STAT3 MODULATION AS A PROMISING THERAPEUTIC OPTION IN A PRECLINICAL MOUSE MODEL OF ULCERATIVE COLITIS

Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD) that predisposes to colorectal cancer (CRC) and is modeled in mice by administration of dextran sodium sulfate (DSS) in drinking water. There are two isoforms of STAT3, STAT3α is pro-inflammatory and anti-apoptotic, while STAT3β has opposing effects on STAT3α. We examined the severity of DSS-induced colitis in transgenic-mice expressing only STAT3α ( / ) and in wild-type (WT) mice administered C188-9, a small molecule direct-inhibitor of STAT3. While manifestations of DSS-induced UC, such as mortality, weight-loss, rectal-bleeding, diarrhea, and colon-shortening, were exacerbated in / transgenic versus cage-control WT mice, all were prevented by C188-9 treatment of WT mice. C188-9 treatment also increased apoptosis of pathogenic CD4+T-cells, reduced colon-levels of IL17-positive cells, down-modulated mRNA-levels of STAT3-genes involved in inflammation, apoptosis-prevention, and colorectal-cancer-metastases. These are the only studies showing efficacy of Thus small-molecule targeting of STAT3 may be a useful novel approach in treating UC and preventing UC-associated colorectal-cancer. We performed genome-wide microarray expression profiling to gain greater understanding of the mechanisms involved in the protective effect of C188-9 in DSS-induced colitis, we examined mRNA levels in the colon of mice receiving DSS or plain water, without or with C188-9 treatment. After the mice were euthanized, their colons were harvested and length measured; a portion was flash frozen in liquid nitrogen to isolate RNA for microarray analyse.