Olaparib and Enzalutamide synergistically suppress HCC progression via the AR-mediated miR-146a-5p/BRCA1 signaling

Abstract

AbstractHepatocellular carcinoma (HCC) is one of most common malignant tumors worldwide, however, the treatment for advanced HCC remains unsatisfactory. Here we found that Olaparib, a FDA approved PARP inhibitor, could enhance the cytotoxicity in HCC cells with a lower BRCA1 expression, and suppressing the AR with either Enz or AR-shRNA could further increase the Olaparib sensitivity to better suppress the HCC cell growth via a synergistic mechanism that may involve suppressing the expression of BRCA1 and other DNA damage response (DDR) genes. Mechanism studies revealed that Enz/AR signaling might transcriptional regulting the miR-146a-5p expression via binding to the AREs on its 5’ promoter region, which could then lead to suppress the homologous recombination-related BRCA1 expression via direct binding to its 3’ UTR of mRNA. Preclinical study using an in vivo mouse model also proved that combined Enz plus Olaparib led to better suppression of the HCC progression. Together, these in vitro/in vivo data suggest that combining Enz and Olaparib may help in the development of a novel therapy to better suppress the HCC progression.