MiR-371a-5p Positively Associates with Hepatocellular Carcinoma Malignancy but Sensitizes Cancer Cells to Oxaliplatin by Suppressing BECN1-Dependent Autophagy

Abstract

Oxaliplatin (OXA)-based chemotherapy demonstrates active efficacy in advanced hepatocellular carcinoma (HCC), while resistance development limits its clinical efficacy. Thus, identifying resistance-related molecules and underlying mechanisms contributes to improving the therapeutic efficacy of HCC patients. MicroRNA-371a-5p (MiR-371a-5p) fulfills an important function in tumor progression. However, little is known about the effect of miR-371a-5p on chemotherapy response. In this study, quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry were used to determine the expression levels of miR-371a-5p, BECN1 and autophagy-related proteins in HCC cells, tissues and serum. The luciferase reporter assay was used to assess the directly suppressive effect of miR-371a-5p on BECN1 mRNA translation. Moreover, gain- and loss-of-function assays and rescue assays were used to evaluate the mediated effect of BECN1-dependent autophagy on the role of miR-371a-5p in the response of HCC cells to OXA. We found that miR-371a-5p was significantly up-regulated in HCC tissues and serum from patients, whereas BECN1 protein was down-regulated in HCC tissues compared to the corresponding controls. We also found that there was a negative correlation between the two molecules in HCC tissues. In addition, we found that miR-371a-5p expression was positively associated with malignant characteristics of HCC and BECN1 protein expression is negatively associated. Contrary to this, we found that miR-371a-5p enhances and BECN1 attenuates the response of HCC cells to OXA. Importantly, the enhanced effect of miR-371a-5p on the response of HCC cells to OXA could be reduced by re-expression of non-targetable BECN1, and then the reduced effect was restored following bafilomycin A treatment. Taken together, we identified a dual role of miR-371a-5p in HCC malignant characteristics and the response of HCC cells to oxaliplatin. Importantly, we reveal that miR-371a-5p enhances oxaliplatin response by target suppression of BECN1-dependent autophagy.