title: Gene silencing via RNAi and siRNA quantification in tumor tissue using MEND, a liposomal siRNA delivery system.
abstract: Small interfering RNA (siRNA) would be predicted to function as a cancer drug, but an efficient siRNA delivery system is required for clinical development. To address this issue, we developed a liposomal siRNA carrier, a multifunctional envelope-type nanodevice (MEND). We previously reported that a MEND composed of a pH-sensitive cationic lipid, YSK05, showed significant knockdown in both in vitro and in tumor tissue by intratumoral injection. Here, we report on the development of an in vivo siRNA delivery system that is delivered by systemic injection and an analysis of the pharmacokinetics of an intravenously administered siRNA molecule in tumor tissue. Tumor delivery of siRNA was quantified by means of stem-loop primer quantitative reverse transcriptase PCR (qRT-PCR) method. PEGylation of the YSK-MEND results in the increase in the accumulation of siRNA in tumor tissue from 0.0079% ID/g tumor to 1.9% ID/g tumor. The Administration of the MEND (3 mg siRNA/kg body weight) showed about a 50% reduction in the target gene mRNA and protein. Moreover, we verified the induction of RNA interference by 5' RACE-PCR method. The collective results reported here indicate that an siRNA carrier was developed that can deliver siRNA to a target cell in tumor tissue through an improved siRNA bioavailability.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sakurai
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatakeyama
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sato
authors.forename: Mamoru
authors.initials: M
authors.lastname: Hyodo
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Akita
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Harashima
mesh_terms: D061605:Administration, Intravenous; D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D018014:Gene Transfer Techniques; D006801:Humans; D008055:Lipids / Q000494:pharmacology; D008081:Liposomes / Q000737:chemistry*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000628:therapy*; D010880:Piperidines / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D018675:Toxicity Tests
chemical_list: D008055:Lipids; D008081:Liposomes; D010880:Piperidines; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C580570:YSK05; D011092:Polyethylene Glycols