INHIBITION OF DNA TOPOISOMERASES I AND II BY DMP840

DMP840 对 DNA 拓扑异构酶 I 和 II 的抑制

• 批准号: 2667975
• 负责人: MARY K DANKS
• 金额: $ 10.25万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-03-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2667975
• 关键词: DNA topoisomerases; antineoplastics; cell cycle; conformation; cytotoxicity; digital imaging; drug screening /evaluation; enzyme inhibitors; fluorescence microscopy; mutagens; neoplasm /cancer chemotherapy; neoplasm /cancer pharmacology; pediatric neoplasm /cancer; phthalimides; physical chemical interaction; tissue /cell culture; topotecan; western blottings

DMP 840 is one of a new class of antitumor agents, bis-naphthalimides, in Phase I clinical trials. In preclinical studies DMP 840 has produced complete regressions at nontoxic concentrations in 5/6 rhabdomyosarcomas grown as xenografts in immune-deprived mice. Our long range goal is to determine the efficacy of DMP 840 in treating pediatric patients with solid tumors. Preliminary biochemical data indicate that DMP 840 is a novel compound in that it inhibits DNA topoisomerases I and II by a mechanisms different from inhibitors of topoisomerases now used clinically. Because the mechanisms of inhibition of topoisomerases by DMP 840 at the molecular level is likely to be a factor in determining the tumor types against which DMP 840 is active and the drugs with which it can be combined effectively, we propose to determine the mechanism of inhibition of topoisomerases I and II by DMP 840. Based on preliminary data, our hypothesis is that DMP 840 prevents the binding of topoisomerases I and II to DNA. If this hypothesis is correct, the cytotoxicity of DMP 840 may be cell cycle-independent, and important factor in treating solid tumors which frequently have low growth fractions. We will use cell lines established from solid tumors having different sensitivities to DMP 840 to examine the effect of this compound on the function of topoisomerases in intact cells. We will also attempt to correlate drug potency with topoisomerase I/II levels, with quantitation on a single cell basis by fluorescence digital imaging microscopy. Isolated enzymes will then be used to determine which step in the catalytic cycle of topoisomerases is inhibited by DMP 840 and effect of DMP 840 on the physical interaction of the compound with DNA, enzyme, or DNA/enzyme complex. These data will then be used for molecular modeling predictions of DNA/drug/enzyme interaction. Additionally, DMP 840 appears to be relatively nontoxic in animal models. However, topoisomerase inhibitors are known to be mutagenic. Therefore, the mutagenic potential of DMP 840 will be evaluated. Our working hypothesis is that because DMP 840 has more than one cellular target, simultaneous mutations would be required in each of these targets to permit cell survival; therefore, DMP 840 may be less mutagenic than topoisomerase inhibitors currently approved for clinical use. Throughout these experiments, we will compare DMP with agents that inhibit either topoisomerase I or II to establish the relative efficacy and toxicity of the three classes of compounds.

DMP 840 是一种新型抗肿瘤剂双萘酰亚胺， I 期临床试验。 在临床前研究中，DMP 840 已产生 5/6 横纹肌肉瘤在无毒浓度下完全消退 在免疫剥夺的小鼠中作为异种移植物生长。 我们的长期目标是 确定 DMP 840 治疗儿科患者的疗效 实体瘤。 初步生化数据表明 DMP 840 是一种新型化合物 它通过不同的机制抑制 DNA 拓扑异构酶 I 和 II 来自目前临床上使用的拓扑异构酶抑制剂。 因为 DMP 840 在分子水平上抑制拓扑异构酶的机制 水平可能是确定肿瘤类型的一个因素 DMP 840 具有活性以及可以与哪些药物联合使用 有效地，我们建议确定抑制机制 DMP 840 进行拓扑异构酶 I 和 II。根据初步数据，我们 假设 DMP 840 阻止拓扑异构酶 I 和 II 的结合 到DNA。 如果这个假设正确，DMP 840 的细胞毒性可能是 细胞周期独立且治疗实体瘤的重要因素 通常具有较低的生长分数。 我们将使用细胞系 由对 DMP 840 具有不同敏感性的实体瘤建立 检查该化合物对拓扑异构酶功能的影响 完整的细胞。 我们还将尝试将药物效力与 拓扑异构酶 I/II 水平，通过单细胞定量 荧光数字成像显微镜。 然后分离出的酶将被 用于确定拓扑异构酶催化循环中的哪一步 DMP 840 抑制以及 DMP 840 对物理相互作用的影响 与DNA、酶或DNA/酶复合物的化合物。 这些数据将 然后用于 DNA/药物/酶的分子建模预测 相互作用。 此外，DMP 840 在动物模型中似乎相对无毒。 然而，已知拓扑异构酶抑制剂具有诱变性。 所以， 将评估 DMP 840 的致突变潜力。 我们的工作 假设是因为 DMP 840 有多个细胞靶标， 这些目标中的每一个都需要同时突变 允许细胞存活；因此，DMP 840 的致突变性可能低于 拓扑异构酶抑制剂目前已批准用于临床。 自始至终 在这些实验中，我们将比较 DMP 与抑制任一药物 拓扑异构酶 I 或 II 以确定其相对功效和毒性 三类化合物。