Oral administration of attenuated S. typhimurium carrying shRNA-expressing vectors as a cancer therapeutic.

RNAi has been successfully applied in genomic research, and it also holds considerable promise as a therapeutic approach to suppress disease-causing gene expression. Here, we show that attenuated S. typhimurium were capable of delivering shRNA-expressing vectors to mammalian cells and inducing RNAi in vitro and in vivo. Upon oral administration, S. typhimurium carrying shRNA-expressing vectors targeting bcl2 induced significant gene silencing in murine melanoma cells that led to a remarkably delayed tumor growth and prolonged survival in the mouse model. These results suggest that bacteria mediated RNAi may be a new potent approach to the treatment of cancers.