ANTIMALARIAL ACTIVITY OF TS INHIBITORS

TS 抑制剂的抗疟活性

• 批准号: 6803888
• 负责人: PRADIPSINH K. RATHOD
• 金额: $ 19.13万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-02 至 2009-04-01
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6803888
• 关键词: Plasmodium falciparum; active sites; antimalarial agents; cell free system; chemical kinetics; chemical structure function; communicable disease control; dihydrofolate reductase; drug resistance; drug screening /evaluation; enzyme inhibitors; enzyme substrate analog; erythrocytes; folate antagonist; host organism interaction; human tissue; intermolecular interaction; malaria; microorganism disease chemotherapy; polyglutamates; protein binding; pyrimidines; tetrahydrofolylpolyglutamate synthase; thymidine monophosphate; thymidylate synthase

The overall program project will test the hypothesis that a combination of thymidine and select antifolates directed at the thymidylate synthase domain of Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (DHFR-TS) can be potent and safe antimalarial agents, worthy of future clinical trials in humans. Blood-stage forms of malaria parasites are completely dependent on de novo pyrimidine biosynthesis and fail to salvage preformed pyrimidines, unlike human cells. Of all the enzymes available in de novo pyrimidine biosynthesis, DHFR-TS is of particular interest. Inhibitors of the DHFR domain are proven drug targets in malaria. The PI's laboratory has previously demonstrated that one TS antifolate (1843U89) inhibits Plasmodium TS with a Ki of 1 nM and inhibits parasite proliferation with an ECs0 of 70 nM. With 10 uM thymidine, mammalian cells show no toxicity to this compound, even at 10,000 times higher concentrations. Starting with this very strong lead, we will develop additional compounds that are even more potent. There are opportunities to derive potent TS antifolates from more than one chemical scaffold. To avert drug resistance, we are particularly interested in compounds which do not require polyglutamylation for optimum TS binding or folate Iransporters to enter cells. The crystal structure of malaria TS is now available and global oncology programs have generated a large aumber of TS inhibitors from multiple chemical classes. Compounds that are in clinical trials, and close 5erivatives, are immediately applicable for "piggy-back" strategies against malaria. Based on preliminary data i'om lead compounds, modeling and NMR-based ligand discovery initiatives, about 50-00 potential TS antifolates per year will be synthesized. This Project will measure the interactions of these new TS antifolates with the target enzyme TS and enzymes which metabolize antifolates. In addition, using P. falciparum in culture, the antiproliferative activity of the TS inhibitors will be evaluated as well as the ease with which parasites acquire resistance to these molecules. Finally, in a validation study, biochemical and genetic approaches will test the mode of action of the candidate TS inhibitors. The best antimalarials will be passed on for safety and efficacy testing.

整个计划项目将测试的假设，胸苷和选择抗叶酸剂的组合针对恶性疟原虫二氢叶酸还原酶-胸苷酸合成酶（DHFR-TS）的胸苷酸合成酶结构域可以是有效和安全的抗疟药，值得在人类的未来临床试验。与人类细胞不同，疟原虫的血液阶段形式完全依赖于从头嘧啶生物合成，并且无法挽救预先形成的嘧啶。在从头嘧啶生物合成中可用的所有酶中，DHFR-TS是特别感兴趣的。DHFR结构域的抑制剂是疟疾中被证明的药物靶标。PI的实验室先前已经证明，一种TS抗叶酸剂（1843 U89）可抑制疟原虫 TS的Ki为1 nM，抑制寄生虫增殖的ECs 0为70 nM。对于10 μ M胸苷，哺乳动物细胞对该化合物没有毒性，即使在10，000倍的浓度下也是如此。从这种非常强的先导化合物开始，我们将开发出其他更有效的化合物。有机会从一个以上的化学支架衍生出有效的TS抗叶酸剂。为了避免耐药性，我们特别感兴趣的化合物，不需要聚谷氨酰化的最佳TS结合或叶酸转运体进入细胞。 疟疾TS的晶体结构现在是可用的，全球肿瘤学计划已经从多个化学类别产生了大量的TS抑制剂。正在进行临床试验的化合物和接近的衍生物可立即用于对抗疟疾的“背负式”策略。基于先导化合物、建模和基于NMR的配体发现计划的初步数据，每年将合成约50-00种潜在的TS抗叶酸剂。本项目将测量这些新的TS抗叶酸剂与目标酶TS和代谢抗叶酸剂的酶的相互作用。此外，使用培养的恶性疟原虫，将评价TS抑制剂的抗增殖活性以及寄生虫获得对这些分子的抗性的容易程度。最后，在验证研究中，生物化学和遗传学方法将测试候选TS抑制剂的作用模式。最好的抗疟药物将被用于安全性和有效性测试。