title: A novel tetraester construct that reduces cationic lipid-associated cytotoxicity. Implications for the onset of cytotoxicity.
abstract: The preparation of cationic amphiphiles that induce minor cytotoxic response during polynucleotide delivery into mammalian cells has been limited by the conventional use of ester, amide, or carbamate linkages to tether either the polar or the hydrophobic domains. The deleterious effects of ammonium-based lipidic salts on cellular processes have been well-established. The present report is the first example of a linchpin tetraester construct that utilizes ester linkages to tether both the polar and hydrophobic domains. Dimyristoyl and dioleoyl analogues were prepared from pentaerythritol, N,N-dimethylglycine, and their corresponding fatty acyl groups via successive diesterifications followed by amine quaternization. The resultant cationic tetraesters were examined in transfection (luciferase) and cell proliferation (MTS) assays using NIH 3T3 and 16HBE14o- cells. The tetraesters exhibited transfection activity comparable to the well-studied lipids DOTAP and DC-cholesterol (DC-chol) in both cell lines. The tetraester construct afforded no cytotoxicity in NIH3T3 cells and provided a significant lowering of cytotoxicity relative to DC-chol in the 16HBE14o- cells. The expression of green fluorescent protein (GFP) in both cell lines also was examined using the lipid panel. Comparison of fluorescent and corresponding phase-contrast images confirmed the chemical cytotoxicity results and revealed that the cytotoxic response was not dependent on transgene expression. Phase-contrast micrographs of cells treated with the cationic lipid panel in the absence of GFP plasmid showed identical morphology to the GFP-transfected cells, suggesting that the onset of a lipid-mediated cytotoxic response might occur at a stage prior to endosomal encapsulation.
authors.affiliation: Department of Chemistry, University of California, Davis, California 95616, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Aberle
authors.forename: F
authors.initials: F
authors.lastname: Tablin
authors.forename: J
authors.initials: J
authors.lastname: Zhu
authors.forename: N J
authors.initials: NJ
authors.lastname: Walker
authors.forename: D C
authors.initials: DC
authors.lastname: Gruenert
authors.forename: M H
authors.initials: MH
authors.lastname: Nantz
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002412:Cations / Q000737:chemistry / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000031:analogs & derivatives / Q000494:pharmacology; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006868:Hydrolysis; D008055:Lipids / Q000737:chemistry* / Q000494:pharmacology*; D008156:Luciferases / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008956:Models, Chemical; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology; D014162:Transfection / Q000379:methods*
chemical_list: D002412:Cations; D005229:Fatty Acids, Monounsaturated; D008055:Lipids; D008164:Luminescent Proteins; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; C070648:3-(N-(N',N'-dimethylaminoethane)carbamoyl)cholesterol; D049452:Green Fluorescent Proteins; D002784:Cholesterol; D008156:Luciferases; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane