MicroRNA-146b-5p suppresses cholangiocarcinoma cells by targeting TRAF6 and modulating p53 translocation

In view of the poor prognosis and high mortality of cholangiocarcinoma, there is a need for new therapeutic strategies. This study aims to reveal the biological function of miR-146b-5p in cholangiocarcinoma cell and its possible mechanism.The expression level and prognostic information on miR-146b-5p in cholangiocarcinoma were obtained in TCGA database. The biological function of miR-146b-5p on proliferation and vitality of cholangiocarcinoma cell HUCCT-1 was examined by EdU and MTT assay, and the apoptosis of HUCCT-1 cells transfected with miR-146b-5p mimic, mimic control, inhibitor, inhibitor control was detected by flow cytometry analysis. The western blot was done to evaluate the effect of miR-146b-5p targeting substrate and the expression of p53 in whole-cell protein and mitochondria fractions.Our finding revealed that miR-146b-5p expression in patients with CHOL was lower than the normal group(p＜0.001). MiR-146b-5p expression was down-regulated in human cholangiocarcinoma HUCCT-1 and RBE cells compared to normal control HIBEC and other cancer cells. The miR-146b-5p mimic could inhibit HUCCT-1 cell proliferation (p＜0.05) and promote HUCCT-1 cell apoptosis significantly (p＜0.05). The results of western blot showed that miR-146b-5p mimic could directly target TRAF6 3'UTR region and up-regulate the expression of p53 in mitochondria and miR-146b-5p inhibitor could down-regulated the level of p53 in mitochondria.MiR-146b-5p is a cholangiocarcinoma suppressor by inhibiting cell proliferation and promoting cell apoptosis with targeting TRAF6, possibly via modulating p53 translocation to mitochondria.