The role and mechanism of action of RNF186 in colorectal cancer through negative regulation of NF-κB.

Colorectal cancer (CRC) is one of the most common malignant gastrointestinal cancers worldwide. RING finger protein 186 (RNF186) is a member of the RING finger protein family. RNF186 has been reported to be involved in the regulation of the intestinal homeostasis through the regulation of endoplasmic reticulum (ER) stress in colonic epithelial cells. However, its role in CRC remains unclear. In this study, we found that colorectal tumours from human patients had decreased levels of RNF186. We demonstrated that overexpression of RNF186 suppressed the growth and migration of CRC-derived cell lines in vitro and inhibited tumour proliferation in vivo. Further, our findings indicated that forced expression of RNF186 inhibited nuclear factor-κB (NF-κB) activation by reducing the phosphorylation of NF-κB. In addition, our results showed that RNF186 mice exhibited significantly increased tumour burden compared to the wild type (WT) mice following treatment with azoxymethane/dextran sulfate sodium (AOM/DSS). Compared to WT mice, the percentage of Ki67 positive cells was increased in the RNF186 mice, indicating that RNF186 is crucial for intestinal cell proliferation during tumorigenesis. Taken together, our data suggest that RNF186 inhibits the development of CRC, and that this effect is mediated through the suppression of NF-κB activity.