Direct inhibition of cyclooxygenase-1 and -2 by the kinase inhibitors SB 203580 and PD 98059 -: SB 203580 also inhibits thromboxane synthase
Direct inhibition of cyclooxygenase-1 and -2 by the kinase inhibitors SB 203580 and PD 98059 -: SB 203580 also inhibits thromboxane synthase
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DOI：
10.1074/jbc.273.44.28766
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发表时间：
1998-10-30
影响因子：
4.8
通讯作者：
Watson, SP
中科院分区：
文献类型：
--
作者：
Börsch-Haubold, AG;Pasquet, S;Watson, SP
据报道，激酶抑制剂SE 203580和PD 98059分别是38-和42/44-kDa丝裂原活化蛋白激酶（MAPK）途径的特异性抑制剂。在本研究中，发现这两种抑制剂可降低低浓度花生四烯酸诱导的血小板聚集，提示它们也干扰花生四烯酸向血栓素A的代谢(2)。为了支持这一点，SE 203580和PD 98059抑制了完整血小板中外源性[H-3]花生四烯酸向[H-3]血栓素的转化。免疫沉淀后血小板环氧合酶-1活性测定显示SE 203580和PD 98059是该酶的直接抑制剂。两种化合物均通过可逆机制抑制纯化的环氧化酶-1和-2，此外，SE 203580（而不是PD 98059）抑制前列腺素H-2诱导的血小板聚集以及前列腺素H-2在完整血小板中转化为血栓素a(2)。SE 203580在血小板微粒体制剂中也能抑制这一途径，提示其对血栓素合成酶有直接抑制作用。这些结果表明，在使用这些化合物研究信号转导途径中的MAPKs之前，必须排除这两种激酶抑制剂对活性花生四烯酸代谢物的直接影响。这与胞质磷脂酶A(2)调控的研究特别相关，因为这两个mapk能够磷酸化胞质磷脂酶A(2)，从而增加其内在活性。
The kinase inhibitors SE 203580 and PD 98059 have been reported to be specific inhibitors of the 38- and 42/44-kDa mitogen-activated protein kinase (MAPK) pathways, respectively. In this study, the two inhibitors were found to decrease platelet aggregation induced by low concentrations of arachidonic acid, suggesting that they also interfere with the metabolism of arachidonic acid to thromboxane A(2). In support of this, SE 203580 and PD 98059 inhibited the conversion of exogenous [H-3]arachidonic acid to [H-3]thromboxane in intact platelets. Measurement of platelet cyclooxygenase-1 activity following immunoprecipitation revealed that SE 203580 and PD 98059 are direct inhibitors of this enzyme. Both compounds were shown to inhibit purified cyclooxygenase-1 and -2 by a reversible mechanism, In addition, SE 203580 (but not PD 98059) inhibited platelet aggregation induced by prostaglandin H-2 and the conversion of prostaglandin H-2 to thromboxane A(2) in intact platelets. SE 203580 also inhibited this pathway in platelet microsome preparations, suggesting a direct inhibitory effect on thromboxane synthase. These results demonstrate that direct effects of the two kinase inhibitors on active arachidonic acid metabolites have to be excluded before using these compounds for the investigation of MAPKs in signal transduction pathways. This is of particular relevance to studies on the regulation of cytosolic phospholipase A(2) as these two MAPKs are capable of phosphorylating cytosolic phospholipase A(2), thereby increasing its intrinsic activity.