title: Dicetyl phosphate-tetraethylenepentamine-based liposomes for systemic siRNA delivery.
abstract: Dicetyl phosphate-tetraethylenepentamine (DCP-TEPA) conjugate was newly synthesized and formed into liposomes for efficient siRNA delivery. Formulation of DCP-TEPA-based polycation liposomes (TEPA-PCL) complexed with siRNA was examined by performing knockdown experiments using stable EGFP-transfected HT1080 human fibrosarcoma cells and siRNA for GFP. An adequate amount of DCP-TEPA in TEPA-PCL and N/P ratio of TEPA-PCL/siRNA complexes were determined based on the knockdown efficiency. Then, the biodistribution of TEPA-PCL modified with poly(ethylene glycol) (PEG) was examined in BALB/c mice. As a result, TEPA-PCL modified with PEG6000 avoided reticuloendothelial system uptake and showed long circulation in the bloodstream. On the other hand, PEGylation of TEPA-PCL/siRNA complexes caused dissociation of a portion of the siRNA from the liposomes. However, we found that the use of cholesterol-conjugated siRNA improved the interaction between TEPA-PCL and siRNA, which allowed PEGylation of TEPA-PCL/siRNA complexes without siRNA dissociation. In addition, TEPA-PCL complexed with cholesterol-conjugated siRNA showed potent knockdown efficiency in stable luciferase-transfected B16-F10 murine melanoma cells. Finally, the biodistribution of cholesterol-conjugated siRNA formulated in PEGylated TEPA-PCL was examined by performing near-infrared fluorescence imaging in Colon26 NL-17 murine carcinoma-bearing mice. Our results showed that tumor targeting with siRNA via systemic administration was achieved by using PEGylated TEPA-PCL combined with active targeting with Ala-Pro-Arg-Pro-Gly, a peptide used for targeting angiogenic endothelium.
authors.affiliation: Department of Medical Biochemistry and Global COE, University of Shizuoka Graduate School of Pharmaceutical Sciences, Shizuoka 422-8526, Japan. asai@u-shizuoka-ken.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Asai
authors.forename: Saori
authors.initials: S
authors.lastname: Matsushita
authors.forename: Eriya
authors.initials: E
authors.lastname: Kenjo
authors.forename: Takuma
authors.initials: T
authors.lastname: Tsuzuku
authors.forename: Norihito
authors.initials: N
authors.lastname: Yonenaga
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koide
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hatanaka
authors.forename: Takehisa
authors.initials: T
authors.lastname: Dewa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Nango
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Maeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Naoto
authors.initials: N
authors.lastname: Oku
mesh_terms: D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism; D005029:Ethylenediamines / Q000737:chemistry*; D005354:Fibrosarcoma / Q000378:metabolism / Q000473:pathology; D020868:Gene Silencing; D006801:Humans; D007275:Injections, Intravenous; D008081:Liposomes / Q000008:administration & dosage / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D057054:Molecular Imaging; D010755:Organophosphates / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*; D013055:Spectrophotometry, Infrared
chemical_list: D005029:Ethylenediamines; D008081:Liposomes; D010755:Organophosphates; D034741:RNA, Small Interfering; C002290:dicetylphosphate; D011092:Polyethylene Glycols; D002784:Cholesterol; C034269:tetraethylenepentamine