Endogenous thioredoxin is required for redox cycling of anthracyclines and p53-dependent apoptosis in cancer cells
Endogenous thioredoxin is required for redox cycling of anthracyclines and p53-dependent apoptosis in cancer cells
复制标题
DOI：
10.1074/jbc.m507192200
复制
发表时间：
2005-12-02
影响因子：
4.8
通讯作者：
Das, KC
中科院分区：
文献类型：
--
作者：
Ravi, D;Muniyappa, H;Das, KC
细胞凋亡是化疗和放疗破坏肿瘤细胞的主要机制。蒽环类抗肿瘤药物在活细胞中经历氧化还原循环，产生大量的活性氧物种和半喹酮自由基，这两者都可以导致DNA损伤，从而引发癌细胞的凋亡性死亡。我们在这里显示，高表达硫氧还蛋白(TRX)的MCF-7细胞对柔红霉素的反应是更多的凋亡。TRX在MCF-7细胞中的过表达增加了经蒽环类药物处理的细胞提取物中超氧阴离子(O-2(.-))的产生。Trx高表达的MCF-7细胞对柔红霉素诱导的O-2(.-)生成的促进作用可被NADPH还原酶抑制剂二苯基碘氯抑制，这表明Trx为柔红霉素的氧化还原循环提供了生物还原酶的等价物。此外，Trx增加了对蒽环类药物的P53-DNA结合和表达。表达突变型氧化还原失活Trx的MCF-7细胞表现出超氧化物生成减少，细胞凋亡减少，P53蛋白和DNA结合减少。此外，小干扰RNA下调内源性Trx的表达，导致caspase-7的表达减少，柔红霉素诱导的聚(ADP-核糖)聚合酶的表达被切割。这些结果表明，内源性Trx在蒽环类药物介导的乳腺癌细胞凋亡中是必需的。综上所述，我们的研究结果表明，在蒽环类药物化疗中，Trx具有一种新的促氧化和促凋亡作用。
Apoptosis is a major mechanism of cancer cell destruction by chemotherapy and radiotherapy. The anthracycline class of antitumor drugs undergoes redox cycling in living cells producing increased amounts of reactive oxygen species and semiquinone radical, both of which can cause DNA damage, and consequently trigger apoptotic death of cancer cells. We show here that MCF-7 cells overexpressing thioredoxin ( Trx) were more apoptotic in response to daunomycin. Trx overexpression in MCF-7 cells increased the generation of superoxide anion ( O-2(.-)) in anthracycline-treated cell extracts. Enhanced generation of O-2(.-) in response to daunomycin in Trx-overexpressing MCF-7 cells was inhibited by diphenyleneiodonium chloride, a general NADPH reductase inhibitor, demonstrating that Trx provides reducing equivalents to a bioreductive enzyme for redox cycling of daunomycin. Additionally Trx increased p53-DNA binding and expression in response to anthracyclines. MCF-7 cells expressing mutant redox-inactive Trx showed decreased superoxide generation, apoptosis, and p53 protein and DNA binding. In addition, down-regulation of endogenous Trx expression by small interfering RNA resulted in decreased expression of caspase-7 and cleaved poly( ADP-ribose) polymerase expression in response to daunomycin. These results suggest that endogenous Trx is required for anthracycline-mediated apoptosis of breast cancer cells. Taken together, our data demonstrate a novel pro-oxidant and proapoptotic role of Trx in anthracycline- mediated apoptosis in anthracycline chemotherapy.