Co-delivery of thioredoxin 1 shRNA and doxorubicin by folate-targeted gemini surfactant-based cationic liposomes to sensitize hepatocellular carcinoma cells.

The overexpression of thioredoxin (Trx) 1 is one of the mechanisms for drug resistance in hepatocellular carcinoma (HCC) treatment. The co-delivery of drugs and a short hairpin RNA (shRNA) against Trx1 to silence its expression might provide a promising approach to improve drug sensitivity to chemotherapeutic agents. In this paper, cationic liposomes containing gemini surfactants, soybean lecithin and DOPE were firstly constructed as gene transfection carriers. The length and symmetrical degree of aliphatic chains of gemini surfactants were found to affect gene transfection efficiency of cationic liposomes. Cationic liposome containing gemini surfactants with symmetrical C16 aliphatic chains (L16-2-16) showed the highest transfection efficiency in HCC Bel7402 cells and also displayed the strongest DNA condensation capacity and the highest cellular uptake. Folic acid (FA) targeting further enhanced the transfection efficiency of L16-2-16 by binding to the folate receptor (FR) in FR-overexpressing Bel7402 cells and lipid raft/caveolae-dependent endocytosis might be involved in FA-L16-2-16-mediated gene delivery. Then the multifunctional co-delivery system for doxorubicin (DOX) and Trx1 shRNA was developed via electrostatic interactions between the FA-L16-2-16 and Trx1 shRNA/DOX complex. Co-delivery of Trx1 shRNA and DOX by FA-L16-2-16 inhibited the cell viability and induced apoptosis of Bel7402 cells more efficiently than co-delivery of control shRNA and DOX. The system for co-delivering DOX and Trx1 shRNA could simultaneously achieve gene transfection and drug release in the same cell and increase the intracellular as well as intranuclear DOX concentrations. These results demonstrated that gemini surfactant-based cationic liposomes were promising carriers for the co-delivery of nucleic acids and chemotherapeutic agents to sensitize HCC chemotherapy.