Enhanced Systemic Anti-Angiogenic siVEGF Delivery Using PEGylated Oligo-d-arginine.

Angiogenesis mainly mediated by upregulation of vascular endothelial growth factor (VEGF) provides a hallmark of rapidly proliferating tumor cells and an essential component of the tumor growth and microenvironment, making it a targetable process for antitumor therapy. RNA interference (RNAi) provides a very effective tool for developing antitumor therapies; however, its application to date has been hampered due to the lack of efficient small interfering RNA (siRNA) delivery systems in vivo. Here, we report a polymeric gene carrier system based on PEGylation of a cationic cysteine-ended 9-mer arginine oligopeptide (CR9C), which provides effective siRNA systemic delivery and specifically suppresses VEGF (siVEGF). The PEG500-CR9C/siVEGF oligopeptoplex provided improved blood circulation, enhanced protection from serum proteases, reduced uptake in the liver and kidneys, enhanced tumor targeting, and down-regulated intratumoral VEGF level, which comprehensively resulted in improved antitumor efficacy without significant toxicity in vivo. PEG500-CR9C has a great potential for safe and efficient siRNA delivery with diverse applications.

Amelioration of atherosclerotic inflammation and plaques via endothelial adrenoceptor-targeted eNOS gene delivery using redox-sensitive polymer bearing l-arginine.

Endothelial dysfunction combined with inflammation leads to atherosclerosis. Endothelium-specific delivery of therapeutic agents at the cellular level-specifically in vivo-is still a difficult task for proper management of atherosclerosis. We designed a redox-sensitive poly(oligo-l-arginine) (rsPOLA) playing dual roles as an endothelium α-2 adrenoceptors(α-2ARs)-targeted gene carrier and as a substrate for endothelial nitric oxide synthase (eNOS). Overexpression of α-2ARs on atherosclerotic endothelial cells was confirmed and the eNOS/rsPOLA nanoplexes following systemic injection demonstrated to 1) enhance eNOS gene delivery into endothelial cells via α-2ARs/l-arginine specific binding, 2) increase intracellular level of nitric oxide, 3) suppress inflammatory response in endothelium and finally 4) reduce atherosclerotic plaque in a Ldlr-/- atherosclerotic mouse model. Among the tested nanoplexes [eNOS/rsPOLA, eNOS/{poly(oligo-d-arginine), rsPODA} and eNOS/(racemic mixture, rsRM)], eNOS/rsPOLA reduced atherosclerotic inflammation most effectively as we hypothesized. Current treatment strategy provides strong potential for further development of a gene therapeutic system to ameliorate inflammation and progressive atherosclerotic plaques.

RNAi-mediated silencing of TNF-α converting enzyme to down-regulate soluble TNF-α production for treatment of acute and chronic colitis.

Elevated level of tumor necrosis factor-α (TNF-α), one of the inflammatory cytokines, is considered to be a potential target for the inflammatory bowel disease (IBD) therapy. Recently, TNF-α converting enzyme (TACE), a sheddase playing an important role in cleaving and releasing bioactive soluble TNF-α, has been challenged with inhibitors to treat inflammatory diseases. Here, we report a novel anti-TNF-α strategy using a short hairpin RNA silencing TACE (shTACE) to prevent and treat colitis. The shTACE formed stable complexes with nona-arginine-based bio-cleavable disulfide bond-linked poly (arginine) (PAs-s) for enhanced gene delivery. Systemically administered shTACE/PAs-s peptoplexes efficiently decreased TNF-α levels, increased survival and alleviated pathophysiological parameters representing colitis severity. Our results demonstrate effectiveness and safety of shTACE/PAs-s peptoplexes with the capacity of overcoming acute and chronic ulcerative colitis through modulation of excessive inflammatory responses in the colon, providing a strong potential as a therapeutic agent for a broad variety of inflammatory diseases.