title: Transfection properties of stabilized plasmid-lipid particles containing cationic PEG lipids.
abstract: Recent work has shown that plasmid DNA can be efficiently encapsulated in well-defined "stabilized plasmid-lipid particles" (SPLP) that have potential as systemic gene therapy vehicles [Gene Ther. 6 (1999) 271]. In this work, we examine the influence of ligands that enhance cellular uptake on the transfection potency of SPLP. The ligand employed is a cationic poly(ethylene glycol) (PEG) lipid (CPL) consisting of a lipid anchor and a PEG(3400) spacer chain with four positive charges at the end of the PEG (CPL(4)). It is shown that up to 4 mol% CPL(4) can be inserted into preformed SPLP, resulting in up to 50-fold enhancements in uptake into baby hamster kidney (BHK) cells. The addition of Ca(2+) to SPLP-CPL(4) (CPL(4)-incorporated SPLP) results in up to 10(6)-fold enhancements in transgene expression, as compared to SPLP in the absence of either CPL(4) or Ca(2+). These transfection levels are comparable to those observed for plasmid DNA-cationic lipid complexes (lipoplexes) but without the cytotoxic effects noted for lipoplex systems. It is concluded that in the presence of Ca(2+) and appropriate ligands to stimulate uptake, SPLP are highly potent transfection agents.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3.
authors.forename: Lorne R
authors.initials: LR
authors.lastname: Palmer
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Angela M I
authors.initials: AM
authors.lastname: Lam
authors.forename: David B
authors.initials: DB
authors.lastname: Fenske
authors.forename: Kim F
authors.initials: KF
authors.lastname: Wong
authors.forename: Ian
authors.initials: I
authors.lastname: MacLachlan
authors.forename: Pieter R
authors.initials: PR
authors.lastname: Cullis
mesh_terms: D000818:Animals; D002118:Calcium; D002413:Cations, Divalent; D002460:Cell Line; D006224:Cricetinae; D015316:Genetic Therapy; D008024:Ligands; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes; D015394:Molecular Structure; D010714:Phosphatidylethanolamines; D010957:Plasmids / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013997:Time Factors; D014162:Transfection / Q000379:methods*
chemical_list: D002413:Cations, Divalent; D008024:Ligands; D008055:Lipids; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011092:Polyethylene Glycols; C020888:1,2-dielaidoylphosphatidylethanolamine; D002118:Calcium