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Cancer Immunology andCancer Immunology andCancer Immunology and Cancer Immunology and ImmunotherapyImmunotherapyImmunotherapyImmunotherapy

-------- The battle between immune system and cancersThe battle between immune system and cancers

Dr Kevin Sun

Department of Molecular Medicine & Department of Molecular Medicine & PathologyPathology

Basic knowledge of cancerBasic knowledge of cancerBasic knowledge of cancerBasic knowledge of cancer

• What is Cancer?• How does cancer occur?• How many types of cancers?• How many types of cancers?• Current therapeutic strategies for cancers

Definitions of CancerDefinitions of Cancer

• Cancer consists of single clones or several• Cancer consists of single clones or several clones of cells that are capable of independent growth in the hostindependent growth in the host.

C ll i f h ll i• Cancer cells arise from host cells via neoplastic transformation or carcinogenesis.

• Physical, chemical and biological agents y , g gmay cause cancer. -- carcinogens

CarcinogensCarcinogensgg• Radiation: Ultraviolet light, sunshine; X-rays, g y

radioactive elements induce DNA damage and chromosome brakes.

• Chemical: smoke and tar, countless chemicals that damage DNA (mutagens).that damage DNA (mutagens).

• Oncogenic viruses: insert DNA or cDNA copies of viral oncogens into the genome of host targetof viral oncogens into the genome of host target cells.Hereditar certain oncogenes are inheritable• Hereditary: certain oncogenes are inheritable.

Neoplastic TransformationNeoplastic Transformation---- CarcinogenesisCarcinogenesis

• Activate growth regulatory genes: Growth factor receptors (erbA, -B, fims, neu); molecules of signal transduction (src, abl, ras); transcription factors (jun, fos ,myc)- referred to as oncogenes.

• Genes that inhibit growth: (p53 controls DNA repair d ll lif ti Rb)and cell proliferation; Rb)-suppressor oncogenes.

G th t l t t i b l 2 B Bid• Genes that regulate apoptosis: bcl-2, Bax, Bid.

Classification of cancerClassification of cancerClassification of cancerClassification of cancer• Carcinoma: epithelial origin involving the skin• Carcinoma: epithelial origin involving the skin,

mucous membranes, epithelial cells in glands• Sarcoma: cancer of connective tissue i e• Sarcoma: cancer of connective tissue, i.e.

liposarcoma, fibrosarcoma• Lymphoma: T cell B cell Hodgkin’s Burkitt’s• Lymphoma: T-cell, B-cell, Hodgkin s, Burkitt s

lymphomas; - solid tumors• Leukemia: disseminated tumors - lymphoid• Leukemia: disseminated tumors - lymphoid,

myeloid, acute and chronic

Current strategies to combatCurrent strategies to combatCurrent strategies to combat Current strategies to combat cancerscancers

M h i 1600BC• Mechanics -- surgery,1600BC• Physics -- radiotherapy,1896• Chemistry -- chemotherapy,1942• Biology -- immunotherapy 1976Biology immunotherapy,1976

Advantages of ImmunotherapyAdvantages of ImmunotherapyAdvantages of Immunotherapy Advantages of Immunotherapy for cancerfor cancer

• Cancer cells are immunogenicg• Single cell kill• Migrate to tissue• Migrate to tissue• Memory• Specific• Life-long protectionLife long protection

Cancer Immunology and Cancer Immunology and gygyImmunotherapyImmunotherapy

• How does the immune system eliminate cancer cells?

• How do cancer cells escape from Immunosurveilance?• How do cancer cells escape from Immunosurveilance?

• How can we help to win the battle between immune t d ? C i thsystem and cancers? – Cancer immunotherapy

• Examples

Cancer ImmunosurveilanceCancer ImmunosurveilanceCancer ImmunosurveilanceCancer ImmunosurveilanceTh h th i fi t d b Eh li h i• The hypothesis was first proposed by Ehrlich in 1909, and modified by Thomas and Burnet in 1957.1957.

• Immunosurveilance: the immunological resistance of the host against the development of gcancer.

• Now referred to “cancer immunoediting” encompassing 3 phases: elimination equilibriumencompassing 3 phases: elimination, equilibrium and escape.

Cells of the Immune System Bone graft

Macrophage

ErythrocytesEosinophil

Mast cell

Erythrocytes

Megakaryocyte

Basophil

Monocyte

Marrow

Hematopoieticstem cell

MegakaryocyteMonocyteBone

Multipotentialstem cell

Pl t l t

NeutrophilMyeloid

progenitor cell

Platelets

D d iti ll

Lymphoid progenitor cell

T lymphocyte Dendritic cell

Natural killer cellB lymphocyte

Army of the host to fight cancersArmy of the host to fight cancers

Antibody

Macrophage

Cancer cellHelper T cell

cytokine

chemokineNK cell

Cytotoxic T cellDendritic cell

Cytotoxic T cells (CTLs)Cytotoxic T cells (CTLs)Cytotoxic T cells (CTLs)Cytotoxic T cells (CTLs)CD8+ T cells: attaching to class I MHC -gpeptide complex, they destroy cancer cells by perforating the membrane withby perforating the membrane with enzymes or by triggering an apoptotic pathwaypathway.

Surface contact

Release of enzymes

Helper T cellsHelper T cellsHelper T cellsHelper T cells

CD4+ T cells: reacting to class II MHC-peptide complex, they secret cytokines.p p p , y y

cytotoxic T cell response (Th1 helper T cells) antibody response (Th2 helper T cells)antibody response (Th2 helper T cells)

Logistics force

Dendritic CellsDendritic CellsDendritic CellsDendritic CellsThe professional antigen-presenting cells In the fi l th f ti ti ï Tfinal common pathway for activating naïve T cells.

Dendritic cell

E l W i Ai ft

T cell

-- Early Warning Aircraft

A novel subset of dendritic cells [IFN-producing killer DC] (IKDC): TRAIL& perforin- tumor cell lysis; via T cell; IFNγ-angiogenesisp y ; ; γ g g

Other cellsOther cellsNK cells: after activation directly killing tumor cellNK cells: after activation, directly killing tumor cell

NKT cells: TRAIL/perforin- tumor cell lysis;

IFNγ-angiogenesis

Macrophages: antigen presentingMacrophages: antigen presenting

NK cell NKT cellM hMacrophage

CytokinesCytokinesCytokinesCytokines• Regulating the innate immune system: NK cells,

macrophages and neutrophils; and the adaptive immunemacrophages, and neutrophils; and the adaptive immune system: T and B cells

• IFN-α -- upregulating MHC class I tumor antigens andIFN α upregulating MHC class I, tumor antigens, and adhesion molecules; promoting activity of B and T cells, macrophages, and dendritic cells.

• IL-2 -- T cell growth factor that binds to a specific tripartite receptor on T cells.

• IL 12 promoting NK and T cell activity and a growth factor• IL-12 – promoting NK and T cell activity, and a growth factor for B cells

• GM-CSF (Granulocyte-monocyte colony stimulating factor) --G CS (G a u ocyte o ocyte co o y st u at g acto )reconstituting antigen-presenting cells.

Antibody Antibody -- produced by B cellsproduced by B cellsyy• Direct attack: blocking growth factor receptors, arresting

proliferation of tumor cells, or inducing apoptosis. -- is not usually sufficient to completely protect the body.

• Indirect attack: -- major protective efforts(1) ADCC (antibody-dependent cell mediated cytotoxicity ) ( ) ( y p y y )-- recruiting cells that have cytotoxicity, such as monocytes and macrophages.

(2) CDC (complement dependent cytotoxicity)(2) CDC (complement dependent cytotoxicity) -- binding to receptor, initiating the complement system, 'complement cascade’, resulting in a membrane attack complex causing cell lysis and deathcomplex, causing cell lysis and death.

Heavy chain

Light chain

Antigen-bindingregion

Light chain

-- missileAssembled antibody molecule

Constant region

Tumor elimination

How does cancer SingleHow does cancer

progress?Single cancer cell

progress?

Escape

Advanced cancer

Cancer Cancer I l /I thI l /I thImmunology/ImmunotherapyImmunology/Immunotherapy

• How does the immune system eliminate cancer cells?

• How do cancer cells escape from Immunosurveilance?• How do cancer cells escape from Immunosurveilance?

• How can we help to win the battle between immune t d ? C i thsystem and cancers? – Cancer immunotherapy

• Examples

Mechanisms of cancer escape from the Immunosurveilance

1 Alt i Th i Ch t i ti

the Immunosurveilance

1. Altering Their Characteristics : Loss/downregulation of MHC class I Down-regulation mutation or loss of tumor antigensDown regulation, mutation, or loss of tumor antigens Loss of costimulation

2. Suppressing the Immune Response : ineffective signals to CTLAlteration in cell death receptor signalingI i t kiImmunosuppressive cytokine

3. Outpacing the Immune Response: Tumour cells can simply proliferate so quickly that the immune p y p q yresponse is not fast enough to keep their growth in check

How cancer cells avoid How cancer cells avoid immunosurveillanceimmunosurveillance

1. Weapons from tumors

2 Defects of imm ne s stem2. Defects of immune system

(1) Loss/down(1) Loss/down--regulation of HLA regulation of HLA class I (MHC I)class I (MHC I)

• Total loss: β2 microglobulin mutation, alteration in antigen processing machinery

• Haplotype loss: LOH in chromosome 6• HLA allelic loss: mutations of HLA class I genesHLA allelic loss: mutations of HLA class I genes • HLA-A, B, C locus down-regulation: alteration of

transcriptional factorstranscriptional factors• Compound phenotype: 2 or more independent

h imechanisms

(2) Down(2) Down--regulation, mutation or loss of regulation, mutation or loss of tumor antigenstumor antigens

Tumor antigens (TA)Tumor associated antigen (TAA)

• Complete loss• Down-modulation

Tumor AntigensTumor Antigensgg• Altered self: K-ras, products of normally unexpressed

genes (MAGE BAGE GAGE) proteins of alternativegenes (MAGE, BAGE, GAGE), proteins of alternative reading frame, - of post-translational modification, -different orders of glycosylation (mucin-CA125, MUC1).g y y ( , )

• Viral antigens: EBNA, E-6,E-7, papilloma virus antigens of cervical carcinomas.

• Oncofetal antigens: alpha-fetoprotein (AFP), Carcinoembryonic antigen (CEA)

• Autoantigens: overexpression c myc in lymphomas• Autoantigens: overexpression - c-myc in lymphomas, leukemias; HER-2/neu epidermal growth factor receptor-breast cancer (Herceptin).( p )

(3) Loss of costimulation(3) Loss of costimulation(3) Loss of costimulation(3) Loss of costimulationCostimulatory molecules recognized:

B7 1(CD80)

Costimulatory molecules recognized:

B7.1(CD80)B7.2(CD86)CD40 L

B7 familyCD40 LCD27, CD30 4-1BB4-1BBOX40ICAM-1ICAM-1

T cell Activation No Activation

T cell T cell

TCRCD28 CD28 TCRCD28 CD28

Peptide/B7.1 B7.2 Peptide/

APC

Peptide/MHC

APC

pMHC

L f ti l tiCo-stimulation Loss of costimulation

The initiation of T cell responses requires two p qdistinct signals

X

(4) Alterations in cell death(4) Alterations in cell death(4) Alterations in cell death (4) Alterations in cell death receptor signallingreceptor signalling

• Defects in Fas/FasL signaling system:Defects in Fas/FasL signaling system:resistance to apoptosis

• Apoptosis resistance: overexpression of Bcl-2

(5) Immunosuppressive (5) Immunosuppressive cytokinescytokines

• a number of immunosuppressive cytokines• a number of immunosuppressive cytokines.• IL-10 inhibits antigen presentation and IL-12

productionproduction.• TGF-beta induces overproduction of IL-10.• VEGF (vascular endothelial growth factor),

avoid immune recognition, inhibit the effector function, prevent T cell activation, cytokine production.

(6) Induction of (6) Induction of Immunosuppressive cellsImmunosuppressive cells

• CD4+CD25+ T cells (constitute 5-10% of CD4+ T cells): immunological tolerance to self-antigens, inhibition of T cell

lif tiproliferation.

• Gr1+CD11b+ myeloid cells: -- Expressing the granulocyte-monocyte markers Gr1+CD11b+, accumulate in spleens, lymph nodes and blood of tumor-bearing mice.

I hibiti tib d d ti CTL ti T ll-- Inhibiting antibody production, CTL generation, T cell function, lymphocytic proliferation, CD3 ζ chain expression.

Regulatory T CellsRegulatory T CellsT cells compete for

t ki i lT cells competef ti cytokine signalsfor same antigen

CytotoxicT cell

Mature dendriticdendritic

cell

Regulatory T cellsRegulatory

T cell

Proliferation

PotentialPotential sources for regulatory T cellsT cells

Possible suppressive mechanisms regulatory T cells

(7) Production of other (7) Production of other ( )( )suppressive factorssuppressive factors

• IDO (Indoleamine 2, 3-dioxygenase): expressed in most human tumour tissuesexpressed in most human tumour tissues and splenic DC subsets, leading to blockage of proliferation of T cellsblockage of proliferation of T cells

• ganglioside (sialic acid containing gl cosphingolipids)glycosphingolipids)

• Prostaglandins

Summary: Main defences of the Summary: Main defences of the tumors against immunitytumors against immunity

1) Alteration of MHC class I and tumor antigen expression1) Alteration of MHC class I and tumor antigen expression

2) Dysregulated expression of adhesion / costimulatory molecules by tumor and/or antigen-presenting cellsmolecules by tumor and/or antigen-presenting cells

3) Changes in T-cell signal transduction molecules, i.e. cell death receptor signallingreceptor signalling

4) Induction of immune suppressive cytokines

5) Induction of immunosuppressive cells

6) S i f i f6) Secretion of suppressive factors

1. Weapons from the tumors

2. Defects of immune system

• Immune defects in T cells

• Malfunction of dendritic cell systemy

Immune defects in T cells in cancerImmune defects in T cells in cancerImmune defects in T cells in cancerImmune defects in T cells in cancer

• Alterations in the expression of signal transduction molecules in immune cells.

• Loss of CD 3ζ chain. TCR-CD3 complex. It functions as a single transducer upon antigen binding.

• Receptor-mediated apoptosis of T cells contributes to T cell dysfunction.

Tumor massu o ss

Vessel

Lymphocyte

FasL+ tumor cell

Apoptotic lymphocyte

Receptor-mediated apoptosis of lymphocytes

Malfunction of dendritic cell systemMalfunction of dendritic cell systemMalfunction of dendritic cell systemMalfunction of dendritic cell system

– Tumor-mediated inhibition of DC generation, differentiation and maturationdifferentiation and maturation

– Functional impairment of DCs: lack of expression of costimulatory moleculesexpression of costimulatory molecules

– Induction of DC apoptosis by tumors

TumorTumor--derived factors with DC inhibitory propertiesderived factors with DC inhibitory properties

Tumor-derived factors Effect on DCs

VEGF tumor infiltration and generation

TGF-beta CD80 and CD86 expression

Gangliosides inhibition of dendropoiesis from hematopoietic precursor cells

IL 6 differentiationIL-6 differentiation

IL-10 differentiation,CD80/CD86/CD40 expression,IL-12 production

Prostanoids,prostaglandins differentiation

PgE2 generation

NO induction of apoptosis

Summary

How do tumors progress?

Activation versus suppression of immunity during tumor progression

Tumor Regression

Cytokines

immunity during tumor progression

g

Activation >suppressionT cellTumor

Suppression> activation

Tumor Progression

DCNK cell

The fortune of tumor cellsThe fortune of tumor cells depends on the battle between p

immune system and tumor cells

The defense of tumor overweighs the anti-t i ittumor immunity

Cytotoxic CD8 cellsDendritic cellsMacrophagesC t ki

Antigen/MHC lossCytokinesAntibodies

T-cell dysfunctionSuppressive cytokineSuppressive T cellsOverweighing effector cells

Balance

Cancer Cancer I l /I thI l /I thImmunology/ImmunotherapyImmunology/Immunotherapy

• How does the immune system eliminate cancer cells?

• How do cancer cells escape from Immunosurveilance?• How do cancer cells escape from Immunosurveilance?

• How can we help to win the battle between immune t d ? C i thsystem and cancers? – Cancer immunotherapy

• Examples

Tumor ImmunotherapyTumor ImmunotherapyTumor ImmunotherapyTumor Immunotherapy

Strategies to improve the tumor-associated immune response byassociated immune response by either boosting components of the immune system that produce animmune system that produce an effective immune response or by inhibiting components that suppress the immune response.p

Immunotherapy Immunotherapy ------ Reverse Reverse the imbalancethe imbalance

Tumor Immunotherapy

Tumor Progression

StrategiStrategiees to supplement the missing or s to supplement the missing or insufficient immune elementsinsufficient immune elements

Immune elements Enhancing ‘the enhancer’

T cells Injection of cytotoxic T cells

Dendritic Cells DC vaccinationDendritic Cells DC vaccination

Natural killer cells Injection of activated NK cells

TAA Peptide, TAA-vector vaccination

Effector cytokines IL-2, IL-12

Strategies to block the suppreStrategies to block the suppresssive sive mechanismsmechanisms

Suppressive elements Inhibiting ‘the inhibitors’Regulatory T cells Blocking their function

dysfunctional DCs Blocking the pathway

Suppressive cytokines Blocking potential common t ki i llicytokine signalling

Suppressive factors Blocking their functionSuppressive factors Blocking their function

Main Mechanisms of Main Mechanisms of ImmunotherapyImmunotherapy

• Stimulating the antitumor response, either by increasingStimulating the antitumor response, either by increasing the number of effector cells or by producing soluble mediators.

• Decreasing suppressor mechanisms.

• Altering tumor cells to increase their immunogenicity and make them more susceptible to immunologic defences.make them more susceptible to immunologic defences.

• Improving tolerance to cytotoxic drugs or radiotherapy, p g y g py,such as stimulating bone marrow function with GM-CSF.

History: NonHistory: Non--specific approachspecific approachHistory: NonHistory: Non--specific approachspecific approach

1892 WB C l b d t i• 1892 - WB Coley observed tumour regression after bacterial infections

• BCG vaccine to treat bladder carcinoma• 1970-80’s – cytokines y

– includes interferons, interleukins and tumor necrosis factor (TNF)necrosis factor (TNF)

– Limited success

Current Immunotherapeutic Current Immunotherapeutic strategies in clinic or clinical trialsstrategies in clinic or clinical trials

• Antibody Therapy• Cytokine Therapy• Adoptive Therapy• Adoptive Therapy• Vaccination• Combinational therapy

ExamplesExamplespp

Antibody TherapyAntibody Therapyy pyy pyRituximab: The first approved antibody by FDA in clinical trial. Targeting CD20. low-grade non-Hodgkin lymphoma

Cytokine therapyCytokine therapyILIL 22---- ILIL--22

Event Author

Discovery of IL-2 Morgan et al.(1976)

Mitogenic IL-2 signal and long-term cultures of tumor-specific CTL Gillis and Smith (1977)

Activating IL-2 signal (LAK cells) Grimm et al.(1982)

Local administration of IL-2 inhibits tumour growth in preclinical models Bubeník et al.(1983)p ( )

Local administration of IL-2 inhibits growth of human tumors Pizza et al. (1984)

Systemic administration of IL-2 inhibits growth of metastatic Rosenberg et al.(1985a)y g g ( )experimental tumours

Utilization of recombinant IL-2 for clinical trials in patientswith generalized tumours Rosenberg et al (1985b)with generalized tumours Rosenberg et al.(1985b)

Local IL-2 gene therapy inhibits tumour growth in preclinical models Bubeník et al.(1988)

Utilization of TIL or tumour cells carrying an inserted IL-2 gene Anderson (1992);Utilization of TIL or tumour cells carrying an inserted IL 2 gene for the first clinical trials

( );Foa et al. (1992)

Local and regional IL-2 administration in cancer patients -selected examples from the early trials

Interleukin-2 Dose Tumour Response (%) Reference ( it / ti t) C l t / ti l(units/patient) Complete/partial

gibbon lymphoid 1.5 x 10-2 – 4.0 x 10-3 urinary bladder carcinomas 30/ 30 Pizza (1984)human recombinant 1.0 x 10-4 – 2.8 x 10-4 lung carcinomas 0/ 82 Yasumoto (1987)

human recombinant 8.0 x 10-2 – 5.4 x 10-3 malignant gliomas 13/ 13 Yoshida (1988)human lymphoid 2.0 x 10-3 squamous cell carcinomas 29/ 29 Forni (1988) human lymphoid 2.0 x 10-3 squamous cell carcinomas 30/ 30 Cortesina (1988)human lymphoid continuous perfusion urinary bladder carcinomas 20/ n.v. Huland and Huland

1.5 x 10-6/week (1989)

n.v., not verified because of incomplete transurethral resection

Adoptive immunotherapyAdoptive immunotherapyAdoptive immunotherapyAdoptive immunotherapy

• Stimulating immune cells by exposing them to tumour cells or antigens in thethem to tumour cells or antigens in the laboratory and then injecting expanded populations of the treated cells intopopulations of the treated cells into patients.

• Patient is both donor and recipient• Patient is both donor and recipient.

Tumor escape mechanism and T-cell adoptive immunotherapy after genetic manipulation

(1) Tumor cells that produce TGFß that exert inhibitory effects on the immune system. Specific CTL can be genetically modified to become resistant to the TGFβ inhibitory effect through transgene expression of a mutant dominant-

ti TGFß t II t (DNR)negative TGFß type II receptor (DNR).

(2) Specific T cells genetically modified to produce IL-12 can overcome IL-10 inhibitory effect.

(3) Tumors express FasL and induce apoptosis of effector T cells. Small interfering RNA (siRNA) can be used to knock-down Fas receptor in specific CTL, allowing a significant reduction of their susceptibility to Fas/FasL-mediated apoptosis.mediated apoptosis.

Adoptive immunotherapyAdoptive immunotherapyThe Journal of Clinical Investigation Vol 113 Number 11 June 2004 pp 1515The Journal of Clinical Investigation Vol 113 Number 11 June 2004 pp 1515

Generation of dendritic cell vaccines from peripheral blood monocytes:p p y1) Monocytes cultures with GM-CSF +IL-4 to produce DCs2) Matured with CD40 ligand3) Pulsed with peptide or tumour lysate4) Re-injected as vaccine to induce T-cell immune response against tumour

Antitumor VaccinesAntitumor Vaccines

Administration of some formAdministration of some formAdministration of some form Administration of some form of antigen to induce a specific of antigen to induce a specific

tit itit iantitumour immune response.antitumour immune response.

Antitumor VaccinesAntitumor Vaccines

Antitumor VaccinesAntitumor Vaccines

Approaches to antitumor vaccinationApproaches to antitumor vaccination

The Journal of Clinical Investigation Vol 113 ( 11) June 2004 pp 1515

APC – antigen presenting cell TAA – tumour associated antigenDC – dendritic cell MHC – major histocompatibility complex

Dendritic Cells That Attack CancerDendritic cell

Complex binds to dendritic cell precursor

matures and is infused back into patient

T cell

Tumor antigen

TumorTumor antigen is linked to a cytokine

Complex is taken in by dendritic celldendritic cell precursor

Cancer cell

T cells attack cancer cell

Combinational Combinational TTherapyherapypypy---- a threea three--stranded cord is not easily brokenstranded cord is not easily broken

• Combination of different immunotherapies pACT+IL-2 + costimulation

• Combining immunotherapy with other therapeutic strategies

Examples from my research workExamples from my research workExamples from my research workExamples from my research work

The immune system can be harnessedas a potent weapon to combat canceras a potent weapon to combat cancer,but only if immunotherapy is combinedwith treatment strategies that target atumour’s weapons of survival, defence,p , ,and attack. If cancer cells are preventedfrom growing they will be unable tofrom growing they will be unable togenerate immune escape variants.

Gene transfer of antisense hypoxia inducible factorGene transfer of antisense hypoxia inducible factor--1α1αGene transfer of antisense hypoxia inducible factorGene transfer of antisense hypoxia inducible factor 1α 1α

enhances the therapeutic efficacy of cancer immunotherapyenhances the therapeutic efficacy of cancer immunotherapy

Sun X et al Gene Therapy 2001; 8: 638 645Sun X, et al. Gene Therapy 2001; 8: 638-645

Potential mechanisms for synergy displayed by combined blocking hypoxia pathway and B7.1-mediated immunotherapy

B7.1+AS-HIFB7 1

AS-HIFNK A iB7.1Tumor

cellApoptosis Necrosis

Tumor

NK

Glycolysis

Activates NK cells

v

Tumorcell Tumor

cell

+ hsp70- tumor

Anti-angiogenesis

vv

B7 1APCMHCI

CTumorcell

B7.1

+ hsp70 tumorAntigen

Heat-shockd i i

Cell vitalityB7.1 MHCI

MHCIICD28

MHCI

CD28

T cell

MHCII

T cell

driven anti-tumorimmunity

Immune suppressive Proliferation

& CTL-mediated

killing

ppelements

TumorCell

Apoptosis

B7H3-meidated Cancer Immunotherapyy

Arsenic trioxide synergizes with B7H3-mediated immunotherapy to eradicate hepatocellular carcinomas

International Journal of Cancer 2006; 118:1823-1830.

C l t di ti f h t ll l i b bi dComplete eradication of hepatocellular carcinomas by combined vasostatin gene therapy and B7H3-mediated immunotherapy. Journal of Hepatology 2007;46: 98-106Journal of Hepatology 2007;46: 98 106

Novel co-stimulatory molecule- B7H3

Molecular StructureSS IgV-like IgC-like Cytoplasmic

Signal peptideMLRGWGGPSVGVCVRTALGVLCLCLTGAVEVQVSEDPVVALVDTDATLRC

IgV-like domain

Transmembrance

gSFSPEPGFSLAQLNLIWQLTDTKQLVHSFTEGRDQGSAYSNRTALFPDLLVQ

GNASLRLQRVRVTDEGSYTCFVSIQDFDSAAVSLQVAAPYSKPSMTLEPNKIgC-like domain

DLRPGNMVTITCSSYQGYPEAEVFWKDGQGVPLTGNVTTSQMANERGLFDDLRPGNMVTITCSSYQGYPEAEVFWKDGQGVPLTGNVTTSQMANERGLFD

VHSVLRVVLGANGTYSCLVRNPVLQQDAHGSVTITGQPLTFPPEALWVTVGTransmembrane Cytoplasmic

LSVCLVVLLVALAFVCWRKIKQSCEDENAGAEDQDGDGEGSKTALRPLKPS

ENKEDDGQEIA

Sun X et al Gene Therapy 2003; 10：1728-1734Sun X, et al. Gene Therapy 2003; 10：1728-1734.

Gene transfer results in expression of B7H3 on the surface of tumor cells

pcDNA3.1 Flag-B7H3

the surface of tumor cells

Flag-B7H3

Tubulin

Combinational therapy led to eradication of large tumorsCombinational therapy led to eradication of large tumors and generation of memorized anti-tumor immunity

1 6

2

2.4e

(cm

)B7H3+As2O3B7H3As2O3pcDNA3.1PBS

0 4

0.8

1.2

1.6

Tum

or S

ize

0

0.4

0 1 2 3 4 5 6 7 9 12Weeks After Therapy

20

Production of anti-tumor cytokine and CTLs by immunotherapy

300

400

500

N-γ

(pg/

ml)

* *Sera

6

8

10

N-γ

(ng/

ml)

* *Supernatants

100

200

300

Leve

l of I

FN

2

4

6

Leve

l of I

FN

0 0

405060

ity (%

)

20:1 E:T Ratio* *

y (%

) PBSCD4+CD8+40

5060

10203040

Cyt

otox

ic 100:1* *

Cyt

otox

icity

CD8+NK

10203040

* * * *

0B7H3+As2O3 B7H3 PBS

010

Treatment of single tumor eradicates multiple distant tumors

0.6

0 4

0.5

met

er) Tumor-1,treated

Tumor-2,untreated

Tumor 3 untreated

0.3

0.4cm

,dia

m Tumor-3,untreated

Tumor-4,untreated

Tumor-5,untreated

0.1

0.2

mor

Siz

e(

0

0 1 2 3 4

Tum

Weeks after therapy

ConclusionConclusionConclusion Conclusion • Immunotherapy may be the next great hope for py y g p

cancer treatment. • While antibodies, cytokines, and vaccines haveWhile antibodies, cytokines, and vaccines have

individually shown some promise, it is likely that the best strategy to combat cancer will be tothe best strategy to combat cancer will be to attack on all fronts.

• The effect of immunotherapy in combination with• The effect of immunotherapy in combination with traditional cancer therapies is another avenue.

Background – mini review

Unclear

Controversial Not reported

Further investigation

ShortcomingsIntroduction

Hypothesis

ExperimentsMaterials and Methods

ResultsDiscussion

Conclusion

Si ifiDiscussion Combined

Future Investigation

Significance

g

DR Kevin Sun Department of Molecular Medicine & PathologyDepartment of Molecular Medicine & PathologyRm 4231Tel:3737599-85935Email:k.sun@auckland.ac.nzEmail:k.sun@auckland.ac.nz