Intestinal epithelial cell autophagy deficiency suppresses inflammation-associated colon tumorigenesis

Colitis-associated cancer (CAC) is closely related to chronic inflammation, whose underlying molecular mechanism, however, has not been elaborated comprehensively. In the current study, an investigation was conducted on the role of autophagy in the initiation and progression of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colon tumors, a mouse model for CAC in humans. Mice with the intestinal epithelial cell (IEC)-specific deletion of the autophagy-related gene 7 (Atg7) saw a significant decrease in tumor number, burden, and risk of high-grade dysplasia. The autophagy deficiency of IECs resulted in the accumulation of T cells, especially CD8⁺ T lymphocytes in colon lamina propria. Furthermore, it was found that autophagy protects against DSS-induced intestinal injury through maintaining epithelial barrier function and promoting the survival and proliferation of IECs. Mechanistically, autophagy in IECs enhanced the activation of epithelial STAT3/ERK to promote the survival and proliferation of colonic epithelial cells during the development of CAC. Therefore, the findings unveil the essential role of autophagy in activating the processes of colonic protection, regeneration, and tumorigenesis.