LAUSR

Synthetic immunosuppressive glucocorticoids (GCs) are widely used to control inflammatory bowel disease (IBD). However, the impact of GC signaling on intestinal tumorigenesis remains controversial. Here, we report that intestinal epithelial glucocorticoid receptor (GR), but not whole intestinal tissue GR, promotes chronic intestinal inflammation-associated colorectal cancer in both humans and mice. In colorectal cancer patients, GR is enriched in intestinal epithelial cells and high epithelial GR is associated with poor prognosis. Consistently, intestinal epithelium-specific deletion of GR (GR iKO) in mice increases macrophage infiltration, improves tissue recovery, and enhances anti-tumor response in a chronic inflammation-associated colorectal cancer model. Consequently, GR iKO mice develop fewer and less advanced tumors than control mice. Furthermore, oral GC administration in the early-phase of tissue injury delays recovery and accelerates the formation of aggressive colorectal cancers. Our study reveals that intestinal epithelial GR signaling represses acute colitis but promotes chronic inflammation-associated colorectal cancer, and suggests that colorectal epithelial GR could serve as a predictive marker for colorectal cancer risk and prognosis. Our findings further suggest that although synthetic glucocorticoid treatment for IBD should be used with caution, there is a therapeutic window for glucocorticoid therapy during colorectal cancer development in immunocompetent patients.