microRNA-146a inhibits proliferation, migration and invasion of human cervical and colorectal cancer cells.

microRNAs (miRNAs) play significant roles in diverse biological processes and their deregulation is implicated in carcinogenesis. miR-146a executes tumour suppressive or oncogenic functions depending on the cancer type, but its effect on human cervical (CaCx) and colorectal (CRC) cancers have not been examined thus far. In this study, miR-146a exhibited high expression in CaCx but poor expression in CRC, in comparison to corresponding normal tissues. Nevertheless, ectopic expression of miR-146a inhibited proliferation in both CaCx and CRC cells and curbed their migration and invasion. When the expression of endogenous miR-146a was suppressed, proliferative, migratory and invasive capacities of CaCx and CRC cells increased, suggesting an anti-tumourigenic function for miR-146a. Re-expression of miR-146a down-regulated the expression of crucial signalling intermediates: CTNNB1, STAT3, RELA, CCND1 and SNAI1, and enhanced TP53 and CDH1 expression. Thus, the present study reveals a hitherto unknown tumour suppressive role for miR-146a providing a plausible mechanistic basis for it.