title: Polyamidoamine dendron-bearing lipids as a nonviral vector: influence of dendron generation.
abstract: Recently, we demonstrated that octadecyl chains are important as alkyl chain moieties of polyamidoamine (PAMAM) dendron-bearing lipids for their serum-resistant transfection activity [Bioconjugate Chem.2007, 18, 1349-1354]. Toward production of highly potent vectors, we examined the influence of the generation of dendron moiety on transfection activity of PAMAM dendron-bearing lipids having two octadecyl chains. We synthesized dendron-bearing lipids with PAMAM G1, G2, and G3 dendrons, designated respectively as DL-G1-2C(18), DL-G2-2C(18), and DL-G3-2C(18). The DL-G2-2C(18) and DL-G3-2C(18) interacted with plasmid DNA effectively and formed stable lipoplexes with small sizes and spherical shape. However, DL-G1-2C(18) interacted with plasmid DNA less effectively and formed tubular-shaped lipoplexes with lower stability and larger size. Cells took up DL-G2-2C(18) and DL-G3-2C(18) lipoplexes efficiently, but cellular uptake of the DL-G1-2C(18) lipoplexes was less efficient. Nevertheless, DL-G1-2C(18) lipoplexes achieved 100-10 000 times higher levels of transgene expression, which was evaluated using luciferase gene as a reporter gene. Confocal scanning laser microscopic analysis of intracellular behaviors of the lipoplexes revealed that DL-G1-2C(18) lipoplexes generated free plasmid DNA molecules in the cytosol more effectively than other lipoplexes did. Moderate binding ability of DL-G1-2C(18) might be responsible for generation of lipoplexes which deliver plasmid DNA into cells, liberate it in the cytoplasm, and induce efficient transgene expression.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan. kono@chem.osakafu-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Kono
authors.forename: Ryuji
authors.initials: R
authors.lastname: Ikeda
authors.forename: Kota
authors.initials: K
authors.lastname: Tsukamoto
authors.forename: Eiji
authors.initials: E
authors.lastname: Yuba
authors.forename: Chie
authors.initials: C
authors.lastname: Kojima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Harada
mesh_terms: D004247:DNA / Q000737:chemistry / Q000235:genetics; D050091:Dendrimers / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry* / Q000633:toxicity; D006367:HeLa Cells; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D010316:Particle Size; D014162:Transfection / Q000379:methods*
chemical_list: D050091:Dendrimers; D004337:Drug Carriers; D008055:Lipids; C104700:PAMAM Starburst; D004247:DNA