title: Enhanced gene delivery to HER-2-overexpressing breast cancer cells by modified immunolipoplexes conjugated with the anti-HER-2 antibody.
abstract: Cationic liposome-mediated gene delivery to tumors has met with only limited success due to the low transfection efficiency and lack of target specificity. We developed a gene delivery system for HER-2-overexpressing cells by adding modified anti-HER-2 Fab' fragments to liposome/DNA complexes (lipoplexes). The modified anti-HER-2-Fab' was conjugated to liposomes containing cationic lipids such as 1,2-dioleoyl-3-(trimethylammonium) propane and cholesterol (1:1 w/w) using a maleimido-polyethyleneglycol-3400-1,2-dioleoyl-3-sn-phosphatidylethanolamine linker. The specific modification constricted the sizes of these immunolipoplexes to a range of 0.3- 0.7 microm, and they remained stable for a longer duration of time compared to the lipoplex controls (0.8-3.2 microm at 4 h). In addition, a 10-fold increase in luciferase activity was achieved after transfecting human breast cancer SK-BR3 cells with immunolipoplexes as compared to the control lipoplexes. Flow cytometry analysis demonstrated that 80% of SK-BR3 cells expressed the green fluorescent protein (GFP) 48 h after being transfected with immunolipoplexes, while only 40% of those with control lipoplexes and 3% of those with naked DNA alone expressed GFP. Furthermore, the anti-HER-2 immunolipoplexes showed specific enhancement of transfection efficiency in HER-2-overexpressing SK-BR3 cells (a 6-fold increase in luciferase activity) but not in HER-2-negative MCF-7 breast cancer cells. The enhancement of gene delivery by anti-HER-2 immunoliposomes was not affected by the presence of serum. These results demonstrate the feasibility of improving target-specific gene delivery to HER-2-overexpressing cells by insertion of lipid-modified anti-HER-2-Fab' into the preformed liposomes.
authors.affiliation: Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, No. 1 Jen-Ai Road, Sec. 1, Taipei 100, Taiwan, ROC.
authors.forename: Chien-Hsin
authors.initials: CH
authors.lastname: Lee
authors.forename: Michael
authors.initials: M
authors.lastname: Hsiao
authors.forename: Yun-Long
authors.initials: YL
authors.lastname: Tseng
authors.forename: Fu-Hsiung
authors.initials: FH
authors.lastname: Chang
mesh_terms: D000912:Antibodies, Neoplasm / Q000235:genetics*; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D018390:Gene Targeting / Q000379:methods*; D006801:Humans; D008081:Liposomes; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000502:physiology*; D014162:Transfection
chemical_list: D000912:Antibodies, Neoplasm; D008081:Liposomes; D018719:Erb-b2 Receptor Tyrosine Kinases