Liu and colleagues have developed an siRNA delivery method that addresses 2 major challenges of using RNA interference for treating diseases: increasing siRNA potency and providing more targeted delivery. Working with in vitro and in vivo model systems for prostate cancer, the scientists used a dendrimer-based, targeted nano-delivery system to transport Dicer Substrate RNAs (DsiRNAs) into PC-3 cells and nude mice bearing PC-3 prostate cancer xenografts.
Coupling this delivery mechanism with DsiRNAs resulted in a much greater RNAi response and, thus, improved therapeutic efficacy, than when conventional siRNAs were used. Further decoration of the DsiRNA/dendrimer complexes with a peptide that simultaneously promotes cancer cell targeting and penetration, led to improved gene silencing and anticancer activity in prostate cancer models in vitro and in vivo.