Role of bacteria in carcinogenesis

Riccardo GuidiFrontiers in Translational Medicine

Karolinska Institutet

Jan 7, 2013

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

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

tumorigenic barrier

1. senescence 2. cell death

normal colon’s cryptssmall tubular

adenomalarge tubular

adenomacarcinoma

the tumorigenic barrier mechanisms

sign

al

proliferation

DNA damage

senescence/death

DNA damage

senescence/death

proliferation

oncogene activation

genomic instability

DDR detection limit

Science 319, 1352–1355 (2008)

normal pre-cancerlesion

cancer

mutation

DNA damage

Cell 144, 646–674 (2011)

genomic instability is not the only enabling characteristic of tumorigenesis

chronic inflammation contributes to carcinogenesis

Cancer Res. 48, 4399–4404 (1988)

“There was a statistically significant deficit among cases in the use of aspirin-containing medication and vitamin supplements, and this was consistent for both colon and rectal cancer and for both males and females.”

CRCCTR

aspirin 20% 12%

RR

0.52

if you are taking aspirin, you have half the risk to be in the CRC group

p

>0.001

vitamin C 13% 4% 0.22 >0.001

if you are taking vitamin C, you have 1/4 the risk to be in the CRC group

epidemiological evidence

AOMAzoxymethane

DSSDextran sulfate sodium

+ Adenocarcinoma=

example of the colon adenocarcinoma

(kills enterocytes)/promoter mutagen/initiator

What exactly of the inflammatory process contributes to carcinogenesis?

animal model evidencechronic inflammation contributes to carcinogenesis

Greten, F. R., et al. (2004). Cell, 118(3), 285–296.

IKK

IkB

NF-κB NF-κB

IkBPP

ChemokinesCytokines

Cox2

CycD1MycCox2

Bcl-XL

IAP-1

inflammation proliferation anti-apoptosisTumor

progression

PRRTNF-receptor

Dangerous Signals

dissecting the inflammatory pathway: NF-kB

gene transcription

Nat. Immunol. 12, 715–723 (2011)

cyto

sol

nucl

eus

tumorigenic barrier

IL-1IL-8

NF-κB inhibition slow down CRC progression

AOMAzoxymethane

DSSDextran sulfate sodium

+ Adenocarcinoma=

Greten, F. R., et al. (2004). Cell, 118(3), 285–296.

tumors are smaller because a) cell death? b) reduced proliferation?

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 KD

In this model, NF-kB plays a role in protecting cell from apoptosis! NF-KB

Inflammation Toxins

How do bacteria contribute to cancer?

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

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)

bact

eroi

dete

sfir

mic

utes

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

antibiotic treatment reduces cancer development

Inflammation Toxins

How do bacteria contribute to cancer?

(bacterial genotoxin)

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)

1. Infection with Colibactin pos.ve strain induces DNA damage in vivo!

2. Infection with Colibactin pos.ve strain induces anaphase bridges and promote anchorage independent growth!

PNAS (2010) 107, 11537-11542!

wt

+ Clb +Clb -

Pathogenic E.coli expressing Colibactin induce DNA damage and promotes genomic instability

PNAS 107, 11537–11542 (2010)

Colibactin expressing E.coli populates inflamed bowelMice with inflammatory bowel disease contain higher proportions of toxin-producing bacteria

il10-/-

microbiota?wt

Does this have a relevance in humans?

AOM+ +Clb +

Clb -

germ-freeil10-/-

CDT carcinogenic properties 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

wt

+ CDT +CDT -

H. hepaticus chronic infection

Cell. Microbiol. 9, 2070–2080 (2007).

-CDT

+CDT -C

DT+C

DT

-CDT

+CDT

-CDT

+CDT

CDT carcinogenic properties in vivo

Home-taking messages

• Genomic instability and chronic inflammation are enabling hallmarks of cancer• Chronic activation of NF-kB leads to overcome the tumorigenic barrier• Bacteria may contribute to cancer with• promotion of inflammation (via PRR)• toxin production that directly cause DNA damage and genomic instability

Thanks

riccardo.guidi@ki.seslides: