Background and objective: The combination of two or more different mechanisms of drugs in the treatment of cancer has become one of the effective methods. The purpose of this study was to successfully prepare a non-viral delivery system that could efficiently co-delivery siRNA and gambogenic acid (GNA) to improve the anti-cancer efficiency in HepG2 cells. Methods: The delivery system was prepared by a two-step method. First, the GNA-anionic liposome took shape by a solvent evaporation method, and then the liposome was bound to the PEI/siRNA complex by electrostatic interaction to form the final carrier system (lipopolyplexes). Agarose gel electrophoresis, MTT, particle size and zeta potential were detected to analyse the lipopolyplexes formation. The transfection efficiency of siRNA was determined by confocal laser scanning microscopy and flow cytometry. Western blotting was used to assess the VEGF protein expression levels of HepG2 cells. The cell apoptosis assay was used to assess the anti-tumour superiority of lipopolyplexes. Results: GNA-PEI/siRNA-liposome (lipopolyplexes) are significantly less cytotoxicity compared to PEI mediated carriers. Simultaneously, the results of flow cytometry and confocal laser scanning microscopy indicated that the lipopolyplexes could successfully carry siRNA into the cytoplasm, and the western-blot result evidence that the delivery system has a potential for VEGF to express down. Also compared with the control group, the results of apoptosis test suggest that the lipopolyplexes can significantly promote cell apoptosis. Conclusion: The delivery system has a potential in the combination of various drugs for cancer therapy in future.
Keywords: Gambogenic acid; VEGF-siRNA; anionic liposome; co-delivery; polyethyleneimine.