The first proof-of-principle study showing that the gene-silencing technique RNA interference (RNAi) can indeed lower levels of gene expression in humans is revealed in Nature. The study, in human tumour biopsies, marks an important step towards the possible therapeutic use of RNAi to target disease.
RNA interference, a naturally occurring form of gene regulation, can be induced experimentally by treatment with small interfering RNAs (siRNAs), double-stranded RNA molecules designed to interfere specifically with key genes. In this study, biopsies from three melanoma patients who had received siRNA infusions revealed dose-dependent reductions in the levels of target messenger RNA and protein.
The results form part of the first in-human phase I clinical trial of systemic siRNA treatment for patients with solid cancers using a targeted, nanoparticle delivery system -- designed to help the siRNA get to where it needs to go. Mark E. Davis and colleagues show that the injected siRNA yields its effects by RNAi, a feat hitherto demonstrated in mouse and non-human primate models. Because RNAi is likely to be applicable to any gene, the study hints that targeted delivery of siRNA by nanoparticles may prove a useful way of controlling many previously unreachable drug targets.
Mark E. Davis (California Institute of Technology, Pasadena, CA, USA)
Abstract available online.
(C) Nature press release.
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