TY - JOUR
T1 - NADPH oxidase NOX5-S mediates acid-induced cyclooxygenase-2 expression via activation of NF-κB in Barrett's esophageal adenocarcinoma cells
AU - Si, Jin
AU - Fu, Xiaoying
AU - Behar, Jose
AU - Wands, Jack
AU - Beer, David G.
AU - Souza, Rhonda F.
AU - Spechler, Stuart J.
AU - Lambeth, David
AU - Cao, Weibiao
PY - 2007/6/1
Y1 - 2007/6/1
N2 - We have shown that the NADPH oxidase NOX5-S may play an important role in the progression from Barrett's esophagus to esophageal adenocarcinoma (EA) by increasing cell proliferation and decreasing apoptosis. However, the mechanism of the acid-induced NOX5-S-mediated increase in cell proliferation is not known. We found that, in SEG1 EA cells, the acid-induced increase in prostaglandin E2 (PGE2) production was mediated by activation of cyclooxygenase-2 (COX2) but not by COX1. Acid treatment increased intracellular Ca2+, and a blockade of intracellular Ca2+ increase inhibited the acid-induced increase in COX2 expression and PGE2 production. Knockdown of NOX5-S or NF-κB1 p50 by their small interfering RNA significantly inhibited acid-induced COX2 expression and PGE2 production in SEG1 cells. Acid treatment significantly decreased IκBα and increased luciferase activity when SEG1 cells were transfected with an NF-κB in vivo activation reporter plasmid, pNF-κB-Luc. In a novel Barrett's cell line overexpressing NOX5-S, IκBα was significantly reduced, and luciferase activity increased when these Barrett's cells were transfected with pNF-κB-Luc. Overexpression of NOX5-S in Barrett's cells significantly increased H 2O2 production, COX2 expression, PGE2 production, and thymidine incorporation. The increase in thymidine incorporation occurring in NOX5-S-overexpressing Barrett's cells or induced by acid treatment in SEG1 EA cells was significantly decreased by COX2 inhibitors or small interfering RNA. We conclude that acid-induced COX2 expression and PGE 2 production depend on an increase in cytosolic Ca2+ and sequential activation of NOX5-S and NF-κB in SEG1 cells. COX2-derived PGE2 production may contribute to NOX5-Smediated cell proliferation in SEG1 cells.
AB - We have shown that the NADPH oxidase NOX5-S may play an important role in the progression from Barrett's esophagus to esophageal adenocarcinoma (EA) by increasing cell proliferation and decreasing apoptosis. However, the mechanism of the acid-induced NOX5-S-mediated increase in cell proliferation is not known. We found that, in SEG1 EA cells, the acid-induced increase in prostaglandin E2 (PGE2) production was mediated by activation of cyclooxygenase-2 (COX2) but not by COX1. Acid treatment increased intracellular Ca2+, and a blockade of intracellular Ca2+ increase inhibited the acid-induced increase in COX2 expression and PGE2 production. Knockdown of NOX5-S or NF-κB1 p50 by their small interfering RNA significantly inhibited acid-induced COX2 expression and PGE2 production in SEG1 cells. Acid treatment significantly decreased IκBα and increased luciferase activity when SEG1 cells were transfected with an NF-κB in vivo activation reporter plasmid, pNF-κB-Luc. In a novel Barrett's cell line overexpressing NOX5-S, IκBα was significantly reduced, and luciferase activity increased when these Barrett's cells were transfected with pNF-κB-Luc. Overexpression of NOX5-S in Barrett's cells significantly increased H 2O2 production, COX2 expression, PGE2 production, and thymidine incorporation. The increase in thymidine incorporation occurring in NOX5-S-overexpressing Barrett's cells or induced by acid treatment in SEG1 EA cells was significantly decreased by COX2 inhibitors or small interfering RNA. We conclude that acid-induced COX2 expression and PGE 2 production depend on an increase in cytosolic Ca2+ and sequential activation of NOX5-S and NF-κB in SEG1 cells. COX2-derived PGE2 production may contribute to NOX5-Smediated cell proliferation in SEG1 cells.
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U2 - 10.1074/jbc.M700297200
DO - 10.1074/jbc.M700297200
M3 - Article
C2 - 17403674
AN - SCOPUS:34447525016
SN - 0021-9258
VL - 282
SP - 16244
EP - 16255
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 22
ER -