title: tPA of human keratinocytes: contribution to cell surface-associated plasminogen activation and upregulation by retinoic acid.
abstract: We tested distinct variants of a human keratinocyte line (HaCaT) for the expression of tissue-type plasminogen activator (tPA)-specific mRNA, as well as cell surface-associated and secreted tPA. Cells of early passages (passage no. 22) only expressed urokinase plasminogen activator (uPA)- but not tPA-specific mRNA. Cells after prolonged culture (passage no. 44) expressed uPA- and tPA-specific mRNA, but did not release tPA in the extracellular space and did not display surface-associated tPA. HaCaT cells transformed with the c-Ha-ras oncogene (HaCaTras) showed both secreted and surface-associated tPA antigen. The secreted and the surface-associated plasminogen activator (PA)-activity of HaCaTras cells were in part inhibitable by anticatalytic anti-tPA antibodies, thus indicating that tPA contributes to extracellular and surface-associated plasminogen activation. Finally, we demonstrate that tPA secretion of HaCaT 44 cells can be induced by retinoic acid, most likely via interaction of retinoic acid with nuclear-associated retinoic acid-receptor(s).
authors.affiliation: Institut für Immunologie der Universität Laboratorium für Immunpathologie, Heidelberg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Buessecker
authors.forename: J
authors.initials: J
authors.lastname: Reinartz
authors.forename: M D
authors.initials: MD
authors.lastname: Kramer
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007641:Keratolytic Agents / Q000494:pharmacology*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology*; D015854:Up-Regulation; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
chemical_list: D007641:Keratolytic Agents; D012333:RNA, Messenger; D014212:Tretinoin; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator