title: STAT5 mediates PAF-induced NADPH oxidase NOX5-S expression in Barrett's esophageal adenocarcinoma cells.
abstract: We have shown that NADPH oxidase NOX5-S is overexpressed in Barrett's esophageal adenocarcinoma (EA) cells and may contribute to the progression from Barrett's esophagus (BE) to EA presumably by increasing cell proliferation and decreasing apoptosis (Fu X, Beer DG, Behar J, Wands J, Lambeth D, Cao W. J Biol Chem 281: 20368-20382, 2006). The mechanism(s) of NOX5-S overexpression in EA, however, is not fully understood. In SEG1 EA cells we found that acid treatment significantly increased platelet-activating factor (PAF) production, which in turn markedly increased NOX5-S expression and hydrogen peroxide (H(2)O(2)) production. Knockdown of NOX5-S by NOX5-S small interfering RNA (siRNA) blocked PAF-dependent H(2)O(2) production. PAF-dependent induction of NOX5-S expression and H(2)O(2) production were significantly decreased by the MAPK kinase 1 inhibitor PD-98059, by the cytosolic phospholipase A(2) (cPLA(2)) inhibitor AACOCF3, and by STAT5 downregulation with STAT5 siRNA. PAF significantly increased the phosphorylation of ERK1/2 MAPK, cPLA(2), and STAT5. Using inhibitors, we demonstrated that PAF-induced STAT5 phosphorylation depends on activation of ERK1/2 MAPK and cPLA(2), whereas PAF-induced cPLA(2) phosphorylation was associated with activation of ERK1/2 MAPK. Given that STAT5 bound to the c-sis-inducible element (TTCTGGTAA) of the NOX5-S promoter, overexpression of STAT5 significantly increased NOX5-S promoter activity. We conclude that acid-induced NOX5-S expression and H(2)O(2) production is mediated in part by production of PAF in SEG1 EA cells, and that PAF-induced increase in NOX5-S expression depends on sequential activation of ERK MAP kinases, cPLA(2), and STAT5 in these cells.
authors.affiliation: Department of Medicine, Brown Medical School and Rhode Island Hospital, Providence, RI 02903, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Si
authors.forename: Jose
authors.initials: J
authors.lastname: Behar
authors.forename: Jack
authors.initials: J
authors.lastname: Wands
authors.forename: David G
authors.initials: DG
authors.lastname: Beer
authors.forename: David
authors.initials: D
authors.lastname: Lambeth
authors.forename: Y Eugene
authors.initials: YE
authors.lastname: Chin
authors.forename: Weibiao
authors.initials: W
authors.lastname: Cao
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001095:Arachidonic Acids / Q000494:pharmacology; D001471:Barrett Esophagus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004938:Esophageal Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D054510:Phospholipases A2, Cytosolic / Q000037:antagonists & inhibitors / Q000378:metabolism; D010742:Phospholipid Ethers / Q000494:pharmacology; D010766:Phosphorylation; D010972:Platelet Activating Factor / Q000378:metabolism*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D015854:Up-Regulation
chemical_list: D001095:Arachidonic Acids; D004791:Enzyme Inhibitors; D005419:Flavonoids; D008565:Membrane Proteins; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D034741:RNA, Small Interfering; D050799:STAT5 Transcription Factor; C081565:arachidonyltrifluoromethane; C037913:CV 3988; D006861:Hydrogen Peroxide; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases; C431571:NOX5 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D054510:Phospholipases A2, Cytosolic; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one