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Attenuated Salmonella typhimurium carrying shRNA-expressing vectors elicit RNA interference in murine bladder tumors.

ABSTRACT: AIM: To examine whether attenuated Salmonella typhimurium (S typhimurium) could be used as an anti-cancer agent or a tumor-targeting vehicle for delivering shRNA-expressing pDNA into cancer cells in a mouse tumor model. METHODS: Mouse bladder transitional cancer cell line (BTT-T739) expressing GFP was used, in which the GFP expression level served as an indicator of RNA interference (RNAi). BTT-T739-GFP tumor-bearing mice (4-6 weeks) were treated with S typhimurium carrying plasmids encoding shRNA against gfp or scrambled shRNA. The mRNA and protein expression levels of GFP were assessed 5 d after the bacteria administration, and the antitumor effects of S typhimurium were evaluated. RESULTS: In BTT-T739-GFP tumor-bearing mice, S typhimurium (1×10(9) cfu, po) preferentially accumulated within tumors for as long as 40 d, and formed a tumor-to-normal tissue ratio that exceeded 1000/1. S typhimurium carrying plasmids encoding shRNA against gfp inhibited the expression of GFP in tumor cells by 73.4%. Orally delivered S typhimurium significantly delayed tumor growth and prolonged the survival of tumor-bearing mice. CONCLUSION: This study demonstrates that attenuated S typhimurium can be used for both delivering shRNA-expressing vectors into tumor cells and eliciting RNAi, thus exerting anti-tumor activity, which may represent a new strategy for the treatment of solid tumors.

SUBMITTER: Yang N

PROVIDER: S-EPMC4002778 | biostudies-other | 2011 Mar

REPOSITORIES: biostudies-other

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Attenuated Salmonella carrying plasmid co-expressing HPV16 L1 and siRNA-E6 for cervical cancer therapy.

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