beta-estradiol stimulation of DNA synthesis requires different PKC isoforms in HepG2 and MCF7 cells.
The role exerted by protein kinase C (PKC) on estrogen-induced DNA synthesis has been investigated in hepatic and mammary gland cells, HepG2 and MCF7. 17-beta-estradiol stimulated DNA synthesis in HepG2 and MCF7 cells, maximal effect occurring at 10 nM. DNA synthesis stimulation was prevented by anti-estrogen ICI 182,780 and by inhibitor of PKC, Ro 31-8220. The rapid estradiol effects in MCF7 cells were determined by following the inositol trisphosphate (IP(3)) production and PKC-alpha membrane translocation. After estradiol treatment the increase of IP(3) production, prevented by anti-estrogen or by phospholipase C (PLC) inhibitor (neomycin), was present in MCF7 cells. In MDA cells, devoid of estrogen receptor, no effect was observed. The PKC-alpha presence on the membranes appeared unchanged in MCF7 cells. The PLC inhibitors, neomycin and U73,122, and PKC-alpha down regulator, phorbol 12-myristate 13-acetate (PMA), were able to prevent estradiol-induced DNA synthesis in hepatoma cells, but ineffective in mammary cells; wortmannin, an inhibitor of phosphoinositide 3-kinases (PI3-K), blocked DNA synthesis in both cell lines. These data show that beta-estradiol, via an estrogen receptor-mediated mechanism, activates more signal transduction pathways, and consequently different PKC isoforms in two responsive cell lines. In both cell lines PI3-K/PKC pathway is functional to the estrogen regulation of DNA synthesis, whereas in HepG2 cells the parallel involvement of the PLC/PKC-alpha pathway is present. The reported results indicate that the DNA synthesis stimulation by beta-estradiol requires the estrogen receptor and utilises one or more activated pathways in dependence on the cell equipment.
Marino
M
M
Dipartimento di Biologia, Università "Roma Tre" Roma, Italy.
Distefano
E
E
Caporali
S
S
Ceracchi
G
G
Pallottini
V
V
Trentalance
A
A
D000730:Androstadienes / Q000494:pharmacology; D001943:Breast Neoplasms; D006528:Carcinoma, Hepatocellular; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002462:Cell Membrane / Q000201:enzymology; D004261:DNA Replication / Q000187:drug effects* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D004963:Estrenes / Q000494:pharmacology; D005260:Female; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008113:Liver Neoplasms; D009355:Neomycin / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013268:Stimulation, Chemical; D013936:Thymidine / Q000378:metabolism / Q000494:pharmacology; D014316:Tritium; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000378:metabolism; D000077191:Wortmannin
D000730:Androstadienes; D004791:Enzyme Inhibitors; D004958:Estradiol; D004963:Estrenes; D007211:Indoles; D007527:Isoenzymes; D009355:Neomycin; D019869:Phosphatidylinositol 3-Kinases; D010726:Phosphodiesterase Inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D011500:Protein Synthesis Inhibitors; D011760:Pyrrolidinones; D013936:Thymidine; D014316:Tritium; D010738:Type C Phospholipases; D000077191:Wortmannin; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C496628:PRKCA protein, human; C064758:Ro 31-8220