title: Disconnecting the yin and yang relation of epidermal growth factor receptor (EGFR)-mediated delivery: a fully synthetic, EGFR-targeted gene transfer system avoiding receptor activation.
abstract: The epidermal growth factor receptor (EGFR) is upregulated within a high percentage of solid tumors and hence is an attractive target for tumor-targeted therapies including gene therapy. The natural EGFR ligand epidermal growth factor (EGF) has been used for this purpose, despite the risk of mitogenic effects due to EGFR activation. We have developed a fully synthetic, EGFR-targeted gene delivery system based on PEGylated linear polyethylenimine (LPEI), allowing evaluation of different EGFR-binding peptides in terms of transfection efficiency and EGFR activation. Peptide sequences directly derived from the human EGF molecule enhanced transfection efficiency with concomitant EGFR activation. Only the EGFR-binding peptide GE11, which has been identified by phage display technique, showed specific enhancement of transfection on EGFR-overexpressing tumor cells including glioblastoma and hepatoma, but without EGFR activation. EGFR targeting led to high levels of cell association of fluorescently labeled polyplexes after only 30 min of incubation. EGF pretreatment of cells induced enhanced cellular internalization of all polyplex types tested, pointing at generally enhanced macropinocytosis. EGF polyplexes diminished cell surface expression of EGFR for up to 4 hr, whereas GE11 polyplexes did not. In a clinically relevant orthotopic prostate cancer model, intratumorally injected GE11 polyplexes were superior in inducing transgene expression when compared with untargeted polyplexes.
authors.affiliation: Center for System-Based Drug Research, Department of Pharmacy, Pharmaceutical Biotechnology, Ludwig Maximilian University, D-81377 Munich, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schäfer
authors.forename: A
authors.initials: A
authors.lastname: Pahnke
authors.forename: D
authors.initials: D
authors.lastname: Schaffert
authors.forename: W M
authors.initials: WM
authors.lastname: van Weerden
authors.forename: C M A
authors.initials: CM
authors.lastname: de Ridder
authors.forename: W
authors.initials: W
authors.lastname: Rödl
authors.forename: A
authors.initials: A
authors.lastname: Vetter
authors.forename: C
authors.initials: C
authors.lastname: Spitzweg
authors.forename: R
authors.initials: R
authors.lastname: Kraaij
authors.forename: E
authors.initials: E
authors.lastname: Wagner
authors.forename: Manfred
authors.initials: M
authors.lastname: Ogris
mesh_terms: D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D016503:Drug Delivery Systems; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000627:therapeutic use*; D011094:Polyethyleneimine / Q000737:chemistry; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D011485:Protein Binding
chemical_list: D010446:Peptide Fragments; D004815:Epidermal Growth Factor; D011094:Polyethyleneimine; C512478:EGFR protein, human; D066246:ErbB Receptors