title: EGF receptor activation decreases retroviral gene transfer through protein kinase C-delta.
abstract: Although much progress has been made in the design of retrovirus vectors, the interactions of recombinant retrovirus with host cells remain largely elusive. The inability of recombinant retrovirus to transduce non-dividing cells prompted several studies to determine optimal cocktails of growth factors and/or extracellular matrix molecules to promote gene transfer to slowly diving cells and stem cells. In contrast to previous reports that growth factors increased gene transfer, we found that treatment of human epidermal keratinocytes and several cell lines with epidermal growth factor receptor (EGFR) ligands EGF, transforming growth factor-alpha, or heparin-binding-EGF decreased gene transfer. Conversely, treatment with an EGFR function-blocking antibody or inhibition of EGFR tyrosine phosphorylation enhanced gene transfer in a dose-dependent manner. In addition, blocking protein kinase C (PKC)-delta but not PKC-zeta, with chemical inhibitors or small interfering RNA reversed the effects of EGF and restored gene transfer, indicating that the effect of EGFR activation is mediated through PKC-delta. Lastly, cell cycle analysis showed that the effect of EGFR activation on retroviral gene transfer was independent of the cell cycle status of target cells. Our results implicate EGFR and PKC-delta in retroviral infection and may have implications for retrovirus gene transfer or design of antiretroviral therapies.
authors.affiliation: Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, State University of New York, Amherst, New York 14260-4200, USA.
authors.forename: Raghvendra
authors.initials: R
authors.lastname: Singh
authors.forename: Stelios T
authors.initials: ST
authors.lastname: Andreadis
mesh_terms: D016475:3T3 Cells; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051745:Protein Kinase C-delta / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D012190:Retroviridae / Q000235:genetics*; D014162:Transfection / Q000379:methods*; D016211:Transforming Growth Factor alpha / Q000494:pharmacology; D000099221:Protein Kinase C zeta
chemical_list: D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D007527:Isoenzymes; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D034741:RNA, Small Interfering; D016211:Transforming Growth Factor alpha; D000099221:Protein Kinase C zeta