title: Cytoplasm-responsive nanocarriers conjugated with a functional cell-penetrating peptide for systemic siRNA delivery.
abstract: To develop a gene carrier for cancer therapy by systemic injection, we synthesized methoxypolyethylene glycol-polycaprolactone (MPEG-PCL) diblock copolymers conjugated with a cytoplasm-responsive cell-penetrating peptide (CPP), CH2R4H2C (C, Cys; H, His; R, Arg). The carrier/small interfering RNA (siRNA) complexes (N/P ratio of 20) had a particle size of approximately 50 nm and stabilized the siRNA against RNase. The cellular uptake ability of the carrier/FAM-siRNA complexes with fetal bovine serum was significantly higher than that of naked FAM-siRNA. In addition, the carrier/anti-vascular endothelial growth factor siRNA (siVEGF) complexes attained a significantly greater silencing effect than naked siVEGF with low cytotoxicity, resulting from higher uptake, early endosomal escape, and efficient release from the complexes in the cytoplasm. Furthermore, intravenous injection of MPEG-PCL-CH2R4H2C/siVEGF complexes had a significantly higher anti-tumor effect in S-180 tumor-bearing mice, which could be attributed to the rigid compaction of siRNA by ionic interactions and disulfide linkages in the CPP polymer micelles in the blood, as well as higher release following cleavage of the disulfide bonds in the reductive cytosol. Taken together, our data demonstrated that these cytoplasm-responsive polymer micelles conjugated with multi-functional CPP, could facilitate siVEGF delivery to tumor tissues after systemic injection and could exert an extremely strong anti-tumor effect.
authors.affiliation: Laboratory of Pharmaceutics and Drug Delivery, Department of Pharmaceutical Science, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Tanaka
authors.forename: Takanori
authors.initials: T
authors.lastname: Kanazawa
authors.forename: Shogo
authors.initials: S
authors.lastname: Horiuchi
authors.forename: Taichi
authors.initials: T
authors.lastname: Ando
authors.forename: Ken
authors.initials: K
authors.lastname: Sugawara
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Takashima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Seta
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okada
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D057846:Cell-Penetrating Peptides / Q000008:administration & dosage* / Q000737:chemistry; D003593:Cytoplasm; D004337:Drug Carriers / Q000008:administration & dosage* / Q000737:chemistry; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D009369:Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D011091:Polyesters / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry; D047368:Tumor Burden / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
chemical_list: D057846:Cell-Penetrating Peptides; D004337:Drug Carriers; D011091:Polyesters; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; C439611:methoxy poly(ethylene glycol-co-epsilon-caprolactone); D011092:Polyethylene Glycols
keywords: Anti-VEGF siRNA; Anti-tumor effect; Cell-penetrating peptide; Cytoplasm-responsive nanocarriers; Disulfide linkage; Systemic delivery polymer micelles