title: Different strategies for formation of pegylated EGF-conjugated PEI/DNA complexes for targeted gene delivery.
abstract: With the aim of generating gene delivery systems for tumor targeting, we have synthesized a conjugate consisting of polyethylenimine (PEI) covalently modified with epidermal growth factor (EGF) peptides. Transfection efficiency of the conjugate was evaluated and compared to native PEI in three tumor cell lines: KB epidermoid carcinoma cells, CMT-93 rectum carcinoma cells, and Renca-EGFR renal carcinoma cells. Depending on the tumor cell line, incorporation of EGF resulted in an up to 300-fold increased transfection efficiency. This ligand-mediated enhancement and competition with free EGF strongly suggested uptake of the complexes through the EGF receptor-mediated endocytosis pathway. Shielded particles being crucial for systemic gene delivery, we studied the effect of covalent surface modification of EGF-PEI/DNA complexes with a poly(ethylene glycol) (PEG) derivative. An alternative way for the formation of PEGylated EGF-containing complexes was also evaluated where EGF was projected away from PEI/DNA core complexes through a PEG linker. Both strategies led to shielded particles still able to efficiently transfect tumor cells in a receptor-dependent fashion. These PEGylated EGF-containing complexes were 10- to 100-fold more efficient than PEGylated complexes without EGF.
authors.affiliation: Institute of Medical Biochemistry, University of Vienna, Dr. Bohrgasse 9/3, A-1030 Vienna and Boehringer Ingelheim Austria, Dr. Boehringer Gasse 5-11, A-1121 Vienna, Austria. blessing@pharma.univ-montp1.fr
authors.forename: T
authors.initials: T
authors.lastname: Blessing
authors.forename: M
authors.initials: M
authors.lastname: Kursa
authors.forename: R
authors.initials: R
authors.lastname: Holzhauser
authors.forename: R
authors.initials: R
authors.lastname: Kircheis
authors.forename: E
authors.initials: E
authors.lastname: Wagner
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism; D015870:Gene Expression; D018014:Gene Transfer Techniques; D006801:Humans; D007624:KB Cells; D007680:Kidney Neoplasms / Q000235:genetics; D008156:Luciferases / Q000235:genetics; D046911:Macromolecular Substances; D051379:Mice; D011092:Polyethylene Glycols / Q000138:chemical synthesis; D011094:Polyethyleneimine / Q000138:chemical synthesis / Q000378:metabolism*; D012004:Rectal Neoplasms / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D046911:Macromolecular Substances; D011092:Polyethylene Glycols; D004815:Epidermal Growth Factor; D011094:Polyethyleneimine; D004247:DNA; D008156:Luciferases; D066246:ErbB Receptors