title: Phosphatidylethanolamine mediated destabilization of lipid-based pDNA delivery systems.
abstract: We have previously reported the development of lipid-DNA particles (LDPs) formed, via a hydrophobic cationic lipid-DNA complex intermediate, when detergent-solubilized cationic lipids are mixed with DNA. This study investigates the influence of zwitterionic co-lipid headgroups on the formation and stability of this intermediate and the subsequent DNA protection and transfection properties afforded by the resultant LDPs. We report that inclusion of diacylphosphatidylethanolamines (diacylPE), but not diacylphosphatidylcholines (diacylPC), as co-lipids destabilizes and prevents the formation of the cationic lipid-DNA intermediate to an extent dependent on the concentration of diacylPE and its acyl chain characteristics. DNA formulated in LDPs containing cationic:zwitterionic lipids at a 1:1 ratio is not readily accessible to the intercalating fluorescent dye, TO-PRO-1. At a lipid ratio 1:4, diacylPC LDPs are associated with significantly greater TO-PRO-1 fluorescence than equivalent diacylPE formulations, a result believed to reflect lipid-dependent penetration of TO-PRO-1 through the supramolecular LDP assembly, rather than condensation and protection of the DNA per se. Transfection studies utilizing the in vitro murine B16/BL6 melanoma cell line and the in vivo intraperitoneal B16/BL6 mouse tumor model demonstrated that only diacylPE LDPs mediated gene transfer. This was found not to be a consequence of differences in DNA delivery or cell toxicity.
authors.affiliation: Department of Advanced Therapeutics, British Columbia Cancer Agency, 601 West 10th Ave., Vancouver, BC, Canada V5Z 1L3.
authors.forename: F M P
authors.initials: FM
authors.lastname: Wong
authors.forename: P
authors.initials: P
authors.lastname: Harvie
authors.forename: Y-P
authors.initials: YP
authors.lastname: Zhang
authors.forename: E C
authors.initials: EC
authors.lastname: Ramsay
authors.forename: M B
authors.initials: MB
authors.lastname: Bally
mesh_terms: D000818:Animals; D002412:Cations; D002626:Chemistry, Pharmaceutical; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry*; D004355:Drug Stability; D005260:Female; D005456:Fluorescent Dyes; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D057927:Hydrophobic and Hydrophilic Interactions; D008546:Melanoma, Experimental / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008823:Micelles; D009829:Oleic Acids; D009930:Organic Chemicals; D010713:Phosphatidylcholines / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D010957:Plasmids / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism; D000644:Quaternary Ammonium Compounds; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D013501:Surface-Active Agents; D014407:Tumor Cells, Cultured
chemical_list: D002412:Cations; D004337:Drug Carriers; D005456:Fluorescent Dyes; D008823:Micelles; D009829:Oleic Acids; D009930:Organic Chemicals; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; C405903:TO-PRO-1; C110439:dioleoyldimethylammonium; D015500:Chloramphenicol O-Acetyltransferase