title: Involvement of ERK and protein tyrosine phosphatase signaling pathways in EGCG-induced cyclooxygenase-2 expression in Raw 264.7 cells.
abstract: Prostaglandins play regulatory roles in a variety of physiological and pathological processes in immune response and inflammation. Epigallocatechin-3-gallate (EGCG) is known to potent antitumor agent with antioxidant property. We first investigated the effect of EGCG on the production of prostaglandin E(2) (PGE(2)) and the expression of cyclooxygenase-2 (COX-2), the rate-limiting enzyme in the synthesis of PGE(2), using macrophage cell line, Raw264.7. Our results showed that COX-2 expression and PGE(2) production are upregulated by EGCG treatment and that this induction of COX-2 is regulated in part at the transcriptional level. In addition, we demonstrated the signal transduction pathway of mitogen-activated protein kinase (MAP kinase) in EGCG-mediated COX-2 expression. The MEK inhibitor (PD098059) prevented EGCG-induced COX-2 expression, whereas sodium orthovanadate (protein-tyrosine phosphatase inhibitor) significantly enhanced COX-2 expression and PGE(2) production. These results suggest that EGCG mediated COX-2 expression and PGE(2) production is associated with the activation of both the ERK and protein-tyrosine phosphatase signaling pathways.
authors.affiliation: Department of Immunology, School of Medicine, Keimyung University, 194 DongSan-Dong Jung-Gu, Taegu, 700-712, South Korea.
authors.forename: J W
authors.initials: JW
authors.lastname: Park
authors.forename: Y J
authors.initials: YJ
authors.lastname: Choi
authors.forename: S I
authors.initials: SI
authors.lastname: Suh
authors.forename: T K
authors.initials: TK
authors.lastname: Kwon
mesh_terms: D000818:Animals; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology*; D002460:Cell Line; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation; D014638:Vanadates / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D007527:Isoenzymes; D012333:RNA, Messenger; D014638:Vanadates; D002392:Catechin; C045651:epigallocatechin gallate; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D017027:Protein Tyrosine Phosphatases; D015232:Dinoprostone; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one