title: Pancreatic cancer therapy by systemic administration of VEGF siRNA contained in calcium phosphate/charge-conversional polymer hybrid nanoparticles.
abstract: Development of an efficient in vivo delivery vehicle of small interfering RNA (siRNA) is the key challenge for successful siRNA-based therapies. In this study, toward systemic delivery of siRNA to solid tumors, a smart polymer/calcium phosphate (CaP)/siRNA hybrid nanoparticle was prepared to feature biocompatibility, reversible stability and endosomal escape functionality using a pH sensitive block copolymer of poly(ethylene glycol) and charge-conversional polymer (PEG-CCP), of which anionic functional groups could be converted to cationic groups in an endosomal acidic condition for facilitated endosomal escape. Nanoparticles were confirmed to be approximately 100nm in size, narrowly dispersed and spherical. Also, the nanoparticle was highly tolerable in medium containing serum, while releasing the entrapped siRNA in a cytoplasm-mimicking ionic condition, presumably based on the equilibrium between CaP complexes and calcium ions. Further, the nanoparticle showed high gene silencing efficiency in cultured pancreatic cancer cells (BxPC3) without associated cytotoxicity. Ultimately, systemic administration of the nanoparticles carrying vascular endothelium growth factor (VEGF) siRNA led to the significant reduction in the subcutaneous BxPC3 tumor growth, well consistent with the enhanced accumulation of siRNA and the significant VEGF gene silencing (~68%) in the tumor. Thus, the hybrid nanoparticle was demonstrated to be a promising formulation toward siRNA-based cancer therapies.
authors.affiliation: Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Frederico
authors.initials: F
authors.lastname: Pittella
authors.forename: Kanjiro
authors.initials: K
authors.lastname: Miyata
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Maeda
authors.forename: Tomoya
authors.initials: T
authors.lastname: Suma
authors.forename: Sumiyo
authors.initials: S
authors.lastname: Watanabe
authors.forename: Qixian
authors.initials: Q
authors.lastname: Chen
authors.forename: R James
authors.initials: RJ
authors.lastname: Christie
authors.forename: Kensuke
authors.initials: K
authors.lastname: Osada
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishiyama
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kataoka
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000008:administration & dosage; D045744:Cell Line, Tumor; D004337:Drug Carriers / Q000008:administration & dosage*; D005260:Female; D020868:Gene Silencing; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles / Q000008:administration & dosage; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000628:therapy*; D011092:Polyethylene Glycols / Q000008:administration & dosage; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
chemical_list: D002130:Calcium Phosphates; D004337:Drug Carriers; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; D011092:Polyethylene Glycols; C020243:calcium phosphate