The loss of MiR-139-5p promotes colitis-associated tumorigenesis by mediating PI3K/AKT/Wnt signaling.

MiR-139-5p down-regulation has frequently been implicated in colorectal carcinoma. However, there is little known about its biological function between inflammation and cancer in vivo. Here, a transgenic murine model of colorectal carcinoma was used to investigate pathogenetic role of miR-139-5p in colitis and colitis-associated tumorigenesis. We showed that miR-139-5p knockout mice were higher sensitive to DSS-induced colitis and enhanced formation of intestinal neoplasia was observed when mice were exposed to AOM/DSS treatment. MiR-139-5p knockout mice exhibited an increased expression of genes involved in Wnt pathway. Such genes are closely associated with cell proliferation and differentiation, promoting the β-catenin nuclear accumulation. Furthermore, biochemical studies in HCT-116 cells revealed that the over-expression of miR-139-5p inhibited the crosstalk between PI3K/AKT and Wnt pathway mediated by IGF-1R. Collectively, these findings indicate that miR-139-5p plays a crucial role in the development and progression of colitis-associated tumorigenesis and suggest that miR-139-5p may serve as a potential therapeutic target for the treatment of colitis-associated cancer in the future.