MicroRNA-520g induces epithelial–mesenchymal transition and promotes metastasis of hepatocellular carcinoma by targeting SMAD7

• MiR-520g is obviously up-regulated in HCC tissues and cells.
• High miR-520g expression correlates with poor prognostic features and short survival.
• Up-regulation of miR-520g promotes HCC cell migration, invasion and EMT.
• SMAD7 is a direct target of miR-520g.
• SMAD7 functions in elevated miR-520g-induced HCC cell mobility and EMT.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Aberrant expression of miRNAs contributes to HCC development. Here, we observed elevated miR-520g expression in tumor samples from HCC patients with relapse and metastasis, and this high miR-520g expression was correlated with poor survival. Through gain- and loss-of-function studies, miR-520g was demonstrated to facilitate HCC cell migration, invasion and epithelial–mesenchymal transition (EMT). SMAD7 was identified as a direct target of miR-520g. Accordingly, we conclude that high miR-520g expression promotes HCC cell mobility and EMT by targeting SMAD7, and this is correlated with reduced survival in HCC patients.