miR-128-3p suppresses hepatocellular carcinoma proliferation by regulating PIK3R1 and is correlated with the prognosis of HCC patients.

microRNAs (miRNAs) are known to be involved in the pathogenesis of hepatocellular carcinoma (HCC). miR-128-3p was recently reported to be deregulated in several types of cancer. However, the biological function and potential mechanisms of miR-128-3p in HCC remain unknown. In the present study, we found that miR-128-3p was frequently downregulated in HCC tissues and cell lines by qRT-PCR analysis. Moreover, functional assays showed that overexpression of miR-128-3p markedly suppressed HCC cell proliferation by inducing G1 phase cell arrest and migration. Mechanistically, miR-128-3p was confirmed to regulate PIK3R1 (p85α) expression thereby suppressing phosphatidylinositol 3-kinase (PI3K)/AKT pathway activation using qRT-PCR and western blot analysis. Furthermore, correlation analysis and Kaplan-Meier estimates revealed an inverse correlation between miR-128-3p and p85α as well as a shorter disease-free survival (DFS) period after HCC resection in patients with low miR-128-3p expression. Hence, we conclude that miR-128-3p, which is frequently downregulated in HCC, inhibits HCC progression by regulating PIK3R1 and PI3K/AKT activation, and is a prognostic marker for HCC patients.