Stimulation by transforming growth factor-alpha of DNA synthesis and proliferation of adult rat hepatocytes in primary cultures: modulation by alpha- and beta-adrenoceptor agonists.
We investigated the effects of transforming growth factor alpha (TGF-alpha) on DNA synthesis and proliferation in primary cultures of adult rat hepatocytes and examined the influence of alpha and beta adrenoceptor agonists on the TGF-alpha-induced responses. TGF-alpha (1.0 ng/ml) produced a 4.1-fold elevation of DNA synthesis during 3 h of culture and a 1.2-fold increase in the nucleus number (proliferation) during 4 h of culture at a cell density of 3.3 x 10(4) cells/cm(2). The TGF-alpha-induced hepatocyte DNA synthesis and proliferation were dose-dependent at EC(50) values of 0.36 ng/ml and 0.45 ng/ml, respectively. Hepatocyte DNA synthesis and proliferation induced by 1.0 ng/ml TGF-alpha did not reduce even at higher initial plating densities (5.0 x 10(4) and 1.0 x 10(5) cells/cm(2)). Increasing concentrations of the beta(2) adrenoceptor agonist metaproterenol (10(-7)-10(-6) M) markedly reduced the proliferative effects of TGF-alpha, whereas those of the alpha(2) adrenoceptor agonist 5-bromo-6-[2-imidazolin-2-yl-amino]-quinoxaline (UK-14304; 10(-6)-10(-5) M) and the alpha(1) adrenoceptor agonist phenylephrine (10(-7)-10(-6) M) significantly potentiated the TGF-alpha action. The proliferative effects of TGF-alpha (1.0 ng/ml) were not affected significantly by a monoclonal antiepidermal growth factor receptor antibody (1-100 ng/ml) and were almost completely blocked by specific inhibitors of signal transducers such as genistein (10(-5) M), 1-6[[17beta-3methoxyestra-1,3, 5(10)-trien-17-yl]amino]hexyl]-1H-pyrrol2,5-dione (U-73122; 0(-5) M), wortmannin (5 x 10(-7) M), sphingosine (5 x 10(-6) M), 2'-amino-3'-methoxyflavone (PD98059; 5 x 10(-5) M), and rapamycin (10 ng/ml). These results suggest that among the elements that link signals of cell surface receptor to the nucleus, the proliferative action of TGF-alpha is mediated, at least, by tyrosine kinase, phospholipase C, phosphatidylinositol 3-kinase, protein kinase C, mitogen-activated protein kinase kinase, and ribosomal protein p70 S6 kinase.
Kimura
M
M
Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan.
Ogihara
M
M
D018674:Adrenergic Antagonists / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000068438:Brimonidine Tartrate; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis / Q000187:drug effects*; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D066246:ErbB Receptors / Q000276:immunology; D007546:Isoquinolines / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000187:drug effects*; D008297:Male; D009921:Metaproterenol / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases; D010656:Phenylephrine / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013110:Sphingosine / Q000494:pharmacology; D013449:Sulfonamides; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D016211:Transforming Growth Factor alpha / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000378:metabolism
D018674:Adrenergic Antagonists; D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D000893:Anti-Inflammatory Agents; D000911:Antibodies, Monoclonal; D007546:Isoquinolines; D011810:Quinoxalines; D013449:Sulfonamides; D016211:Transforming Growth Factor alpha; D010656:Phenylephrine; D000068438:Brimonidine Tartrate; D009921:Metaproterenol; D003907:Dexamethasone; D004247:DNA; D011494:Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D020794:Receptor Protein-Tyrosine Kinases; D019893:Ribosomal Protein S6 Kinases; D011493:Protein Kinase C; D020929:Mitogen-Activated Protein Kinase Kinases; D010738:Type C Phospholipases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate