Extrinsic pathway- and cathepsin-dependent induction of mitochondrial dysfunction are essential for synergistic flavopiridol and vorinostat lethality in breast cancer cells
Extrinsic pathway- and cathepsin-dependent induction of mitochondrial dysfunction are essential for synergistic flavopiridol and vorinostat lethality in breast cancer cells
复制标题
DOI：
10.1158/1535-7163.mct-07-0561
复制
发表时间：
2007-12-01
影响因子：
5.7
通讯作者：
Dent, Paul
中科院分区：
文献类型：
--
作者：
Mitchell, Clint;Park, Maragret A.;Dent, Paul
目前的研究已经确定了细胞周期蛋白依赖性激酶抑制剂flavopiridol和组蛋白脱乙酰酶抑制剂辛二酰苯胺异羟肟酸（SAHA;伏立诺他; Zolinza）之间的相互作用是否发生在乳腺癌细胞中。在体外用flavopiridol（25 - 100 nmol/L）和vorinostat（125-500 nmol/L）处理MDA-MB-231和MCF 7细胞，并确定细胞杀伤机制。同时用夫拉匹醇和伏立诺他处理细胞或用夫拉匹醇和伏立诺他处理细胞以大于加和的方式促进细胞杀伤。用CDK抑制剂roscovitine获得了类似的数据。Flavopiridol抑制c-FLIP-1/s和BCL-xL的表达，而伏立诺他减少BCL-xL的表达，并且组合暴露于Flavopiridol和伏立诺他降低了MCL-1和X染色体连锁的凋亡蛋白抑制剂（XIAP）水平。半胱天冬酶-8的药理学或遗传抑制降低了flavopiridol毒性，但消除了伏立诺他的杀伤作用和伏立诺他/ flavopiridol方案引起的细胞死亡。BAX/巴克功能的丧失或BID功能的丧失适度地降低了flavopiridol毒性，但消除了伏立诺他介导的flavopiridol毒性增强，半胱天冬酶-9的抑制也是如此。组织蛋白酶B功能的抑制和/或缺失显著减弱伏立诺他/夫拉吡醇致死性。Flavopiridol抑制细胞外信号调节激酶1/2（ERK 1/2）和AKT活性，并且AKT和促分裂原活化蛋白/ERK激酶1的活化形式的表达维持c-FLIP-I/s、BCL-xL和XIAP表达，并且保护细胞免受Flavopiridol/伏立诺他致死。c-FLIP-s和BCL-xL的过表达消除了flavopiridol/伏立诺他的致死性。总的来说，这些数据表明，flavopiridol增强伏立诺他在乳腺癌细胞中的致死性，部分是通过抑制AKT和ERK 1/2功能，导致外源性和内源性凋亡途径的多种抑制剂的表达减少，以及组织蛋白酶蛋白酶依赖性途径的激活。
The present studies have determined whether interactions between the cyclin-dependent kinase inhibitor flavopiridol and the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA; vorinostat; Zolinza) occur in breast cancer cells. MDA-MB-231 and MCF7 cells were treated with flavopiridol (25 - 100 nmol/L) and vorinostat (125-500 nmol/L) in vitro, and mechanisms of cell killing were determined. Concurrent treatment of cells with flavopiridol and vorinostat or treatment of cells with flavopiridol followed by vorinostat promoted cell killing in a greater than additive fashion. Similar data were obtained with the CDK inhibitor roscovitine. Flavopirldol suppressed c-FLIP-l/s and BCL-xL expression, whereas vorinostat reduced expression of BCL-xL, and combined exposure to flavopiridol and vorinostat reduced MCL-1 and X-chromosome -linked inhibitor of apoptosis protein (XIAP) levels. Pharmacologic or genetic inhibition of caspase-8 reduced flavopiridol toxicity, but abolished killing by vorinostat and cell death caused by the vorinostat/ flavopiridol regimen. Loss of BAX/BAK function or loss of BID function modestly reduced flavopiridol toxicity, but abolished vorinostat-mediated potentiation of flavopiridol toxicity, as did inhibition of caspase-9. Inhibition and/or deletion of cathepsin B function significantly attenuated vorinostat/flavopiridol lethality. Flavopiridol suppressed extracellular signal-regulated kinase 1/2 (ERK1/2) and AKT activity and expression of activated forms of AKT and mitogen-activated protein/ERK kinase 1 maintained c-FLIP-I/s, BCL-xL, and XIAP expression and protected cells against flavopiridol/vorinostat lethality. Overexpression of c-FLIP-s and BCL-xL abolished the lethality of flavopiridol/ vorinostat. Collectively, these data argue that flavopiridol enhances the lethality of vorinostat in breast cancer cells in part through the inhibition of AKT and ERK1/2 function, leading to reduced expression of multiple inhibitors of the extrinsic and intrinsic apoptosis pathways, as well as activation of cathepsin protease-dependent pathways.