title: Regulation of EGF-induced tenascin-C by steroids in tenascin-C-non-producing human carcinoma cells.
abstract: Tenascin-C, a 6-armed extracellular matrix glycoprotein, is expressed in a temporally and spatially restricted pattern during tumorigenesis in association with stromal-epithelial interactions. We have previously shown that de novo synthesis of tenascin-C is induced by the diffusible factor EGF in tenascin-C-non-producing human epidermoid carcinoma cells in stromal-epithelial interactions. We now demonstrate that the addition of human tenascin-C or tenascin-C peptides to the culture medium of these cells had little effect on the induction of tenascin-C. The physiological regulators of tenascin-C induction through the EGF receptor, however, have not yet been characterized. We show that steroid hormones down-regulate EGF-induced tenascin-C glycoprotein and its mRNA in these tenascin-C-non-producing carcinoma cells. Of the steroids examined, hydrocortisone most effectively inhibited the secretion of tenascin-C. These steroids did not affect EGF-induced autophosphorylation or de novo synthesis of EGF receptors, nor did they compete for the binding of EGF to its receptor. Our results indicate that the induction of tenascin-C by EGF and its down-regulation by steroids might proceed in these carcinoma cells through separate signal transduction pathways.
authors.affiliation: Division of Hemopoiesis, Jichi Medical School, Tochigi, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.forename: H
authors.initials: H
authors.lastname: Kawakatsu
authors.forename: Y
authors.initials: Y
authors.lastname: Furukawa
authors.forename: M
authors.initials: M
authors.lastname: Saito
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D004347:Drug Interactions; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D008024:Ligands; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D013256:Steroids / Q000494:pharmacology*; D019063:Tenascin / Q000096:biosynthesis* / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D008024:Ligands; D013256:Steroids; D019063:Tenascin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors