time (EAPC, men 2·0-21·0%; women 1·6-27·2%). Rate differences between 1995 and 2007 were typically small (men: 0·8-2·2; women: 0·2-1·7). The incidence showed barely any change in some populations (men: US blacks, Japan, Norway, Denmark; women: Denmark, Norway, Sweden). Incidences from 2003-2007 were highest in Australia, New Zealand, the US, and Israel among men and in New Zealand, Australia, Ireland and the Netherlands among women. The incidence among Non-Hispanic white males was positively associated with living closer to the equator. The proportion of MCC on the head was higher in men and with advanced age. The head was a less likely primary site among blacks as compared to any other ethnicity.

Conclusion: Several countries showed increases in MCC incidence among Non-Hispanic whites over time. Latitude closer to the equator was associated with the MCC incidence in men, but barely in women, possibly due to occupational sunlight exposure patterns. Funding: Supported by a grant, German Federal Ministry of Education and Science (BMBF), grant number 01ER1704.

For further information please contact: Andreas Stang ([email protected])

Center of Clinical Epidemiology


T6


CANCER IMMUNOTHERAPY


Chromosomal alterations predispose to the development of immunotherapy resistance

Sonia Leonardelli, Susanne Horn, Antje Sucker, Dirk Schadendorf, Klaus Griewank, Annette Paschen

Introduction: Melanoma is one of the most immunogenic malignancies. Many types of immunotherapies have been developed in the recent years in order to activate cytotoxic CD8+ T lymphocytes (CTLs) against the tumor. This led to impressive clinical responses in 30-40 % of melanoma patients when treated with immuno-modulating anti-PD1 antibodies releasing CTLs from suppressive signals in the tumor microenvironment. Nevertheless, in the majority of patients, tumors are primarily resistant or acquire resistance under treatment, and the underlying mechanisms are still poorly defined. Recently, it was demonstrated that mutations in the JAK1/2-STAT1 signaling pathway protect tumor cells from anti-proliferative and pro-apoptotic activity of T cell-derived IFNγ and mediate resistance to immunotherapy.

Materials and Methods: Mutational status of JAK2 in the analyzed cell lines was defined by targeted sequencing. JAK2 and p16 expression was demonstrated by immunoblot analyses and immunohistochemical staining. Screening single nucleotide polymorphism (SNP) array data was used for 46 melanoma cell lines to demonstrate deletions on Chr.9p encompassing CDKN2A and JAK2 in all cases. The Cancer Genome Atlas (TCGA) data sets were used to show association of CDKN2A and JAK2 deletions in different tumor tissues, applying cBioPortal for Cancer Genomics. Visualization of the Chr.9p segments in TCGA tissue samples from different tumors was achieved using the UCSC Xena Browser.

Results: In this study we asked how IFNγ-resistant tumor cells genetically evolve. In JAK2-deficient melanoma cells we detected inactivating mutations in one JAK2 allele and losses of the second allele. In general, allelic loss was due to a large deletion on chromosome 9p to which the JAK2 gene maps in close proximity to the tumor suppressor CDKN2A. Interestingly, we observed co-deletion of the tumor suppressor CDKN2A and JAK2 in a large fraction of samples from different tumor types suggesting that tumors harboring allelic CDKN2A deletions may be more prone to become immunotherapy resistant due to associated JAK2 allele losses.

Conclusion: We were able to demonstrate that melanomas and other cancers with allelic CDKN2A loss frequently show a JAK2 co-deletion on chromosome 9p. Patients with tumors showing these co- deletions may be more prone to become resistant to immunotherapy, given the possibility of a second hit – the JAK2 mutation.

For further information please contact: Sonia Leonardelli ([email protected])



T7



CLINICAL STUDIES

Olfactory Function as Independent Prognostic Factor in Glioblastoma Multiforme

Sied Kebir, Elke Hattingen, Michael Niessen, Laurel Rauschenbach, Rolf Fimmers, Thomas Hummel, Niklas Schäfer, Theophilos Tzaridis, Frederic Mack, Christina Schaub, Moritz Stuplich, Ulrich Herrlinger, Björn Scheffler#, Martin Glas

Purpose: Olfactory dysfunction is a common disease-related symptom in many neurological, especially neurodegenerative disorders. In brain tumor patients, however, the relevance of hyposmia remains unclear as no study hasexamined this issue so far. We sought to test olfactory function in glioblastoma patients to assess its prognostic value.

Patients and Methods: Olfactory testing was performed in 73 patients with diagnosed primary glioblastoma (study cohort) prior to the onset of first-line treatment and at consecutive follow-ups. An age-matched control cohort consisted of 49 patients with neurological diseases excluding those known to affect olfactory function per se. Depending on the olfactory testing score, patients were allotted to a hyposmia group (HG) or normosmia group (HG). Magnetic resonance imaging (MRI) analysis was performed to assess whether the tumor's location affects olfactory pathways. Overall and progression-free survival (OS and PFS) were assessed with the HG and NG in each cohort to detect a possible prognostic value of olfactory dysfunction.

Results: The olfactory function tests showed no relevant treatment-induced changes over time. Significantly more patients in the study cohort had olfactory dysfunction as compared with the control cohort (p=0.003). In the study cohort, canonical prognostic factors (age, Karnofsky Performance Score, MGMT, tumor histology) were balanced between HG and NG. On multivariate analysis, patients in the HG with the tumor not involving olfactory pathways on MRI had worse OS than those in the NG (Hazard Ratio, 0.43; p=0.042).

Conclusion:

Olfactory dysfunction is shown to be an independent prognostic factor in glioblastoma. Further studies are needed to explore the predictive value of the olfactory function in glioblastoma.

For further information please contact: Sied Kebir ([email protected])

DKTK Division Translational Neurooncology / Department Neurology


T8


CANCER IMMUNOTHERAPY PRECLINICAL MODELS

Merkel cell carcinoma derived miR-375 reprograms fibroblasts into MCC associated fibroblasts

Cathrin Ritter, Kaiji Fan, Ivelina Spassova, Anja Lange, Niels Ødum, David Schrama, Jürgen C. Becker

Merkel cell carcinoma (MCC) is a very aggressive skin cancer characterized by an invasive growth pattern and early metastasis. MCC cells share features with Merkel cells, but there is no obvious direct histogenetic link between MCC and Merkel cells. mir-375 is highly expressed in MCC cell lines in vitro and MCC tumors in situ, however inhibiting this microRNA neither impacted proliferation, morphology nor signaling of MCC cells. Notably, the enrichment of miR-375 in MCC-derived exosomes suggests its intercellular signaling function. Indeed, miR-375 containing exosomes were horizontally transferred to fibroblasts, which caused their polarization towards a cancer-associated fibroblast (CAF)-like phenotype including an increased expression of α-SMA, CXCL2 and IL-1β. Fibroblast polarization was inhibited by miR-375 antagomirs or mimicked by ectopic miR-375 expression. This observation could be translated into the clinical situation as miR-375 was readily detectable by in situ hybridization both in MCC cells and MCC-associated fibroblasts. Furthermore, miR-375 expression in MCC lesions is significantly correlated with α-SMA protein expression.

For further information please contact: Cathrin Ritter ([email protected])

DKTK Translational Skin Cancer Research


T9


CANCER IMMUNOTHERAPY EX VIVO STUDIES /

CORRELATIVE SCIENCE

NGS-based characterization of HLA immune escape by leukemia after immunotherapy

Müberra Ahci, Cristina Toffalori, Vinzenz Lange, Ludger Klein-Hitpaß, Luca Vago, Dietrich W. Beelen, Katharina Fleischhauer

Relapse accounts of 50% of deaths after leukemia immunotherapy by hematopoietic stem cell transplantation (SCT). Immune escape via selective loss of the mismatched HLA haplotype (“HLA loss”) is present in 30% of relapses after haploidentical SCT. Diagnosis of HLA loss relapse is relevant to decide on the most appropriate treatment options, and to assess its incidence and risk factors after SCT from unrelated donors (UD), the most frequent SCT donor source to date. Here we used targeted next generation sequencing of exon 2 and 3 of HLA class I and II genes to track HLA loss after mismatched UD-SCT by direct counting of reads for the shared or unshared allele(s). Serial dilutions of genomic DNA from pairs of unrelated individuals into each other revealed a sensitivity of 0.1-1%, with the number of non-specific background allele reads representing the main limitation. So far, we have analyzed 38 informative relapses (>5% blasts) of acute leukemia or myeloid malignancies after UD-SCT at UK-Essen. No HLA loss was detected in 29 patients whose UD was 10/10 HLA-matched but HLA-DPB1 mismatched. In contrast, potential HLA loss was found in 2/13 (15.3%) of relapses after ≤9/10 HLA-matched UD-SCT. The incidence and clinical risk factors of HLA immune escape of leukemia relapsing after SCT from different donor sources, either by genomic loss or by HLA-specific somatic neo-mutations, is under investigation within national and international study networks.

For further information please contact: Katharina Fleischhauer ([email protected])

Experimental Cellular Therapy


T10



Homing to suppress – the role of GPR15 on Treg trafficking during colon cancer

Alexandra Adamczyk, Eva Pastille, Astrid M. Westendorf

A persistent and chronic inflammation of the colon, as it occurs in patients suffering from ulcerative colitis (UC), can predispose the tissue to cancer formation. The underlying immunological mechanisms that cause cancer induction and progression in UC patients are not well understood. Our previous studies already pointed out an important impact of regulatory T cells (Tregs) on the pathogenesis of colorectal cancer (CRC), as we showed that the transient ablation of tumor-infiltrating Tregs improves CD8+ T cell mediated anti-tumoral immunity. The modulation of Treg trafficking to the colon therefore might be a promising approach to specifically decrease Treg frequencies in the colon and thereby boosting anti-tumoral immunity. One potential candidate in the regulation of Treg homing during CRC might be the G-Protein coupled receptor 15 (GPR15), a recently identified colon-homing receptor. In a mouse model for colon cancer, we identified enhanced expression of GPR15 on tumor-infiltrating Tregs. The induction of colon cancer in GPR15-KO mice resulted in reduced tumor growth that was associated with a reduced frequency of Tregs in the tumorous tissue, as well as enhanced anti-tumoral CD8+ T cell responses. Interestingly, we also detected increased expression of GPR15 on Tregs in the peripheral blood of CRC patients that were previously shown to have enhanced suppressive capacity. In conclusion, GPR15 present a promising novel therapeutic molecule to target tumor-infiltrating Tregs during CRC.

For further information please contact: Alexandra Adamczyk ([email protected])

Institute of Medical Microbiology , Essen


T11



Type I interferon-mediated neutrophil activation during tumorigenesis may contribute to infectious complications

E. Pylaeva, S. Bordbari, I. Spyra, S. Lang and J. Jablonska

Cancer is often associated with nosocomial infections. Type I IFNs are part of the host antitumor response; anticancer therapies activating IFNs or IFNa treatment are used. We aimed to estimate the effect of type I IFNs on neutrophil-mediated anti-P.aeruginosa immunity and to reveal the mechanisms responsible for infectious complications in cancer. The model of P.aeruginosa-induced pneumonia in IFN-deficient tumor-bearing mice was used. Antibacterial properties (reactive oxygen species, ROS, neutrophil extracellular traps, NETs, migration to LPS) of lung neutrophils were studied in vitro. Histological examination of lungs (HE, histone-1) was performed. IFN-mediated neutrophil activation was assessed in human specimens isolated from head-and-neck cancer (HNC) patients vs. healthy controls. IFN deficiency in animal models was associated with improved bacterial clearance and decreased neutrophil infiltration. In IFN-deficiency neutrophils showed diminished capacity to release NETs and produce ROS. Such animals were characterized with lower lung tissue damage, compared to WT. In HNC neutrophils demonstrated higher antibacterial activity (ROS, chemokine release, migratory activity); IFNb treatment enhanced ROS production. Enhanced neutrophil activation by type I IFNs in cancer possibly supports P.aeruginosa biofilm formation, their persistence and resistance to antibiotics or immunity. Targeting these mechanisms may help to develop effective antibacterial strategies in cancer patients.

For further information please contact: Ekaterina Pylaeva ([email protected])

Department of Otorhinolaryngology


T12


RADIATION ONCOLOGY AND IMAGING CLINICAL STUDIES

PriCoTTF: A phase I/II single-arm trial of Tumor Treating Fields prior and concomitant with radiotherapy and temozolomide in newly

diagnosed glioblastoma Niklas Schäfer, Ulrich Sure, Beate Timmermann, Martin Stuschke, Michael Forsting, Gerrit H Gielen, Laurèl Rauschenbach, Anja Wieland, Andreas Till, Roman Reinartz, Matthias Simon, Pitt Niehusmann, Ulrich Herrlinger, Torsten Pietsch, Björn Scheffler and Martin Glas

Objective: Glioblastoma multiforme (GBM) treatment remains challenging although the EF-14 trial has shown that TTFields (tumor-treating fields) plus adjuvant temozolomide (TMZ) following combined radiochemotherapy significantly increased long-term survival rates, patients’ overall (OS) and progression-free survival (PFS). In the EF-14 trial, TTFields treatment was initiated 4-7 weeks after completion of radiochemotherapy and was administered on average 3.8 months after diagnosis. It is well established that tumor cells are most sensitive to radiotherapy in the M and G2 phase during cell division. TTFields affect tumor cells during mitosis and preclinical data showed additive and synergistic effects by combining TTFields with radiotherapy. This phase I/II trial will evaluate safety and efficacy of TTFields initiated prior and concomitant with combined radiochemotherapy in newly diagnosed GBM.

Methods: A total number of 20 patients will be enrolled in this multicenter trial. Enrolment will begin with 6 patients and continue afterwards up to 20 patients provided that treatment is well tolerated. Patients will be subjected to TTFields after complete wound-healing following surgery and 1-2 weeks before the onset of combined radiochemotherapy. TTFields will be carried on throughout combined radiochemotherapy and thereafter as monotherapy in the 4-weeks break. After that, TTFields will continue and will be administered in conjunction with adjuvant TMZ. In total, TTFields treatment will cover a duration of approximately 9 months. Then, TTFields therapy is paused and the enrolled patients will undergo rechallenge of TTFields at first tumor recurrence until second recurrence.

Results: Primary endpoints are safety and tolerance based on frequency of pre-specified adverse events, such as skin toxicity. Secondary endpoints consist in particular of frequency of adverse events, PFS and OS.

Conclusion:This trial objective is to demonstrate that the administration of TTFields prior and concomitant to combined radiochemotherapy with temozolomide is feasible and safe. Moreover, data obtained on first efficacy (phase 2) will serve as a basis for a potential randomized phase III trial.

For further information please contact: Martin Glas ([email protected])

Division of Clinical Neurooncology, Department of Neurology/ DKTK Division Translational Neurooncology


T13



PriCoTTF: A phase I/II single-arm trial of Tumor Treating Fields prior and concomitant with radiotherapy and temozolomide in newly

diagnosed glioblastoma Niklas Schäfer, Ulrich Sure, Beate Timmermann, Martin Stuschke, Michael Forsting, Gerrit H Gielen, Laurèl Rauschenbach, Anja Wieland, Andreas Till, Roman Reinartz, Matthias Simon, Pitt Niehusmann, Ulrich Herrlinger, Torsten Pietsch, Björn Scheffler and Martin Glas

Objective:

Glioblastoma multiforme (GBM) treatment remains challenging although the EF-14 trial has shown that TTFields (tumor-treating fields) plus adjuvant temozolomide (TMZ) following combined radiochemotherapy significantly increased long-term survival rates, patients’ overall (OS) and progression-free survival (PFS). In the EF-14 trial, TTFields treatment was initiated 4-7 weeks after completion of radiochemotherapy and was administered on average 3.8 months after diagnosis. It is well established that tumor cells are most sensitive to radiotherapy in the M and G2 phase during cell division. TTFields affect tumor cells during mitosis and preclinical data showed additive and synergistic effects by combining TTFields with radiotherapy. This phase I/II trial will evaluate safety and efficacy of TTFields initiated prior and concomitant with combined radiochemotherapy in newly diagnosed GBM.

Methods:

A total number of 20 patients will be enrolled in this multicenter trial. Enrolment will begin with 6 patients and continue afterwards up to 20 patients provided that treatment is well tolerated. Patients will be subjected to TTFields after complete wound-healing following surgery and 1-2 weeks before the onset of combined radiochemotherapy. TTFields will be carried on throughout combined radiochemotherapy and thereafter as monotherapy in the 4-weeks break. After that, TTFields will continue and will be administered in conjunction with adjuvant TMZ. In total, TTFields treatment will cover a duration of approximately 9 months. Then, TTFields therapy is paused and the enrolled patients will undergo rechallenge of TTFields at first tumor recurrence until second recurrence.

Results:

Primary endpoints are safety and tolerance based on frequency of pre-specified adverse events, such as skin toxicity. Secondary endpoints consist in particular of frequency of adverse events, PFS and OS. Conclusion:This trial objective is to demonstrate that the administration of TTFields prior and concomitant to combined radiochemotherapy with temozolomide is feasible and safe. Moreover, data obtained on first efficacy (phase 2) will serve as a basis for a potential randomized phase III trial.


Division of Clinical Neurooncology, Department of Neurology/ DKTK Division Translational Neurooncology


T13



Treatment of sarcomas at West German Proton Therapy Center Essen (WPE)

Stefanie Schulze Schleithoff, Theresa Steinmeier, Dirk Geismar, Xavier Vermeren, Gudrun Fleischhack, Stephan Tippelt, Christoph Blase, Sebastian Bauer, Beate Timmermann

Introduction: At West German Proton Therapy Center Essen (WPE), proton therapy (PT) is given to the majority of sarcomas of the trunk since 2013, forming a unique cohort for clinical and preclinical research. The sarcoma center of the West German Cancer Center (WTZ) ensures an optimal multidisciplinary approach.

Materials and Methods: All pat. with sarcomatous tumors treated at WPE until October 2017 were included in this analysis. Pat., treatment and standardized FU data was documented in the prospective registries KiProReg and ProReg. Treatment was applied according to diagnosis-specific guidelines, national guidelines or in-house standards. Adverse events were scored according to CTCAE v4.0.

Results: Until October 2017, 297 pat. with sarcomas (med. age 15.3 years, range, 0.9-85.5) were irradiated at WPE. Histopathologies were rhabdomyosarcoma (33.3%), CH/CS (24.6%), Ewing sarcoma (14.1%) and others. 47.8% of pat. received concomitant chemotherapy. 164 pat. underwent resection before PT, being gross total in only 75. Med. total PT dose was 55.8 Gy with a med. fraction number of 31. Med. FU time after first diagnosis was 1.5 years (range, 0.2-24.9). Tumor control was achieved in about 80%. 63 pat. experienced failure (29 local, 27 distant, 5 combined, 1 SM outside RT field). 35 pat. deceased, in the majority due to systemic failure. High grade acute toxicity (CTCAE grade >2) mainly occurred for bone marrow, skin, general and GI. After 3 months severe myelosuppression was found in 2 patients. After 1 year 1 pat. experienced grade 3 toxicities affecting musculosceletal & connective tissue or general, and 1 pat. grade 3 lymphedema.

Conclusion: Early results of PT in sarcomas demonstrate excellent feasibility of PT in sarcomas. The conduction of prospective studies and registries will contribute as a backbone for further research in this rare entity. PT is considered standard in chordomas and skull base chondrosarcomas thereby offering a unique patient cohort for both retrospective studies and innovative translational combination studies to improve local control. With regard to clinical studies, the international “SACRO-trial” on sacral chordomas will be launched, WPE serving as the national coordinator for Germany. In addition, a detailed pattern of relapse analysis for sarcomas within the WPE registries is foreseen including an evaluation of risk factors. The role of molecular biological markers and radiosensitizers for PT in sarcomas may be another important focus of future research within the WTZ/sarcoma center.

For further information please contact: Stefanie Schulze Schleithoff ([email protected])

West German Proton Therapy Centre Essen (WPE)


T14


CANCER GENOME SEQUENCING AND PROTEOME ANALYSIS


Proteogenomics and high-throughput drug screening for novel brain tumor therapies – it takes two to tango

Marc Remke, Daniel Picard, Nan Qin, Jasmin Bartl, Maike Langini, Viktoria Marquardt, David Pauck, Ute Fischer, Anja Stefanski, Thomas Kurz, Kai Stühler, Arndt Borkhardt and Guido Reifenberger

Introduction: Proteogenomics provides an integrative, multi-omics perspective on pediatric brain tumor biology. Here, we describe the analytical pipeline and demonstrate the added value of this approach to improve biological classification, and, to reveal novel therapeutic vulnarabilities for medulloblastomas, the most common malignant brain tumor in childhood.

Materials and Methods: Our proteogenomics approach utilizes matched next-generation sequencing data (RNAseq, miRNAseq, WGS), high-resolution DNA methylation / copy number profiling data, and (phospho-) proteomic profiling data to determine the biological heterogeneity of medulloblastomas using similarity network fusion. Integrative genomics dissects aberrant pathway activation in biological subgroups. Lastly, in-house high-throughput drug screening data using conventional and phase III/IV clinical trial drugs in medulloblastoma culture models complements our proteogenomics approach.

Results: Using proteogenomics in primary human medulloblastoma, we unraveled distinct epigenetic and post-translational regulation leading to highly divergent oncogenic signaling and kinase activity profiles in medulloblastoma subgroups. Specifically, transcriptomic and (phospho-)proteomic analyses reveal novel miRNA/long non-coding RNAs or aberrant pathway activation as oncogenic drivers in medulloblastoma subgroups, respectively, which were not previously apparent in single layer omics studies.

Conclusion: Overall, our integrative proteogenomic approach identifies previously unknown oncogenic pathway activation and potential therapeutic vulnerabilities in the most common malignant brain tumor in childhood.

For further information please contact: Marc Remke ([email protected])


Seminar Room 0.019 Poster Nbr.

T15


MOLECULARLY TARGETED THERAPY PRECLINICAL MODELS

Targeting of MYC downstream pathways in pediatric refractory T-ALL

Heinz Ahlert, Sanil Bhatia, Viktoria Marquardt, David Pauck, Marc Remke, Arndt Borkhardt, Julia Hauer

Introduction: Patients who suffer from therapy refractory acute T-lymphoblastic leukemia (T-ALL) have a very poor prognosis. In many cases refractory ALL is associated with the deregulation of the pleiotropic transcription factor MYC and thus it is a promising therapeutic target. Approaches of targeting MYC directly were not efficacious in T-ALL; therefore targeting signaling pathways regulated by MYC, for instance Aurora Kinase A, BET, CDK or HSP90 are novel promising approaches.

Materials and Methods: 23 different leukemia cell lines were analyzed for MYC expression on transcript and protein level. A drug library comprising potential MYC inhibitors (MYCi) was designed and MYC dependent cell line models are analyzed on a high throughput drug screening platform. Two GEMMs of pediatric LMO2+ T-ALL are fully characterized for the testing of most promising candidate drugs in vivo.

Results: For the identification of MYC dependent models we screened 20 different leukemic cell lines including 10 ALL, 3 AML, 6 BCL-ABL1+ models and 1 LMO2+ T-ALL model. LMO2+ T-ALL, BCR-ABL1+ and AML cell lines revealed markedly increased MYC expression relative to healthy MNCs, both at mRNA and protein level. We designed a drug library for MYC downstream pathways, comprising 4 Aurora Kinase, 4 CDK, 3 BET and 12 HSP90 inhibitors. All MYC dependent cellline models will be run on a semi automated drug screening platform (Dr. Remke, DKTK junior research group). Furthermore LMO2 T-ALL GEMMs are fully characterized and T-ALL reveled markedly increased MYC expression. GEMMs are extended with respect to Rosa26 LMO2 x Mb1-Cre and Rosa26 Lmo2 x AID-Cre mouse lineages to decipher the role of downstream MYC expression not only in T-ALL but also in pre-leukemic T- and B- precursor cells.

Conclusion: MYC expression is high in therapy resistant T-ALL and thus an important drugable target. We have set up the requirements for an in vitro high throughput screening of indirect MYC inhibitors and aim to validate the most promising compounds in vivo in order to offer novel therapeutic approaches in the treatment of therapy refractory T-ALL.

For further information please contact: Julia Hauer ([email protected])

Department of Pediatric Oncology, Hematology and Clinical Immunology


T16



Functional characterization of epigenetic targeting with dual active BET/HDAC-inhibitors in model systems of pancreatic cancer

Tim Zegar, Xin Zhang, Tim Weiser, Stefan Knapp, Jens T. Siveke

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human cancers and quite resistant to conventional treatments. The tumors are driven by several genetic but also epigenetic alterations. Targeting these epigenetic pathways may yield new therapeutic strategies for pancreatic cancer. It has been shown, that inhibitors of the bromodomain and extraterminal domain (BET) family like JQ1 decrease the Myc activity and suppress tumor development in PDAC. Inhibition of histone deacetylases (HDACs) with small molecules like SAHA (vorinostat) is another way to target epigenetic regulators. The co-treatment with both inhibitors could lead to a reduction of cell viability and shows synergistic effects on tumor suppression. Based on these results and in cooperation with other workgroups, we aim for the development and optimization of a dual-active HDAC/BET inhibitor.

Materials and Methods: At the very beginning of this project we want to identify inhibitor combinations, which show activity on both targets, myc expression and acetylation of histones. Biomarkers, which can predict the sensitivity of a cell line to BET and HDAC inhibitors are also a field of interest. Therefore we use methods like western blots, qRT-PCRs and FRET-based assays. High-throughput screenings and cell viability assays should also help to identify the best combination of BET and HDAC inhibitors and optimize them.

Results: Right now, one dual active BET/HDAC inhibitor shows activity on both targets and can induce apoptosis and cell differentiation in some cell lines. This molecule could be used as possible lead structure for optimizing a potent inhibitor.

Conclusion: Targeting epigenetic pathways is a potential way to overcome the resistance to conventional treatments of PDAC. We aim for combining the synergistic effects of HDAC and BET inhibitors in one dual-active molecule to find a new epigenetic based therapy for pancreatic cancer.

For further information please contact: Tim Zegar ([email protected])

DKTK Division of Solid Tumor Translational Oncology


T17


MOLECULARLY TARGETED THERAPY EX VIVO STUDIES /

CORRELATIVE SCIENCE

Retrograde translation in a BLU-285-resistant PDGFRA-D842V mutant GIST

S. Grunewald; J. Falkenhorst, O. Schmitt-Kittler, T. Mühlenberg , S. Bauer

Introduction: Gastrointestinal stromal tumors (GIST) harboring activating D842V activation loop mutations (exon 18) represent 8-10% of all GIST and show resistance against all approved tyrosine kinase inhibitors. The small-molecule inhibitor BLU-285 is a novel potent and highly-selective oral inhibitor of PDGFRA D842 mutants that has shown a 100% clinical benefit rate in the first-in-human phase I study. To date, mechanisms of resistance to BLU-285 are unknown.

Materials and Methods: Plasma-samples as well as pre- and posttreatment tumor samples were analyzed by BEAMing (emulsion digital PCR), panel sequencing (Guardant360), WES, RNA-sequencing. Cell lines were established both from pre- and post-treatment biopsies for functional validation studies.

Results: Both response to BLU-285 as well as secondary progression was paralleled by a massive decrease and increase of D842V mutated ctDNA (10% to < 0,1% to >10% MAF). Deep sequencing of the post-progression plasma sample revealed three novel PDGFRA mutations with MAF ranging between 0.2 and 9% MAF. Comparison of WES results of pre- and post-progression samples confirmed the primary PDGFRA D842V (91,2% MAF) mutation in both samples and an additional mutation only in the post-progression sample (V658A 90,3% MAF). In silico reconstruction of secondary mutations confirmed a steric clash conferred by the V658 mutation. A novel BLU-285-resistant GIST cell line was developed (Trash-1) and validated to be resistant to all available KIT inhibitors. Resistance was overcome by inhibition of downstream signaling pathways (MEK), destabilization of PDGFRA using HSP90 or siRNA against PDGFRA thus confirming PDGFRA to remain an important oncogenic driver.

Conclusion: Despite universal clinical activity of BLU-285 in D842V-mutant GIST, patients may develop secondary resistance by mechanisms similarly to those seen in KIT mutant GIST, i.d. poly-clonal outgrowth of PDGFRA-mutations harboring secondary resistance mutations (exon 14 and 15). Our findings are the starting point to develop inhibitors against these mutants.

For further information please contact: Susanne Grunewald ([email protected])

Department of Medical Oncology (Translational Sarcoma Research)


T18


MOLECULARLY TARGETED THERAPY EX VIVO STUDIES / CORRELATIVE

SCIENCE

Molecular mechanisms in urachal cancer: potential targets for therapeutic intervention

Reis H, van der Vos KE, Thiem S, Niedworok C, Herold T, Krafft U, Módos O, Szendrői A, Hager T, Ingenwerth M, Vis DJ, Behrendt MA, de Jong J, van der Heijden MS, Peyronnet B, Mathieu R, Wiesweg M, Ablat J, Okon K, Tolkach Y, Bremmer F, Gaisa NT, Chlosta P

Introduction: Urachal cancer (UrC) is a rare but aggressive cancer. Due to its rarity and limited effectiveness of chemotherapy, rationale-based targeted therapy approaches gain importance in advanced disease. However, still little is known about its molecular background.

Materials and Methods: An international cohort of 70 urachal adenocarcinomas from centers in Germany, the Netherlands, Hungary, Canada, France, and Poland was created and subjected to targeted next-generation sequencing. In addition, in situ and protein expression analyses were conducted and clinicopathological data were collected. Hotspot TERT-promoter mutations were analyzed in a sub-cohort (n=23) by PCR and Sanger sequencing. Statistical analyses including Kaplan-Meier and univariable/multivariable Cox regression models were performed.

Results: The majority (79%) of patients exhibited any genetic alteration (55/70). Pathogenic genetic sequence variations (Cosmic, ClinVar) were detected in TP53 (66%), KRAS (21%), BRAF (4%), PIK3CA (4%), MET (1%), NRAS (1%), FGFR1 (1%), and PDGFRA (1%). Gene amplifications were detected in ERBB2, EGFR, and MET. A TERT-promoter mutation was detected in one case (4%; C228T). No prognostic significance of the detected molecular alterations was detected.

Conclusion: Intracellular signal transduction pathways such as RAS/RAF/PI3K were affected in 31% of UrCs which holds implications for anti-EGFR therapy. In ERBB2 (HER2), MET, and PDGFRA further potentially actionable alterations were detected. Our data additionally strengthen the notion that UrC more closely resembles colorectal cancer than urothelial carcinoma at the genomic level.

For further information please contact: Henning Reis ([email protected])

Institute of Pathology (Department of Urology)


T19


ABSTRACTS FOR POSTERS P1 – P79



Unrevealing the metabolic subtypes in pancreatic cancer

Marija Trajkovic-Arsic, Sinan Karakaya, Sven Liffers, Smith Sengwawoh- Lueong, Achim Buck, Axel Walch, Amy Harms, Wei Yang, Thomas Hankemeier, Jens T. Siveke

Introduction: Recent genetic and molecular advances demonstrate that Pancreatic Ductal Adenocarcinoma (PDAC) should not be considered as a homogeneous disease with uniform therapy approaches but rather as a complex, molecularly, physiologically and metabolically heterogeneous disease that can be classified in different subtypes. Interruption of essential metabolic processes is potentially the way to successful cancer therapy.

Materials and Methods: Pancreatic Cancer cell lines and primary lines isolated from Patient Derived Xenografts are used as a model system for metabolic phenotyping of PDAC. Different methods for evaluation of metabolic phenotype are used: MALDI-imaging for identification of differentiating metabolites, HPLC-based metabolite profiling, Seahorse analysis of principal metabolic fuels used by the cells, metabolic inhibitor studies and gene expression profiling.

Results: PDAC cell lines classify genetically and morphologically into 2 major subtypes, classical PDAC with epithelial properties, and quasi-mesenchymal PDAC with rather mesenchymal properties. Metabolite profiling showed strong differences in metabolites found in epithelial vs mesenchymal cell lines. MALDI-imaging identified N-acetyl-aspartate and phosphatidylethanolamine amine as subtype differentiating metabolites. However, Seahorse analyses demonstrate high flexibility in the usage of glucose, glutamine or fatty acids as major metabolic fuels in all cell lines with no clear trends towards the preferred fuel. Metabolic inhibitor screens identified Triascin C as a drug with preferentially stronger effect towards mesenchymal cells.

Conclusion: Based on metabolite expression, response to inhibitors and gene expression profile, we aim to establish a methodological platform for prediction of metabolic subtypes of the PDAC. The results of the PDAC cell lines profiling are currently being compared with the results obtained from PDX models. We aim to identify the metabolic phenotype of PDX lines to be able to suggest the suitable treatment fitted to the metabolic profile of the single PDAC.

For further information please contact: Marija Trajkovic-Arsic ([email protected])


Ground Floor, Main Hall Poster Nbr.

P1



PRECLINICAL MODELS

Targeting the long non-coding RNA HHIP-AS1 in sonic hedgehog driven brain tumors

Jasmin Bartl, Sarah Göbbels, Mascha Korsch, Christina Mölders, Arndt Borkhardt, Guido Reifenberger, Marc Remke

Introduction: Aberrant activation of the sonic hedgehog (SHH) pathway is one of the key drivers of tumorigenesis in aggressive pediatric brain tumors. However, SHH pathway inhibitors for the treatment of brain tumors demonstrated only limited responses indicating that a better knowledge of SHH pathway regulators is needed.

Results: To determine the contribution of long non-coding RNAs (lncRNAs), which play an important role in the development and propagation of SHH-driven brain tumors, we analyzed the transcriptome of several thousand normal and neoplastic tissues with and without SHH activation. We identified the long non-coding RNA Hedgehog interacting protein anti-sense 1 (HHIP-AS1) as a promising candidate significantly upregulated in SHH-driven tumors compared to control cohorts. Furthermore, in vitro experiments demonstrated that HHIP-AS1 expression was up- and downregulated upon SHH activation or inhibition, respectively. After stable knockdown of HHIP-AS1 in different in vitro models, we found that it is functionally important for proliferation (EdU incorporation), viability (cell titer glow assay) and colony formation (single cell clonogenic assay) of SHH driven tumor cells, since in all used cell models these aspects were significantly decreased. In vivo validation in orthotopic medulloblastoma mouse model could confirm less tumor growth and a better overall survival.

Conclusion: These observations suggest that HHIP-AS1 may play an important role in SHH-driven tumorigenesis and comprises an attractive therapeutic target.

For further information please contact: Jasmin Bartl ([email protected])



P2



Ga-PSMA PET/CT mapping of early biochemical recurrence after primary surgery in 270 prostate cancer patients: Impact on Salvage

Radiotherapy Planning Jeremie Calais, Johannes Czernin, Minsong Cao, Amar Kishan, John Hegde, Narek Shaverdian, Kiri Sandler, Fang-I Chu , Michael L. Steinberg, Isabel Rauscher, Nina Hegemann, Thorsten Poeppel, Philipp Hetkamp, Francesco Ceci, Ken Herrmann, Wolfgang P. Fendle

Introduction: Target volume delineations for salvage prostate radiotherapy (SRT) are drawn in the absence of visibly recurrent disease. 68Ga-PSMA PET/CT detects recurrences at very low serum PSA values. Aim is to map the recurrence pattern of prostate cancer (PCa) early biochemical recurrence (BCR) after radical prostatectomy withPET/CT in patients with serum PSA levels <1 ng/ml, to determine how often consensus clinical target volumes (CTV) based on the Radiation Therapy Oncology Group (RTOG) guidelines cover PET/CTdefined disease, and to assess the potential impact on SRT.

Materials and Methods: This is a post-hoc analysis of 270 PCa patients who underwent 68Ga-PSMA PET/CT for BCR after prostatectomy without prior radiotherapy at PSA<1 ng/mL. RTOG consensus CTV that included both the prostate bed and pelvic lymph nodes were contoured on the CT dataset by a radiation oncologist blinded to the PET component. PET/CT images were analyzed by a nuclear medicine physician. PSMApositive lesions not covered by planning volumes based on the consensus CTV were considered to have a potential impact on treatment planning.

Results: Median PSA was 0.48 ng/ml. 49% patients had a positive PET/CT. 19% had at least one PSMA-positive lesion not covered by the consensus CTV. 12% had extra-pelvic PSMA-positive lesions and 7% had PSMA-positive lesions within the pelvis but not covered by consensus CTV. The two most common PET-positive lesion locations outside the consensus CTV were bone (44%) and perirectal lymph nodes (31%).

Conclusion: Post-hoc analysis of 68Ga-PSMA PET/CT implies a major impact on SRT planning in 52/270 patients (19%) with PCa early BCR (PSA<1.0 ng/ml). This justifies a randomized imaging trial of SRT with or without 68Ga-PSMA PET/CT investigating its potential benefit on clinical outcome.

For further information please contact:

Philipp Hetkamp ([email protected]) Klinik für Nuklearmedizin


P3




Profiling cell types in glioblastoma using transcriptomes

Celia Dobersalske, Mihaela Keller, Martin Glas, Björn Scheffler and Igor Cima

Introduction: Immunotherapy is a promising, yet challenging approach for treating glioblastoma (GBM). Knowledge of how the immune system operates during human progression of disease is still limited, therefore we hypothesize that unbiased profiling of immune cell types in GBM tissues may reveal unknown immunologic networks associated to clinical outcomes.

Materials and Methods: We applied an in-house, in silico deconvolution method to expose 45 different cell types including 25 immune cells, using exclusively transcriptome data from 172 GBM tissue samples with well-annotated clinical information. Resulting “cellular landscapes” were further analyzed by machine learning to identify candidate prognostic indicators. Immunofluorescence labelling was used to validate the presence of immune cell types that appeared associated to clinical outcomes.

Results: k-means clustering identified two groups of GBM patients characterized by unique immune cell patterns. Remarkably, the separated patient populations also showed differences in overall survival. We identified myeloid and B-cell progenitors and their descendants as particularly strong prognostic indicators among these samples and we validated their presence in clinical tissue samples. Further in vitro studies using fresh tissue biopsies are planned to scrutinize the functional aspects of myeloid and B-cell progenitor cell presence in human glioblastoma.

Conclusion: We describe a „systems immunology“ approach that can be applied to expose the cellular landscape of clinical GBM tissues. By discovering new cellular mediators associated with the individual courses of disease and with overall outcome measures we may eventually enable proper patient stratification and discovery of new therapeutic targets in the field of GBM immunotherapy.

For further information please contact: Igor Cima ([email protected])

DKTK Division of Translational Neurooncology


P4



Fibroblast plasticity and heterogeneity in skin cancer

Ivelina Spassova, Cathrin Ritter, Linda Kubat, Anita Melior, Kaiji Fan, Joachim Klode, Jürgen C. Becker

The tumor microenvironment plays a crucial role during cancer development by providing tumor promoting as well as inhibiting signals, which show an impact on tumor origination, growth, invasion and metastatic behavior. Fibroblasts are the most common cell type in the tumor microenvironment (TME), responsible for a wide variety of processes like extracellular matrix remodeling and angiogenesis, thus modulating tumor progression. However, research on fibroblast function in the TME is challenging because of the heterogeneity as well as high plasticity of this cell type. Our work focuses on the phenotypic characterization of fibroblast subpopulations in skin cancer including their spatial distribution, as well as on how the tumor-stoma interaction induces this functional diversity. Multiplex staining with diverse fibroblast markers of skin cancer tissue (Merkel cell carcinoma and Melanoma) confirmed fibroblast heterogeneity by the presence of different stromal cell subpopulations located in a defined manner around and in the tumor area. The spatial distribution of fibroblast subpopulations reveals that the subpopulations may also have different functionality. Fibroblasts in proximity to the tumor cells express Caveolin-1 (Cav-1) and S100A4, which is a characteristic of metastasis-associated fibroblasts. Since tumor cells are able to activate resting fibroblasts in normal tissue to become cancer-associated fibroblasts (CAFs), we wanted to reproduce this activation in vitro to allow functional analysis. Therefore we generated primary fibroblast cultures (n=16) from healthy human skin. Surprisingly, primary fibroblasts display high plasticity and in some cases are activated even by default culturing conditions. Culture on polystyrene surface could induce CAF-related features (i.e. expression of α-SMA, Cav-1 and S100A4) and senescent behavior. These phenotypic changes were omitted by culturing the cells on a collagen matrix. In co-culture with Squamous (SCL-1) and Merkel cell carcinoma (WaGa) cell lines in hanging drops, presence of fibroblasts allowed more solid spheres and enhanced growth of the tumor cells. In this model, fibroblasts also displayed an activated phenotype based on their α-SMA expression, thus verifying the bi-directional crosstalk between tumor cells and fibroblasts. In the chicken chorioallantoic membrane (CAM) model we observed that fibroblasts induced strong angiogenesis, resulting in bleeding into the tumor, which was not observed in the tumors without fibroblasts. In summary our data demonstrates that fibroblast polarization in skin cancer depends on their spatial distribution. This observation could be reproduced in vitro and in preclinical in vivo models, which will enable us to scrutinize the respective functional consequences.

For further information please contact: Ivelina Spassova ([email protected])

DKTK Translational Skin Cancer Research


P5



AML–associated mesenchymal stromal cells (AMSCs) support the growth of leukemia cells in vivo and in vitro

Yahya S. Al-Matary, Lacramioara Botezatu, Aniththa Thivakaran, Renata Köster, Judith Schütte, Ulrich Dührsen, Bertram Opalka and Cyrus Khandanpour

Introduction: The growth of many solid tumors, lymphoma and some types of leukemia is not only dependent on the genetic and epigenetic alterations of the leukemic cells but also on the microenvironment. Mesenchymal stromal cells (MSCs) represent a fundamental compartment of the bone marrow (BM) microenvironment that harbor and support the growth of normal and leukemic hematopoietic stem cells. We studied the interaction between MSCs and leukemia cells and we also investigated the underlying molecular mechanism.

Materials and Methods: We used primary cells as well as cell lines to study the interaction between leukemic cells and MSC in-vitro. Different murine models of human AML were used in our study to confirm the results in-vivo. MSCs were characterized by differentiation assay, flow cytometry and RT-PCR.

Results: AML-MSCs from AML patients or from murine models of human leukemia supported in vitro the growth of leukemic cells better than MSCs from non-leukemic patients or mice. The interaction between AMSCs and leukemia cells was dependent on cell contact. Co-culture of MSCs with AML cells lead to a shift in the cell cycle state of the leukemic cells in vitro towards the DNA replication phase (S) and reduced the frequency of cells in the quiescence phases (G0/G1). To investigate the molecular pathways, we sorted primary MSCs and AMSCS and found that AMSCs from leukemic mice show enrichment of pathways governing epithelial mesenchymal trasition (EMT) genes, Notch and IL2-STAT5 signaling. On a regulation level, the transcription factor Growth factor independence 1 (Gfi1) plays an essential role for the AML-supporting function of MACs and loss of Gfi1 abrogated the tumor-supporting state of AMSCs

Conclusion: AMSCs support the growth of AML cells in vitro and Gfi1 regulates the polarization of AMSCs towards an AML supporting state.

For further information please contact: Yahya S. Al-Matary ([email protected])



P6



Characterization and Epigenetic Targeting of Acquired Therapy Resistance in Pancreatic Cancer

Dierichs L.., Forster J., Schröder C. , Lueong S.S.., Rahmann S., Zeschnigk M., Siveke J.T.

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumor entities with a poor 5-year survival rate <8 %. It is marked by extraordinary resistance to most conventional therapies such as chemotherapy and radiation but also targeted therapies due to inherent and acquired drug-resistant cell states in tumor cells. Previous studies revealed a strong impact of epigenetic mechanisms including DNA methylation, chromatin regulation and transcriptional activity on tumor progression and therapy resistance.

Materials and Methods: To address the role of DNA methylation and transcriptomic activity in acquired therapy resistance, we applied an in vitro resistance model system of genetically engineered mouse model (GEMM)-based PDAC using trametinib (MEKi). We used whole genome bisulfite sequencing and RNAseq for characterization of global methylation patterns and transcriptomic activity in combination with functional analysis.

Results: Acquired trametinib-resistance is accompanied by enriched expression signatures for EMT and upon drug withdrawl reversibility occurs. Trametinib-resistant cells display an increased vulnerability to decitabine (DNMTi) in accordance with hypermethylated differentially methylated regions (DMRs) indicating an important role of DNA methylation in development and maintenance of the drug resistant phenotype.

Conclusion: Thus, DNMTi could potentially act as a ´re-sensitizer´ in MEKi-resistant PDAC.

For further information please contact: Laura Dierichs ([email protected])



P7



CORRELATIVE SCIENCE

HUSARC – the Human Sarcoma Model Initiative

Ketzer, Christoff, Treckmann, Podleska, Steinau, Mekicar, Wetter, Theysohn, Feller, Farzaliyev, Touma, Dirksen, Schaefer, Mühlenberg, Grunewald, Bauer

Introduction: Sarcomas comprise a highly heterogeneous group of mesenchymal tumors that represent less than 2% of all cancers. Outcome of patients with advanced disease remains poor with the exception of few genetically well-defined subtypes, such as GIST. For the majority of sarcomas very few and poorly characterized cell lines or no models at all are available for cancer research. We have set up a systematic program for the development of novel sarcoma models.

Materials and Methods: We have established SOPs for sample handling and processing of fresh tissue which include collaborative distribution and storing together with the WBE. In addition to snap freezing tumors and collecting liquid biopsies we also routinely inject tumor cell suspensions derived from surgical specimen into nude mice for development of xenografts. Tumor cells are further cultivated with the aim to develop novel sarcoma cell lines. We have further expanded some of the few existing cell lines by re-capitulating development of resistance both using selective pressure or genomic modifications (siRNA or CRISPR-Cas).

Results: Tumor samples from 400 surgeries have been collected to date with additional 124 pts with liquid biopsies (only). 108 samples were injected into mice of which 36 engrafted at least temporarily. Ten novel stable tumor lines and 11 stable sarcoma cell lines have been established among which are GIST with unique genomic background (first-of-its kind: NF1-associated GIST, PDGFRA-mutant GIST), undifferentiated sarcomas, small-blue-round cell sarcomas and others. Numerous cell lines have been collected from collaborating sites worldwide to expand the HUSARC program. Existing GIST cell lines have been extensively modified to reflect the complex heterogeneity of imatinib-resistant tumors.

Conclusion: Systematic processing of fresh tumor tissue following a standardized approach allows the development of novel cancer cell lines even in rare cancer subtypes such as sarcomas which is a prerequisite for rational validation of novel treatments.

For further information please contact: Julia Ketzer ([email protected])



P8



Molecularly targeted treatment of novel malignant pleural effusion derived cell models

Luca Hegedüs, Dominika Rittler, Özlem Okumus, Ildikó Kovács, József Tóvári, Balazs Döme, Kurt W. Schmid, Dirk Schadendorf, Elisabeth Livingstone, Dagmar Führer, Balazs Hegedüs, Clemens Aigner

Introduction: Metastases are the major cause of cancer related death and malignant pleural effusion confers particularly poor prognosis. Recently established, effusion derived thyroid cancer and melanoma cell models were tested for tumorigenicity and drug sensitivity.

Materials and Methods: Adherent cell lines were cultured from effusions. After treatment with BRAF, MEK or HDAC inhibitors cell cycle was analyzed and cell migration was measured by videomicroscopy. Orthotopic pleural carcinosis modeIs were established by intrapleural injection in immunocompromised mice.

Results: The novel line PF49 was established from the effusion of a patient with BRAF mutant anaplastic thyroid cancer. Cells were treated with mutant BRAF (V600) inhibitor vemurafenib or MEK kinase inhibitor selumetinib alone or in combination. We found that inhibition of the BRAF-MEK-ERK pathway profoundly altered cellular morphology, inhibited proliferation and decreased the migratory capacity of the cells but it could not induce cell death. Within two weeks after intrapleural injection of the tumor cells developed wide spread tumor nodules developed in the chest and invaded the lung, muscle and heart. The new line PF130 was derived from the effusion of a melanoma patient who underwent several lines of systemic therapy. The lack of BRAF mutation resulted in insensitivity against BRAF and MEK inhibition, but treatment with HDAC inhibitor SAHA evoked an arrest in the G2/M phase and partially induced cell death, while valproic acid strongly inhibited DNA synthesis. After intrapleural injection the cells were able to survive and form macroscopic tumors in the chest cavity within two months.

Conclusion: Pleural effusion derived tumor cell cultures are promising models to test therapeutic sensitivity in an individualized fashion for precision medicine.

For further information please contact: Luca Hegedüs ([email protected])

Thoracic Surgery, Ruhrlandklinik, UKE


P9


EXPLOITATION OF ONCOGENIC MECHANISMS EX VIVO STUDIES /

CORRELATIVE SCIENCE

Human CD30+ B cells represent unique B-cell subsets related to Hodgkin lymphoma cells

Marc A. Weniger, Enrico Tiacci, Stefanie Schneider, Judith Arnolds, Sabrina Rüschenbaum, Janine Duppach, Marc Seifert, Claudia Döring, Martin-Leo Hansmann, and Ralf Küppers

Introduction: The tumor necrosis factor receptor family member CD30 is expressed on malignant cells of several lymphoma entities, including the Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma. In normal lymph nodes, few B cells in germinal centers (GC) and extrafollicular (EF) regions express CD30. However, their relationship to HRS cells and specific features are unclear but clinically relevant as the FDA-approved anti-CD30 antibody-drug conjugate Brentuximab vedotin targets CD30-expressing cells. Material and Methods: We characterized FACS-sorted CD30+ GC and EF B cells by gene expression profiling, and compared their transcriptomes to the ones of major B cell subsets as well as laser-microdissected HRS cells.

Results: CD30+ GC and EF B cells express a strong MYC signature, indicating a distinct, highly active and pro-proliferative differentiation stage. Hence, CD30+ GC B cells resemble murine MYC+ centrocytes that re-differentiate into centroblasts, and CD30+ EF B cells resemble activated memory B cells that differentiate into plasma cells. The transcriptomes of HRS cells are more similar to the ones of CD30+ B cells, in particular CD30+ EF B cells, than to any conventional major B cell subset, including GC B cells. Thus, HRS cells possibly originate from these lymphocytes or acquired characteristic features during lymphomagenesis.

Conclusion: The results have implications for the development of T cell-dependent immune responses and the pathogenesis of CD30+ B cell malignancies.

For further information please contact: Marc A. Weniger ([email protected])



P10



Proton beam therapy for CNS tumors at the West German Proton Therapy Centre Essen (WPE) – Early experiences and future

perspectives

S. Frisch, D. Geismar, C. Bäumer, S. Tippelt, M. Stuschke, U. Sure, M. Glas, B. Timmermann

Introduction: Proton beam therapy (PT) is of increasing interest when treating patients with CNS tumors. However, prospective data is still limited proving the clinical benefit of PT or allowing investigation of complication probability or translational research projects.

Materials and Methods: Since May 2013, all patients with CNS diseases were enrolled in the prospective registry studies for adults (ProReg) and children (KiProReg) to assure reliable documentation on treatment data, information on adverse events (AE) and disease control. A standardized follow-up (FU) scheme was part of the registries. AEs were scored according to CTCAE v4.0. A clinical subgroup for a DKTK research project on normal tissue complication probability (NTCP) modelling was identified.

Results: Up to now, 469 patients (median age 12.7 years, range 0.9-79.6) with CNS tumors were registered. Histopathologies were glioma (n=141), ependymoma (n=104), medulloblastoma (n=69), meningioma (n=54), atypical teratoid/rhabdoid tumor (n=35), craniopharyngeoma (n=31), miscellaneous (n=35). Gross total resection was achieved in only 33.1% of patients. Concomitant chemotherapy (CTx) was administered in 28.8 %. The median PT dose was 54.0 Gy applied in 30 fractions mean. The median FU time after initial diagnosis was 1.5 years (range 0.2-33.5). New higher-grade (≥ CTCAE °3) acute AEs occurred in 31 patients, predominantly regarding bone marrow when receiving concomitant CTx. Within 2 years after PT, 13 new higher-grade late AEs (predominantly on bone marrow) were documented. So far, disease control was achieved in 79.8% of the patients. Local and distant or combined failure occurred in 55, 23 and 11 patients, respectively. 34 patients died so far. Within a DKTK co-operative project with the University Dresden, data sets of 74 adult CNS tumor patients from WPE were submitted to enable NTCP modelling.

Conclusion: PT for CNS diseases in adults and children represents a major focus at the WPE. Early prospective data on feasibility and outcome are promising. In addition, the establishment of the prospective WPE’s registry study in 2013 enables dose-effect analyses on toxicity and outcome in a large patient cohort treated with protons. Therefore, WPE is an attractive partner for DKTK sites enabling translational research of PT. Currently, a clinical randomized study on adult gliomas is initiated in Essen and under discussion with the DKTK partners.

For further information please contact: Sabine Frisch ([email protected])

West German Proton Therapy Centre Essen (WPE)


P11



Intestinal helminth infection drives carcinogenesis in colitis-associated colon cancer

Eva Pastille, Henry J. McSorley, Rick M. Maizels, Astrid M. Westendorf

Introduction: Ulcerative colitis (UC) is a chronic inflammatory disorder of the gastrointestinal tract, associated with an increased risk of colorectal cancer development. Since the etiology of UC is still unknown, therapies are able to alleviate the acute inflammation but fail to cure the patients. The application of helminths appears to be a novel promising approach as they provoke an immunosuppressive state in the host by releasing immunomodulatory molecules and inducing regulatory T cells (Tregs). On the contrary, specific parasite infections are well known to be linked to carcinogenesis. We aimed to unravel the controversial function of helminths in a mouse model of colitis-associated colon cancer (CAC).

Materials and Methods: CAC was induced in BALB/c mice by an i.p. injection of Azoxymethane followed by 3 cycles of dextran sulfate sodium salt (DSS) given via the drinking water. Mice were infected with an oral gavage of 200 L3 larvae of Heligmosomoides (H.) polygyrus. Tumor scores were determined by murine colonoscopy at week 12.

Results: The treatment with H. polygyrus at the onset of colitis and CAC does not ameliorate colonic inflammation but further facilitates tumor development. More precisely, H. polygyrus infection before the induction of DSS mediated colitis exacerbates pathology in the colon accompanied by increased levels of IL-6 and CXCL1, and strong activation of CD4+ effector T cells. Furthermore, H. polygyrus infection induced an expansion of highly activated Foxp3+ Tregs and a prolonged reduction of CD8+ effector T cells frequencies in the colon.

Conclusion:Our results demonstrate that the therapeutic application of helminths during CAC might have tumor-promoting effects and therefore should be well-considered.

For further information please contact: Eva Pastille ([email protected])

Institute of Medical Microbiology , Essen


P12


RADIATION ONCOLOGY AND IMAGING PRECLINICAL MODELS

Identification of novel targets for rational chemoradiotherapy strategies in non-small-cell lung cancer

S. Kalmbach, F. Breitenbücher, S. Nothdurft, A.Sak, B.M. Grüner, A. Schramm, M. Schuler

Introduction: Lung cancer is the leading cancer fatality worldwide, with non-small cell lung cancers (NSCLC) accounting for approximately 85% of all cases. Radiotherapy is an important modality in the curative and palliative treatment of patients with advanced NSCL, and its efficacy is enhanced by simultaneous administration of radiosensitizing drugs. Current chemoradiotherapy protocols, however, still fall short in capitalizing on the recent progress in characterization of distinct NSCLC entities by genomic and additional biomarkers. Against this background, we set out to identify and validate novel targets for personalized chemoradiotherapy strategies in NSCLC.

Materials and Methods: We conducted a functional genomic in vitro screen using a lentivirally encoded shRNA library in a human NSCLC model to identify novel modulators of the radiation response. Clonal cell lines with stable shRNA expression for target validation were generated and conventional in vitro assays were conducted. Mechanistic studies deciphering the modes of radioresistance and in vivo target validation using an orthotopic mouse mode are ongoing.

Results: We identified a putative modulator of the radiation response in NSCLC that is involved in the cells vesicular trafficking. Target knockdown revealed an increased radiosensitivity in vitro.

Conclusion: Our studies provide a framework for preclinical development of novel personalized chemoradiotherapy strategies in lung cancer.

For further information please contact: Sophie Kalmbach ([email protected]) Department of Internal Medicine (tumor research)


P13



CORRELATIVE SCIENCE

Inhibition of MDM2 via Nutlin-3A – A Potential Therapeutic Approach for Pleural Mesotheliomas with MDM2-Induced Inactivation of P53

Robert F. H. Walter, Robert Werner, Jan Schmeller, Michael Wessolly, Elena Mairinger, Sabrina Borchert, Jens Kollmeier, Thomas Mairinger, Thomas Hager, Agnes Bankfalvi, Daniel C. Christoph, Wilfried E. E. Eberhardt, Till Plönes, Kurt W. Schmid, Jeremias Wohlschläger, Fabian D. Mairinge

Introduction: Previously, our group demonstrated that nuclear expression of MDM2 in malignant pleural mesothelioma (MPM) is significantly associated with decreased overall survival. A possible explanation may be that overexpression of MDM2 leads to a proteasomal degradation of TP53 resulting in a loss of TP53-induced apoptosis and senescence. It is well known from other tumor entities that restoration of TP53 activity, e.g. by MDM2 inhibition, results in an instant TP53-induced stress and/or DNA-damage response of cancer cells. Nutlin-3A has been described as a potent and selective MDM2 inhibitor preventing MDM2-TP53-interaction.

Materials and Methods: In the present study, the effect of MDM2 inhibition in MPM via nutlin-3A and standard platinum based chemotherapeutic agents were comparatively tested in three MPM cell lines (NCI-H2052, MSTO-211H, NCI-H2452) showing different expression profiles of TP53, MDM2 and its physiological inhibitor P14/ARF.

Results: Our in vitro experiments on MPM cell lines revealed that nutlin-3A in combination with cisplatin resulted in an up to 9.75 times higher induction of senescence (p=0.0050) and up to 5 times higher apoptosis rate (p=0.0067) compared to the commonly applied cisplatin and pemetrexed regimens.

Conclusion: Thus nutlin-3A is associated with a significant induction of senescence and apoptosis in MPM cell lines, making nutlin-3A a promising substance for a targeted therapy in the subgroup of MPM showing MDM2 overexpression.

For further information please contact: Fabian Dominik Mairinger ([email protected])

Institute of Pathology


P14



Identification of a selective histone deacetylase inhibitor for MYC-driven medulloblastoma by high-throughput drug screening

Viktoria Marquardt, Johanna Theruvath, Finn K. Hansen, David Pauck, Daniel Picard, Jörg Felsberg, Samuel Cheshier, Guido Reifenberger, Arndt Borkhardt, Thomas Kurz, Siddharta Mitra, Marc Remke

Introduction: Inhibitors of histone deacetylases (HDACs) represent a promising compound class for the treatment of various oncologic malignancies and are increasingly evaluated in clinical trials. Medulloblastoma represent the most common malignant brain tumor in children with frequent metastatic dissemination. This tumor entity can be divided into four distinct molecular subgroups (WNT, SHH, Group 3 and Group 4), which are characterized by different genetic background, clinical and prognostic features. Despite multimodal treatment approaches, patients with MYC-driven Group 3 MBs have a particularly dismal prognosis.

Methods / Results: Employing our drug screening platform, we evaluated an in-house library of more than 200 HDAC inhibitors in a panel of cell lines derived from different brain tumor entities including glioblastoma, medulloblastoma and atypical teratoid/rhabdoid tumors. We could thereby identify a clinically established HDAC inhibitor that selectively inhibits proliferation in MYC-driven medulloblastoma. Besides a decrease in cell viability, the class I selective HDAC inhibitor induces apoptosis and shows synergism with an NFκB inhibitor. Lastly, we demonstrated a significantly prolonged survival, a concomitant decrease in tumor growth and spinal metastasis in two orthotopic medulloblastoma xenograft mouse models.

Conclusion: In all, our results suggest a MYC-dependent response to HDAC inhibition in medulloblastoma and provide compelling rationale for further development of a novel, potentially highly effective therapeutic strategy against the primary site and importantly the metastatic compartment in this fatal disease.

For further information please contact: Viktoria Marquardt ([email protected])



P15



PD-L1 inhibition – a new therapeutic opportunity in cutaneous angiosarcoma?

Rainer Hamacher, Selma Ugurel, Dietrich Kämpfe, Marit Ahrens, Kirsten Reuter-Jessen, Martin Schuler, Jürgen C. Becker, Hans-Ulrich Schildhaus, Sebastian Bauer

Introduction: Cutaneous angiosarcomas (cAS) represent a particularly challenging sarcoma subtype frequently occurring in pretreated patients as consequence of radiation therapy or chronic lymphedema. Local treatments are complicated due to affection by previous surgery and irradiation. Moreover, cAS lesions lack a clear delineation.

Materials and Methods: We identified 180 angiosarcomas from our institutional database of which 64 originated in the skin, in particular primary cAS of the scalp and post-radiogenic secondary cAS of the breast. Clinical characteristics and outcome was analyzed. Moreover, 37 tumor tissues were tested for expression of PD-L1 and infiltration of immune cells.

Results: Response to classical chemotherapeutic drugs was highest for taxanes and liposomal doxorubicin. Whereas first- and second-line therapy showed a good Clinical Benefit Response (CBR), in third-line therapy the CBR decreased dramatically. Using IHC we observed several cases of cAS that showed a significant expression of PD-L1 by 10-20% of tumor cells. In addition, infiltration of immune cells was observed. One patient with PD-L1-positive cAS who had progressed after several lines of chemotherapy was treated with pembrolizumab. He showed a dramatic improvement of symptoms with complete healing of a large area of ulcerating and bleeding skin with ongoing remission after 6 months of treatment.

Conclusion: Given the high rate of advanced stages and multilocular dissemination of cAS, there is an imperative need for novel systemic treatments. Based on this study, PD-1/PD-L1-directed therapy may represent a particular opportunity for cAS given the high frequency of PD-L1 expression and infiltration ofimmune cells. Our findings suggest prospective immunotherapy studies in this sarcoma subtype.

For further information please contact: Rainer Hamacher ([email protected])



P16



CORRELATIVE SCIENCE

Clonally expanding temozolomide-resistant tumor cells in recurrent glioblastoma.

Andreas Till, Celia Dobersalske, Daniel Trageser, Laurèl Rauschenbach, Roman Reinartz, Matthias Simon, Pitt Niehusmann, Igor Cima, Ulrich Sure, Guido Reifenberger, Holger Fröhlich, Martin Glas and Björn Scheffler

Emerging drug resistance keeps challenging the care of glioblastoma patients. Fatal relapse occurs almost universally, even in patients that initially benefit from the current gold standards involving postsurgical combinations of radiochemotherapy. In this study, we investigated paired cell- and tissue samples resembling the pre- vs. post-status of standard temozolomide (TMZ)-based chemotherapy. Transcriptional profiling, in vitro- and in vivo experimentation as well as confirmatory in situ studies on the original patient material revealed a causative role of aldehyde dehydrogenase 1A1 (ALDH1A1) as a marker for clonally expanding drug-resistant tumor cell subpopulations. Notably, we could show that these cells acquire resistance to alkylating agents secondary to the exposure of TMZ. Hyperactivation of the AKT pathway in these ALDH1A1 / pAKT-double positive cells is evident, both, in TMZ resistant cell cultures (in vitro) and in patient-derived tumor tissues (in situ). Scoring of ALDH1A1+/pAKT+ cells in situ revealed a negative correlation with clinical survival parameters (OS / PFS) thus rendering this drug resistant phenotype as a predictive and prognostic biomarker for glioblastoma. Furthermore, using a xenograft mouse model we could demonstrate a significant survival benefit upon combination of TMZ with the clinical grade AKT inhibitor MK2206. Together, these findings further our understanding of clonally-mediated therapy resistance, implementing a straight-forward approach for clinical follow-up in recurrent glioblastoma.

For further information please contact: Björn Scheffler ([email protected])

DKTK Division of Translational Neurooncology


P17



CORRELATIVE SCIENCE

Clinical relevance and suppressive capacity of human MDSC subsets

Kirsten Bruderek, Benedikt Höing, Oliver Kanaan, Nina Dominas, Timon Hussain, Freya Droege, Christian Eyth, Stephan Lang and Sven Brandau

Introduction: Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of pathologically expanded myeloid cells with immunosuppressive activity. In human disease three major MDSC subpopulations can be defined as monocytic M-MDSC, granulocytic PMN-MDSC and early stage e-MDSC, which lack myeloid lineage markers of the former two subsets. It was the purpose of this study to determine and compare the immunosuppressive capacity and clinical relevance of each of these subsets in patients with head and neck cancer. Methods and Design: The frequency of MDSC subsets in the peripheral blood was determined by flow cytometry in a cohort of 49 patients with advanced oropharyngeal and oral cavity tumors. Sorted and purified MDSC subsets were tested in vitro for their T cell suppressive capacity. Frequency of circulating MDSC was correlated with overall survival of patients.

Results: A high frequency of PMN-MDSC most strongly correlated with poor overall survival. T cell suppressive activity was higher in PMN-MDSC compared with M-MDSC and e-MDSC. A subset of CD66b+/CD11b+/CD16+ mature PMN-MDSC, was superior to the other subsets in suppressing proliferation and cytokine production of T cells in multiple test systems. High levels of this CD11b+/CD16+ PMN-MDSC, but not other PMN-MDSC subsets, strongly correlated with adverse outcome.

Conclusion: A subset of CD11b+/CD16+ PMN-MDSC was identified as the MDSC subset with the strongest immunosuppressive activity and the highest clinical relevance.

For further information please contact: Kirsten Bruderek ([email protected])

Research Division of the Dept. of Otorhinolaryngology


P18



CORRELATIVE SCIENCE

Loss of EZH2 increases therapy resistance to combinational treatment with carboplatin and Taxol in ovarian cancer

Johanna Naskou, Ruan van Rensburg, Yvonne Beiter, Dieter Niederacher, Tanja Fehm, Markus F. Templin, Hans Neubauer

Introduction: The primary treatment ovarian cancer (OC) comprises surgery and chemotherapy, usually with paclitaxel (TX) and carboplatin (CP). Approximately 15% of women with OC will have tumor progression or recurrence within 1 year. Although it is a reliable treatment since decades, very little is known about molecular resistance mechanisms. The aim of this study was to identify and characterize proteins, which are associated with resistance development in OC.

Materials and Methods: Expression levels of EZH2 were matched to OC patients’ progression free survival (PFS) after treatment with CP or CP and TX using TCGA data and Kaplan-Meier analysis. Furthermore, EZH2 protein levels of eight ovarian cancer cell lines were matched to their resistance against CP and TX treatment. EZH2 expression was reduced by siRNA-knockdown in A2780 cells and effects on response to CP, TX and CPTX treatment were measured using viability assays.

Results: Amongst other proteins exhibiting a significant differential expression and activation between resistant and sensitive OC, histone-lysine N-methyltransferase EZH2 (Enhancer of zeste homolog 2) was identified and selected for further analysis. Kaplan-Meier analyses revealed that high EZH2 levels correspond to a better progression free survival in women treated with a therapy containing CP as well as CP and TX. In OC cell lines, TX-resistance and EZH2 protein level are negatively correlated. Reducing the EZH2 protein amount by 80% in a cell line sensitive to TX/CP treatment significantly increased resistance to treatment with CP.

Conclusion: Since EHZ2 seems to play a role in regulating response to TX/CP treatment, further investigation of its functions may lead to a better understanding of resistance development in OC.

For further information please contact: Johanna Naskou ([email protected])

Department of Gynecology and Obstetrics


P19



PRECLINICAL MODELS

Quantitative Proteomics – a versatile tool for translational cancer research

Anja Stefanski, Kai Stühler

Introduction: Proteins are important mediators of biological processes in living systems. Mass spectrometry (MS)-based protein analysis according to the proteomic concept has fundamentally changed the way in which biological systems are interrogated because of its ability to measure thousands of proteins and posttranslational modifications in parallel. This enables investigations at all levels of biological complexity, ranging from protein complexes to whole lysates of human tissue.

Materials and Methods: Tissue samples, body fluids as well as cell culture samples from cancer patients are subjected to tryptic digestion. The resulting peptides are separated via nanoHPLC and analyzed by online-coupled high-resolution mass-spectrometry determining retention times and masses. Database searches of generated mass spectra were performed enabling the identification of proteins and peptides and signal intensities were taken as the basis for their quantification.

Results: With shot-gun proteomics modern LC-MS systems are capable of identifying and quantifying up to 10,000 proteins spanning over five orders of magnitude from a given sample. The application of statistics and bioinformatics enables afterwards putting this quantitative data into biological context by generating functional networks, identifying deregulated processes, define unknown interaction partners as well as the identification of biomarkers involved in tumorigenesis.

Conclusion: The investigation of proteins is continuing to provide important insights into many processes involved in tumor biology. Therefore, a summary of mass spectrometry as an important technique for the investigation of proteins is presented focusing on its application in biomarker discovery, functional analysis and drug screening.

For further information please contact: Anja Stefanski ([email protected])

BMFZ-MPL (DUS)


P20



CORRELATIVE SCIENCE

Evolution of melanoma cross-resistance to CD8+ T cells and MAPK inhibition in the course of BRAFi treatment

Natalia Pieper, Franziska Noelle Harbers, Anne Zaremba, Sonia Leonardelli, Marion Schwamborn, Silke Lübcke, Barbara Schrörs, Alexander Schramm, Sebastian Haferkamp, Antje Sucker, Volker Lennerz, Thomas Wölfel, Dirk Schadendorf, Bastian Schilling, Annette Paschen, Fang Zhao

Introduction: The profound but frequently transient clinical responses to BRAFV600 inhibitor (BRAFi) treatment in melanoma emphasize the need for combinatorial therapies. Here, using human autologous T-cell/melanoma models we studied the impact of prolonged BRAFi exposure on tumor immunogenicity to support the development of a rationale for combining targeted and immunotherapies.

Materials and Methods: T-cell activation by autologous tumor cells was determined by using IFNg-ELISPOT, IFNg-ELISA or intracellular cytokine staining. In case available, studies were performed with in vitro expanded tumor-infiltrating lymphocytes (TILs) to mimic T cells present in the tumor-microenvironment. In addition, BRAFi-treated melanoma cells were analyzed for diverse antigen expression via qRT-PCR or Western blot, and their surface expression of HLA-class I and PD-L1 was determined by flowcytometry.

Results: While efficiently recognizing short-term (3, 7 days) BRAFi-treated melanoma cells, TILs were less responsive towards long-term (14, 21 days) exposed tumor cells. Similar results were obtained with four out of five CD8+ T-cell clones due to a time-dependent downregulation of their respective target antigens (three shared antigens, one neoantigen). Only a second neoantigen was steadily recognized independent of treatment duration.

Conclusion: BRAFi strongly alters the tumor antigen expression profile over time, favoring evolution of melanoma variants cross-resistant to both T cells and BRAFi. Our data suggest that simultaneous treatment with BRAFi and immunotherapy could be most effective for tumor elimination.

For further information please contact: Fang Zhao ([email protected])



P21




TruRisk® gene panel analysis in familial breast and ovarian cancer patients

Honisch E., Hinssen N., Vesper A., Fehm T., Niederacher D.

Introduction: Pathogenic BRCA1/BRCA2 germline mutations are rare in familial BC/OC patients. Therefore the German Consortium for Hereditary Breast and Ovarian Cancer (GC-HBOC)has established a multi-gene panel (TruRisk),enabling genetic testing beyond BRCA1/2. It comprises 10 diagnostic "core genes" and 24 candidate genes, which are validated concerning their relevance. The TruRisk panel has been used at the Center for Family Breast and Ovarian Cancer at the University Hospital Duesseldorf since October 2015. An updated panel version is currently implemented in our laboratory. Included in this evaluation are index patient results up to September 2017.

Materials and Methods: NGS libraries from blood DNA samples were generated using the SureSelect QXT technology (Agilent), based on enzymatic DNA fragmentation followed by hybridization-mediated panel gene enrichment.

Results: As of September 2017, 892 TruRisk index analyzes have been evaluated. Pathogenic mutations in BRCA1/2 were identified in 10.4% (92/892) of patients (class 4/5 according to IARC). In further 5.0% (45/892) pathogenic mutations were detected in the other eight core genes. Variants of unclear clinical significance (class 3)in BRCA1/2 were detected in 4.4% (39/892) and 17.0% (152/892) in the "core" genes. In 3.8% (27/892) of the cases, unclear variants were detected in extended panel genes. In 66.1% (524/892) neither pathogenic nor unclear variants were found.

Conclusion:Our TruRisk panel results confirm the low mutation frequencies in non BRCA1/2 core genes while detecting many variants of unclear relevance. This high VUS-prevalence underscores the need for their further characterization to finally reclassify them in benign/ pathogenic variants.

For further information please contact: Ellen Honisch ([email protected])


Ground Floor, Room 0.05 Poster Nbr.

P22



CORRELATIVE SCIENCE

Potent anti-leukemic activity of a specific cyclin-dependent kinase 9 inhibitor in mouse models of chronic lymphocytic leukemia

Karlotta Kahmann, Stefanie Weber, Marco Luciani, Michael Möllmann, Ulrich Dührsen, Hugh Rienhoff, Joachim R. Göthert

Introduction: Onset of progression even during therapy with novel drugs remains an issue in chronic lymphocytic leukemia (CLL). Approaches targeting cyclin-dependent kinases (CDK) have reached the clinical trial stage. CDK9 mediating RNA transcriptional elongation is the evolving pivotal CLL CDK inhibitor target. However, more CDK9 selective compounds are desirable.

Materials and Methods: First, activity and selectivity of the novel CDK9 inhibitor LDC526 were studied in enzymatic kinase assays. Next, anti-CLL activity was examined using the CLL cell-line MEC-1 and primary human CLL samples. Finally, anti-leukemic activity was studied in the in the human CLL NOD/scid/γcnull (NSG) xenograft and in the CLL TCL1 transgenic mouse models.

Results: LDC526 displayed a low nanomolar biochemical activity against CDK9 and an at least 50-fold selectivity against other CDKs. In vitro MEC-1 and human CLL cell cytotoxicity was established. In human CLL transplanted NSG mice LDC526 administration (75 mg/kg) for 5 days resulted in a 77% reduction of human CLL cells in spleens compared to carrier control treatment. Next, we longitudinally studied the LDC526 impact on circulating CLL cells in the TCL1 transgenic mouse model. LDC526 (50 mg/kg) administration for two days led to a 16-fold reduction of blood CLL cell numbers. Remarkably, residual CLL cells exhibited significantly increased intracellular BCL-2 levels. The LDC526 cytotoxic effect was not restricted to CLL cells as also declining numbers of normal B and T lymphocytes were observed in LDC526 treated TCL1 mice.

Conclusion:Taken together, our in vivo data provide a strong rational for continued LDC526 development in CLL therapy and argue for the combination with BCL-2 inhibitors.

For further information please contact: Joachim Göthert ([email protected])



P23



CORRELATIVE SCIENCE

Pharmacologic LSD1 inhibition perturbs terminal human granulopoiesis while preserving monopoiesis

Karlotta Kahmann, Stefanie Weber, Marco Luciani, Michael Möllmann, Ulrich Dührsen, Hugh Rienhoff, Joachim R. Göthert

Introduction: Histone modifications such as methylation were shown to be severely perturbed in myeloid leukemias. We previously demonstrated the central role of the lysine-specific histone demethylase 1 (LSD1) in normal murinehematopoiesis (Sprüssel et al, Leukemia 2012). Remarkably, in human acute myloid leukemia (AML) LSD1 expression is de-regulated and therefore represents an attractive AML therapeutic target. In fact, first generation LSD1 inhibitors were shown to induce AML cell differentiation and apoptosis in combination with all-trans-retinoic acid (ATRA) exposure. However, the exact mechanisms-of-action and hematopoietic side effects of LSD1 inhibition in normal human hematopoiesis and AML are not yet fully understood.

Materials and Methods: We studied the impact of the novel LSD1 inhibitor IMG-7289 on the colony forming unit (CFU) potential of human CD34+ progenitor in vitro. Furthermore, IMG-7289 anti-AML activity was investigated with AML cell lines.

Results: 20% of MPM patient samples showed detectable expression of MT. MT expression varies significantly in different MPM subtypes. MT-expression could only be detected in tumors without remission and mainly in progressive tumors. MT expressing MPMs show a significantly shortened overall survival rate as well as progression free survival rate compared to MPM samples without expression of MT. Platinum containing compounds induce apoptosis in MPM cell lines leading to high response rates with weak or absent MT expression.

Conclusion: Taken together, pharmacologic LSD1 inhibition interferes with normal human hematopoietic differentiation while preserving normal progenitor potential. IMG-7289 displays AML cytotoxicity at nanomolar concentrations in vitro.

For further information please contact: Joachim Göthert ([email protected])



P24




TruRisk® gene panel analysis in familial breast and ovarian cancer patients

Jan Schmeller, Fabian D. Mairinger, Michael Wessolly, Elena Mairinger, Sabrina Borchert, Jens Kollmeier, Thomas Hager, Thomas Mairinger, Daniel C. Christoph, Robert F. H. Walter, Wilfried E.E. Eberhardt, Till Plönes, Jeremias Wohlschlaeger, Bharat Jasani, Kurt Werner Schmid, Agnes Bankfalvi

Introduction: Malignant pleural mesothelioma (MPM) is an aggressive tumour arising from the pleura, leading to a dismal prognosis. Platin-analoga are the drug of choice for the treatment of MPM, resulting in a response rate of merely 6 to 16%. The heavy metal detoxifying effect of metallothionein (MT) may be the reason for heavy metal drug resistance of MPM.

Materials and Methods: 105 MPM patients’ samples treated with platinum compounds were retrospectively analysed immunohistochemically for their MT expression levels. Possible influence on platinum-based chemotherapy response and survival were proved in human mesothelioma cell culture models. Apoptosis rate of MPM cell lines was determined using the Promega Caspase-Glo3/7 assay. Results: 20% of MPM patient samples showed detectable expression of MT. MT expression varies significantly in different MPM subtypes. MT-expression could only be detected in tumors without remission and mainly in progressive tumors. MT expressing MPMs show a significantly shortened overall survival rate as well as progression free survival rate compared to MPM samples without expression of MT. Platinum containing compounds induce apoptosis in MPM cell lines leading to high response rates with weak or absent MT expression.

Conclusion: Our results indicate a possible resistance to platinum-based chemotherapy by expression of MT. The MT expression may serve as predictive and prognostic marker for platinum treated MPM making MT a potent biomarker for stratification to chemotherapeutical regimen.

For further information please contact: Jan Schmeller ([email protected])



P25


RADIATION ONCOLOGY AND IMAGING EX VIVO STUDIES /

CORRELATIVE SCIENCE

Medical physics research in proton therapy centers: combining DKTK activities with European collaborations

C. Bäumer, W. Budach, P.H. Kramer, S. Schulze-Schleithoff, B. Timmermann

Introduction: The capacities in Europe for treatment of cancer using proton beams will grow in Europe on mid-term, because new centers are being built and existing centers are expanding their clinical operation. The growing importance of proton therapy in radiation oncology is also related to an extension of the indication spectrum, e.g. to localizations affected by respiratory motion. In order to translate novel radiotherapy techniques, e.g. adaptive proton therapy and MRI-guided proton therapy, into clinical application, co-operations between proton therapy centers have to be established.

Materials and Methods: The German proton therapy sites Dresden, Heidelberg and Essen are directly linked through DKTK. In this an online platform is available allowing treatment plan intercomparisons between DKTK sites. A first example is the radiation therapy of head&neck tumors. On European level the European Particle Therapy Network (EPTN), a task force of the ESTRO, has been established. The seven working groups of EPTN cover aspects like quality assurance, image-guided proton therapy and treatment planning. Additionally, the European consortium PROxIMO, which includes the DKTK sites Dresden and Essen/Düsseldorf, applied for a grant to conduct training and translational research in the frame of the MARIE-SKLODOWSKA-CURIE Training program.

Conclusion: The clinical introduction of new technical options in proton therapy and the extension of radiation therapy with proton fields to localizations in the abdomen and thorax require a common line of action in the national and European context. To this end the DKTK partner site Essen/Düsseldorf with its proton therapy center WPE is embedded into the corresponding working groups and consortia.

For further information please contact: Christian Bäumer ([email protected]) West German Proton Therapy Centre Essen (WPE)


P26


EXPLOITATION OF ONCOGENIC MECHANISMS CLINICAL STUDIES

PGRMC1 Promotes Tumour Progression of Breast Cancer through Upregulation of ERα Expression

Marina Willibald, Vanessa Stahlhut, Nina Kessler, Wiebke Ehrlich, Tanja Fehm, Hans Neubauer

Introduction: The hormone receptor progesterone receptor membrane component-1 (PGRMC1) is upregulated in breast cancer and elevated expression of PGRMC1 is associated with increased tumour growth and poorer outcome, indicating a contribution of PGRMC1 in carcinogenesis of breast cancer. However, the role of PGRMC1 in breast cancer is not fully understood yet. Therefore, the aim of the present study was to investigate the role of PGRMC1 in breast cancer progression.

Materials and Methods: Expression of PGRMC1 in breast cancer subtypes was investigated using TCGA data and correlated with overall- and metastasis free survival. The effect of PGRMC1 overexpression and –knockdown on proliferation was examined in vitro and in a xenograft model. With the aim to further elucidate PGRMC1 signalling in breast cancer, we searched for signalling pathways which might be regulated by PGRMC1.

Results: Expression of PGRMC1 was observed in every breast cancer subtype and high expression of PGRMC1 correlated with poorer outcome. Overexpression of PGRMC1 in the hormone-receptor positive cell lines MCF7 and T47D resulted in significant enhanced proliferation and tumour growth. Analysis of PGRMC1-dependent expression and activation of proteins revealed upregulation of ERα and ERα-dependent genes, as well as activation of EGFR signalling cascade. PGRMC1 phosphorylation at S56 and S181 was identified to be essential for enhanced proliferation and upregulation of ERα and ERα-dependent genes.

Conclusion: Our results emphasize an important role of PGRMC1 in breast cancer progression and display a potential embedding of PGRMC1 in important breast cancer signalling pathways. PGRMC1 might therefore be an interesting target for anti-cancer therapy.

For further information please contact: Marina Willibald ([email protected])



P27



CLINICAL STUDIES

Incidence rates of testicular cancer according to the updated WHO classification of testicular cancer, North Rhine-Westphalia, Germany

2008-2013

Andreas Stang, Carsten Rusner, Britton Trabert, Katherine A. McGlynn, Oliver Heidinger

Introduction: In 2016, the WHO introduced an updated classification for testicular cancers. The application of this updated classification to cancer registry data requires the review of pathology reports. The aim of this study was to provide up-to-date population-based incidence estimates according to the updated classification.

Materials and Methods:

We reviewed 2,251 pathology reports (42.9%) out of 5,252 testicular cancers at the cancer registry of North Rhine-Westphalia for the years 2008-2013. We used population counts to estimate age-standardized incidence rates per million person-years (EUROSTAT revised European Standard Population).

Results: The new classification scheme required that 9.3% of codes had to be reassigned. Among 4,935 TGCT, 76.2% were of single histological type and 23.8% were of more than one type. Among the 1,835 nonseminomas, 64.0% were of more than one histologic type. Of the 1,175 TGCTs with more than histology, 58.8% were of two types, 25.5% of three types, 8.6% of four types, and 0.7% of five types. Embryonal carcinoma was the most commonly second histology among yolk sac tumors (83.5%), teratomas (80.2%), and choriocarcinomas (81.9%). The incidence of TGCTs with a single histological type was 70.0 (standard error 1.2) and of TGCTs with more than histology was 22.4 (0.7).

Conclusion: Among TGCTs with more than one histology, embryonal carcinoma is the most frequently occurring histological type. Incidence trend analyses including periods before and after the introduction of the updated classification may produce artifacts because a substantial proportion of histology codes have to be recoded according to the updated classification.




P28



CLINICAL STUDIES

Skin cancer rates in North Rhine-Westphalia, Germany before and after the introduction of the nationwide skin cancer screening program

(2000-2015)

Andreas Stang, Karl-Heinz Jöckel, Oliver Heidinger

Introduction: Germany is the first nation that implemented a nationwide skin cancer screening program in 2008. The aim is to study the effect of the program on skin cancer rates and to estimate the number needed to screen for an unselected and a hypothetical high-risk population in Germany. Material and Methods: We used population-based data on skin cancer incidence (2000-2014), mortality, hospitalization and sick leave (2000-2015) from North Rhine-Westphalia, Germany (18 million population). We calculated annual age-standardized rates per 100,000 person years and calculated the relative change of the rates (%) including 95% confidence intervals (95%CI).

Results: Between 2007 and 2014, the estimated annual percentage change (EAPC) of the age-standardized incidence rate of skin melanoma was 3.8% among men and women. These increases were accompanied by increases of the age-standardized mortality rates (EAPC men 3.2%, women 2.0%) and age-standardized sick leave rates (EAPC men 11.0%, women 6.1%). Hospitalization rates showed barely any change. All types of rates for nonmelanoma skin cancer showed marked increases. The number needed to screen for skin melanoma death would be 34,000 if the risk reduction due to screening would be 50%. In a hypothetical high-risk approach with 10% of the population at high risk, that is, a relative risk of melanoma death of 4.0, a skin melanoma mortality risk reduction of 50% among these people due to screening would result in a reduction of the skin melanoma mortality by 15% in the total population. However, this reduction would require a number needed to screen of 11,141.

Conclusions: Seven years after the introduction of the skin cancer screening program, there is no discernible beneficial effect at population level with the exception of hospitalization rates for skin melanoma that showed a slight decrease. The estimated number needed to screen for skin melanoma in an unselected approach is high and a realistic high-risk approach is currently not feasible




P29




Effects of Protein Kinase C Iota (PRKCI) expression on the development of metastases and /or recurrent tumors.

Marc Schulte, Alexander Schramm

Introduction: Neuroblastoma (NB) is a common childhood cancer most often situated in the adrenal glands, but can also develop in the neck, chest, abdomen, or spine. Even if the tumor shows good initial treatment response, difficult to treat metastases and recurrent tumors are often developed. We previously observed an increased expression of Protein Kinase C Iota (PRKCI) in recurrent NBs compared to the paired primary tumors. Therefore, PRKCI might play a yet unknown role in the development of difficult to treat metastases and /or recurrent tumors.

Materials and Methods: We used modern CRISPR / Cas9 gene editing approaches to knockout and overexpress PRKCI in NB cells. Both, knockout and overexpression were confirmed by qPCR and Western Blot analysis and the cells were analyzed with regards to proliferation, clonal outgrowth, migratory capacity and invasiveness.

Results: PRKCI knock out surprisingly increased proliferation compared to parental cells and cells with overexpression of PRKCI. However, migratory capacity was reduced for PRKCI KO cells compared to the parental once. Further investigation of migratory and invasive capacity by Boyden chamber assays showed that overexpression of PRKCI results in increased invasiveness of SHEP cells, however, this did not reach statistical significance.

Conclusion: Although PRKCI is found to be elevated in aggressive and recurrent NB tumors, both CRISPR-mediated PRKCI knock-down or overexpression resulted in formation of viable subclones in SHEP cells. While PRKCI knock-down reduced migratory capacity, it surprisingly increased clonal survival and proliferation. In vivo experiments will be necessary to clarify the role, if any, for PRKCI in modulating neuroblastoma aggressiveness.

For further information please contact: Marc Schulte ([email protected])

Laboratory of Molecular Oncology, Department of Medical Oncology

Ground Floor, Small Hall Poster Nbr.

P30



PRECLINICAL MODELS

The role and influence of ecto-5´-nucleotidase (CD73) and the programmed cell death receptor (PD-1) in tumor microenvironment

and progression in a PTC mouse model

Judith M. Hönes, Sören Latteyer, Sarah Synoracki, Helena Rakov, Sebastian Hönes, Denise Zwanziger, Kurt Werner Schmid, Lars Möller, Dagmar Führer

Papillary thyroid cancer (PTC) is the most frequent endocrine cancer and shows a remarkable biological heterogeneity. While PTC is mostly cured by surgery with or without radioiodine therapy, some patients experience recurrence with loss of radioiodine avidity and in a minority PTC presents as incurable metastasized radioiodine refractory disease at initial diagnosis. PTC prognosis cannot be deduced from its genetic hallmark, the constitutive activation of MAPK signaling. In this project we link tumor intrinsic properties with tumour microenvironment to understand how both interact and influence PTC biology. . Using a mouse model which recapitulates human PTC by thyrocyte-specific BRAFV600E expression, we analyzed composition and changes in tumor stroma during PTC development and progression. An increase of CD3+ immune cells and a high number of TAMs and Tregs was found in thyroids of BRAFV600 mice. Further we noticed a decrease of natural killer cells, CD4+ and CD8+ cells. Moreover expression of the adenosinergic pathway CD73 and programmed cell death receptor ligand PD-L1 was upregulated in BRAFV600E thyroids compared to age matched controls and correlated with occurrence and progression of lung metastases. In line with murine data, dedifferentiated human PTC cell lines (BcPAP and TPC-1) showed upregulation of CD73- and PD-L1-expression compared to the non-cancerous thyroid cell line (Nthy-ori). Our data suggest that the tumor microenvironment changes during PTC development with upregulation of CD73 and PD-L1, which may correlate with tumor progression and metastatic potential of PTC.

For further information please contact: Judith Hönes ([email protected])

Department of Endocrinology, Diabetes and Metabolism


P31



High-throughput drug screening reveals novel therapeutic vulnerabilities of ependymomas.

David Pauck, Sevgi Sarikaya-Seiwert, Thomas Beez, Viktoria Marquardt, Jasmin Bartl, Daniel Picard, Lena Blümel, Mara Maue, Michaela Kuhlen, Ute Fischer, Hans Jakob Steiger, Guido Reifenberger, Arndt Borkhardt, Marc Remke

Introduction: Drug screening of primary brain tumor cultures entails compelling opportunities to elucidate tumor biology and to provide novel strategies for personalized therapy in neuro-oncological patient care. We aimed to establish a high-throughput drug screening (HTS) pipeline for patient-derived, primary cultures to identify novel targeted therapeutic approaches for ependymomas (EP), a common childhood primary brain tumor that is highly chemoresistant.

Materials and Methods: We developed a protocol to reliably establish primary brain tumor cultures from samples generated during neurosurgical tumor resection. The required total number of cells for in vitro viability assays was drastically reduced using 1536-well microplates. HTS was then performed using a clinical inhibitor library (n=199) comprising established chemotherapeutic agents and novel anti-cancer compounds currently in phase III and IV studies. The Infinium HD Methylation Assay was employed to compare DNA methylation and copy number profiles generated from primary tumors and matched primary cultures.

Results: DNA methylation and copy number profiles revealed that short-term primary cultures faithfully recapitulate the genomic and epigenetic landscape of the corresponding primary tumors. We subsequently processed ten primary cultures derived from EP and conducted HTS. Bioinformatic analysis of dose-response data revealed extraordinary chemoresistance of EP as well as promising active agents targeting CDK4, CDK6, EGFR, ERBB2, HDAC and VEGF.

Conclusion: In all, we have established a HTS pipeline for primary cultures investigating 199 clinical inhibitors at once. HTS analysis of ten EP provided targets for further analysis and potential in vivo follow-up studies.

For further information please contact: David Pauck ([email protected])



P32



Role of sphingolipid signaling/metabolism in hematopoietic stem and progenitor cell (HSPC) mobilization

Eyad Naser, Joachim Göthert, Maher Hanoun, Alexander Carpinteiro

Introduction: The aim of this study is to investigate the role of sphingolipid signaling in hematopoietic stem and progenitor cell HSPC mobilization and improve the outcome of standard clinical mobilizing agents G-CSF and AMD3100 by targeting enzymes in the sphingolipid pathway.

Materials and Methods: C57BL/6 acid sphingomyelinase-knockout (Asm-/-) mice, transgenic mice overexpressing acid ceramidase (CAG-Asah1 tg), and control wild-type littermates (wt) were injected s.c. with rhG-CSF 250μg/kg/d for 5 days. On day 5, peripheral blood (PB), spleen and bone marrow were collected. PB was analyzed phenotypically, functionally in vitro (CFU-C) assay and in vivo. Wild-type mice were treated with Amitriptyline, an inhibitor of Asm. Amitriptyline was applied in the drinking water beginning 2 weeks before and during treatment with rhG-CSF.

Results: CAG-Asah1 tg but not Asm-/- mice showed significantly increased numbers of the lineage- Sca-1+ c-kit+ (LSK) population and CFU-C/mL PB compared with their wt littermates. PB from G-CSF-treated donors was transplanted into lethally irradiated CD45.1 mice. Recipients transplanted with PB from CAG-Asah1 tg but not Asm-/- donors showed significantly increased CD45.2 donor-derived PB chimerism compared with recipients transplanted with PB from CAG-Asah1 wt littermates. Amitriptyline synergizes with G-CSF and significantly increases LSK cells, CFU-C/mL PB and CD45.2 chimerism but, at least partially, via mechanisms independent of Asm inhibition.

Conclusion: Overexpression of acid ceramidase enhances G-CSF mediated HSPC mobilization via yet not defined mechanisms. Amitriptyline enhances G-CSF mobilization. Outlook: Utilization of Asm-/- model and pharmacological inhibition of Asm with Amitriptyline to enhance the rapid AMD3100- mediated HSPC mobilization.

For further information please contact: Alexander Carpinteiro ([email protected]; [email protected])



P33




Searching predictive biomarkers for ovarian cancer – establishment of a new mRNA-based scoring system

Elena Mairinger, Fabian D. Mairinger, Thomas Hager, Robert F.H. Walter, Daniela Westerwick, Sabine Kasimir-Bauer, Pawel Mach, Kurt W. Schmid, Rainer Kimmig, Agnes Bankfalvi, Paul Buderath

Introduction: Ovarian carcinomas are considered the most lethal gynecological malignancies with a 5-year overall survival of only 41%. At present standard treatment is a combination of surgery and a platinum based adjuvant chemotherapy. Although ovarian cancers usually have a high primary chemosensitivity there is a relatively high recurrence rate with tumors gaining platinum resistance. The mechanism of this resistance is not fully understood yet. The aim of the present study is to identify prognostic and predictive markers to identify patterns associated with response to platinum based chemotherapy.

Materials and Methods: We analyzed 24 ovarian cancers with and without response to platinum based chemotherapy using the NanoString nCounter technique for digital expression measurement. Therefore the specimens were analyzed via the PanCancer Immune Profiling Panel as well as a custom based panel, consisting overall of 1136 mRNA target sequences with respect to tumor microenvironment. Prominent immune cell markers were stained by immunochemistry.

Results: Cox-Regression revealed e set of 7 mRNA-expression levels as independent prognostic markers for ovarian cancer under platinum based chemotherapy. Additionally regression based random forest models identified a pattern consisting of 11 targets as predictive pattern for therapy response. A scoring system resulting out of these allows estimation of risk-of-resistance based on logistic regression.

Conclusion: The proposed predictive scoring system allows a classification of platin-response in ovarian cancers in advance. This has the potential to improve patients’ clinical management. These findings now have to be validated in a prospective cohort.

For further information please contact: Elena Mairinger ([email protected])



P34



Melanoma cross-resistance between BRAFV600E inhibition and radiotherapy depends on therapy timing

Shannan B, Matschke J, Chauvistre H, Vogel F, Klein D, Meier F, Westphal D, Bruns J, Rauschenberg R, Utikal J, Forschner A, Berking C, Terheyden P, Dabrowski E, Gutzmer R, Rafei-Shamsabadi D, Meiss F, Heinzerling L, Zimmer L, Varaljai R, Hoewner A, Horn S

Introduction: Treatment of patients with metastatic melanoma is hampered by drug-resistance and often requires combination with radiotherapy as last-resort option. However, also after radiotherapy clinical relapses are common. Here, we identified the H3K4 demethylase JARID1B/KDM5B as cellular marker for cross-resistance between BRAFV600E inhibition and radiotherapy.

Materials and Methods: Cell culture-based assays as well as animal experiments were used to analyze JARID1B expression following combined sequential treatment. Human melanoma brain tissues were stained for JARID1B expression, and stage IV melanoma patient data provided information on intracranial responses following combined sequential therapy.

Results:

JARID1Bhigh cells appeared more frequently in vitro and in vivo under upfront BRAFV600E inhibition followed by radiation as compared to the reverse sequence. Accordingly, retrospective follow-up data from irradiated melanoma brain metastases showed a reduced response of MAPKi-pretreated compared to MAPKi-naïve metastases. JARID1B favors cell survival by transcriptional regulation of genes controlling cell cycle, DNA repair, and cell death.

Conclusion: JARID1B may represent a therapy-overarching resistance marker that could guide future therapy sequencing or represent a therapeutic target itself to overcome resistance.

For further information please contact: Batool Shannan ([email protected])



P35


EXPLOITATION OF ONCOGENIC MECHANISMS EX VIVO STUDIES / CORRELATIVE

SCIENCE

Antiviral HCV therapy with sofosbuvir reduces HCC recurrence by inhibition of hepatocyte proliferation

Katja Piras-Straub, Peri Kocabayoglu, Ruth Bröring, Hideo A. Baba, Guido Gerken, Kerstin Herzer

Introduction: The treatment of hepatitis C virus infection (HCV) by direct acting antivirals (DAA) is highly effective and promises the decrease of HCV-related liver cirrhosis and hepatocellular carcinoma (HCC). Contrary observations concerning the incidence of HCC recurrence after DAA therapy reflects the necessity of deeper investigation. Therefore we analysed the influence of DAAs on viability, apoptosis and proliferation of human liver cells in vitro and ex vivo.

Materials and Methods: Primary human hepatocytes (PHH) and hepatoma cell lines (Huh7, Con1) were treated with the DAA sofosbuvir (SOF). Cell proliferation was analysed by BRDU-, apoptosis by Caspase-3/7 activity- and cell viability by MTT- and LDH-assay. The explanted liver tissue of 36 HCV patients were immunohistolochemicaly analysed for proliferation by Ki67 and apoptosis by cleaved-caspase 3 staining. Genexpression was analysed by qrtPCR.

Results: The treatment of Huh7 and Con1 cells with SOF in vitro resulted in a significant reduction of cell proliferation to 50% in Huh7 and 60% in Con1 cells after 72h. In PHHs the treatment with SOF resulted in a significant decreased expression of Ki67 to 48% after 72h. Neither the cell lines nor PHHs showed alterations in cell viability. The hepatocyte proliferation in the explanted liver sections of patients receiving SOF was significantly lower (median: 1.3, 95%CI: 0.5-1.7) than in patients who received no DAA therapy (median: 2.3, 95%CI: 1.6-3.3) or a therapy without SOF (median: 2.6, 95%CI: 0.7-4.2). In the liver tissue apoptosis was not affected by SOF.

Conclusion: The herein presented results suggest an antiproliferative effect of SOF and therefore no cancerogenic influence in the liver.

For further information please contact: Katja Piras-Straub ([email protected])

Clinic for Gastroenterology and Hepatology


P37




HCC progression is fostered by an allele specific impairment of TRAIL expression

Katja Piras-Straub, Peri Kocabayoglu, Ruth Bröring, Hideo A. Baba, Guido Gerken, Kerstin Herzer

Introduction: Hepatocellular carcinoma (HCC) is one of the most malignant cancers worldwide with a considerable high recurrence rate after therapy. We identified a SNP in the promoter of the apoptosis related factor TRAIL which directly regulates the TRAIL expression and thus influences the progress and recurrence risk for HCC.

Materials and Methods: Demographic and clinical data of patients who received liver transplantation or resection in cause of HCC were collected and the tumor and liver tissue was used for DNA- and RNA isolation. The sequence analysis of the human TRAIL promoter was performed by sequencing. Gene expression was analysed by qrtPCR. Promoter functionality was analysed be reporter gene assay and transcription factor binding by electrophoretic mobility shift assay. TRAIL knockdown was performed by siRNA. Cell migration of Huh7 cells was analysed by boyden-chamber assay.

Results: The expression of TRAIL negatively correlates with the tumor stage in HCC patients and is significantly lower in the HCC tissue than in the corresponding liver tissue. Due to the -1573T>C SNP about 44% of these patients carrying at least one loss-of-function allel at position -1573 within the human TRAIL promoter. This -1573C genotype impairs the binding of transcription factors and significantly correlates with lower TRAIL expression. The impaired TRAIL expression resulted in enhanced migration activity of hepatoma cells.

Conclusion: Our findings identified the -1573C allel in the human TRAIL promoter as major responsibility for the impaired TRAIL expression in human HCC with the consequence of enhanced growth and migration of tumor cells, ultimately resulting in the progression of the HCC.

For further information please contact: Katja Piras-Straub ([email protected])

Clinic for Gastroenterology and Hepatology


P38



PRECLINICAL MODELS

The regulatory effect of Type I IFNs on neutrophil angiogenic capability in tumor microenvironment

Sh. Bordbari , E. Pylaeva , I. Spyra, S. Lang and J. Jablonska

Introduction: Tumor-associated neutrophils (TANs) influence tumor growth and angiogenesis, depending on IFNs availability in milieu. Since angiogenesis plays a crucial role in tumor progression, the aim of this study is to determine how TANs regulate tumor vascularization, and how IFNs impact this process.

Materials and Methods: In vitro experiments were done on proliferation and tube formation assay of endothelial cells after co-culture with neutrophils from IFN-deficient versus WT mice blood and tumor and head and neck tumor patients. For in vivo experiment, presence of TANs in tumors and vasculature development of tumors grown in IFN-deficient versus WT mice was analyzed.

Results: We observed elevated tumor growth and higher TAN numbers in IFN-deficient mice. TANs were mainly associated with tumor vasculature and strongly released pro-angiogenic factors. Tumors in such mice show better-developed vasculature and increased tumor hypoxia. Co-culture of endothelial cells with IFN-deficient TANs led to significantly upregulated proliferation and sprouting of such cells.

Conclusion: Taken together, our results suggest that IFN-deficient TANs of pro-angiogenic phenotype can efficiently stimulate tumor vascularization and tumor growth.

For further information please contact: Sharareh Bordbari ([email protected])

Department of Otorhinolaryngology


P39



DKTK MASTER Essen – A single center experience

Johanna Falkenhorst, Julia Ketzer, Jens Theysohn, Axel Wetter, Jens Siveke, Martin Schuler, Stefan Kasper, Rainer Hamacher, Sebastian Bauer

Introduction: The DKTK MASTER program evaluates the outcome of an individualized, biology-driven therapy in younger adults with advanced-stage cancer and pts with rare tumors.Material and Methods: Whole exome and RNA sequencing of tumor and reference tissue (blood), validation of results and discussion of therapeutic options in an interdisciplinary tumor board. Evaluation of therapeutic impact and pt treatment. Follow-up (3, 6, 12 months) for pt outcome.

Results: Since May 2016 75 pts consented participation, and 65 were included (23 pending). 75 tumor samples were sent for analysis, 24 of which were not evaluable. Histologic subtypes were sarcoma and GIST (54 pts), carcinoma (13 pts), (uveal) melanoma (5 pts) and other (2 pts). In one pt RNA-seq led to a change of diagnosis. Results of 38 pts have been discussed within the molecular tumor board, and 9 pts were treated accordingly. One pt showed a short-lasted response (3 mo), and one tumor board finding explained the response of a previous treatment line. The median time from pt inclusion to treatment recommendation was 99 days (51-140 d), 10 pts died before a treatment could be applied. Informed consent, sample acquisition and preparation, pt registration, tumor board discussion, and documentation of follow-up takes about 3-4 hours/pt.

Conclusion: Besides confirmation or revision of histological diagnoses and generation of additional therapeutic options for patients, this program provides insights into the biology of rare cancers. The obtained data can now be used for additional projects. Missing implementation of recommendations may be explained by lack of clinical evidence, clinical data and studies, denial of financial coverage (insurances), more promising conventional therapeutic options and the time lag between inclusion of patients and treatment recommendation.

For further information please contact: Johanna Falkenhorst ([email protected])


Ground Floor, Hall in front of Seminarroom 0.019 Poster Nbr.

P40



CLINICAL STUDIES

Endocrine disorders in adult survivors of childhood cancer

Unger N, Jedanowski J, Kiewert C, Grasemann C, Kreitschmann-Andermahr I, Sure U, Stuschke M, Timmermann B, Reinhardt D, Schuendeln MM, Fuhrer D

Introduction: Cancer treatment in children may lead to endocrine and other medical comorbidities even later in life. Still, many countries lack tailored surveillance programs for such patients so that potential health problems may remain unrecognized. The present study investigates endocrine impairment in a single centre university setting in adult patients treated for cancer in childhood.

Material and Methods: Adult survivors of childhood cancer were investigated during transition from paediatric to adult care and follow-up. Endocrine evaluation included measurement of basal cortisol, TSH, fT4, LH, FSH, testosterone, estradiol, prolactin, IGF-1, parathyroid hormone, 25-hydroxyvitamin D [25(OH)D] and stimulation testing where appropriate. Bone mineral density and body composition was measured by DXA scan.

Results: One hundred and twenty-three (47 f, 76 m) survivors were evaluated, including patients treated for leukemia (31), lymphoma (11), brain tumours (55), sarcoma (7), papillary thyroid carcinoma (4) and other cancer (15). Median age was 20.5 years (17.2 – 33.5) at last follow-up. Frequent endocrine disorders were pituitary hormone deficiency, osteopenia, high total fat mass and compensated hypergonadotropic hypogonadism in male patients.

Conclusion: Endocrinopathies are common disorders in childhood cancer survivors. The results of the present study underscore the need for organized medical assessment and treatment of late sequelae of patients even years after multimodal cancer treatment.

For further information please contact: Nicole Unger ([email protected])



P41



The Role of Gfi1 in Genome Stability

Daria Frank,Judith Schütte, Aniththa Thivakaran, Yahya Al-Matary, Pradeep Kumar Patnana, Marina Suslo, Renata Köster, Klaus Lennatz, Thomas Liehr, Shaymaa Azawi, Ulrich Pascheberg, Ulrich Dührsenund Cyrus Khandanpour

Introduction: Acute myeloid leukemia (AML) is a hematological disorder and leads to a clonal expansion of hematopoietic progenitor cells. Growth Factor Independence 1 (Gfi1) is a transcriptional repressor which regulates the proliferation and differentiation of hematopoietic stem cells (HSCs). The team could already show that less expression levels of Gfi1 promote the development of myelodysplastic syndrome (MDS) and AML. Additionally, a single nucleotide polymorphism variant in which the Serine (S) on position 36 is exchange with Asparagine (N), contribute to the development of MDS and AML. AML patients and leukemic mice which have a low expression level of Gfi1 as well as the expression of Gfi1-36N have a poor prognosis. In Gfi1 knockdown hematopoietic cells there is a downregulation in genes which are involved in the DNA-repair. Due to these results can be assumed that Gfi1 has a non-identified function in the DNA-repair. Furthermore patients with the expression of GFI1-36N show more complex cytogenetic aberrations than the GFI1-36S patient cohort indicating that GFI1-36N is associated with genomic instability. The aim of this work is to identify the exact role of Gfi1 especially GFI1-36N with regard to the DNA-repair and chromosomal stability to investigate potential new therapeutics. Materials and Methods: To investigate the DNA-repair and DNA-damage at different time points after irradiation (X-rays) we performed the γH2AX-Assay. To confirm these results we used the alkaline Comet-Assay to detect the DNA-damage directly on DNA-level. For the study of the chromosomal aberrations we serial transplant different mouse genotypes to test if there are more cytogenetic aberration and therefore less genomic stability in GFI1-KD and -36N- mice compared to GFI1-WT-mice. To detect the chromosomal aberrations in the leukemic cells we perform mFISH. In addition we determine apoptosis and the cell surface based on expression markers with FACS-stainings. Results: We found that the cells from GFI1-KD- and GFI1-36N-mice have more γH2AX-Foci after 1 h and 2 h after irradiation than GFI1-36S which means that GFI1-KD- and GFI1-36N-cells have a reduced DNA-repair ability than the WT-cells. This was confirmed on the DNA-level with the Comet-Assay. The cytospin analysis of the leukemic BM-cells from the transplanted mice showed that the GFI1-KD- & GFI-36N-cells have significant more alterations in the cell shape and nuclei than GFI-WT. This leads to the assumption that in the cells from GFI1-KD- and GFI1-36N-mice are more chromosomal aberrations which induce changes in the cell morphology. Conclusion: There are first evidences that GFI1 plays a role in the DNA-repair and has an influence on the chromosomal stability. A higher number of mutations as a result of a reduction in the DNA-repair and less genome stability could explain the poor prognosis of MDS-/AML-patients which have less expression levels of GFI1 or express GFI1-36N. So GFI1 could be a new target for leukemia therapy.

For further information please contact: Daria Frank ([email protected])



P42




BRCAness phenotype is common in MPM and is associated with response to olaparib in vitro

Sabrina Borchert, Michael Wessolly, Jan Schmeller, Elena Mairinger, Jens Kollmeier, Thomas Hager, Thomas Mairinger, Daniel C. Christoph, Robert F. H. Walter, Agnes Bankfalvi, Wilfried E.E. Eberhardt, Till Plönes, Jeremias Wohlschlaeger, Clemens Aigner, Kurt Werner Schmid, Fabian D. Mairinger

Introduction: MPM is an aggressive tumor with poor prognosis. The remission rate during the most effective chemotherapeutical regimen is only 40%. The reasons for the poor efficacy remain largely unknown; we assume, that HRR plays a crucial role. An inhibition of this pathway with the PARPinhibitor olaparib could possibly withdraw this benefit and induce apoptosis.

Materials and Methods: We analyzed the response of four MPM and lung fibroblast cell lines to treatment with pemetrexed, cisplatin and/or olaparib. Furthermore, we investigated correlations between response and gene expression patterns associated with a BRCAness phenotype in 91 MPM specimens with digital gene expression of HRR members.

Results: We observed a BRCAness-dependent increase of apoptosis and senescence during olaparib-based treatment. Those gene expression pattern could be found in a separated group of approximately 10% of patients.

Conclusion: Defects in HRR compiled under the term BRCAness are a common event in MPM. The present data lead to a better understanding of the underlaying mechanisms and open the chance for new therapeutic approaches.

For further information please contact: Sabrina Borchert ([email protected])



P43




Genome-wide mutational analysis of Hodgkin lymphoma

Farsijani, NM; Schneider, M; Hansmann, ML; Küppers R

Introduction: Hodgkin- and Reed/Sternberg (HRS) cells are the malignant transformed cells in Hodgkin lymphoma (HL). Due to the scarcity of HRS cells in HL comprehensive genetic analyses to unravel the molecular pathogenesis of HL by next generation sequencing (NGS) on whole biopsy samples is not feasible. We describe two approaches to enrich HRS cells and subsequently sequence the oncogenome of primary HL cases.

Materials and Methods: Enrichment by microdissection: 3000 HRS and control lymphocytes were microdissected from frozen biopsy sections. Samples were split in 2 - 3 aliquots and each aliquot was subjected to whole genome amplification (WGA), followed by whole exome sequencing of each aliquot. Enrichment by fluorescence-activated cell sorting (FACS): lymph node suspensions from primary HL biopsies were stained with an 8-color antibody panel to identify HRS cells.

Results: Combined analysis of all sequenced WGA-aliquots per case suggested a median number of 969 non-synonymous variants (range: 230 – 2714). Selected putative mutations were validated by Sanger sequencing in independently microdissected HRS cells. 12 of 25 examined putative mutations were validated. Variant-calling with variant presence in >1 WGA-aliquot per case reduced the median non-synonymous variants number to 29 (range: 4 – 71). Of those, all 7 examined mutations could be validated. Using flow cytometry HRS cells could be visualized and isolated. In some cases, enough cells were obtained to perform whole genome sequencing without WGA.

Conclusion: Microdissection and FACS are feasible methods to enrich HRS cells for NGS analysis. Artefact creation and incomplete coverage after WGA-amplification mandate cautious data analysis. Whole genome sequencing of a WGA-free library from sorted HRS cells is currently pending.

For further information please contact: Navid Farsijani ([email protected])



P44




The role of RMST, a functional long-noncoding RNA, in glioblastoma

Nan Qin, Maike Langini, Daniel Picard, Anja Stefanski, Arndt Borkhardt, Guido Reifenberger, Kai Stühler, Marc Remke

Introduction: Glioblastoma (GBM) is the most common and malignant brain tumour in adults. In publicly available data, we identified rhabdomyosarcoma 2-associated transcript (RMST) as a long non-coding RNA, which is specifically overexpressed in patients with short-term survival. Stable RMST overexpression (OE) cell lines will be used to characterize RMST’s role in GBM.

Materials and Methods: RMST and SOX2 expression levels were confirmed via RT-qPCR. Stable RMST OE cell lines were generated via Lentivirus. Cell viability, migration rate and colony forming capacity were measured by in-vitro assays. Proteins were analysed via quantitative high resolution mass spectrometry (HRMS).

Results: Primary patient derived GBM cells exhibit higher RNA levels of RMST and SOX2, an essential factor for cell pluripotency and known RMST interaction partner, under stem cell compared to routine culture conditions. Initial results indicate a significant increase in cell viability, migration rate and colony forming capacity due to RMST OE in the cell lines generated, supporting RMST as having a role in GBM oncogenicity. Through label-free proteomic analysis of RMST OE and respective control cell lines applying HRMS, we have quantified 64 significantly regulated proteins.

Conclusion: The data obtained could hint to a regression in tumour cell differentiation levels. Next, we will perform RNA-protein pulldowns analysed by quantitative HRMS to investigate potential RMST interactors.

For further information please contact: Maike Langini ([email protected])

BMFZ-MPL (DUS)


P45




HTSeq analyses of genetic diversity of cellular repertoires in oncological contexts

Simo Kitanovski, Mohammadkarim Saeedghalati∗, Farnoush Farahpour∗, Jürgen C. Becker, Astrid Westendorf, Ralf Küppers, Daniel Hoffmann∗

Even within organisms, functional diversity is often realized by genetically diverse repertoires (GDRs), for instance in B or T cell receptor repertoires with their highly variable regions responsible for antigen recognition, in viral quasispecies, or in genetically and functionally diverse gut microbiomes. Recent advances in high-throughput sequencing (HTSeq) technology have enabled the exhaustive genetic analysis of GDRs, and thus discovery of associations of GDR diversity with pathologies. Since the data resulting from HTSeq experiments are highly complex, computational analysis is indispensable. Here we present several examples of computational analyses of GDRs in oncological contexts: Changes in B cell receptor repertoires of patients infected by Hepatitis C Virus (HCV), showing patterns reminiscent of early stages of B cell lymphoma; differential diversity patterns in human T cell receptor repertoires under different treatments for skin cancer; differential microbiome patterns in mouse guts with induced colon cancer and inflammation.

For further information please contact: Simo Kitanovski ([email protected]; [email protected])

Bioinformatics und Computational Biophysics (UDE)


P46



PRECLINICAL MODELS

The role of TGF-β in malignant pleural mesothelioma progression

Paul Stockhammer, Till Plönes, Christine Pirker, Julia Zach, Andras Czirok, Walter Berger, Balazs Hegedus, Clemens Aigner

Introduction: Emerging evidence indicates a functional role of transforming-growth factor (TGF)-ß, a complex modulator of cell growth, differentiation and morphogenesis, in the pathogenesis of malignant pleural mesothelioma (MPM). MPM is a highly aggressive malignancy with limited response to chemo- or immunotherapy. A better understanding of the role of TGF-ß in the progression of MPM might be pivotal in order to develop novel targeted therapeutics.

Materials and Methods: Diagnostic pleural effusion samples from 23 MPM patients and 9 patients with pleuritis were measured by ELISA for TGF-ß levels. Furthermore, 30 established MPM cell lines were cultured in special 3D-printed culture dishes in order to observe in vitro nodule formation. In this context, concomitant treatment with TGF-ß and gene expression profiling was performed by using whole transcriptome microarrays.

Results: TGF-ß levels significantly differed between MPM malignant effusions, MPM benign effusions and pleuritis effusions. 16 (53%) of our cell lines spontaneously formed 3D nodules within 14 days in vitro. Nodule formation was strongly associated with non-epithelioid histotype, hTERT promotor mutation, and high cell proliferation. Upon TGF-ß treatment, nodule formation and expression of immunosuppressive markers including PD-L1, IL-33 and VEGFA increased.

Conclusion: Our findings suggest that TGF-ß is abundantly present in MPM effusions and supports nodule formation in vitro. TGF-ß and its superfamily might represent promising novel targets for the treatment of MPM patients.

For further information please contact: Paul Stockhammer ([email protected])

Thoracic Surgery, Ruhrlandklinik, UKE


P47



PRECLINICAL MODELS

Comparative and functional analysis of MYC-dependent secretome perturbations in medulloblastoma

N. Qin, M. Langini, D. Picard, F. Meyer, K. Stühler, A. Stefanski, A. Borkhard, G. Reifenberg, M. Remke

Introduction: Medulloblastoma (MB) is the most common malignant brain tumor of childhood and is a genetically heterogeneous disease. Amongst all MB subgroups, MYC-amplified MBs have the worst prognosis, are commonly metastatic, and are resistant to standard therapy. However, MYC amplification is restricted to a cellular subpopulation within MYC-amplified tumors. The underlying mechanisms mediating this cellular heterogeneity remain poorly understood. Hypothesis: We hypothesize that secreted factors from MYC-amplified subclones might essentially contribute to a tumor-promoting microenvironment.

Methods and Results:

Using patient-derived cell lines and stable MYC overexpression cell lines, we first observed that pre-conditioned media from MYC-driven cell cultures improved survival of non-MYC-driven cells under serum starvation conditions. Importantly, we further demonstrated that MYC-driven cells promote invasive growth patterns and proliferation of non-MYC-driven cells in contacting and non-contacting co-culture systems. Finally, we performed label-free mass-spectrometric-based proteomic analysis in a total of eight MB models with and without MYC activation. We identified Insulin like growth factor binding protein 2 (IGFBP2) as a candidate secreted factor, which might contribute to the aggressive phenotype observed in MBs with cellular subclones harboring MYC amplification.

Conclusion: The crosstalk between MYC-driven and non-MYC driven cells might facilitate tumor growth and metastasis. Understanding the contribution of MYC-driven cells in the microenvironmental niche could open up new strategies for the diagnosis, prognosis and therapy of MYC-amplified MB.

For further information please contact: Nan Qin ([email protected])



P48



CORRELATIVE SCIENCE

Spatial profiling of neutrophils and T cells in the human head and neck cancer microenvironment

Yu Si, Anthony Squire, Stephan Lang, Sven Brandau

Introduction: New immunotherapies show promise also for HNSCC, which makes it important to better understand the local immunological tumor microenvironment in this type of cancer. Published work associates a dense T cell infiltrate with good prognosis, while patients with tumors strongly infiltrated with tumor-associated granulocytes (TAG) have a poor outcome. It is the aim of this study to uncover the interaction of TAG and tumor-infiltrating T cells (TIL) in patients with HNSCC using digital pathology and quantitative image analysis.

Materials and Methods: The tumor tissue of patients with stage I–IV HNSCC was analyzed. Immunofluorescence was used to explore the specific phenotype and spatial distribution of TAG and TIL. Granulocyte and T cell marker CD66b and T cell markers were combined with markers indicative of cellular differentiation and activation states. The whole slide was scanned with Apotome and subjected to digital image analysis using the Definiens platform.

Results: We developed algorithms to distinguish tumor islands from stromal regions for separate immune cell quantification. Lower tumor to stroma ratio was correlated with lymphatic metastasis and poor survival. TAG prefer to infiltrate in the stroma, but Granzyme B+TILs in epithelial tumor islands. About 1/3 of the tumor and stromal areas are composed of mixed regions with intensive TAG/TIL interaction. Low densities of TAG and high densities of Granzyme B+TILs predicted good survival, independent of tumor stage.

Conclusion: Our data suggest a functional compartmentalization of the tumor microenvironment with hot spots of Granulocyte-T cell interaction relevant for tumor progression and patients survival

For further information please contact: Yu Si ([email protected])

Research Division of the Dept. of Otorhinolaryngology


P49



PRECLINICAL MODELS

Prevailing starvation resistance by glutaminase inhibition

Katharina Koch, Rudolf Hartmann, Hans-Jakob Steiger, Jaroslaw Maciaczyk and Ulf Dietrich Kahlert

Introduction: Glioblastoma (GBM) is the most common brain-born cancer and currently no therapy with satisfying clinical outcome is available. Exploiting metabolic dependencies is an emerging field to efficiently and selectively eradicate cancer stem-like cells (CSCs). Starvation has been shown to have therapeutic benefit, but emergence of resistance hurdles the clinical translation. Other, more comprehensive anti-CSC therapies are warranted.

Methods: We non-targeted analyzed the global metabolome in in vitro extracts of a collection of GBM neurospheres both in stemness enriched or differentiation conditions with proton nuclear magnetic resonance spectroscopy.

Results:

We identified intracellular glycine and phosphopcholine to be enriched in stem cells as compared to differentiated counterparts. Moreover, relative abundances of intracellular glutamine to glutamate (Gln/Glu), inform on the tumor´s resistance level to glutamine deprivation which was independent of MYC activation status. In contrast, both types of GBM-CSCs are efficiently targeted when blocking Gln to Glu conversion. Conclusion:Our group previously identified Glutaminase (GLS1) in GBMs as a novel downstream target of stem cell signaling Notch. We now extend the importance of GLS1 as a therapeutic target to overcome starvation resistance in both MYChigh/low brain tumors and the quantification of its enzymatic educt/product ratio may have utilities in predicting starvation resistance, information which can be acquired though non-invasive imaging.

For further information please contact: Ulf Kahlert ([email protected])

Department of Neurosurgery


P50



Phenotypic modulation as a new therapeutic strategy in melanoma

H. Chauvistré , B. Shannan , F. Vogel , N. Lorberg , A. Höwner , O. Keminer , D. Picard , M. Remke , C. Krepler , M. Herlyn , S. Daignault , N. K. Haass , F. Kaschani , M. Kaiser , A. Sechi , D. Schadendorf , A. Roesch

Melanoma therapy leads in most patients to tumor relapse due to drug resistance. Cell plasticity, where various tumor cell subpopulations dynamically change, is one of the reasons for developing resistance. However, melanoma heterogeneity and plasticity and their role in maintenance of tumor progression and therapy resistance are poorly understood. To study this, we modulated a well-defined multi-therapy resistant subpopulation in melanoma, which is characterized by the high expression of the histone H3K4 demethylase JARID1B/KDM5B. Our current data indicate that the endogenous heterogeneity of the expression status of JARID1B leads to a continuous maintenance of the overall tumor growth. Interestingly, the homogeneous overexpression of JARID1B across all melanoma cells led to the gradual decline of the total population. Thus, the tumor re-population capacity was lost as a result of forced phenotypic synchronization. In summary, phenotypic synchronization might be a new therapeutic strategy to overcome development of drug resistance in melanoma.

For further information please contact: Heike Chauvistré ([email protected])



P51




Enrichment, isolation and PIK3CA mutational analysis of patient-matched EpCAMhigh and EpCAMlow/negative CTCs in metastatic

breast cancer

Rita Lampignano, Liwen Yang, André Franken, Dorothee Köhler, Tanja Fehm, Dieter Niederacher, Hans Neubauer

Introduction:

Circulating tumor cells (CTCs) are observed in the blood stream of cancer patients and are mostly enriched by EpCAM-based systems, overlooking mesenchymal cells. In the metastatic breast cancer (MBC), the PIK3CA is the most mutated oncogene and its mutations were correlated with patients´ outcomes. Our aim was to collect patient-matched EpCAMlow/negative and EpCAMhigh CTCs in MBC and characterize the PIK3CA status within single CTCs.

Materials and Methods: In 52 MBC blood samples, EpCAMhigh CTCs were enriched via CellSearch®. The EpCAM-depleted blood was further processed within the size-selective Parsortix™ to enrich EpCAMlow/negative CTCs. After in situ staining, CTCs were detected by fluorescence microscopy (DAPI+, cytokeratins+, EpCAMlow/-, CD45-) and were isolated via CellCelector™ micromanipulator. Genomes of CTCs were amplified (WGA) and WGA products were Sanger sequenced for PIK3CA hotspot regions.

Results:

We detected both EpCAMhigh and EpCAMlow/negative CTCs in 54% of patients without any correlation in positivity rate. In 13 patients, high DNA integrity was observed in 28% EpCAMhigh CTCs vs. 8% EpCAMlow/negative CTCs. CTCs with PIK3CA hotspot mutations were detected in 4/10 patients. One patient carried the mutation 9/E545K only in EpCAMlow/negative CTCs and two patients carried the mutations 20/H1047R/L in the EpCAMhigh CTCs only. The fourth patient exhibited PIK3CA mutations in both CTC-subgroups: 9/E545K in EpCAMlow/negative cells and 20/H1047L in EpCAMhigh cells.

Conclusion: In summary, we provide a robust workflow to enrich and isolate patient-matched EpCAMhigh and EpCAMlow/negative CTCs, and for the first time, we show the heterogeneous PIK3CA mutational status in both EpCAMlow/negative and EpCAMhigh CTCs are mostly enriched by EpCAM-based systems, overlooking mesenchymal cells. In the metastatic breast cancer (MBC), the PIK3CA is the most mutated oncogene and its mutations were correlated with patients´ outcomes. Our aim was to collect patient-matched EpCAMlow/negative and EpCAMhigh CTCs in MBC and characterize the PIK3CA status within single CTCs.

For further information please contact: Rita Lampignano ([email protected])

Department of Obstetrics and Gynecology, Uni DUS


P52



The Role of Programmed Death 1 in Myocardial Injury

L. Michel, U. Hendgen-Cotta, I. Helfrich, T. Rassaf, M. Totzeck

Background: Programmed Death 1 (PD-1) inhibition is a promising approach for the treatment of advanced malignant tumors. By inhibition of this immune checkpoint, an endogenous response against tumor cells can be induced. However, recent experimental and clinical data showed a potential cardiotoxic effect following disruption of the PD-1/PD-L1 axis. The underlying pathomechanisms remain incompletely characterized.

Methods: The acute and chronic myocardial consequences of PD-1 disruption were assessed using histopathology combined with echocardiography in mice. Following acute myocardial ischemia/reperfusion injury, cardiac PD-L1 expression was evaluated. In a further chronic approach, cardiac function was assessed in C57BL/6 PD-1-/- mice and signs for autoimmune disease e.g. antibody formation were examined.

Results: We found that PD-L1 is expressed on healthy murine cardiomyocytes and that myocardial injury leads to a significant downregulation of PD-L1. Unlike previously published in BALB/c PD-1-/- mice, there was no evidence of left ventricular dysfunction in C57BL/6 PD-1-/- mice. This was despite of myocardial antibody deposits found in both strains.

Discussion: Whereas BALB/c PD-1-/- mice show fatal cardiomyopathy, C57BL/6 PD-1-/- mice display autoantibody formation against cardiomyocytes without functional impairment as a sign for a strain-specific effect. Ischemia-dependent expression of PD-L1 on murine cardiomyocytes suggests direct PD-1/PD-L1 effects independent of an autoimmune reaction. Taken together, PD-1/PD-L1 preserves myocardial integrity and disruption of the PD-1/PD-L1 axis in immune checkpoint inhibitor therapy could be an underestimated risk for myocardial damage.

For further information please contact: Lars Michel ([email protected])

Department of Cardiology and Vascular Medicine


P53



TARGETING PRIMARY CILIOGENESIS IN ATYPICAL TERATOID/RHABDOID TUMORS

Lena Blümel, Johannes Berlandi, Katharina Thiel, Isabel Tegeder, Astrid Jeibmann, Nan Qin, Frauke D. Meyer, Bastian Malzkorn, Max C. Liebau, Pascal D. Johann, Serap Erkek, Michael C. Frühwald, Stefan M. Pfister, Marcel Kool, Arndt Borkhardt, Guido Reifenberger, Martin Hasselblatt, Marc Remke

Introduction: Atypical teratoid/rhabdoid tumors (AT/RT) are highly malignant CNS tumors commonly diagnosed in infants. Comprehensive genomic studies elucidated three distinct molecular subtypes (TYR, MYC, SHH). As primary cilia (PC) have already been shown to play an important role in other tumor entities, we aimed to characterize the distribution of PC in AT/RT and to target primary ciliogenesis in these tumors with dismal prognosis.

Materials and Methods: We performed immunofluorescence of PC in AT/RT cell lines and primary tumor sections. The functional role of PC was investigated by knockdown of KIF3A and pharmacological inhibition using Ciliobrevin D. The relevance of primary ciliogenesis in AT/RT biology was elucidated using a fly model of SMARCB1 deficiency.

Results: We detected PC in all AT/RT cell lines and primary tumor sections investigated in this study. Notably, TYR-AT/RT were highly ciliated (12-22%), while MYC- and SHH-AT/RT showed a variable degree (4-29%) and a low proportion (2-6%) of cells with PC, respectively. Knockdown of KIF3A significantly reduced cell proliferation and stem cell properties. Additionally, death receptor 5 signaling was significantly upregulated. Pharmacological inhibition phenocopied these results, specifically after induction of primary ciliogenesis. In a fly model of SMARCB1 deficiency concomitant knockdown of several cilia-associated genes reversed the lethal phenotype significantly.

Conclusion: For a long time, PC have been regarded as rudimentary organelles, while a crucial role for PC is now emerging in cancer. Our results implicate PC as a universal feature of AT/RT and suggest primary ciliogenesis as a potential therapeutic target, especially in TYR-AT/RT.

For further information please contact: Lena Blümel ([email protected])



P54




Longitudinal heterogeneity in glioblastoma – moving targets in recurrent versus primary tumors

Niklas Schäfer, Gerrit H Gielen, Laurèl Rauschenbach, Anja Wieland, Andreas Till, Roman Reinartz, Matthias Simon, Pitt Niehusmann, Ulrich Herrlinger, Torsten Pietsch, Björn Scheffler and Martin Glas

Purpose: Molecularly targeted therapies using receptor inhibitors, small molecules or monoclonal antibodies are routinely applied in oncology. Verification of target expression should be mandatory before initiating therapy, yet, determining the expression status is most challenging in recurrent glioblastoma (GBM) where most patients are not eligible for second-line surgery. Because very little is known on the consistency of marker/target expression along the clinical course we here explored common drug targets in paired primary vs. recurrent tumor tissue samples.

Material and Methods: Paired tumor samples were used from a homogeneously pretreated cohort of 34 GBM patients. All patients received radiotherapy and temozolomide chemotherapy. Verification of common drug targets included immunohistological analysis of PDGFR-β, FGFR-2, FGFR-3, VEGFR-3, and mTOR-pathway (phospho-mTORSer2448) components as well as molecular MLPA-based analysis of copy number aberrations at the gene loci of PDGFR-α, ALK, MET, EGFR, VEGFR-2/KDR, and FGFR1.

Results:

Paired tumor tissue exhibited dissimilar expression status in 9 of the 11 investigated targets (82%). Two targets (FGFR-1 and VEGFR-3) were assessed as “unchanged”, since dissimilar expression was observed in only one paired tumor tissue. The discordance rate between primary and recurrent tissue depended on the investigated target and varied between 18-56% in our cohort of GBM patients.

Discussion: The high incidence of dissimilar target expression status in primary vs. recurrent disease suggests clinically relevant heterogeneity along the course of disease. Molecular target expression, as determined at primary resection, may not necessarily present rational treatment clues for the care of recurrent GBM. Further studies need to analyze the therapeutic impact of longitudinal heterogeneity in GBM.


Division of Clinical Neurooncology, Dep. of Neurology/ DKTK Division Translational Neurooncology


P55



Identification of novel metastasis-modulating factors in non-small-cell lung cancer

S. Nothdurft, F. Breitenbücher, R.A. Okimoto, A. Schramm, B.M. Grüner, S. Kalmbach, M. Schuler

Introduction: Lung cancer is the leading cause of cancer-related deaths worldwide. Approximately 85% of lung cancer patients are diagnosed with non-small-cell lung cancer (NSCLC). The majority of patients is diagnosed in advanced NSCLC stages with metastatic progression associated with poor clinical outcome. Current therapies aiming to reduce the risk of NSCLC metastasis include cisplatin-based adjuvant chemotherapy and radiation, both showing only moderate effects in terms of reducing the risk of metastatic relapse and increasing survival. Hence, there is a high need for novel therapies.

Materials and Methods: In order to identify new potential therapeutic targets, we performed a functional in vivo shRNA screen in an orthotopic NSCLC mouse model. Primary tumors and metastases were retrieved and subjected to massively parallel sequencing in order to identify expression levels of barcoded shRNAs. Expression of selected shRNAs in the NSCLC cell line NCI-H1975 allowed for in vitro assessment of altered invasive and migratory capacity as a surrogate marker of metastatic potential.

Results: Specific shRNA clones that were differentially represented between primaries and metastases were found to modulate invasive and migratory capacity of H1975 cells in vitro. Promising candidate genes were included in in vivo validation experiments in an orthotopic mouse model. The shRNA-mediated suppression of one target gene was confirmed to have metastasis modulating properties in vivo.

Conclusion: Using an unbiased functional approach, we were able to identify putative modulators of the metastatic process in NSCLC. The clinical relevance is to be determined by correlation studies in cohorts of patient with resected NSCLC from our institutional biobank.

For further information please contact: Silke Nothdurft ([email protected])

Department of Internal Medicine (tumor research)


P56



Influence of Trametinib on Tumor-Associated Macrophages in Pancreatic Ductal Adenocarcinoma

Neander, Christian; Cheung, Phyllis Fung-Yi ; Siveke, Jens T.

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is the fourth deadliest form of cancer and because of its insufficient reaction to conventional therapies there is an urgent need for identifying new therapeutic targets. It was shown that PDAC is not only characterized by an oncogenic KRAS mutation but also by a tremendous immune cell infiltration, with tumor associated macrophages (TAMs) frequently occurring, which are correlated to poor prognosis, due to their immunosuppressive capacity. Until now, little is known about the influence of MEK inhibitors onto the tumor microenvironment and especially onto the immune landscape. Therefore, we want to investigate whether there are alterations in immune cell composition upon MEK inhibitor treatment. Subsequent experiments will be conducted to investigate how potential changes in the immune profile influence the response to PDAC treatment and how these alterations might lead to treatment failure. Materials and Methods: To confirm macrophage polarization states, we use a panel of techniques, including FACS and qPCR. Furthermore, we measure cell metabolism with mitochondrial stress tests and we perform cytokine profiling. After confirmation of different polarization states, we want to test whether, and if so, how MEK inhibitors change the polarization state by the above mentioned techniques. Following in vitro experiments, we want to focus on how MEK inhibitors change immune cell composition in the tumor microenvironment in vivo by immunhistochemistry and flow cytometry.

Results: Gene set enrichment analysis confirmed downregulation of anti-inflammatory macrophages after MEKi treatment, which was validated by immunohistochemistry and nanostring analysis. Furthermore, macrophage polarization towards a pro- and anti-inflammatory phenotype was confirmed by qRT-PCR as well as by flow cytometry and on metabolic basis by measuring cellular mitochondrial respiration.

Conclusion: MEKi treatment downregulates M2 macrophages in PDAC and different macrophage phenotype-specific gene and protein expression pattern are confirmed on gene, protein as well as metabolic basis

For further information please contact: Christian Neander ([email protected])


1st Floor Poster Nbr.

P57



Identification of compounds inducing differentiation in solid tumors using a novel cell-based screening system.

Knud Esser; Andrea Kulik; Dieter Niederacher; Hans Neubauer; Tanja Fehm

Introduction: Targeting tumor specific differentiation blocks by activating cellular differentiation programs is a promising strategy for tumor treatment. Differentiating agents are supposed to potently reduce solid cancer cell tumorigenicity and to render cells more prone to common therapies. However, the pathophysiological mechanisms leading to maturation arrest in solid tumors are only poorly understood hampering development of targeted drugs.

Materials and Methods: We developed a cell-based phenotypic high-throughput screening system which allows the identification of potential differentiation inducing agents via the quantification of two innovative differentiation markers. MDA-MB-231 and A549 cells were used as in vitro models for early and late differentiation arrest, respectively. Differentiation-inducing potency of the identified substances was validated by quantifying the expression of characterized differentiation markers by qRT-PCR analysis and analyzed by immunofluorescence microscopy.

Results: Testing a databank of over one-thousand pharmacologically active compounds identified ten substances as possible hit-candidates. Validation experiments confirmed two hit-to-lead candidates with a high differentiation-inducing potential in each tumor model. All candidates showed no significant toxic effect in a preclinical toxicity test in primary human hepatocytes.

Conclusion: We have successfully revealed a so far undescribed differentiating effect for two different substance classes in MDA-MB-231 and A549 cancer cell lines. Further studies will be performed to investigate the compounds’ molecular mechanisms of action and their potential suitability for anti-tumor drug development.

For further information please contact: Knud Kess ([email protected])



P58



CLINICAL STUDIES

Onset and progression of bone metastases in neuroendocrine tumors

Lahner H, Sancar E, Poeppel TD, Herrmann K, Theysohn J, Unger N, Fuhrer D

Introduction: Frequency and course of bone metastases (BM) in neuroendocrine tumours (NET) are virtually unknown. At initial diagnosis, more than 50% of NET patients present with distant metastases, predominantly found in the liver and/or lymph nodes. In contrast, BM are reported in <15% of cases. However, the true prevalence of BM is probably underestimated, since the reported figures are based on heterogeneous examination methods. Furthermore, knowledge concerning their clinical or prognostic relevance is rare.

Materials and Methods: Between 2010 and 2017, 566 patients treated in the European Neuroendocrine Tumor Society (ENETS) center in Essen were analyzed in terms of occurrence and clinical course of BM using our NET database and hybrid imaging with 68Ga-DOTATOC PET/CT, the most sensitive detection method.

Results: BM became manifest in 156/566 patients (27.6%). Of these, 106 patients (67.9%) presented with detectable BM at initial examination, while 50 patients (32.1%) developed BM during follow-up. Mean age of patients at NET diagnosis was 57.5 years (range, 13.0–88.0), at initial diagnosis of BM 62.5 years (range, 19.0–89.0). 48.4% had G1, 44.5% G2 and 7.1% G3 neoplasms. Within the observation period, 65/156 patients (41.7%) with BM died whereas 40/410 patients (9.8%) without BM died.

Conclusion: The presence of BM is of high prognostic and clinical relevance. The frequency of BM in NET is substantially higher than previously reported.

For further information please contact: Harald Lahner ([email protected])



P59


MOLECULARLY TARGETED THERAPY CLINICAL STUDIES

Impact of STZ based chemotherapy versus targeted therapy for outcome of pancreatic neuroendocrine tumors


Introduction: The role of streptozotocin-based chemotherapy (STZ CTx) in advanced, differentiated pancreatic neuroendocrine tumors (pNET) is a subject of controversial discussion. Objective response rates (ORR) range from 6-69%. In 2010 and 2011 competing targeted therapies were approved. However, the best sequence of treatment in advanced pNET remains unclear. We aimed to evaluate the efficacy of STZ CTx in a large pNET cohort.

Materials and Methods: Data from 49 pNET patients treated with STZ CTx in our centre between 2010 and 2017 were analysed retrospectively. Endpoints of the study were ORR, time to tumor progression (TTP) and overall survival (OS).

Results: Mean age of patients at the start of chemotherapy was 58.1 years (range, 27.2–82.1). STZ CTx was the 1st line treatment in 51.0%. 4.1% had G1, 93.9% G2 and 2.0% G3 neoplasms. Baseline progression was evident in all patients prior to start of treatment. Objective response rate was 36.7%. Other 36.7% of patients showed stable disease as best response while 26.6% showed progressive disease. Treatment was discontinued due to toxicity in 1 patient. Median TTP and OS were 12.0 (95% confidence interval (CI), 7.7–14.1) and 22.0 months (95% CI, 17.1–26.9), respectively.

Conclusion: Treatment with STZ CTx was associated with considerable ORR and reasonable TTP. These findings along with excellent tolerability strengthen the value of this regimen for the management of unresectable pNET.




P60


MOLECULARLY TARGETED THERAPY CLINICAL STUDIES

Everolimus in Neuroendocrine Tumors of the Gastrointestinal Tract and Unknown Primary


Introduction: The RADIANT-4 randomized phase 3 study has previously demonstrated significant prolongation of median progression-free survival (PFS) with everolimus compared to placebo in patients with advanced, progressive, nonfunctional gastrointestinal (GI) and lung neuroendocrine tumors (NET). The present analysis specifically evaluated response in NET patients with GI tumours and NET of unknown primary origin.

Materials and Methods: Patients in the RADIANT-4 trial were randomized 2: 1 to everolimus 10 mg/day or placebo. The effect of everolimus on PFS was evaluated in patients with NET of the GI tract or unknown primary site.

Results: Of the 302 patients enrolled, 175 had GI NET (everolimus, 118; placebo, 57) and 36 had unknown primary (everolimus, 23; placebo, 13). In the GI subset, the median PFS by central review was 13.1 months (95% CI 9.2–17.3) in the everolimus arm versus 5.4 months (95% CI 3.6–9.3) in the placebo arm; the hazard ratio (HR) was 0.56 (95% CI 0.37–0.84). In the unknown primary NET patients, the median PFS was 13.6 months (95% CI 4.1–not evaluable) for everolimus versus 7.5 months (95% CI 1.9–18.5) for placebo; the HR was 0.60 (95% CI 0.24–1.51). Everolimus efficacy was also demonstrated in both midgut and non-midgut NET tumours; a 40–46% reduction in the risk of progression or death was reported for patients in the combined GI and unknown primary NET subgroup.

Conclusion: Everolimus showed a PFS benefit in patients with advanced progressive nonfunctional NET of GI and unknown primary.



1st Floor Poster Nbr. P61



PRECLINICAL MODELS

Epigenetic modulation of cell metabolism and its effects on cell survival in melanoma

Felix Vogel, Heike Chauvistré, Batool Shannan, Anna Hoewner, Natalie Bordag, Elmar Zügner, Christoph Magnes, Antje Sucker, Dirk Schadendorf, Alexander Roesch

Introduction: Melanoma is an aggressive tumor with a median survival of only 6-12 month after occurrence of metastasis. In detail, one key factor of drug resistance mechanism in melanoma pathogenesis is cell heterogeneity. A defined cell subpopulation of slow cycling cells marked by a high histone demethylase JARID1B expression are therapy resistant and are most likely responsible for tumor repopulation. Moreover, cells with a slow cycling phenotype are described to modulate metabolism under targeted therapy. Therefore, the aim of my thesis is to characterize metabolic ‘hubs’ within metabolic landscaping analysis of melanoma cells.

Materials and Methods: We induced JARID1Blow and JARID1Bhigh phenotypes in WM3734 melanoma cells via shRNA-mediated knockdown and Doxycyclin-inducible Tet3G-Overexpression and prepared for a subpopulation-specific LC/MS based metabolomics landscaping analysis.

Results: JARID1Bhigh expressing melanoma cells show upregulated metabolites of glutathione-redox-system and pentose phosphate pathway. Moreover, several upregulated metabolites in JARID1Bhigh melanoma cells confirm existing data stating that those tumor cells do not follow the Warburg effect, but rather depend on mitochondrial OXPHOS to gain ATP and maintain a multi-resistant phenotype.

Conclusion: Our present metabolic landscaping analysis unraveled heterogeneous metabolic profiles in melanoma pointing to a possible relevance for therapy resistance of distinct melanoma cell subpopulations. In detail, we could profile the metabolome of multi-drug resistant JARID1Bhigh melanoma cells including their underlying enzymatic hubs. To overcome drug resistance in future, such hubs could be either directly targeted or indirectly by inhibiting their epigenetic regulators.

For further information please contact: Felix Vogel ([email protected])



P62


CANCER IMMUNOTHERAPY EX VIVO STUDIES / CORRELATIVE

SCIENCE

Processing escapes, a new resistance mechanism in immune therapy

M. Wessolly, J. Schmeller, E. Mairinger, S. Borchert, J. Kollmeier, T. Hager, T. Mairinger,D.C. Christoph, R.F.H. Walter, W.E.E. Eberhardt, T. Plones, J. Wohlschlager, K.W.Schmid, A. Bankfalvi, F.D. Mairinger

Introduction: Perhaps the most sophisticated approach in modern cancer therapy is immune checkpoint inhibition. Most renowned for usage in clinical trials are αCTLA-4 and αPD-1/PDL-1 antibodies. However, 60% of tumours acquire resistances during treatment. We propose the novel concept of “processing escapes” as one possible explanation.

Materials and Methods: 300 whole exome sequencing data of patients diagnosed with neuroendocrine lung cancers (NELCs) and lung adenocarcinomas, were examined for occurrence of potential “processing escape”-variants. We utilized prediction models for proteasomal cleavage, subsequently followed by survival analysis and regression models to verify the clinicopathological impact of such variants. In addition, mRNA expression data of distinct immune factors were correlated to the amount of escape variants.

Results: Alternative processing of epitopes is a common event within the investigated tumour specimens, independent of the tumour grading. High amounts of escape variants were significantly associated with downregulation of Granzyme K, CD40L and CD20. Regression models revealed a significantly compromised overall survival of patients, while “processing escapes” were present.

Conclusion: Based on this collective, “processing escapes” may be a potent marker for failure of immune checkpoint inhibition. After necessary improvements, this approach can be used to select patients with possible immune therapy resistance and provide them with an alternative therapy.

For further information please contact: Michael Wessolly ([email protected])



P63



Multiplexed in vivo small molecule screening for immediate drug repositioning reveals novel therapeutic targets in metastatic pancreatic

cancer

Madeleine Dorsch, Christopher J. Schulze, Dian Yang, Alexander Schramm, Martin Schuler, Jens T. Siveke, Matthew Bogyo, Monte M. Winslow, & Barbara M. Grüner

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease in which early occurring metastasis and its consequences to the patient are the primary cause of cancer deaths. Aim of this study is to apply a newly established multiplexed in vivo screening platform to screen two libraries for inhibitors of metastatic seeding in PDAC to identify novel therapeutic targets in an immediate drug repositioning approach.

Materials and Methods: We applied a multiplexed small molecule in vivo screening platform for identifying novel regulators of PDAC metastatic seeding in immunocompetent mice. This approach integrates molecular cell barcoding, in vitro compound pretreatment and in vivo selection to allow multiplexed compound screening in mice.

Results: Using the established platform, we screened the library of FDA approved inhibitors as well as the ICCB library of Known Bioactive compounds. The initial screen and dose-dependent secondary screen identified 5 top compounds with a specific yet so far unknown effect on metastatic seeding in vivo. Complementary in vitro assays confirmed their minor effects on overall tumor cell viability.

Conclusion: We identified 5 top compounds that reduce PDAC metastatic seeding by using the multiplexed small molecule in vivo screening platform. We performed various standard in vitro assays to characterize these compounds in PDAC. Now, we will validate the top five compounds in vivo for their application in treatment of metastatic PDAC.

For further information please contact: Madeleine Dorsch ([email protected])

Department of Medical Oncology


P64



CLINICAL STUDIES

Presentation of acute coronary syndromes in cancer patients

S. Mrotzek, R. Ludwig, T. Rassaf, M. Totzeck

Introduction: The risk for cardiovascular diseases increases significantly in patients undergoing chemotherapy or radiation. The development of an acute coronary syndrome (ACS) including the relevance of cardiac enzymes (e.g., troponin) during tumor-therapy is incompletely characterized.

Materials and Methods: A retrospective, descriptive data analysis of patients, which were hospitalized in West German Cancer Center between 2012 and 2017 sustaining an ACS during cancer treatment followed by cardiac catheter examination, was performed. We conducted statistical analyses of patient characteristics including cancer types, concurrent therapy, previous treatments, medication and the individual patient’s medical history.

Results: The correlation of troponin-positive ACS (STEMI, non-STEMI) with the results of cardiac catheter examination showed that in most patients a significant coronary lesion requiring intervention could be found. Overall in all ACS patients (STEMI, non-STEMI, unstable angina), in 25% of the patients no relevant coronary lesion was detectable, which is comparable to a non-cancer patient cohort. Remarkably, in 48% of the patients having received mediastinal radiation and in 66% of the patients following anthracycline-based chemotherapy did not require coronary-intervention despite of ECG-changes, troponin-elevation or typical symptoms.

Conclusion: Cancer patients on treatment have a higher risk for ACS, especially patients receiving drugs with know cardiotoxicity or mediastinal radiation. An elevated troponin could be less sensitive due to additional myocardial injury caused by the therapy. Nevertheless overall, an ACS in cancer patients correlates with significant coronary lesions in almost the same manner than expected in non-cancer patient and should be followed by diagnostic clarification.

For further information please contact: Simone Mrotzek ([email protected])

Westdeutsches Herz- und Gefaßzentrum, Klinik fur Kardiologie und Angiologie, Universitatsklinikum Essen


P65



A comparative analysis of merkel cell carcinoma cell lines by means of differential methylation

Jan Gravemeyer

Introduction: Merkel cell carcinoma (MCC) is an aggressive skin cancer – recent results suggest that it is also a very heterogenous skin cancer. While in most cases MCC carcinogenesis is associated with the clonal integration of the Merkel cell polyomavirus (MCPyV), in a subgroup of MCCs a UVcarcinogenesis is assumed. Yet another dichotomy in MCCs is based on the growth characteristics of MCC cell lines. While classical MCC cell lines show a neuroendocrine growth pattern i.e. in suspension as spheroids, variant MCC cell lines grow as adherent cells. To scrutinize the bases of these differences, we compared the methylation pattern of the variant MCC cell lines MCC13, MCC26 and UISO (all MCPyV-) to nine classical MCC cell lines (7x MCPyV+, 2x MCPyV-).

Materials and Methods: Methylation analyses was performed using the Illumina infinium EPIC bead chip covering over 850 000 methylation sites. This offers a single base resolution and probes CpG sites in promoter regions, shelfs, shores, enhancers as well as gene bodies. The bioinformatic analysis was carried out by following the cross-package workflow of Maksimovic et al., in R [1]. This includes the Rpackages for array analysis “minfi” and “limma”.

Results: Using unsupervised clustering and multi-dimensional scaling plots, we demonstrate, that variant MCC cell lines cluster closer to SCC than to classical MCC cell lines. In accordance, the number of unique differentially methylated CpG sites between classical MCCs vs. SCCs and variant MCCs vs. SCCs this more than 350 fold higher. A gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment of genes associated with differentially methylated CpGs, revealed an over-presentation of adhesion related ontologies and pathways, when comparing classical to variant MCC lines.

Conclusion: Our findings suggest that, variant MCC cell lines are closer related to SCC than classical MCC cell lines. Thus, their differences in growth pattern are mirrored in the epigenetic landscape.

For further information please contact: Jan Gravemeyer ([email protected]) DKTK Translational Skin Cancer Research


P66



CLINICAL STUDIES

CTCEndo: Endocrine Resistance in breast cancer circulating tumor cells

Hans Neubauer, Dieter Niederacher, Michael Pawlak, Wolfgang Janni, Tanja Fehm, for the DETECT study group

The overcoming of therapeutic resistances in the treatment of metastatic breast cancer (MBC) is of utmost importance. So far, therapeutic decisions in the metastatic situation are often based on characteristics of the primary tumor. Beside the prognostic value of circulating tumor cells (CTCs) which has been shown in several trials their predictive value is currently under investigation. The DETECT studies aim to evaluate their impact on therapeutic decisions in patients with MBC. Associated with this network of studies are several translational research projects consolidated in the translational oncology collaboration “DETECT-CTC”. One of the consolidated subprojects will be presented in the following. Several mechanisms have been described in resistance to endocrine therapy (ET) such as lower levels and heterogeneity of estrogen receptor (ER) expression, ER-independent signaling including the PI3K/AKT/mTOR pathway, as well as stem cells and epithelial-mesenchymal-transition. In single CTCs, the importance of such mechanisms has not been investigated systematically so far. The innovative aspect of CTCEndo is to characterize EpCAMpos and EpCAMneg CTCs isolated from MBC patients treated within the DETECT trials with ET at genome, transcriptome and at protein level by reverse phase protein arrays for mechanisms rendering them ET-resistant. The major aims are to detect resistance mechanisms activated in CTCs in order to develop an optimized CTC-based ET approach and to validate the predictive capacity of the suggested assays with defined clinical samples.

For further information please contact: Hans Neubauer ([email protected])



P67



Role of GFI1 in Acute myeloid leukemia (AML) and the functional role in metabolic regulation

Pradeep Kumar Patnana, Aniththa Thivakaran, Judith Hönes, SymoneVitoriano da Conceição Castro, Yahya Al-Matary, Klaus Lennartz, Renata Köster, Marina Suslo, Bernd Giebel, Ulrich Dührsen, and Cyrus Khandanpour

Introduction: Acute Myeloid Leukemia is a myeloproliferative disorder with abnormal accumulation of immature myeloblast cells in blood and bone marrow. Growth Factor Independence 1 (GFI1) is a transcriptional repressor that regulates the hematopoietic progression and its expression levels regulates AML development. Earlier data from human samples shows gradient expression of GFI1 influences the AML progression and survival. In the current study, we increased the expression of GFI1 in various human leukemic cell lines and observed increased differentiation potential. Furthermore, genome expression study in the over expressed cells shows altered metabolism such as increased oxidative phosphorylation and Reactive Oxygen Species pathways. In addition, we also observed increase in rate of oxidative phosphorylation and reduced glycolysis in GFI1 overexpressed human leukemic cells. The functional role of GFI1 in leukemic cells metabolism further need to be identified. Materials and Methods: We have used Real-Time PCR and western blot to measure the gene and protein expression levels respectively. To identify the differentiation potential, we have performed methyl cellulose colony forming (CFC) assay. To check the whole genome expression profile, we have performed microarray (Clariom S). For studying the influence of GFI1 in metabolism, Oxygen Consumption Rate (OCR) and Extracellular Acidification rate (ECAR) was measured with mitostress sea horse experiment. Results: Earlier data from patient cohort studies shows low expression of GFI1 is associated with poor prognosis. Mice that received MLL-AF9-transduced GFI1-KD cells succumbed much faster to leukemia than mice transplanted with MLL-AF9-transduced GFI1-KI cells. Loss of one Gfi1 allele increased the incidence and shortened the latency of AML development compared to Gfi1-WT NUP98-HOXD13-tg animals. We observed, increased expression of GFI1 in various AML cell line models shows increased differentiation potential in both liquid culture and semi-solid medium. Genome array in the GFI1 overexpressed cell lines shows upreguation of oxidative phosphorylation, ROS and electron transport chain (ETC) pathways. To further identify the influence of GFI1 in leukemic cells metabolism, we have performed sea horse mitostress assay. Sea horse analysis shows, increased OCR and reduced ECAR in GFI1 over expressed cells which represents increased oxidative phosphorylation and reduced glycolysis.

Conclusion:

- Overexpression of GFI1 promotes differentiation and inhibits proliferation of human leukemic cells.

- GFI1 regulates leukemic cells metabolism. - The functional role of overexpressed GFI1 in leukemic cells metabolism to be

observedfurther in leukemic mice models.

For further information please contact: Pradeep Kumar Patnana ([email protected])


2nd Floor Poster Nbr.

P68



Application of unaltered and genetically modified natural killer (NK) cells for cancer therapy

Shakhlo Muminova, Cathrin Ritter, Anita Melior, Winfried Wels, Achim Temme, Matthias Theobald, Michael Bachmann, Torsten Tonn, Jürgen C. Becker

Natural killer (NK) cells are key players for innate host immune response against virally infected and neoplastic transformed cells. NK cells can directly exert cytolytic activity against altered and stressed cells, which makes them potential candidates for cancer immunotherapy. In order to direct NK cell specificity towards cancer cells, they can be genetically modified to express a universal linker able to bind recombinant antigen binding moieties of a desired specifity; the latter being termed universal epitope-specific chemiric antigen receptor (uniCAR). Binding moieties can be both single chain antibodies and T cell receptors. In the proposed project, the activity of uniCARs together with different antigen binding moieties will be compared to unaltered NK cells derived from peripheral blood lymphocytes (PBLs) of healthy donors. Focusing on immunogenic skin cancers characterized by loss of MHC class I molecules, antitumor activity of uniCAR and unaltered NK cells will be analyzed. As a first step, cytoxicity of uniCARs and NK cells against melanoma and Merkel cell carcinoma cells will be evaluated in 2D and 3D cultures. Subsequently, a preclinical in vivo model based on xenotransplants in the chicken chorioallantoic membrane (CAM) model will be used. This model does not only allow to test homing, tumor infiltration and cytolytic activity of NK cells at fixed time points but also to monitor these activities in a real time by intra vital microscopy. For these experiments fluorescent labeled tumor and NK cell lines will be used. In conclusion, this study will provide the basis for early phase clinical trials and, more generally, it will employ a pipeline for a good manufacturing practice (GMP) production of cellular therapeutics in cancer immunotherapy.

For further information please contact: Shakhlo Muminova ([email protected]) DKTK Translational Skin Cancer Research


P69



CTCs from Leukapheresis Products Can Be Isolated by Parsortix System for Subsequent Culture

André Franken, Christiane Driemel, Bianca Behrens, Florian Reinhardt, Rita Lampignano, Dieter Niederacher, Nikolas H. Stoecklein, Johannes C. Fischer, Tanja Fehm, Hans Neubauer

Introduction: Solid tumors are releasing circulating tumor cells (CTCs) into the circulatory system. Especially viable CTCs can be of high interest to gain therapeutically relevant information. However, their extremely low frequency is one main limiting factors to obtain CTCs for functional studies. To overcome this challenge we tested to isolate viable CTCs from diagnostic leukapheresis (DLA) products.

Materials and Methods: 18 DLA samples and matched peripheral blood (PB) samples of metastasized breast cancer patients were collected and CTC numbers were determined with CellSearch. Viable cells were enriched with Parsortix. Initially, Parsortix was adapted with cells from MCF7 cell line spiked in DLA products. Enrichment efficiency of CTCs from DLA product with Parsortix was compared to CellSearch. Subsequently, enriched CTCs were cultured.

Results: CTCs were detected in 12 PB and matched DLA samples and in 3 more DLA samples whose corresponding PB samples were CTC negative. CTC number per ml was increased by an average of 17.0x. 46,2% of spiked cells were successfully enriched from DLA product with Parsortix. 20% to 30% of CTCs could be enriched from different patient samples compared to CellSearch. One sample containing many EpCAMlow CTCs exceeded CTC numbers of CellSearch by 4x. We could grow viable CTCs from 3 out of 11 CTC positive DLA samples.

Conclusion: DLA provides greater numbers of viable CTCs which can be enriched with Parsortix in order to enable their in vitro cultivation. This workflow will allow future functional studies.

For further information please contact: André Franken ([email protected])



P70



CORRELATIVE SCIENCE

Identification of novel therapeutic targets in Ewing sarcoma utilizing innovative pooled screening approach in a tumorcell-specific

environment.

Schaefer C, Mallela N, Seggewiß J, , Korsching E, Grünewald T, Dirksen U, Potratz J

Introduction: Ewing sarcomas (ES) are high risk sarcomas of bone and mostly affect children and young adults. ES is defined by characteristic genetic alterations that lead to oncogenic transcription factors, EWS-FLI1 in most cases. Successfully targeting of EWS-FLI1 in clinical approaches remains abortive. Therefore, identification of EWS-FLI1 cooperating pathways, which contribute to the EWS-FLI1-induced tumor transformation, serves as novel potential targets. To identify such target pathways, we established a pooled EWS-FLI1-synthetic lethal shRNA screening approach.

Materials and Methods: 709 human protein kinases targeted by 4.675 distinct shRNAmir constructs (Decode Pooled Lentiviral shRNA Screening Library) were screened in a phenotype related cell model. Populations will be selected for positive transduction and integrated shRNA identified and analyzed via Next-Generation Sequencing. shRNAs that are depleted from the target cell population serves as potential targets.

Results: We could identify BUB1B as a potential target structure in Ewing sarcoma and CDK4, which is already published as ES-transcriptional target and confirmed our screen data. First functional approaches show that depletion of BUB1B in ES leads to a slightly decreased proliferation, but nearly abolished potential to form colonies in soft agar assay. Additionally findings show first evidence that the EWS-FLI1 transcriptional target FOXM1 has a critical role in BUB1B regulation.

Conclusion: We identified BUB1B with a putative EWS-FLI1, FOXM1 connection. Further understanding of BUB1B and the corresponding function in ES could expand the development of novel therapeutic strategies in this disease. Therefore we like to inhibit FOXM1 expression in EWS-FLI1 –on/ off system.

For further information please contact: Christiane Schaefer ([email protected])

Department of Pediatrics III, Hematology-Oncology


P71


EXPLOITATION OF ONCOGENIC MECHANISMS CLINICAL STUDIES

A 6 bp in frame germline deletion in exon 7 of RET leads to increased RET

phosphorylation, ERK activation and MEN2A

Kohler H, Hoenes GS, Latteyer S, Synoracki S, Schulte JH, Liao XH, Refetoff S, Schmid KW, Führer D, Möller LC

Introduction: Multiple endocrine neoplasia (MEN) 2 is usually caused by missense mutations in the proto-oncogene RET. We aimed to determine the mutation underlying MEN2A in a female patient diagnosed with bilateral pheochromocytoma and with medullary thyroid carcinoma (MTC). Material and Methods: Exome and Sanger sequencing from leukocyte DNA. Wild-type RET and mutants were expressed in HEK293 cells. Activation of MAPK/ERK and PI3K was analyzed by Western blotting and luciferase assays. The effect of RET mutants on cell proliferation was tested in a colony forming assay.

Results: Exome sequencing revealed a 6 nucleotide/2 amino acid in-frame deletion in exon 7 of RET (p.505_506del). In vitro expression showed that phosphorylation of the crucial tyrosine 905 was much stronger in the RET mutant compared to wild type RET, indicating ligand-independent autophosphorylation. Furthermore, the p.505_506del RET mutant induced a strong activation of the MAPK/ERK and the PI3K pathways. Finally, the p.505_506del RET mutant cells increased HEK293 colony formation fourfold compared to wild-type RET.

Conclusion: Exome sequencing revealed a 6 bp deletion in exon 7 of RET, an exon not yet associated with MEN2. Increased ligand-independent phosphorylation of the p.505_506del RET mutant, increased activation of downstream pathways and stimulation of cell proliferation demonstrated the pathogenic nature of the mutation. We, therefore, recommend screening the whole sequence of RET in MTC and pheochromocytoma patients.

For further information please contact: Lars Möller ([email protected])



P72



ALK activation promotes an aggressive thyroid carcinoma in mice, resembling human poorly differentiated carcinoma (PDTC)


Introduction: Radioiodine refractory dedifferentiated thyroid cancer is a major clinical challenge. The anaplastic lymphoma kinase (ALK) has been suggested to promote thyroid carcinogenesis. To determine the oncogenic role of ALK in thyroid carcinogenesis, we developed a mouse model for thyrocyte-specific expression of a constitutively active ALK mutation (ALKF1174L). Material and Methods: Thyrocyte-specific expression of ALKF1174L was achieved by crossing lox-stoplox- ALKF1174L mice with mice expressing tamoxifen-inducible Cre recombinase driven by the thyroglobulin promoter.

Results: ALKF1174L mice developed massively enlarged thyroids with an early loss of normal follicular architecture. Dedifferentiation was confirmed by a significant decrease in thyroglobulin and Nkx2-1 expression. Histologically, the mice developed a carcinoma resembling human poorly differentiated thyroid cancer (PDTC). The tumors showed extrathyroidal extension into the surrounding muscles and developed lung metastases. Survival of ALKF1174L mice was significantly reduced to 5 months after tamoxifen injection.

Conclusion: We demonstrate that thyroid-specific ALKF1174L expression leads to development of aggressive metastasizing thyroid cancer resembling human PDTC. This single gene approach identified ALKF1174L as a driver mutation of thyroid carcinogenesis. Therefore, these data open perspectives for targeted treatment of radioiodine-refractory thyroid cancer harboring activating mutations in the ALK gene.




P73



PRECLINICAL MODELS

Targeted next-generation sequencing for TP53, RAS, BRAF, ALK and NF1 mutations in anaplastic thyroid cancer


Introduction: Anaplastic thyroid carcinoma (ATC) is the most aggressive thyroid cancer with a median survival of 4-6 months. Identification of mutations contributing to aberrant activation of signaling cascades in ATC may provide novel opportunities for targeted therapy.

Material and Methods: Thirty-nine ATC samples were studied by next-generation sequencing (NGS) with an established gene panel. High quality readout was obtained in 30/39 ATC. Results: Twenty-eight ATC harbored a mutation in at least one of the studied genes. In 17/30 ATC (54 %) mutations were found in two or more genes. Twenty-one of the identified variants are listed in COSMIC as somatic mutations reported in other cancer entities. In three ATC samples no mutations were detected and none of the ATCs was positive for BRAFV600E. The most frequent mutations were found in TP53 (60 %), followed by NF1 (37 %). ALK mutations were detected in 20% of ATC and were more frequent than RAS or BRAF mutations. ATRX mutations were identified in 10% of the ATC samples. Conclusion: These sequencing data from 30 ATC samples demonstrate the accumulation of genetic alterations in ATC because in 90% of samples mutations were already found in the investigated nine genes alone. Mutations were found with high prevalence in established tumor suppressor and oncogenes in ATC, such as TP53 and H/K/NRAS, but also, although less frequent, in genes that may harbor the potential for targeted treatment in a subset of ATC patients, such as ALK and NF1.




P74



Thyroxine promotes tumor growth in an orthotopic lung cancer mouse model


Introduction: Thyroid hormones are important for physiology and homeostasis. Besides the nuclear thyroid hormone receptors, a plasma membrane protein, integrin αvβ3, acts as a receptor for both T3 and T4. Our hypothesis was that thyroid hormone signaling via avβ3 promotes tumor growth.

Material and Methods: To test this hypothesis, murine lung carcinoma cells (3LL), stably transfected with luciferase, were injected into mouse lungs. Mice then remained untreated or were rendered hypothyroid and treated with T3 or T4 with or without the αvβ3 inhibitor Tetrac. Tumor growth was determined by serial in vivo imaging of bioluminescence emitted from the injected luciferase expressing 3LL cells. Tumor weight and neoangiogenesis were determined at the end of the experiment.

Results: Tumor growth was reduced in hypothyroid mice and increased in T4 treated mice. Strikingly, only T4, but not T3, treatment promoted tumor growth. This T4 effect was completely abrogated by co-treatment with the αvβ3 inhibitor Tetrac. Tumor weight and neoangiogenesis were increased only in tumors of T4 treated mice. Again, the T4 effect was abolished by Tetrac.

Conclusion: We demonstrate that thyroid hormone promotes tumor growth in an orthotopic lung cancer mouse model. This tumor promoting effect includes increased neoangiogenesis and is exclusively mediated by T4 via the plasma membrane integrin avβ3. Such effects of T4 need to be considered in cancer patients on T4 substitution.




P75



Effects of pharmacological compounds in patient derived cell culture models

Svenja Mergener, Sven-T. Liffers, Jan Forster, Smiths Lueong, Björn Weißner, Ina Landel, Daniel Rauh, Stephan A. Hahn, Jens T. Siveke

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human cancers. The high degree of mutational heterogeneity between PDACs cannot be reflected by using well established tissue culture cell lines. To overcome this deficiency, new preclinical model systems that reflect the physiological status of the disease are needed. Patient-derived organoids are a model system, which holds promise to open the avenue to predict drug response in a personalized fashion and to monitor the individual development of PDAC to a certain degree.

Materials and Methods: This study focused on four cell lines derived from our molecularly characterized PDX-collection. The selected cell lines resembled the classical and quasimesenchymal subtype of PDAC. Here, we culture PDX-derived tumor cells both two- (2D) and three-dimensionally (3D) and compare the respective structures regarding morphology, RNA expression and responding to different metabolic and epigenetic inhibitors. The effect of the compounds was monitored by cell viability assays.

Results: All of the tested cell lines retain their ability to form organoids. There was a clear association between molecular subtype and degree of differentiation of the organoid model. With regard to the different treatment regimens we observed differences in the dose response between 2D and 3D culture conditions.

Conclusion: Our study underpins that our cell lines maintain their ability of organoid formation during the course of cultivation. Furthermore, we show that the vulnerability of the analyzed compounds display different efficacies depending on the chosen culture conditions.

For further information please contact: Svenja Mergener ([email protected];)



P76



Academic drug development in genomically well-defined cancer models using drug-screens and rational design approaches

Thomas Mühlenberg, Helena Katsioutou, Julia Ketzer, Joern Weisner, Jonas Lategahn, Marina Keul, Daniel Rauh, Sebastian Bauer

Introduction: Acquired resistance to kinase inhibitors is a common problem in modern targeted cancer therapy and creates the need for more potent and more specific in inhibitors. We have teamed up with the Dept. of Chemical Biology (TU Dortmund, D. Rauh) to co-develop improved kinase-inhibitors to overcome or prevent resistance.

Materials and Methods: A compound library screen for KIT-inhibitors in 384well format in GIST-T1-D816E vs. KIT-neg. GIST48B (internal GIST-specific negative control) was performed using an acoustic dispenser (ECHO 555). In addition, KIT-inhibitors with improved binding of KIT-D816 and -V654 mutations as well as novel covalent AKT- and EGFR-inhibitors were designed and synthesized. Cellular validation was performed by Cell Titer Glo and western blot.

Results: Screening the first 5K/35K compounds yielded 26 “hits”, showing differential activity in KIT-pos. vs. KIT-neg. cells. Hit compound “RSL28377” yielded IC50s in the sub-micromolar range in KIT pos. cell lines (D816E = 0.4μM, V654A = 0.6μM), and in GIST48B ~18μM. The most potent novel KIT-inhibitor displayed IC50s of 23nM - 141nM in KIT-pos. cells vs. ~2μM in GIST48B. Novel co-valent EGFRinhibitors were validated as potent, mutant specific, and able to overcome afatinib resistance. The allosteric covalent AKT-inhibitor “borussitinib” has been patented and is being tested in several cancer models in vivo.

Conclusion: Our compound screens using disease-specific negative controls yields 0.5% target-specific hit compounds for further characterization, chemical refinement and optimization. Newly synthesized KIT-, EGFR and AKT-inhibitors show promising activity in vitro and are being forwarded to in vivo testing. This collaboration underscores the potential of academic drug development especially in thecontext of rare molecular subtypes.

For further information please contact: Thomas Mühlenberg ([email protected])



P77



ABT263 overcomes hypoxia-mediated resistance to radiotherapy

Violetta Ritter, Franziska Krautter, Diana Klein, Verena Jendrossek, Justine Rudner

Introduction: Hypoxia, a characteristic of most human solid tumors, is a major factor driving malignant progression and limiting the cytotoxic action of chemo- and radiotherapy. While acute hypoxia reduces the damage induced radiotherapy, chronic intermitted hypoxia allows tumor cells to adapt to averse environmental conditions by increasing cell survial.

Materials and Methods: NCI-H460 lung adenocarcinoma cells were exposed to 25 cycle of severe hypoxia (0.2% oxygen) and reoxygenation to mimic chronic intermitted hypoxia. Gene expression analysis was performed to analyze the changes in hypoxia-selected (HS) NCI-H460 cells that were compared to non-selected (NS) cells. Results were confirmed by qRT-PCR and Western Blot analysis. Deregulated Bcl-2 Rheostat was targeted by Bcl-2/Bcl-xL inhibitor ABT263. Short-term survival and apoptosis induction in response to radiotherapy was measured by flow cytometry, while long-term survival was measured by colony formation assay. To analyze the effects of acute hypoxia on ABT263- and ionizing radiation (IR)-induced cytotoxicity, treatment occurred in severe hypoxia (0.2% oxygen). In addition, the effect of ABT263 and ionizing radiation on HS and NS cells was analyzed in a xenograft mouse model.

Results: Gene expression analysis revealed a deregulated Bcl-2 rheostat that increased resistance to radiotherapy. While ABT263 alone hardly induced cell death, it greatly enhanced IR-induced toxicity in tumor cells in short-term and long-term survival assays as well as in the xenograft mouse model.

Conclusion: The combination of systemically applied ABT263 and locally administered radiotherapy overcomes hypoxia-induced resistance to IR and improves cytotoxic response of tumor cells.

For further information please contact: Justine Rudner ([email protected])



P78



The Role of Gal-1 in modulating radioresistance of neuroblastoma cell lines

Katharina Batzke, Gabriele Büchel, Alexander Schramm

Introduction: We had previously identified up-regulation of Gal-1 in preclinical models of aggressive neuroblastoma (NB), the most common solid body tumour of childhood. However, the clinical and biological relevance of Gal-1 in this tumor entity remains unclear. Galectin-1 (Gal-1), a multifunctional protein, has been described to promote tumor growth by inducing angiogenesis, to contribute to tumor immune escape and to contribute to radioresistance.

Materials and Methods: Irradiation of different murine and human neuroblastoma cell lines was achieved using an X-ray source. Gal-1 expression was investigated via Western Blot and semi-quantitative RT-PCR. Cell viability was analysed via MTT-Assay and long term survival by colony formation assays on murine cell lines with different Gal-1 expression levels.

Results: In neuroblastoma cell lines, upregulation Gal-1 was induced by ionizing radiation as revealed by qPCR and Western Blot analyses. Downregulation of Gal-1 by Gal-1 specific shRNA in murine neuroblastoma cell lines significantly decreased cell viability upon high doses of ionizing radiation. However Gal-1 levels did not affect apoptosis or clonogenic cell survival upon IR.

Conclusion: These results are in line with a paracrine rather than an autocrine role of Gal-1 in modulating responses to radiotherapy. Interfering with Gal-1 functions in vivo will inform about of the Gal-1 axis in response to radiation and contribute to a better understanding of the complex tumour-host interaction during chemo- and radiotherapy of neuroblastoma.

For further information please contact: Katharina Batzke ([email protected])

Laboratory of Molecular Oncology, Department of Medical Oncology


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INDEX PRESENTERS AND POSTERS Adamczyk, Alexandra [email protected]

Ahmadov, Ulvi [email protected] Al-Matary, Yahya [email protected] Bartl, Jasmin [email protected] Batzke, Katharina [email protected] Bäumer, Christian [email protected] Scheffler, Björn [email protected] Blümel, Lena [email protected] Borchert, Sabrina [email protected] Bordbari, Sharareh [email protected] Bruderek, Kirsten [email protected] Carpinteiro, Alexander [email protected] Cima, Igor [email protected] Chauvistré, Heike [email protected] Dierichs, Laura [email protected] Dobersalske, Celia [email protected] Dorsch, Madeleine [email protected] Falkenhorst, Johanna [email protected] Farsijani, Navid [email protected] Fleischhauer, Katharina [email protected]

Frank, Daria [email protected] Franken, André [email protected] Frisch, Sabine [email protected] Glas, Martin [email protected] Göthert, Joachim [email protected] Gravemeyer, Jan [email protected] Grunewald, Susanne [email protected]

Hamacher, Rainer [email protected] Hanoun, Maher [email protected]

Hauer, Julia [email protected]

Hegedüs, Luca [email protected]

Herrmann, Ken [email protected] Hetkamp, Philipp [email protected] Hönes, Judith [email protected] Honisch, Ellen [email protected] Kahlert, Ulf [email protected] Kalmbach, Sophie [email protected] Kebir, Sied [email protected] Kess, Knud [email protected] Ketzer, Julia [email protected] Kitanovski, Simo [email protected]

Kumar Patnana, Pradeep [email protected] Lahner, Harald [email protected] Lampignano, Rita [email protected] Langini, Maike [email protected]

Leonardelli, Sonia [email protected]

Mairinger, Elena [email protected] Mairinger, Fabian [email protected] Naser, Eyad ; [email protected]; Marquardt, Viktoria [email protected] Matschke, Johann [email protected]

Mergener, Svenja [email protected];

mailto:[email protected]













mailto:[email protected];


INDEX PRESENTERS AND POSTERS Michel, Lars [email protected] Möller, Lars [email protected] Mrotzek, Simone [email protected] Mühlenberg, Thomas [email protected] Muminova, Shakhlo [email protected] Naskou, Johanna [email protected] Neander, Christian [email protected] Neubauer, Hans [email protected] Nothdurft, Silke [email protected] Pastille, Eva [email protected] Pauck, David [email protected] Picard, Daniel [email protected]

Piras-Straub, Katja [email protected]

Pylaeva, Ekaterina [email protected]

Qin, Nan [email protected] Reifenberger, Guido Reifenberger Reis, Henning [email protected]

Remke, Marc [email protected] Ritter, Cathrin [email protected]

Rudner, Justine [email protected]

Schaefer, Christiane [email protected] Scheffler, Björn [email protected] Schmeller, Jan [email protected] Schuler, Martin [email protected] Schulte, Marc [email protected] Schulze-Schleithoff, Stefanie [email protected]

Shannan, Batool [email protected] Si, Yu [email protected] Siveke, Jens [email protected] Spassova, Ivelina [email protected]

Stang, Andreas [email protected]

Stefanski, Anja [email protected] Stockhammer, Paul [email protected] Trajkovic-Arsic, Marija [email protected] Unger, Nicole [email protected] Varaljai, Renata [email protected]

Vogel, Felix [email protected] Weniger, Marc [email protected] Wessolly, Michael [email protected] Willibald, Marina [email protected] Zegar, Tim [email protected]

Zhao, Fang [email protected]












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