MicroRNA-301b-3p contributes to tumour growth of human hepatocellular carcinoma by repressing vestigial like family member 4.

MicroRNAs (miRNAs) are key regulators in the tumour growth and metastasis of human hepatocellular carcinoma (HCC). Increasing evidence suggests that miR-301b-3p functions as a driver in various types of human cancer. However, the expression pattern of miR-301b-3p and its functional role as well as underlying molecular mechanism in HCC remain poorly known. Our study found that miR-301b-3p expression was significantly up-regulated in HCC tissues compared to adjacent non-tumour tissues. Clinical association analysis revealed that the high level of miR-301b-3p closely correlated with large tumour size and advanced tumour-node-metastasis stages. Importantly, the high miR-301b-3p level predicted a prominent poorer overall survival of HCC patients. Knockdown of miR-301b-3p suppressed cell proliferation, led to cell cycle arrest at G2/M phase and induced apoptosis of Huh7 and Hep3B cells. Furthermore, miR-301b-3p knockdown suppressed tumour growth of HCC in mice. Mechanistically, miR-301b-3p directly bond to 3' UTR of vestigial like family member 4 (VGLL4) and negatively regulated its expression. The expression of VGLL4 mRNA was down-regulated and inversely correlated with miR-301b-3p level in HCC tissues. Notably, VGLL4 knockdown markedly repressed cell proliferation, resulted in G2/M phase arrest and promoted apoptosis of HCC cells. Accordingly, VGLL4 silencing rescued miR-301b-3p knockdown attenuated HCC cell proliferation, cell cycle progression and apoptosis resistance. Collectively, our results suggest that miR-301b-3p is highly expressed in HCC. miR-301b-3p facilitates cell proliferation, promotes cell cycle progression and inhibits apoptosis of HCC cells by repressing VGLL4.