Hoarau Marie, Sermmai Patpanat, Varatthan Thaveechai, Thiabma Ratthiya, Jantra Tararat, Rattanajak Roonglawan, Vitsupakorn Danoo, Vanichtanankul Jarunee, Saepua Siriporn, Yuthavong Yongyuth, Thongpanchang Chawanee, Kamchonwongpaisan Sumalee
National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency Pathum Thani 12120 Thailand
RSC Med Chem. 2023 Jul 24;14(9):1755-1766. doi: 10.1039/d3md00242j. eCollection 2023 Sep 19.
dihydrofolate reductase (DHFR), a historical target for antimalarials, has been considered compromised due to resistance inducing mutations caused by pyrimethamine () overexposure. The clinical candidate has demonstrated that inhibitors could efficiently target both -sensitive and -resistant parasites through careful drug design. Yet, clinical development has been limited by its pharmacokinetic profile, incompatible with single dose regimen. Herein, we report the design of new DHFR inhibitors using fragment-based design, aiming at improved lipophilicity and overall drug-like properties. Fragment-based screening identified hits binding in the pABA site of the enzyme. Using structure-guided design, hits were elaborated into leads by fragment linking with 2,4-diaminopyrimidine. Resulting compounds display nM range inhibition of both drug-sensitive and resistant DHFR, high selectivity against the human isoform, drug-like lipophilicity and metabolic stability. Compound 4 and its ester derivative 3 kill blood stage TM4/8.2 parasite at nM concentrations while showing no toxicity against Vero cells.
二氢叶酸还原酶（DHFR）是抗疟药物的一个历史靶点，由于乙胺嘧啶过度暴露导致的耐药性诱导突变，该靶点已被认为受到损害。临床候选药物已证明，通过精心的药物设计，抑制剂可以有效地靶向对药物敏感和耐药的寄生虫。然而，其临床开发受到药代动力学特征的限制，与单剂量方案不兼容。在此，我们报告了基于片段设计的新型DHFR抑制剂的设计，旨在提高亲脂性和整体类药性质。基于片段的筛选确定了在该酶的对氨基苯甲酸（pABA）位点结合的命中物。使用结构导向设计，通过与2,4-二氨基嘧啶进行片段连接，将命中物优化为先导化合物。所得化合物对药物敏感和耐药的DHFR均显示出纳摩尔级别的抑制作用，对人同工型具有高选择性，具有类药亲脂性和代谢稳定性。化合物4及其酯衍生物3在纳摩尔浓度下可杀死血液期TM4/8.2寄生虫，同时对Vero细胞无毒性。
