Expression of the novel adipokine C1qTNF-related protein 4 (CTRP4) suppresses colitis and colitis-associated colorectal cancer in mice.

Inflammatory bowel disease (IBD) is an important factor in the induction of colon cancer, but its mechanism is unclear. Colitis and colitis-associated colorectal cancer (CAC) models induced using both dextran sulfate sodium (DSS) and the azoxymethane/DSS protocol were established in wild-type (WT) and CTRP4 transgenic (CTRP4-tg) C57BL6/J mice. Body weight, stool consistency and the presence of blood in the stool were analyzed; tumor quantity, size and histological characteristics were analyzed during the development of CAC. The CTRP4-tg mice exhibited significantly reduced colitis and developed far fewer macroscopic tumors; these tumors were smaller in size, and a majority of the colon tumors in these mice were restricted to the superficial mucosa. Tumors of lower grades were observed in the CTRP4-tg mice. Interleukin-6 was markedly downregulated in the CTRP4-tg mice during CAC tumorigenesis. The phosphorylation of ERK, signal transducer and activator of transcription 3 and Akt in the colon and the proliferation of intestinal epithelial cells were decreased in the CTRP4-tg mice. The injection of recombinant CTRP4 protein significantly reduced the colitis symptoms of the WT mice. CTRP4 plays an important role in inflammation and inflammation-associated colon tumorigenesis, and our research may provide a novel method for the treatment of IBD and CAC.