title: Expression of cyclooxygenase-2 is regulated by glycogen synthase kinase-3beta in gastric cancer cells.
abstract: Cyclooxygenase-2 (COX-2) expression is a marker of poor prognosis in gastric cancer patients, and its inhibition suppresses gastric tumorigenesis in experimental animal models. The mechanism that leads to COX-2 overexpression in this tumor type is unknown. We have now shown that inhibition of phosphatidylinositol 3-kinase by LY294002 suppresses both basal and phorbol myristate acetate-induced COX-2 expression in TMK-1 and MKN-28 gastric cancer cells. Furthermore, inhibition of glycogen synthase kinase-3beta (GSK-3beta) by SB415286 induced expression of COX-2 mRNA and protein as well as the enzyme activity in the gastric cancer cells. The effect of SB415286 was confirmed by the use of two additional GSK-3beta inhibitors, lithium chloride and SB216763. SB415286 had a modest 1.6-fold stimulatory effect on a 2-kb COX-2 promoter reporter construct, but more importantly, it was shown to block the decay of COX-2 mRNA. In contrast to modulation of phosphatidylinositol 3-kinase/Akt/GSK-3beta pathway, inhibitors of mitogen-activated protein kinases (MEK 1/2, p38, JNK) or the mammalian target of rapamycin did not alter COX-2 expression in gastric cancer cells. Our data show that inhibition of GSK-3beta stimulates COX-2 expression in gastric cancer cells, which seems to be primarily facilitated via an increase in mRNA stability and to a lesser extent through enhanced transcription.
authors.affiliation: Department of Pathology, Helsinki University Central Hospital, and Molecular and Cancer Biology Research Program, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Thiel
authors.forename: Mira
authors.initials: M
authors.lastname: Heinonen
authors.forename: Johanna
authors.initials: J
authors.lastname: Rintahaka
authors.forename: Tuija
authors.initials: T
authors.lastname: Hallikainen
authors.forename: Annabrita
authors.initials: A
authors.lastname: Hemmes
authors.forename: Dan A
authors.initials: DA
authors.lastname: Dixon
authors.forename: Caj
authors.initials: C
authors.lastname: Haglund
authors.forename: Ari
authors.initials: A
authors.lastname: Ristimäki
mesh_terms: D000627:Aminophenols / Q000494:pharmacology; D015152:Blotting, Northern; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002867:Chromones / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D015232:Dinoprostone / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D018021:Lithium Chloride / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D008954:Models, Biological; D015233:Models, Statistical; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection
chemical_list: D000627:Aminophenols; D002867:Chromones; D051546:Cyclooxygenase 2; D015232:Dinoprostone; D004791:Enzyme Inhibitors; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D007211:Indoles; D018021:Lithium Chloride; D008301:Maleimides; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D012313:RNA; D012333:RNA, Messenger; D013755:Tetradecanoylphorbol Acetate; C417520:3-(3-chloro-4-hydroxyphenylamino)-4-(4-nitrophenyl)-1H-pyrrole-2,5-dione; C417521:SB 216763; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C000605506:GSK3B protein, human