ABSTRACT
Signal transducer and activator of transcription (STAT) 3 is a critical transcription factor for cell proliferation and survival. It is activated within cells by many cytokines to mediate immune and inflammatory responses to injury. Inflammatory bowel disease (IBD), represented by Crohn′s disease (CD) and ulcerative colitis (UC), is a chronic inflammatory disease of the intestinal tract. STAT3 has been shown to be abnormally activated in IBD colon tissues by many pro-inflammatory cytokines, leading to disruption of the intestinal mucosal barrier and excessive innate immune and Th17 responses. The persistent chronic inflammation eventually leads to intestinal fibrosis and stenosis. In addition to immune responses, STAT3 is also involved in intestinal fibrosis in IBD by promoting the transcription of fibrosis-related genes. Colitis-associated cancer (CAC) is a particularly aggressive subtype of colorectal cancer and is associated with chronic inflammation-induced IBD. STAT3 has also been associated with CAC initiation and development. STAT3 is overactivated in tumors, which leads to suppression of the anti-tumor activity of immune cells and promotion of cancer cell proliferation, tumor angiogenesis, invasion, and migration. In the present article, we summarize the role of STAT3 in IBD and CAC and the research progress of the related drugs developed for UC and CAC treatment.