醛氧化酶和氰基水解酶介导的创新药物代谢机制研究

In recent years, more and more cases of drug attrition during clinical development were reported, which were resulted from the lack of understanding of non-P450 enzymes mediated unusual drug metabolism. With regard to this issue, this project focuses on studying the unusual metabolic pathways of two classes of drugs, triazolo fused heterocyclic c-MET inhibitors and cyanopyrrolidine DPPIV inhibitors. Various in vitro metabolic models will be used to identify the subcellular localization of metabolic reactions and the enzyme phenotypes. Isotope labelled compounds and chemical derivatives will be synthesized to study the biochemistry mechanism of metabolism, the substrate selectivity, and the influences of substituent effects and steric hindrance on the metabolism. In silico approaches will be used to establish the chemical structure-metabolism relationships and investigate the in vitro-in vivo correlation as well as laboratory animals-humans correlation for metabolism. The model will be built to predict drug pharmacokinetics and evaluate safety in humans from animal data. Specific substrates for these enzymes will be identified, and aldehyde oxidase and nitrilase based drug-drug interactions will be unveiled. Additionally, the adverse drug reactions will be predicted.. On the basis of the comprehensive understandings of structure-metabolism relationship, species differences, and drug-drug interactions, the current available metabolism evaluation systems will be improved, and the strategies to reduce the metabolic clearance mediated by aldehyde oxidase and nitrilase will be explored. Consequently, the attrition in drug development due to the metabolism by these non-P450 enzymes will be avoided.

由于对一些非P450酶催化的特殊代谢途径认识不足，导致药物临床开发失败的案例越来越多。针对此问题，本项目拟研究以醛氧化酶代谢为主的三唑并稠杂环类c-MET抑制剂和以氰基水解为主的氰基吡咯烷类DPPIV抑制剂的代谢机制。采用多种体外代谢模型，明确代谢发生的部位，确定代谢酶表型；结合同位素标记化合物和合成系列衍生物，研究代谢的生物化学机制、酶的底物选择性以及结构中取代基和空间位阻对代谢的影响，通过计算机模拟建立化学结构-代谢的相关性；进行体内-体外代谢相关性、动物和人体内代谢相关性研究，构建可预测人体相关代谢的体外和动物模型；筛选特异性底物，发现基于醛氧化酶和氰基水解酶的药物相互作用，预测不良反应的发生。通过对药物结构与代谢关系、代谢种属差异和药物相互作用的深入认识，完善醛氧化酶和氰基水解酶代谢的评价体系，探索降低代谢清除速率的结构修饰策略，避免由于这些非P450酶代谢导致的药物开发失败。

对一些非P450酶催化的特殊代谢途径认识不足，导致药物临床开发失败的案例越来越多。针对此问题，本项目以三唑并稠杂环类c-MET激酶抑制剂和氰基吡咯烷类DPPIV抑制剂为模型化合物探讨了醛氧化酶和二肽基肽酶介导的创新药物代谢机制，获得了以下研究成果：(1) 研究了三唑并稠杂环类化学结构与醛氧化酶介导的代谢相关性；使用 SimpleCart 计算程序，以底物及底物与醛氧化酶形成四面体的能量差（ΔEinter）和底物与醛氧化酶活性位点的空间位阻（Steric），建立了判断醛氧化酶代谢位点的决定树DTAOX。与已报道的方法相比，本项目建立的DTAOX能对分子结构中的多个代谢位点进行判断，不仅局限于对单个优势位点进行判断，预测的准确率为93.33%。(2) 研究了以氰基水解为主的氰基吡咯烷类DPPIV抑制剂的代谢机制。采用多种体外代谢模型，发现二肽基肽酶，特别是DDP2和DPP4介导氰基水解代谢，并进一步研究了DPPs酶的底物选择性以及结构中取代基和空间位阻对代谢的影响，明确底物要进入由Ser630、Asp708和His740组成催化三联体空腔中，通过与Ser630的共价结合进入DPPs酶的催化活性部位而被水解，酰胺代谢物的形成是DPPs酶介导氰基水解的限速步骤。本项目的研究扩展了药物代谢酶谱，提高了对氰基水解代谢的认识。(3) 筛选醛氧化酶具有临床意义的诱导剂和抑制剂。首次证明非甾体抗炎药尼美舒利可以诱导人和大鼠的醛氧化酶活性，探索了诱导机制、确定了醛氧化酶体外诱导评估体系。(4) 通过对药物结构与代谢关系、代谢种属差异和药物相互作用的深入认识，完善醛氧化酶和二肽基肽酶代谢的评价体系，探索降低代谢清除速率的结构修饰策略，避免由于这些非P450酶代谢导致的药物开发失败。相关研究对指导化合物的结构优化、合理选择安全性评价动物种属、判断药物是否有继续开发的价值并尽早避免代谢导致的药物开发失败、预测临床可能的药物相互作用等多方面均具有重要价值。 (5) 作为通讯作者，发表SCI收录的期刊论文7篇，其中在药物代谢领域的国际核心期刊Drug Metab Dispos上发表相关研究论文6篇；J Med Chem发表论文1篇。