DNA TOPOISOMERASES AS TARGET OF ACTION OF ANTICANCER DRUGS

DNA拓扑异构酶作为抗癌药物的作用靶点

• 批准号: 2463710
• 负责人: Y POMMIER
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 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/2463710
• 关键词: DNA topoisomerases; antineoplastics; apoptosis; camptothecin; cell growth regulation; cytotoxicity; drug design /synthesis /production; drug interactions; drug screening /evaluation; enzyme activity; enzyme inhibitors; enzyme mechanism; point mutation; tissue /cell culture; tumor suppressor genes

DNA topoisomerase I and II (top1 and top2) are primary targets for cancer chemotherapy. Topo-isomerase poisons act by stabilizing enzyme-linked DNA breaks which can be detected as protein-associated DNA breaks in drug-treated cells (cleavable complexes). However, topoisomerases exist both in normal and cancer cells, and the mechanism(s) of drug selectivity for cancer cells remain(s) poorly understood. The goal of this project is to elucidate the antitumor mechanisms of topoisomerase poisons, and their selectivity for cancer cells. Secondary targets which are different in cancer cells could be used for drug development in association with topoisomerase inhibitors or other DNA damaging agents. We have studied the human colon and ovarian cancer cell lines from the NCI Anticancer Drug Screen to identify the parameters that are best correlated with cytotoxicity and could be used in the clinic to predict and monitor the response to topoisomerase inhibitors. Top1 protein levels appear comparable among cell lines and thus are not predictive, while top1 cleavable complexes are better correlated with cytotoxicity. Cleavable complexes are, however, not always predictive . Using cells lines with comparable cleavable complexes, we demonstrated the importance of the G2 checkpoint and replicon repair, downstream from the cleavable complexes for cytotoxicity. We have shown that the presence of p53 provides a survival advantage against camptothecin cytotoxicity. This may contribute to the selectivity of camptothecins for cancer cells with p53 mutations. We and others have proposed that apoptosis is a key response of cancer cells to chemotherapeutic agents, especially in leukemia cells exposed to topoisomerase inhibitors. We have shown that HL60 cells rapidly upregulate and downregulate cyclin B/cdc2 kinase activity before undergoing apoptosis after DNA damage. We have also set up an in vitro cell-free system to study the biochemical pathways of apoptosis. It appears that human leukemia HL60 cells induce a protease cascade including both ICE/CED3 and serine proteases in response to DNA damage following camptothecin treatment and that the protease(s) activate(s) preexisting nuclear pronuclease(s). 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（top1和top2）是DNA异构酶的主要靶点。 癌症化疗 拓扑异构酶毒物通过稳定 酶联DNA断裂，可检测为蛋白质相关 药物处理细胞中的DNA断裂（可裂解复合物）。 然而，在这方面， 拓扑异构酶存在于正常细胞和癌细胞中， 对癌细胞的药物选择性机制仍然很差 明白 本项目的目标是阐明抗肿瘤 拓扑异构酶毒物的机制及其对癌症的选择性 细胞 在癌细胞中不同的次要靶点可能是 用于与拓扑异构酶抑制剂联合的药物开发 或其他DNA损伤剂。 我们已经研究了人类结肠癌和卵巢癌细胞系， NCI抗癌药物筛选，以确定最佳参数 与细胞毒性相关，可用于临床预测 并监测拓扑异构酶抑制剂的反应 Top1蛋白 细胞系之间的水平似乎是相当的并且因此不是预测性的， 而TOP 1可裂解复合物与细胞毒性更好地相关。 然而，可裂解的复合物并不总是预测性的。 使用细胞 线与可比的可裂解的复合物，我们证明了 G2检查点和复制子修复的重要性， 用于细胞毒性的可裂解复合物。 我们已经证明， p53的存在提供了抵抗喜树碱的存活优势 细胞毒 这可能有助于喜树碱的选择性 p53基因突变的癌细胞 我们和其他人已经提出细胞凋亡是癌症的关键反应， 细胞对化疗剂，特别是在暴露于化疗剂的白血病细胞中， 拓扑异构酶抑制剂。 我们已经证明，HL 60细胞迅速 上调和下调细胞周期蛋白B/cdc 2激酶活性， 在DNA损伤后发生凋亡。 我们还建立了一个体外 无细胞系统来研究细胞凋亡的生化途径。 它 人白血病HL 60细胞诱导蛋白酶级联反应， 包括ICE/CED 3和丝氨酸蛋白酶 在喜树碱处理后， 预先存在的核原核酸酶。 新的方法，旨在触发 或抑制细胞凋亡可能会提供新的治疗策略， 有助于减少药物副作用。