Targeted Delivery to Neuroblastoma of Novel siRNA-anti-GD2-liposomes Prepared by Dual Asymmetric Centrifugation and Sterol-Based Post-Insertion Method

Abstract

To optimise and simplify preparation of targeted liposomes for efficient siRNA delivery to neuroblastoma, the most common solid tumour in early childhood. Liposomes containing siRNA were prepared by combining the novel dual asymmetric centrifugation (DAC) method and the recently optimised sterol-based post-insertion technique (SPIT) to couple anti-GD2 antibody for selective interaction with neuroblastoma cells. Cultured human neuroblastoma cell lines were used to evaluate the efficiency of siRNA delivery. The size of liposomes prepared by DAC ranged from 190 to 240 nm; siRNA encapsulation efficiency was up to 50%. An average of 70 and 100 molecules of anti-GD2 antibody per particle were coupled. A significant association of liposomes with neuroblastoma cells as well as effective siRNA delivery was observed only when anti-GD2 antibody was coupled. Preliminary data suggest delivery of siRNA using anti-GD2-liposomes occurs via GD2-mediated endocytosis. Vascular endothelial growth factor A (VEGF-A) was down-regulated using siRNA delivered by anti-GD2-liposomes. DAC and SPIT allow for the straightforward preparation of liposomes for the targeted delivery of siRNA. Anti-GD2-liposomes thus produced can serve as versatile carriers of siRNA to neuroblastoma cells.