Study on co-delivery of pemetrexed disodium and Bcl-2 siRNA by poly-γ-glutamic acid-modified cationic liposomes for the inhibition of NSCLC

Due to the complexity of the pathophysiology of non-small cell lung cancer (NSCLC) and the susceptibility of single chemotherapy to drug resistance, the combination of drugs and small interfering RNA (siRNA) may produce a desired therapeutic effect on NSCLC through the action of multiple pathways. We designed to develop poly-γ-glutamic acid-modified cationic liposomes (γ-PGA-CL) to co-deliver pemetrexed disodium (PMX) and siRNA to treat NSCLC. Firstly, γ-PGA was modified on the surface of PMX and siRNA co-loaded cationic liposomes by electrostatic interaction (γ-PGA modified PMX/siRNA-CL). In order to evaluate whether the prepared γ-PGA modified PMX/siRNA-CL could be taken up by tumor cells and exert significant anti-tumor effects, in vitro and in vivo studies were performed, with A549 cells and LLC-bearing BABL/c mice as experimental models, respectively. The particle size and zeta potential of γ-PGA modified PMX/siRNA-CL was (222.07 ± 1.23) nm and (−11.38 ± 1.44) mV. A preliminary stability experiment showed the complex could protect siRNA from degradation. In vitro cell uptake experiment indicated the complex group exerted stronger fluorescence intensity and expressed higher flow detection value. Cytotoxicity study showed the cell survival rate of γ-PGA-CL was (74.68 ± 0.94)%. Polymerase chain reaction (PCR) analysis and western blot technology displayed that the complex could inhibit the expression of Bcl-2 mRNA and protein to promote cell apoptosis. In vivo anti-tumor experiments represented the complex group showed a significant inhibitory effect on tumor growth, while the vector showed no obvious toxicity. Therefore, the current studies proved the feasibility of combining PMX and siRNA by γ-PGA-CL as a potential strategy for the treatment of NSCLC.