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

4

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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Thanksriccardo.guidi@ki.se

@riccardoguidi87

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