title: Folate-targeted, anionic liposome-entrapped polylysine-condensed DNA for tumor cell-specific gene transfer.
abstract: We have developed a lipidic gene transfer vector, LPDII, where DNA was first complexed to polylysine at a ratio of 1:0.75 (w/w) and then entrapped into folate-targeted pH-sensitive anionic liposomes composed of dioleoyl phosphatidylethanolamine (DOPE)/cholesteryl hemisuccinate/folate-polyethlene glycol-DOPE (6:4:0.01 mol/mol) via charge interaction. LPDII transfection of KB cells, a cell line overexpressing the tumor marker folate receptor, was affected by both the lipid to DNA ratio and the lipid composition. At low lipid to DNA ratios (e.g. 4 and 6), LPDII particles were positively charged; transfection and cellular uptake levels were independent of the folate receptor and did not require a pH-sensitive lipid composition. Meanwhile, transfection and uptake of negatively charged LPDII particles, i.e. those with high lipid to DNA ratios (e.g. 10 and 12), were folate receptor-dependent and required a pH-sensitive lipid composition. The transfection activity of LPDII was lost when the inverted cone-shaped DOPE was replaced by dioleoyl phosphatidylcholine. LPDII particles with lipid to DNA ratios of 4, 6, 10, and 12 were approximately 20-30 times more active than DNA.3-beta-[N-(N',N'-dimethylethane)carbamoyl]cholesterol cationic liposome complexes in KB cells and were much less cytotoxic. On the sucrose gradient, LPDII particles had a migration rate in between those of the free DNA and the DNA.polylysine complex. An electron micrograph of LPDII showed a structure of spherical particles with a positively stained core enclosed in a lipidic envelope with a mean diameter of 74 +/- 14 nm. This novel gene transfer vector may potentially be useful in gene therapy for tumor-specific delivery.
authors.affiliation: Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Lee
authors.forename: L
authors.initials: L
authors.lastname: Huang
mesh_terms: D000838:Anions; D014408:Biomarkers, Tumor; D004247:DNA / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism; D005492:Folic Acid / Q000737:chemistry / Q000378:metabolism*; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D008081:Liposomes; D046911:Macromolecular Substances; D011107:Polylysine / Q000737:chemistry; D013329:Structure-Activity Relationship; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000838:Anions; D014408:Biomarkers, Tumor; D008081:Liposomes; D046911:Macromolecular Substances; D011107:Polylysine; D004247:DNA; D005492:Folic Acid