Celecoxib simulates respiratory burst through pertussis toxin-sensitive G-protein, a possible signal for beta...

The superoxide anion-generating effect of celecoxib (4-[5-(4-methylpheny)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide); SC58633), a selective cyclooxygenase-2 inhibitor, on human neutrophils was evaluated in this study. Celecoxib induced superoxide anion generation in a concentration-dependent manner in human neutrophils. The EC50 value of celecoxib on superoxide anion generation was 15.5+/-2.5 microM. A NADPH oxidase inhibitor, diphenyliodonium (20 microM), and superoxide dismutase (150 U/ml) completely inhibited the free radical generation caused by celecoxib, indicating that the respiratory burst was activated by celecoxib. 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA/AM;10 microM) and staurosporine (200 nM) completely inhibited the superoxide anion release caused by celecoxib, respectively. These data indicated that celecoxib increased superoxide anion release by increasing intracellular calcium and protein kinase C activation. Moreover, 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-C)-carbazole (Go-6976; 1 microM) and 3-[1-[3-(amidinothio)propyl-1H-indol-3-yl]-3-(1-methyl-1H-indol-3-yl)maleimide, methane sulfate (Ro-31-8220; 0.5 microM), specific inhibitors of conventional protein kinase C isotypes (alpha, beta(I) and beta(II)), significantly inhibited superoxide anion release caused by celecoxib. Rottlerin (5 microM), a protein kinase C delta inhibitor, did not affect the free radical generation caused by celecoxib. Celecoxib caused translocation of protein kinase C alpha, beta(I) and beta(II) from the cytosol to the cellular membrane. 2-[2-amino-3-methoxyphenyl]-4H-1-benzopyran-4-one (PD98059; 20 microM) and wortmannin (100 nM) did not decrease the superoxide anion generation caused by celecoxib, indicating that Mitogen-activated protein (MAP) kinase and phosphatidylinositol 3-kinase (PI3 kinase) were not involved in the respiratory burst induced by celecoxib. Pertussis toxin (2 microg/ml), a Gi-protein sensitive inhibitor, significantly inhibited superoxide anion release. Moreover, pertussis toxin significantly inhibited intracellular calcium mobilization and protein kinase C alpha, beta(I) and beta(II) translocation from the cytosol to the membrane. Celecoxib increased beta(2)-integrin expression on human neutrophils and this effect was inhibited by BAPTA/AM (10 microM), superoxide dismutase (150 U/ml), genistein (25 microM) and PD98059 (20 microM). This information indicated that intracellular calcium, superoxide anion, tyrosine kinase and MAP kinase are involved in beta(2)-integrin expression. Furthermore, BAPTA/AM, superoxide dismutase and genistein inhibited celecoxib-increased MAP kinase activity, indicating that MAP kinase is a downstream signal for beta(2)-integrin expression. In conclusion, celecoxib stimulates superoxide anion release from human neutrophils by activating pertussis toxin sensitive G-protein. An increase in intracellular calcium and protein kinase C alpha, beta(I) and beta(II) is involved in this process. Celecoxib also regulates beta(2)-integrin expression through superoxide anion release, tyrosine kinase and p42/p44 MAP kinase on human neutrophils.