Suppression of Antimicrobial Defense and Stabilization of STAT3 by IRAK-M Expression in Tumor Cells Promotes Colorectal Carcinogenesis

ABSTRACT

Different environmental and genetic factors have been attributed to the etiology of colorectal cancer. Dysbiotic gut microbiota is associated with initiation and progression of colon carcinogenesis. Hyperactivation of STAT3 promotes carcinogenesis by upregulating cell proliferation, survival, tumor-induced immunosupression and angiogenesis. IRAK-M is a negative regulator of toll-like receptor signaling and inhibits innate immune response. The cancer cell may exploit this property of IRAK-M and evade host immune surveillance. Recently, it has been found that IRAK-M provide controlled feed back to bacteria involved in colorectal cancer by reducing antibacterial response in mice. Furthermore, IRAK-M increased the stability of STAT3 in tumor cells that support tumor promotion by upregulating cell proliferation and survival. Thus, it is suggested that IRAK-M promotes colitis associated colon cancer by enhancing bacterial colonization and stabilization of STAT3.