siRNA: novel therapeutics from functional genomics.

Long-term research on RNA interference led to an unfathomed understanding of the mechanism of siRNA-mediated silencing and finally siRNA has emerged as a powerful therapeutic tool. With siRNAs virtually every gene in the human genome contributing to a disease becomes amenable to regulation, thus opening unprecedented opportunities for drug discovery. siRNA has a well-established role as a tool for in vitro target screening and validation, besides these recent progresses of siRNA delivery in vivo, this has raised more expectations for siRNA-based drugs as the up-and-coming 'magic bullet'. Although a plethora of articles have been published with siRNA, the fundamentals of siRNA-mediated gene silencing and transforming the functional genomics to novel therapeutics are reviewed in this article with consideration to present hurdles as a new generation challenge.