PROTEIN-ASSOCIATED DNA BREAKS AS INDICATOR OF TOPOISOMERASE INHIBITION

蛋白质相关 DNA 断裂作为拓扑异构酶抑制的指标

• 批准号: 3752315
• 负责人: Y POMMIER
• 金额: --
• 依托单位: DIVISION OF CANCER TREATMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3752315
• 关键词: DNA repair; DNA topoisomerases; antineoplastics; apoptosis; cell cycle; cell cycle proteins; cell differentiation; cytotoxicity; drug hypersensitivity; drug interactions; drug resistance; enzyme inhibitors; enzyme mechanism; gene expression; neoplasm /cancer chemotherapy; neoplastic cell; protein kinase; tissue /cell culture

DNA topoisomerase I and II (top 1 and 2) are major targets for cancer chemotherapy. Topoisomerase poisons act by stabilizing enzyme-linked DNA breaks which can be detected as protein- associated DNA breaks in drug-treated cells. The goal of this project is to study drug interactions with cellular DNA and to elucidate the antitumor mechanisms of top 1 and 2 poisons, their selectivity for cancer cells, and the functions of topoisomerases in normal and cancer cells. We have studied the cellular effects of several new topoisomerase inhibitors including the top 2 inhibitor, azatoxin (NCI patent), and the various top 1 inhibitors presently in clinical trials. Also, we are studying the differential sensitivity and resistance of the cell lines from the NCI cell Screen to identify the parameters that are best correlated with cytotoxicity and that could be used in the clinic to predict and monitor the response to topoisomerase inhibitors. We and others have recently described apoptosis as a mode of cell death, especially in malignant hematopoietic cells exposed to topoisomerase inhibitors. Interestingly, HL-60 cells die in interphase by apoptosis within 3 hours after drug treatment, while human colon carcinoma HT-29 cells die by G2 block after 24-48 hours. We have studied the changes in cell cycle-related protein kinases/ phosphatase in HL-60 cells treated with topoisomerase I inhibitors. We find that cyclin B/cdc2 kinase become down regulated as cells undergo DNA fragmentation and apoptosis. We are using our in vitro assay that reconstitutes the internucleosomal DNA fragmentation during apoptosis in HL-60 cells to elucidate the biochemical pathways involved. New approaches aimed at triggering or suppressing apoptosis may provide new therapeutic strategies and help reduce drug side effects.

DNA拓扑异构酶I和II（顶部1和2）是 癌症化疗 拓扑异构酶毒素通过稳定 酶联DNA断裂，可以检测到蛋白质- 相关的DNA断裂。这个目标 项目是研究药物与细胞DNA的相互作用， 阐明前1和前2种毒物的抗肿瘤机制， 对癌细胞的选择性，以及拓扑异构酶的功能 在正常和癌细胞中。 我们研究了几种新的拓扑异构酶的细胞效应 抑制剂包括前2名抑制剂，氮杂毒素（NCI专利）， 以及目前在临床试验中的各种顶级抑制剂。 此外，我们正在研究微分灵敏度和电阻 NCI细胞筛选的细胞系，以鉴定 与细胞毒性最相关的参数， 可以用于临床预测和监测对 拓扑异构酶抑制剂。 我们和其他人最近将细胞凋亡描述为细胞凋亡的一种模式， 死亡，特别是在恶性造血细胞接触 拓扑异构酶抑制剂。有趣的是，HL-60细胞在 在药物处理后3小时内通过凋亡的间期，而 人结肠癌HT-29细胞在24-48小时后被G2阻滞而死亡 小时 我们研究了细胞周期相关蛋白的变化 拓扑异构酶I对HL-60细胞中激酶/磷酸酶的影响 抑制剂的 我们发现细胞周期蛋白B/cdc 2激酶表达下调 当细胞经历DNA片段化和凋亡时进行调节。 我们 使用我们的体外试验， HL-60细胞凋亡过程中DNA断裂的研究 参与的生化途径。 新的方法，旨在触发 或抑制细胞凋亡可能提供新的治疗策略， 有助于减少药物副作用。