Effects of RNA interference-mediated knockdown of livin and survivin using monomethoxypolyethylene glycol-chitosan nanoparticles in MG-63 osteosarcoma cells

Abstract

MG-63 human osteosarcoma cells were transfected with short hairpin RNA (shRNA) against livin and survivin using monomethoxypolyethylene glycol-chitosan (mPEG-CS) nanoparticles (NPs) as carriers, with the aim of evaluating the effect on cell proliferation and apoptosis. mPEG-CS NPs sized ∼100 nm were prepared by ionic crosslinking. mPEG-CS-livin shRNA, mPEG-CS-survivin shRNA and mPEG-CS-(livin shRNA + survivin shRNA) NPs were constructed by electrostatic adsorption at NP suspension/gene solution ratios of 3:1 to transfect MG-63 cells. The expression levels of livin and survivin mRNA and protein were measured by reverse transcription-polymerase chain reaction and western blotting, respectively. The inhibitory effects of downregulated livin and survivin expression on cell proliferation were measured using an MTT assay. The apoptosis-inducing effects of livin and surivin knockdown were investigated using a Hoechst staining kit. All shRNA groups resulted in reduced expression of livin and survivin mRNA and protein in MG-63 cells. The MTT assay and Hoechst staining indicated that simultaneous knockdown of livin and survivin genes inhibited the proliferation of MG-63 cells and promoted their apoptosis, to a greater extent than knocking down either gene individually. The simultaneous interference mediated by mPEG-CS NPs significantly reduced livin and survivin expression in MG-63 cells, suppressed proliferation and facilitated apoptosis, to a greater extent than knockdown of either livin or survivin alone were. Thus the results indicate a synergistic effect of livin and survivin.