title: Rapid and transient induction of cyclo-oxygenase 2 by epidermal growth factor in human amnion-derived WISH cells.
abstract: The central enzyme in the prostaglandin (PG) biosynthetic cascade is PGH2 synthase or cyclo-oxygenase (COX). At present, two distinct isoforms of PGH2 synthase/COX have been identified: COX-1 and COX-2. In many systems, COX-1 is a constitutively expressed isoform that is responsible for normal physiological production of PGs, whereas COX-2 is an inducible isoform that responds to cytokines, endotoxin and growth factors by producing high levels of PGs. The regulation of COX-2 mRNA and protein, and the subsequent production of PGE2, were therefore examined in amnion-derived WISH cells stimulated with epidermal growth factor (EGF). Treatment of WISH cells with EGF (0.01-100 ng/ml) elicited dose-dependent synthesis of COX-2 mRNA and protein de novo. In addition, stimulation of WISH cells with EGF (10 ng/ml) induced steady-state levels of COX-2 mRNA and protein that appeared within 30 min and then declined rapidly to near baseline levels within 2-4 h. In contrast, COX-1 protein was unchanged in response to treatment with EGF. PGE2 production was also rapid and transient. Preincubation of cells with the novel COX-2 enzymic inhibitor NS-398 (10(-5)-10(-10) M) completely prevented PGE2 formation in a dose-dependent manner. Preincubation of cells in dexamethasone (Dex; 0.1 microM), however, resulted in only a 31% decrease in PGE2 formation in response to EGF (10 ng/ml) while completely attenuating PGE2 biosynthesis in tumour necrosis factor alpha (TNF-alpha)-stimulated cells. In addition, Dex (0.1 microM) was only partly effective at preventing EGF-induced COX-2 mRNA and protein expression de novo, whereas Dex completely inhibited TNF-alpha-promoted COX-2 mRNA and protein expression. Thus the results presented here demonstrate that EGF induces the rapid but transient expression of COX-2 mRNA and protein and the subsequent production of PGE2 in WISH cells.
authors.affiliation: Department of Cell Biology, Neurobiology and Anatomy, The Ohio State University, College of Medicine, Columbus 43210, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Perkins
authors.forename: D A
authors.initials: DA
authors.lastname: Kniss
mesh_terms: D000650:Amnion / Q000378:metabolism*; D015152:Blotting, Northern; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins; D009578:Nitrobenzenes / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D009578:Nitrobenzenes; D012333:RNA, Messenger; D013449:Sulfonamides; D014409:Tumor Necrosis Factor-alpha; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D004815:Epidermal Growth Factor; D003907:Dexamethasone; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone