Application of RNA interference (RNAi) in the clinic has improved with the development of novel delivery reagents (e.g., lipidoids). Although RNAi promises a therapeutic approach at silencing gene expression, practical methods for enhancing gene production still remain a challenge. Previously, we reported that double-stranded RNA (dsRNA) can activate gene expression by targeting promoter sequence in a phenomenon termed RNA activation (RNAa). In the present study, we investigate the therapeutic potential of RNAa in prostate cancer xenografts by using lipidoid-based formulation to facilitate in vivo delivery. We identify a strong activator of gene expression by screening several dsRNAs targeting the promoter of tumor suppressor p21WAF1/ Cip1 (p21). Chemical modification is subsequently implemented to improve the medicinal properties of the candidate duplex. Lipidoid-encapsulated nanoparticle (LNP) formulation is validated as a delivery vehicle to mediate p21 induction and inhibit growth of prostate tumor xenografts grown in nude mice following intratumoral injection. We provide insight into the stepwise creation and analysis of a putative RNAa-based therapeutic with antitumor activity. Our results provide proof-ofprinciple that RNAa in conjunction with lipidioids may represent a novel approach for stimulating gene expression in vivo to treat disease
Bibliographical noteFunding Information:
This work was supported by funds from the National Cancer Institute (1R21CA131774-01), National Institutes of Health (1R01GM090293-0109), Department of Defense (W81XWH-08-1-0260), California Institute for Regenerative Medicine (RL1-00660-1), Special Program of Research Excellence (SPORE) in prostate cancer (P50CA89520), and Alnylam Pharmaceuticals. Alnylam Pharmaceuticals holds licenses for intellectual property related to the RNAa technology and lipidoid-based delivery system. RNA Therapeutics acknowledges having received funds from Alnylam Pharmaceuticals. R.M., M.M., K.C., and R.D. are employees at Alnylam Pharmaceuticals. R.F.P. is employed at RNA Therapeutics. All other authors declared no conflict of interest.
- Gene activation
- Gene therapy
- Lipid nanoparticles
- Prostate cancer