Targeted delivery to neuroblastoma of novel siRNA-anti-GD2-liposomes prepared by dual asymmetric centrifugation and sterol-based post-insertion method.

PURPOSE: To optimise and simplify preparation of targeted liposomes for efficient siRNA delivery to neuroblastoma, the most common solid tumour in early childhood.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.