title: Cationic liposomes coated with polyethylene glycol as carriers for oligonucleotides.
abstract: Modification of liposome surface with polyethylene glycol was used to improve oligodeoxyribonucleotide (ODN) loading, stability of the resulting complexes, and specificity of cellular delivery of ODN by cationic liposomes. Liposomes composed of a cationic lipid (DOTAP, DOGS, DDAB), a neutral lipid (DOPE), and a phospholipid derivative of polyethylene glycol (PEG-PE) formed a complex with 18-mer phosphorothioate up to ODN/lipid molar ratio of 0.25. The complexes showed intact vesicular structures similar to original liposomes and their size (100-130 nm) was unchanged after several weeks of storage, whereas complexes lacking PEG-PE showed progressive aggregation and/or precipitation. After exposure to human plasma, PEG-modified cationic liposomes retained over 60% of the originally bound ODN. PEG-coated complexes resulted in 4-13-fold enhancement of the ODN uptake by human breast cancer cells in serum-supplemented growth medium, relative to free ODN. Complexes containing conjugated anti-HER2 F(ab') fragments at the distal termini of PEG chains efficiently delivered ODN primarily into the cytoplasm and nuclei of HER2 overexpressing cancer cells and greatly enhanced the biological activity of antisense ODN. The development of PEG-modified cationic liposomes may lead to improved ODN potency in vivo.
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94143, USA.
authors.forename: O
authors.initials: O
authors.lastname: Meyer
authors.forename: D
authors.initials: D
authors.lastname: Kirpotin
authors.forename: K
authors.initials: K
authors.lastname: Hong
authors.forename: B
authors.initials: B
authors.lastname: Sternberg
authors.forename: J W
authors.initials: JW
authors.lastname: Park
authors.forename: M C
authors.initials: MC
authors.lastname: Woodle
authors.forename: D
authors.initials: D
authors.lastname: Papahadjopoulos
mesh_terms: D000818:Animals; D002412:Cations; D004285:Dogs; D004337:Drug Carriers / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005614:Freeze Fracturing; D006801:Humans; D008081:Liposomes / Q000378:metabolism*; D008854:Microscopy, Electron; D009841:Oligonucleotides / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D011092:Polyethylene Glycols; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D002412:Cations; D004337:Drug Carriers; D008081:Liposomes; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; D011092:Polyethylene Glycols; D019253:Proto-Oncogene Proteins c-bcl-2; D018719:Erb-b2 Receptor Tyrosine Kinases