MicroRNA-125a-5p Is a Downstream Effector of Sorafenib in Its Antiproliferative Activity Toward Human Hepatocellular Carcinoma Cells.

Sorafenib is an antitumor drug for treatment of advanced hepatocellular carcinoma (HCC). It acts as a multikinase inhibitor suppressing cell proliferation and angiogenesis. Human microRNA-125a-5p (miR-125a) is endowed with similar activities and is frequently downregulated in HCC. Looking for a potential microRNA-based mechanism of action of the drug, we found that sorafenib increases cellular expression of miR-125a in cultured HuH-7 and HepG2 HCC cells. Upregulation of the microRNA inhibited cell proliferation by suppression of sirtuin-7, a NAD(+)-dependent deacetylase, and p21/p27-dependent cell cycle arrest in G1. Later, recruitment of miR-125a in the antiproliferative activity of sorafenib was inquired by modulating its expression in combination with the drug treatment. This analysis showed that intracellular delivery of miR-125a had no additive effect on the antiproliferative activity of sorafenib, whereas a miR-125a inhibitor could counteract it. Finally, evaluation of other oncogenic targets of miR-125a revealed its ability to interfere with the expression of matrix metalloproteinase-11, Zbtb7a proto-oncogene, and c-Raf, possibly contributing to the antiproliferative activity of the drug. J. Cell. Physiol. 232: 1907-1913, 2017.