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Updated: May 11, 2026
In vitro Organoid Culture of Primary Mouse Colon Tumors
Published on: May 17, 2013
A20 restricts wnt signaling in intestinal epithelial cells and suppresses colon carcinogenesis
Ling Shao1, Shigeru Oshima, Bao Duong
1Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.
Abstract:
Colon carcinogenesis consists of a multistep process during which a series of genetic and epigenetic adaptations occur that lead to malignant transformation. Here, we have studied the role of A20 (also known as TNFAIP3), a ubiquitin-editing enzyme that restricts NFκB and cell death signaling, in intestinal homeostasis and tumorigenesis. We have found that A20 expression is consistently reduced in human colonic adenomas than in normal colonic tissues. To further investigate A20's potential roles in regulating colon carcinogenesis, we have generated mice lacking A20 specifically in intestinal epithelial cells and interbred these with mice harboring a mutation in the adenomatous polyposis coli gene (APC(min)). While A20(FL/FL) villin-Cre mice exhibit uninflamed intestines without polyps, A20(FL/FL) villin-Cre APC(min/+) mice contain far greater numbers and larger colonic polyps than control APC(min) mice. We find that A20 binds to the β-catenin destruction complex and restricts canonical wnt signaling by supporting ubiquitination and degradation of β-catenin in intestinal epithelial cells. Moreover, acute deletion of A20 from intestinal epithelial cells in vivo leads to enhanced expression of the β-catenin dependent genes cyclinD1 and c-myc, known promoters of colon cancer. Taken together, these findings demonstrate new roles for A20 in restricting β-catenin signaling and preventing colon tumorigenesis.
Insights
A20 protein loss promotes colon cancer by enhancing beta-catenin signaling. Reduced A20 expression in intestinal cells leads to larger polyps and increased tumor development.
Area of Science:
- Oncology
- Molecular Biology
- Gastroenterology
Background:
- Colon carcinogenesis is a multistep process involving genetic and epigenetic changes.
- A20 (TNFAIP3) is a ubiquitin-editing enzyme that regulates NFκB and cell death signaling.
- A20 expression is decreased in human colonic adenomas compared to normal tissues.
Purpose of the Study:
- To investigate the role of A20 in intestinal homeostasis and colon tumorigenesis.
- To determine how A20 deficiency affects the development of intestinal polyps.
- To elucidate the molecular mechanisms by which A20 influences colon cancer progression.
Main Methods:
- Generated mice with A20 specifically deleted in intestinal epithelial cells (A20(FL/FL) villin-Cre).
- Interbred these mice with APC(min) mice (adenomatous polyposis coli mutation).
- Analyzed polyp formation, A20 binding to the β-catenin destruction complex, and expression of β-catenin dependent genes.
Main Results:
- A20-deficient mice exhibited significantly increased numbers and sizes of colonic polyps compared to controls.
- A20 was found to bind the β-catenin destruction complex, restricting canonical Wnt signaling.
- Acute A20 deletion in vivo enhanced β-catenin dependent gene expression (cyclinD1, c-myc).
Conclusions:
- A20 plays a critical role in restricting β-catenin signaling within intestinal epithelial cells.
- Loss of A20 function promotes colon tumorigenesis by stabilizing β-catenin.
- A20 acts as a tumor suppressor in the colon, highlighting its therapeutic potential.
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