bacteria&cancer biomed dec_2013
TRANSCRIPT
Role of bacteria in carcinogenesis
Riccardo GuidiFrontiers in Translational Medicine
Karolinska Institutet
Dec 17 , 2013
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epidemiological evidence
for H. pylori: Nat. Rev. Cancer 2, 28–37 (2002)
for Salmonella: Lancet 343, 83–84 (1994)
Am. J. Gastroenterol. 95, 784–787 (2000)J. Surg. Oncol. 93, 633–639 (2006)
for IBD: Cell Host & Microbe 3, 417–427 (2008)
Cancer 91, 854–862 (2001)Cancer 67, 2015–2020 (2006)
Salmonella enterica serovar Typhi
Inflammatory Bowel Disease
Barry J. Marshall and J. Robin Warren - Nobel 2005
Helicobacter pylori
increase risk of peptic ulcers --> gastric cancer
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tumorigenesis is a step-wise transformation
normal colon’s cryptssmall tubular
adenomalarge tubular
adenomacarcinoma
loss of APCbeta-catetin
KRas activaiton
TSG101 loss
PIK3CA/PTENactivation
TP53/BAXloss
DNA hypomethylation
Genomic Instability
HISTO
LOG
ICA
L LEVELM
OLEC
ULA
R LEVEL
Weinberg RA, “The Biology of Cancer”, GS edition, 2007
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tumorigenic barrier
1. senescence 2. cell death
normal colon’s cryptssmall tubular
adenomalarge tubular
adenomacarcinoma
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the tumorigenic barrier mechanisms
sign
algenomic instability
Science 319, 1352–1355 (2008)
normal pre-cancerlesion
cancer
cell proliferation
cell senescence/death
DNA damage
DNA damage
cell senescence/death
DDR detection limit
cell proliferation
replicative stress
oncogene activation
mutation
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Cell 144, 646–674 (2011)
genomic instability is not the only enabling characteristic of tumorigenesis
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chronic inflammation contributes to carcinogenesisepidemiological evidence
“three pooled RCTs that aspirin significantly reduces the recurrence of sporadic adenomatous polyps after one to three years.”
[RR 0.77 (95% CI 0.61, 0.96), (NNT 12.5 (95% CI 7.7, 25)]*
*RR: risk ratio;NNT: number needed to treat
NSAID placebo
1-3y
?
The Cochrane Library , 26 Jan 2004
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AOMAzoxymethane
DSSDextran sulfate sodium
+ Adenocarcinoma=
(kills enterocytes)/promoter mutagen/initiator
animal model evidence (example from colorectal carcinoma)chronic inflammation contributes to carcinogenesis
Greten, F. R., et al. (2004). Cell, 118(3), 285–296.
normal tumor
beta
-cat
enin
c-m
yccy
clin
D1
WHY does chronic inflammation contribute to cancer?
DNA damage
chronic inflammation
AOM DSS DSS DSS
10 weeks
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IKK
IkB
NF-κB NF-κB
IkBPP
ChemokinesCytokines
Cox2*
CycD1MycCox2
Bcl-XL
IAP-1
inflammation proliferation anti-apoptosisTumor
progression
Dangerous SignalsInflammation
dissecting the inflammatory pathway: NF-kB
gene transcription
Nat. Immunol. 12, 715–723 (2011)
cyto
sol
nucl
eus
tumorigenic barrier
TNFIL6
IL23
TNF receptorsPattern Recognition Receptors
*pro
stag
land
in E
2 ->
in
flam
mat
ory
sign
al +
feve
r
9
block of NF-κB reduces CRC progression
AOMAzoxymethane
DSSDextran sulfate sodium
+ Adenocarcinoma=
Greten, F. R., et al. (2004). Cell, 118(3), 285–296.
Ikkβ!wt!
IkkβΔ!Ep!
Ikkβ wt! IkkβΔ Ep!
Tunnel staining#
Ikkβ wt! IkkβΔ Ep!
Teresa Frisan, CMB, KI
Ikkβ wt!
IkB DM ON!IkB DM ON!IkB DM ON!
IkB DM OFF!IkB DM OFF!CTR!
IκB wt!
IκB DM!ON!
IκB DM!OFF!
WT Ikk KO
In this model, NF-kB plays a role in protecting cell from apoptosis! NF-KB
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but...
does NF-κB influence tumor progression also in the context of
bacteria?
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overview of bacterial-induced inflammation
Macrophage!
Intraepitelial T cells!
Peyer’s patch!
LAMINA PROPRIA!
MUCOSAL EPITHELIUM!
M cell!
DC!
PMN!
IL1!
TNFα!
IL6!
IL8!
TLRs!
IL6!TNFα!
STAT3!NFκB!
PRR
TLR1: Lipopeptides!TLR2: PGN, LTA (G+)!TLR3: dsRNA (virus)!TLR4: LPS (G-)!TLR5: Flagellin!TLR9: CpG!
(lipoteichoic acid)
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Myd88 KO model
Myd88
TLRs TLR1: Lipopeptides!TLR2: PGN, LTA (G+)!TLR3: dsRNA (virus)!TLR4: LPS (G-)!TLR5: Flagellin!TLR9: CpG!
Science (2007): 317, 124 -127!
APCmin/+ Myd88 WT
Myd88 KOAPCmin/+
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TRUC model for Ulcerative Colitis
Garrett, W. S., et al. Cancer Cell, 16(3), 208–219.
T-bet -/- + RAG2 -/- = TRUC --> Ulcerative colitis
lack adaptive immunity(lack of Treg)
host-commensal homeostasis(high TNF-alfa)
CTR TRUC
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H. pylori cause chronic inflammation in the stomach1) H. pylori induce COX2 gene transcription
Romano, M. et al. J. Biol. Chem. 273, 28560–28563 (1998)Fu, S. et al. Gastroenterology 116, 1319–1329 (1999)
2) H. pylori induce IL1-beta, pro-inflammatory cytokine that contributes to gastric cancer
El-Omar, E. M. et al., Gastroenterology 124, 1193–1201 (2003)
epithelial cells
in vitro
NB
in vivo
WB
(increased expression of IL-1B)
Conclusion: increased expression of IL-1B higher the risk of gastric cancer in H. pylori patients, strengthening the link:bacteria -> inflammation -> cancer
controlsesophageal cancergastric cancer
H. pylori +
pro-inflammatory polymorphisms?
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you got it now:
bacterial-induced inflammation contributes to cancer onset!
but is that all...?
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Toxins
Can bacterial toxins directly contribute to cancer?
• invade the epithelial layer• enter the cell• avoid lysosomal digestion• move the cell• change the cell cytoskeleton• decrease inflammation• avoid the immunosystem
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H. pylori toxin CagA contributes to cancer1) CagA translocates b-catenin to the nucleus
50% gastric cancer has increased b-catenin expression
2) CagA interacts with E-cadherin
b-catenin
E-cadherin
proliferationgenes
b-catenin model of action in epithelial cells:
Oncogene. 2007 Jul 12;26(32):4617-26Peek, R. M. & Blaser, M. J. Nat. Rev. Cancer 2, 28–37 (2002).
b-catenincagA
proliferaiton
b-catenin
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Bacterial genotoxins: cytolethal distending toxin (CDT) and Colibactin!
CdtB!
CdtC!CdtA!
clbM! clbL!
clbK! clbJ! clbI! clbH!
clbG! clbF!clbE! clbD!
clbC! clbB!
clbR! clbA!
clbN!clbO!
clbP!clbQ!
ORF2!
intP4!
ORF21!ORF22!ORF23!
Accessory proteins!Polyketide magasynthase PKS! Non ribosomal peptide magasynthase (NRPS)!Hybrid NRPS/PKS!
CDT is a trimeric toxin. CdtB: active subunit, homologous to DNase I, CdtA/CdtC: binding to cell surface!
Produced by several Gram negative bacteria, including Escherichia coli, Salmonella typhi, Campylobacter sp, Helicobacter sp!
Colibactin produced by commensal strains of E. coli!
Synthesized by a cluster of genes encoding for non ribosomal peptide synthetases (polyketide peptide) !
(and pathogenic)
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genotoxin effects in vitro
Cell. Microbiol. (2012).doi:10.1111/cmi.12034
6 months
CDT CDT CDT CDT CDT
1. genomic instability 2. gene mutations
3. anchorage independent growth
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Does this have a relevance in humans?
AOM+ +Clb +
Clb -
germ-freeil10-/-
genotoxin effects in vivo
Clb + Clb - Clb + Clb -
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Home-taking messages
• G.I.: tumor is a step-wise disease• Inflammation promotes proliferation and blocks apoptosis
1) Genomic instability and chronic inflammation are enabling hallmarks of cancer
• epidemiology• CRC mice model
2) Chronic NF-kB activation helps overcoming the tumorigenic barrier
Inflammation Toxins
• H. pylori CagA• bacterial genotoxins
3) Bacteria may contribute to cancer via
• Myd88 mice model• TRUC mice model• H.pylori infection
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