Advances in synthetic siRNA delivery.

The application of RNA interference-based gene silencing technologies has the potential to treat a variety of illness. Preclinical studies and some early clinical trials have already demonstrated the utility of small interfering RNAs (siRNAs) as a potential novel therapy for the treatment of cancer, viral infections, as well as a wide range of additional diseases. To be effective, an siRNA must be taken up by specific cells, enter the cytoplasm, and be loaded onto the Argonaute protein, the catalytic core of the RNA induced silencing complex (RISC) to direct the cleavage of the homologous transcripts. To meet this need, a variety of novel siRNA delivery strategies have been developed. As our understanding of the molecular mechanisms underlying the RNAi pathway has increased so has the ability to rationally design effective silencing and delivery strategies. This review will examine the latest advances in non-viral delivery of siRNA, with special reference to targeted siRNA delivery to specific target tissues and cell types in vivo in preclinical animal models.