Abstract
The success of small interfering RNA (siRNA)-mediated gene silencing for cancer therapy is still limited because of its instability and poor intracellular internalization. Traditional cationic carriers cannot adequately meet the need for clinical application of siRNA. We herein report a dual-functional liposome containing a cholesterol derivative of metformin, i.e., LipoMET, which takes advantage of the fusogenic activity as well as intrinsic tumor apoptosis inducing ability of biguanide moiety to achieve a combinational anti-oncogenic effect. In this study, the vascular endothelial growth factor (VEGF)-specific siRNAs were first electrostatically condensed into a ternary nanocomplex composed of polycation and hyaluronate, which was subsequently enveloped by LipoMET through membrane fusion. In comparison with common cationic control group, the resulting envelope-type nanoparticles (PH@LipoMET nanoparticles [NPs]) showed the ability of rapid cellular internalization and effective endosomal escape of siRNA during intracellular trafficking studies. Systemic administration of the targeted LipoMETs was capable of inducing apoptosis and tumor growth inhibition in the NCI-H460 xenograft model. When carrying VEGF-specific siRNAs, PH@LipoMET NPs remarkably downregulated the expression of VEGF and led to even more tumor suppression in vivo. Thus, LipoMET originated envelope-type nanoparticles may serve as a potential dual-functional siRNA delivery system to improve therapeutic effect of oncogene silencing.