Downregulation of human farnesoid X receptor by miR-421 promotes proliferation and migration of hepatocellular carcinoma cells.

The farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily that is highly expressed in liver, kidney, adrenal gland, and intestine. It plays an important role in regulating the progression of several cancers including hepatocellular carcinoma (HCC). So it is necessary to study the regulation of FXR. In this study, we found that the expression of miR-421 was inversely correlated with FXR protein level in HCC cell lines. Treatment with miR-421 mimic repressed FXR translation. The reporter assay revealed that miR-421 targeted 3' untranslated region of human FXR mRNA. Furthermore, downregulation of FXR by miR-421 promoted the proliferation, migration, and invasion of HCC cells. These results suggest that miR-421 may serve as a novel molecular target for manipulating FXR expression in hepatocyte and for the treatment of HCC.