Wang X, Martindale J L, Holbrook N J
Cell Stress and Aging Section, Laboratory of Biological Chemistry, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224-6825, USA.
J Biol Chem. 2000 Dec 15;275(50):39435-43. doi: 10.1074/jbc.M004583200.
Cisplatin activates multiple signal transduction pathways involved in coordinating cellular responses to stress. Here we demonstrate a requirement for extracellular signal-regulated protein kinase (ERK), a member of the mitogen-activated protein kinase family in mediating cisplatin-induced apoptosis of human cervical carcinoma HeLa cells. Cisplatin treatment resulted in dose- and time- dependent activation of ERK. That elevated ERK activity contributed to cell death by cisplatin was supported by several observations: 1) PD98059 and U0126, chemical inhibitors of the MEK/ERK signaling pathway, prevented apoptosis; 2) pretreatment of cells with TPA, an activator of the ERK pathway, enhanced their sensitivity to cisplatin; 3) suramin, a growth factor receptor antagonist that greatly suppressed ERK activation, likewise inhibited cisplatin-induced apoptosis; and, finally, 4) HeLa cell variants selected for cisplatin resistance showed reduced activation of ERK following cisplatin treatment. Cisplatin-induced apoptosis was associated with cytochrome c release and subsequent caspase-3 activation, both of which could be prevented by treatment with the MEK inhibitors. However, the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone protected HeLa cells against apoptosis without affecting ERK activation. Taken together, our findings suggest that ERK activation plays an active role in mediating cisplatin-induced apoptosis of HeLa cells and functions upstream of caspase activation to initiate the apoptotic signal.
顺铂激活多种参与协调细胞应激反应的信号转导途径。在此，我们证明细胞外信号调节蛋白激酶（ERK）是丝裂原活化蛋白激酶家族的成员，在介导顺铂诱导的人宫颈癌HeLa细胞凋亡中是必需的。顺铂处理导致ERK的剂量和时间依赖性激活。以下几个观察结果支持ERK活性升高导致顺铂诱导的细胞死亡：1）MEK/ERK信号通路的化学抑制剂PD98059和U0126可防止细胞凋亡；2）用ERK途径的激活剂佛波酯（TPA）预处理细胞可增强其对顺铂的敏感性；3）苏拉明是一种生长因子受体拮抗剂，可极大地抑制ERK激活，同样也抑制顺铂诱导的细胞凋亡；最后，4）选择对顺铂耐药的HeLa细胞变体在顺铂处理后ERK激活降低。顺铂诱导的细胞凋亡与细胞色素c释放和随后的半胱天冬酶-3激活有关，这两者都可以通过MEK抑制剂处理来预防。然而，半胱天冬酶抑制剂苄氧羰基-Val-Ala-Asp-氟甲基酮可保护HeLa细胞免受细胞凋亡，而不影响ERK激活。综上所述，我们的研究结果表明ERK激活在介导顺铂诱导的HeLa细胞凋亡中起积极作用，并在半胱天冬酶激活上游发挥作用以启动凋亡信号。
