ENHANCED APOPTOSIS BY TARGETING PROTEIN REDOX STATUS

描述（由申请人提供）：新型抗癌药物irofulven和奥沙利铂是肿瘤细胞中一致且有效的凋亡诱导剂。Irofulven和奥沙利铂与细胞DNA以及蛋白质巯基结合。虽然DNA加合物和蛋白质加合物都是重要的凋亡刺激物，但irofulven和奥沙利铂的蛋白质反应性的潜在致死后果仍未得到充分研究。本研究的目的是验证irofulven和奥沙利铂靶向关键氧化还原控制蛋白的假设，以及随后细胞蛋白氧化还原状态的扭曲会增强癌细胞的凋亡。蛋白质氧化还原稳态主要由抗凋亡硫氧还蛋白（Trx）系统控制。Trx被认为是治疗干预的潜在靶点，因为许多肿瘤通过提高其Trx水平获得生长优势。肿瘤细胞持续处于异常氧化状态，因此可能对阻碍Trx功能的药物特别敏感。初步数据表明，Trx系统在irofulven和奥沙利铂的疗效中起作用。第一个目的是研究irofulven和奥沙利铂在其纯化形式和癌细胞中与Trx和其他关键氧化还原调节蛋白的结合。第二个目的是确定irofulven和奥沙利铂对细胞氧化还原蛋白功能的影响以及细胞氧化还原状态的扭曲。全球细胞氧化还原平衡的调节将在正常细胞对irofulven和奥沙利铂的抗性的背景下进行研究。第三个目标是建立Trx系统的靶向、蛋白质氧化还原状态的整体扭曲以及irofulven和奥沙利铂诱导细胞凋亡之间的因果关系。这将包括评估氧化还原依赖性ASK1介导和alf介导的途径，以及缺氧条件下trx依赖性HIF-1信号的作用。重点是前列腺癌模型，这与这些药物的临床特性高度相关。这些目标的成功完成将确定Trx系统作为irofulven和奥沙利铂的靶标的作用，这将显著改善这些药物的临床使用。最终，这些结果应该为结合靶向氧化还原控制蛋白和其他特异性抗癌药物来最大限度地减少对DNA损伤剂有抵抗力的癌细胞的凋亡奠定基础。

DESCRIPTION (provided by applicant): The novel anticancer drugs irofulven and oxaliplatin are consistent and potent apoptosis inducers in tumor cells. Irofulven and oxaliplatin bind to cellular DNA as well as to protein sulfhydryls. While both DNA adducts and protein adducts are important apoptotic stimuli, the potentially lethal consequences of protein reactivity of irofulven and oxaliplatin remain understudied. The purpose of this proposal is to test the hypothesis that irofulven and oxaliplatin target key redox-controlling proteins and the subsequent distortion of the redox status of cellular proteins enhances apoptosis in cancer cells. Protein redox homeostasis is predominantly controlled by the anti-apoptotic thioredoxin (Trx) system. Trx is recognized as a potential target for therapeutic intervention, as many tumors gain growth advantage by elevating their Trx levels. Tumor cells are constantly under abnormally oxidative conditions and, therefore, may be particularly sensitive to drugs impeding the functions of Trx. Preliminary data implicate the Trx system in the effects of irofulven and oxaliplatin. The first aim is to investigate the binding of irofulven and oxaliplatin to Trx and other key redox regulating proteins in their purified forms and in cancer cells. The second aim is to determine the effects of irofulven and oxaliplatin on the functions of cellular redox proteins and the distortion of the redox status of the cell. Modulation of the global cellular redox balance will be examined in the context of the demonstrated resistance of normal cells to irofulven and oxaliplatin. The third aim is to establish a causative link between the targeting of the Trx system, the global distortion of protein redox status, and the induction of apoptosis by irofulven and oxaliplatin. This will include assessing the roles of redox-dependent ASK1 -mediated and AlF-mediated pathways, as well as Trx-dependent HIF-1 signaling under hypoxic conditions. The focus is on prostate cancer models, which are highly relevant to the clinical properties of these drugs. Successful completion of these aims will define the role of the Trx system as a target for irofulven and oxaliplatin, which could significantly improve the clinical use of these drugs. Ultimately, the outcomes should establish a rationale for combining targeting of redox controlling proteins with other specific anti-cancer drugs to maximize apoptosis in cancer cells that are resistant to DNA damaging agents.