title: Calcium enhances the transfection potency of plasmid DNA-cationic liposome complexes.
abstract: It is shown that calcium increases the in vitro transfection potency of plasmid DNA-cationic liposome complexes from 3- to 20-fold. The effect is Ca(2+) specific as other cations, such as Mg(2+) and Na(+), do not give rise to enhanced transfection and the effect can be inhibited by the presence of EGTA. It is shown that Ca(2+) increases cellular uptake of the DNA-lipid complexes, indicating that increased transfection potency arises from increased intracellular delivery of both cationic lipid and plasmid DNA in the presence of Ca(2+). In particular, it is shown that the levels of intact intracellular plasmid DNA are significantly enhanced when Ca(2+) is present. The generality of the Ca(2+) effect for enhancing complex-mediated transfection is demonstrated for a number of different cell lines and different cationic lipid formulations. It is concluded that addition of Ca(2+) represents a simple and useful protocol for enhancing in vitro transfection properties of plasmid DNA-cationic lipid complexes.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, 2146 Health Sciences Mall, Vancouver, BC, Canada. milam@interchange.ubc.ca
authors.forename: A M
authors.initials: AM
authors.lastname: Lam
authors.forename: P R
authors.initials: PR
authors.lastname: Cullis
mesh_terms: D000818:Animals; D002118:Calcium; D002250:Carbon Radioisotopes; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003587:Cytomegalovirus / Q000235:genetics; D004337:Drug Carriers; D004533:Egtazic Acid / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006801:Humans; D008081:Liposomes; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D010714:Phosphatidylethanolamines / Q000493:pharmacokinetics; D010957:Plasmids / Q000008:administration & dosage / Q000187:drug effects; D011401:Promoter Regions, Genetic; D000644:Quaternary Ammonium Compounds / Q000493:pharmacokinetics; D014162:Transfection / Q000379:methods*; D014407:Tumor Cells, Cultured
chemical_list: D002250:Carbon Radioisotopes; D004337:Drug Carriers; D008081:Liposomes; D008164:Luminescent Proteins; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; D049452:Green Fluorescent Proteins; C015831:dimethyldioctadecylammonium; D004533:Egtazic Acid; C020888:1,2-dielaidoylphosphatidylethanolamine; D002118:Calcium