Inactivation of CYLD in intestinal epithelial cells exacerbates colitis-associated colorectal carcinogenesis - a short report

Abstract

Purpose

CYLD is a tumor suppressor that has been linked to the development of various human malignancies, including colon cancer. The tumor-suppressing function of CYLD is associated with its deubiquitinating activity, which maps to the carboxyl-terminal region of the protein. In the present study we evaluated the role of intestinal epithelial CYLD in colitis-associated cancer using a conditional mouse CYLD inactivation model.

Methods

In order to evaluate the role of CYLD in intestinal epithelial carcinogenesis, mice (IEC-Cyld ^Δ9 mice) that carry a mutation that eliminates the deubiquitinating domain of CYLD in intestinal epithelial cells (IEC) were generated by crossing Villin-Cre transgenic mice to previously generated mice carrying a loxP-flanked Cyld exon 9 (Cyld ^flx9 mice).

Results

We found that IEC-Cyld ^Δ9 mice did not present spontaneous intestinal abnormalities up to one year of age. However, upon challenge with a combination of genotoxic (AOM) and pro-inflammatory (DSS) agents we found that the number of adenomas in the IEC-Cyld ^Δ9 mice was dramatically increased compared to the control mice. Inactivation of CYLD in intestinal epithelial cells did not affect the classical nuclear factor-kappaB (NF-κB) and c-Jun kinase (JNK) activation pathways under physiological conditions, suggesting that these pathways do not predispose CYLD-deficient intestinal epithelia to colorectal cancer development before the onset of genotoxic and/or pro-inflammatory stress.

Conclusions

Our findings underscore a critical tumor-suppressing role for functional intestinal epithelial CYLD in colitis-associated carcinogenesis. CYLD expression and its associated pathways in intestinal tumors may be exploited for future prognostic and therapeutic purposes.

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