ENHANCED APOPTOSIS BY TARGETING PROTEIN REDOX STATUS

描述(申请人提供)：新型抗癌药物艾罗富文和奥沙利铂在肿瘤细胞中是一致和有效的凋亡诱导剂。伊罗富芬和奥沙利铂可与细胞DNA和蛋白质巯基结合。虽然DNA加合物和蛋白质加合物都是重要的凋亡刺激因素，但伊罗富芬和奥沙利铂的蛋白质反应性的潜在致命性后果仍未得到充分研究。这项建议的目的是验证这样的假设，即伊罗富芬和奥沙利铂针对关键的氧化还原控制蛋白，随后细胞蛋白氧化还原状态的扭曲增强了癌细胞的凋亡。蛋白质氧化还原动态平衡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水平而获得生长优势。肿瘤细胞经常处于异常的氧化条件下，因此，可能对阻碍TRX功能的药物特别敏感。初步数据表明，TRX系统与艾罗富芬和奥沙利铂的作用有关。第一个目标是研究艾罗富芬和奥沙利铂与TRX和其他关键氧化还原调节蛋白在其纯化形式和癌细胞中的结合。第二个目的是确定伊罗富芬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伊罗富文和奥沙利铂耐药的背景下进行检查。第三个目的是建立靶向TRX系统、蛋白质氧化还原状态的全球扭曲以及伊罗富芬和奥沙利铂诱导细胞凋亡之间的因果联系。这将包括评估氧化还原依赖的ASK1和Alf介导的通路的作用，以及低氧条件下依赖TRX的HIF-1信号。重点放在前列腺癌模型上，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系统作为伊罗富文和奥沙利铂靶标的作用，这将显著改善这些药物的临床使用。最终，这些结果应该为将氧化还原控制蛋白与其他特定的抗癌药物结合起来，以最大限度地促进对DNA损伤剂具有抗药性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.