Synergistic antitumor effect between vorinostat and topotecan in small cell lung cancer cells is mediated by generation of reactive oxygen species and DNA damage-induced apoptosis
Synergistic antitumor effect between vorinostat and topotecan in small cell lung cancer cells is mediated by generation of reactive oxygen species and DNA damage-induced apoptosis
复制标题
DOI：
10.1158/1535-7163.mct-09-0254
复制
发表时间：
2009-11-01
影响因子：
5.7
通讯作者：
Budillon, Alfredo
中科院分区：
文献类型：
--
作者：
Bruzzese, Francesca;Rocco, Monia;Budillon, Alfredo
拓扑异构酶-I (topo-I) 抑制剂托泊替康 (topotecan) 是喜树碱的衍生物，是治疗复发性小细胞肺癌 (SCLC) 的唯一注册药物。组蛋白脱乙酰酶抑制剂伏立诺他在血液恶性肿瘤和实体瘤（包括 SCLC）中显示出临床前和临床抗肿瘤活性，最近已被批准用于治疗皮肤 T 细胞淋巴瘤。在本研究中，我们分析了伏立诺他联合拓扑替康或喜树碱对拓扑Ⅰ抑制剂敏感的H209和抑制剂耐药的H526 SCLC细胞的抗肿瘤作用。同时或连续暴露于任一试剂（延迟 24 小时）会在两种细胞系中产生强烈的协同细胞毒性作用，如计算组合指数所示，并通过软琼脂中的生长证实。通过亚二倍体峰形成、膜联蛋白 V 结合、DNA 断裂和线粒体破坏测量，联合治疗增加了 S 期细胞周期停滞，同时也增加了细胞凋亡。细胞凋亡过程是由 caspase 依赖性机制触发的，可归因于 H2AX（DNA 双链断裂的报告基因）的磷酸化。这些效应与联合治疗诱导的拓扑 I/DNA 共价复合物的增加相平行，表明伏立诺他可增强拓扑替康诱导的 DNA 损伤。最后，氧化损伤在观察到的致死率增强中发挥了重要的功能作用，因为抗氧化剂 N-乙酰基-L-半胱氨酸的共同给药阻止了伏立诺他/托泊替康组合诱导的活性氧生成、细胞凋亡和线粒体破坏。据我们所知，这是拓扑替康和伏立诺他在 SCLC 中协同抗肿瘤作用的首次证明。由于对于复发性 SCLC 患者尚无成熟的治疗方法，因此我们的结果表明应该在临床上探索这种药物组合。 [摩尔癌症疗法 2009;8(11):3075-87]
The topoisomerase-I (topo-I) inhibitor topotecan, derivative of camptothecin, is the only registered drug for relapsed small cell lung cancer (SCLC). The histone deacetylase inhibitor vorinostat has shown preclinical and clinical antitumor activities in hematologic malignancies and solid tumors, including SCLC, and has recently been approved for the treatment of cutaneous T-cell lymphomas. In this study, we analyzed the antitumor effect of vorinostat combined with topotecan or camptothecin in topo-I inhibitor-sensitive H209 and inhibitor-resistant H526 SCLC cells. Simultaneous or sequential exposure (24 h delay) to either agent resulted in strong synergistic cytotoxic effect in both cell lines, as shown by calculating combination index, and confirmed by growth in soft agar. Combination treatments increased S-phase cell cycle arrest paralleled by apoptosis as measured by hypodiploid peak formation, Annexin V binding, DNA fragmentation, and mitochondria destruction. The apoptotic process was triggered by a caspase-dependent mechanism and can be ascribed to the phosphorylation of H2AX, a reporter of DNA double-strand breaks. These effects were paralleled by an increase of topo-I/DNA covalent complexes induced by combination treatment and suggest a potentiation by vorinostat of topotecan-induced DNA damage. Finally, oxidative injury played a significant functional role in the observed enhanced lethality because coadministration of the antioxidant N-acetyl-L-cysteine blocked reactive oxygen species generation, apoptosis, and mitochondria destruction induced by the vorinostat/topotecan combination. To our knowledge, this is the first demonstration of a synergistic antitumor effect between topotecan and vorinostat in SCLC. Because no well-established treatment is available for recurrent SCLC patients, our results indicate that this drug combination should be explored clinically. [Mol Cancer Ther 2009;8(11):3075-87]