Delivery of miR-375 and doxorubicin hydrochloride by lipid-coated hollow mesoporous silica nanoparticles to overcome multiple drug resistance in hepatocellular carcinoma

Multidrug resistance (MDR) due to overexpression of P-glycoprotein (P-gp) is a major obstacle that hinders the treatment of hepatocellular carcinoma (HCC). It has been shown that miR-375 inhibits P-gp expression via inhibition of astrocyte elevated gene-1 (AEG-1) expression in HCC, and induces apoptosis in HCC cells by targeting AEG-1 and YAP1. In this study, we prepared lipid-coated hollow mesoporous silica nanoparticles (LH) containing doxorubicin hydrochloride (DOX) and miR-375 (LHD/miR-375) to deliver the two agents into MDR HCC cells in vitro and in vivo. We found that LHD/miR-375 overcame drug efflux and delivered miR-375 and DOX into MDR HepG2/ADR cells or HCC tissues. MiR-375 delivered by LHD/miR-375 was taken up through phagocytosis and clathrin- and caveolae-mediated endocytosis. Following release from late endosomes, it repressed the expression of P-gp in HepG2/ADR cells. The synergistic effects of miR-375 and hollow mesoporous silica nanoparticles (HMSN) resulted in a profound increase in the uptake of DOX by the HCC cells and prevented HCC cell growth. Enhanced antitumor effects of LHD/miR-375 were also validated in HCC xenografts and primary tumors; however, no significant toxicity was observed. Mechanistic studies also revealed that miR-375 and DOX exerted a synergistic antitumor effect by promoting apoptosis. Our study illustrates that delivery of miR-375 using HMSN is a feasible approach to circumvent MDR in the management of HCC. It, therefore, merits further development for potential clinical application.