Mir-186-5p Regulates WNT Signaling Pathway by Targeting TCF4 Transcription Factor

The evolutionarily conserved Wnt signaling pathway plays essential roles during embryonic development, tissue homeostasis and differentiation. This pathway is deregulated in many cancers especially colorectal cancer. MiRNAs are a class of small noncoding RNAs that may play a major role in post transcriptional regulation of many genes and signaling pathway such as WNT signaling pathway. Here, we intended to investigate if miR-186-5p is capable of regulating WNT signaling pathway wia suppression TCF4 gene expression. miR-186-5p was bioinformatically predicted as a candidate regulator of TCF4 gene expression and then, in this experimental study, miR-186-5p was overexpressed in SW480 cell line and its increased expression was detected through quantitative reverse transcription polymerase chain reaction (RT-qPCR). The effect of miR-186-5p on WNT pathway was analysied with TOP/FOP flash assay in SW480 cell line. Finally, flow cytometery was used to inves tigate the effect of miR-186-5p overexpression on cell cycle progression in SW480 cell line. miR-186-5p was overexpressed in the SW480 cell line and its overexpression resulted in significant reduction of the TCF4 mRNA level. TOP/FOP flash assay, confirmed the negative effect of miR-186-5p on the Wnt pathway in SW480 cells. Finally, Overexpression of miR186-5p in SW480 cells resulted in cell cycle arrest in subG1 phase, detected by flow cytometry. Overall, accumulative results indi-cated that miR-186-5p by targeting TCF4 is potentially one of the regulators of the WNT signaling pathway.