PALLAVI GARG Ph.D.

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Overexpression of MMP9 in colonic epithelium mediates protection in colitis associated cancer PALLAVI GARG Ph.D.

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PALLAVI GARG Ph.D. Overexpression of MMP9 in colonic epithelium mediates protection in colitis associated cancer. Disclosures. Nothing to Disclose. Matrix Metalloproteinases (MMPs). - PowerPoint PPT Presentation

Transcript of PALLAVI GARG Ph.D.

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Overexpression of MMP9 in colonic epithelium mediates protection in colitis associated cancer

PALLAVI GARG Ph.D.

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Disclosures

Nothing to Disclose

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Matrix Metalloproteinases (MMPs)

Are a family of zinc-dependent proteolytic

enzymes with the ability to degrade extracellular matrix substrates such as

collagen, gelatin and proteoglycans

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Colitis Associated Cancer (CAC) & Colorectal Cancer• CAC is an important complication of Ulcerative Colitis or colonic Crohn’s Disease

that results in significant morbidity and mortality

• It causes 1/6 of all deaths in patients with ulcerative colitis

• Colon cancer develops in flat dysplastic tissue among IBD individuals

• CAC is often multiple, anaplastic, broadly infiltrating, rapidly growing and occurs at a younger age

• The pathogenesis of CAC is not known

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MMP9 and its role in acute colitis

•MMP9 is not expressed in normal tissues and is one of the predominant MMPs that is up-regulated in several animal models of colitis and human IBD

•MMP9 mRNA and protein levels are increased in the inflamed colonic mucosa of patients with IBD

•MMP9 activity correlates with active inflammation

•MMP9 activates Notch1 signaling in colonic epithelium

Castaneda et al, 2005, GastroenterologyGarg et al, 2007, Gastroenterology

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Role of MMP9 in CAC

• MMP9-/- mice show increased susceptibility to CAC

• CAC in MMP9-/- mice is associated with decreased apoptosis compared to WT mice

• CAC in MMP9-/- mice showed decreased levels of p21WAF1/Cip1

and p53

• MMP9 mediates its tumor suppressive role via activation of Notch1 signaling

Garg et al, 2010, Cancer ResearchGarg et al, 2011, Gastroenterology

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Which MMP9 protects from CAC ?

Aim

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In vivo model

C57/B6

WT Tg-villin-MMP9

Water

Water

DSS (3 cycles)

DSS= Dextran Sodium Sulfate (3% in drinking water)

DSS (3 cycles)

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In vivo protocol

0Days

49 7 14 28 35

DSS Cycle (1st) starts

DSS Cycle(2nd ) starts

Recovery(1st) starts

Recovery(2nd) starts

DSS Cycle(3rd ) starts

Recovery(3rd) starts

53 85

sacrifice

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* *

*B

ody

wei

ght g

ain

in p

erce

ntag

e

DSS cycle 1

Recovery cycle 1

DSS cycle 2

Recovery cycle 2

SacrificeDSS cycle 3

Recovery cycle 3

1 2 3

Tg-villin-MMP9WT

*

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A B

WT CAC

Tg-villin-MMP9 CAC

Num

ber

of d

yspl

asti

c le

sion

s

Num

ber

of p

olyp

s

WT CAC

Tg-villin-MMP9 CAC

*

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X10 X20

WT CAC

Tg-villin-MMP9 CAC

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MMP9, 104 kD

β-tubulin

A

B NICD, 80 kD

β-tubulin

p53, 53 kD

GAPDH

C

WT, CAC

Tg-villin-MMP9, CAC

1 2 3 4 5 6

1 2 3 4 5 6

1 2 3 4 5 6

WT, CAC

Tg-villin-MMP9, CAC

WT, CAC

Tg-villin-MMP9, CAC

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Bax-1, 37 kD

p21WAF1/Cip1, 21kDA

B

1 2 3 4 5 6

WT, CAC

Tg-villin-MMP9, CAC

WT, CAC

Tg-villin-MMP9, CAC

GAPDH

GAPDH1 2 3 4 5 6

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Overexpression of MMP9 in MMP9-/- MEFs showed increased levels of Notch1 and p53

MMP-9, 104 kD

MMP9-/- MEFs

WT MEFs

A

B NICD, 80 kD

1 2 3 4 5 6

p53, 53 kDC

GAPDH

1 2 3 4 5 6

MMP9-/-MEFs + MMP9

GAPDH

MMP9-/- MEFs

WT MEFs

MMP9-/-MEFs + MMP9

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•Epithelial-derived MMP9 plays a tumor suppressive role in CAC

• Overexpression of MMP9 in colonic epithelium is associated with altered levels of p53, Notch1, Bax1 and p21WAF1/Cip1

• Overexpression of MMP9 in MMP9-/-exhibited increased levels of NICD and p53

Summary

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Inflammation

cytosol

nucleus

MMP-9

+

Notch-1 +

ARF

+ARFMdm2

Mdm2

+

p53+

Molecular mechanism of p53 regulation by MMP9 via Notch1

Mdm2

-

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Conclusions

• Despite being a mediator of acute inflammation, epithelial derived- MMP9 acts as a tumor suppressor in CAC

• MMP9 mediated p53 activation via Notch1 signaling is necessary and sufficient for its tumor suppressive effect in CAC

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Acknowledgement

Didier Merlin Lewins Walter

Crohn’s & Colitis Foundation of AmericaCareer Development Award, (#3057)