title: VEGF siRNA delivery system using arginine-grafted bioreducible poly(disulfide amine).
abstract: Small interfering RNAs (siRNAs) are able to silence their target genes when they are successfully delivered intact into the cytoplasm. Delivery systems that enhance siRNA localization to the cytoplasm can facilitate gene silencing by siRNA therapeutics. We describe an arginine-conjugated poly(cystaminebisacrylamide-diaminohexane) (poly(CBA-DAH-R)), a bioreducible cationic polymer, as an siRNA carrier for therapeutic gene silencing for cancer. After intracellular uptake of the siRNA/poly(CBA-DAH-R) polyplexes, the reductive environment of the cytoplasm cleaves the disulfide linkages in the polymeric backbone, resulting in decomplexing of the siRNA/poly(CBA-DAH-R) polyplexes and release of siRNA molecules throughout the cytoplasm. The siRNA/poly(CBA-DAH-R) polyplexes, which demonstrate increased membrane permeability with arginine modification, have a similar level of cellular uptake as siRNA/bPEI polyplexes. The VEGF siRNA/poly(CBA-DAH-R) polyplexes, however, inhibit VEGF expression to a greater degree than VEGF siRNA/bPEI in various human cancer cell lines. The improved RNAi activity demonstrated by the VEGF siRNA/poly(CBA-DAH-R) polyplexes is due to enhanced intracellular delivery and effective localization to the cytoplasm of the VEGF siRNAs. These results demonstrate that the VEGF siRNA/poly(CBA-DAH-R) polyplex delivery system may useful for siRNA-based approaches for cancer therapy.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: Sun Hwa
authors.initials: SH
authors.lastname: Kim
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Jeong
authors.forename: Tae-il
authors.initials: TI
authors.lastname: Kim
authors.forename: Sung Wan
authors.initials: SW
authors.lastname: Kim
authors.forename: David A
authors.initials: DA
authors.lastname: Bull
mesh_terms: D001120:Arginine / Q000737:chemistry*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D024202:Electrophoretic Mobility Shift Assay; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D011073:Polyamines / Q000138:chemical synthesis / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000737:chemistry*; D014162:Transfection / Q000379:methods; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism
chemical_list: D011073:Polyamines; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; D001120:Arginine