Hypoxia-inducible MicroRNA-210 augments the metastatic potential of tumor cells by targeting vacuole membrane protein 1 in hepatocellular carcinoma

UNLABELLED: As the "master" microRNA that is induced by hypoxia, miR-210 is involved in multiple processes in the hypoxia pathway. However, whether miR-210 mediates hypoxia-induced tumor cell metastasis still remains unclear. Here, we demonstrate that miR-210 is frequently up-regulated in hepatocellular carcinoma (HCC) samples and promotes the migration and invasion of HCC cells. Furthermore, miR-210 can be induced by hypoxia in HCC cells and mediates hypoxia-induced HCC cell metastasis. We identify vacuole membrane protein 1 (VMP1) as the direct and functional downstream target of miR-210; in addition, we show that its expression is negatively correlated with the expression of miR-210 in HCC. Intriguingly, VMP1 is reduced by hypoxia, and down-regulation of VMP1 by miR-210 mediates hypoxia-induced HCC cell metastasis. CONCLUSION: These findings extend our understanding of the function of miR-210 in the hypoxia pathway, and this newly identified hypoxia/miR-210/VMP1 pathway should facilitate the development of novel therapeutics against hypoxic tumor cells.