FOLATE POLYGLUTAMATION/TRANSPORT IN CANCER THERAPEUTICS

描述：（申请人摘要）本项目的总体目标是 叶酰聚谷氨酸酯新底物和抑制剂的合成 合成酶（FPGS），以确定结构要求 与活性位点紧密结合，并更好地了解 这种生理上重要的酶的分子作用机制。 在 此外，这些研究将产生新的信息， 叶酸类似物通过还原的 叶酸载体和膜叶酸结合蛋白转运 途径。 希望通过这些研究获得的知识将 有助于开发叶酸多聚谷氨酰化抑制剂 和/或作为用于癌症治疗的独立类别的抗叶酸剂被摄取。 待合成的化合物的具体类型将包括：（1） FPGS反应的中间产物和过渡态类似物;（2） 叶酸和四氢叶酸类似物保留谷氨酸部分， 在由B-环、桥、芳基组成的“湾区”中被修饰， CONH部分;（3）γ-CO2 H基团被NO2取代的类似物， SO2 H和PO 2 H2基团;（4）具有γ，γ-二氟鸟氨酸侧的类似物 链;和（5）GSH-活化的和其他前药衍生物的最佳 可用的鸟氨酸型类似物。 这些相互作用的动力学 与FPGS的化合物将被确定为一个既定的 与R.G.博士合作莫兰（弗吉尼亚医学院，里士满）， 而它们在不同细胞中的膜转运特性将是 与G博士合作。詹森（自由大学医院， 阿姆斯特丹）。 此外，如果需要进行此类研究，化合物将 与FPGS共结晶，并通过X射线分析晶体 晶体学来获得关于FPGS抑制剂如何 绑定到活动站点。 晶体学研究将是 与V. Cody博士（Hauptman-Wood医学研究中心）的持续合作 研究所，布法罗）。 希望这些互动研究可以 最终导致开发出一种基于 利用结合中的定性或定量差异 在肿瘤中被认为存在于FPGS同种型之间的特异性 和非肿瘤组织，并且原则上也可以存在于肿瘤组织中。 膜转运水平。 除了结合和摄取测定外， 将测试从该项目中获得的新化合物的能力， 抑制培养的肿瘤细胞的生长，希望能找到一种 或更有希望的候选物用于放大合成和进一步的临床前研究。 发展

DESCRIPTION: (Applicant's Abstract) The overall goal of this project is the synthesis of novel substrates and inhibitors of folylpolyglutamate synthetase (FPGS) with a view to defining the structural requirements for tight binding to the active site and gaining a better understanding of the molecular mechanism of action of this physiologically important enzyme. In addition, these studies will yield new information about the optimal structural features for cellular uptake of folate analogs via the reduced folate carrier (RFC) and membrane folate-binding protein (mFBP) transport pathways. It is hoped that knowledge gained through these studies will contribute to possible development of inhibitors of folate polyglutamylation and/or uptake as a discrete class of antifolates for cancer therapeutics. Specific types of compounds to be synthesized will include: (1) intermediate product and transition state analogs of the FPGS reaction; (2) folate and tetrahydrofolate analogs that retain the glutamic acid moiety but are modified in the `bay region' comprised by the B-ring, bridge, aryl, and CONH moieties; (3) analogs in which the gamma-CO2H group is replaced by NO2, SO2H, and PO2H2 groups; (4) analogs with gamma,gamma-difluoroornithine side chains; and (5) GSH-activated and other prodrug derivatives of the best available ornithine-type analogs. The kinetics of interaction of these compounds with FPGS will be determined as part of an established collaboration with Dr. R.G. Moran (Medical College of Virginia, Richmond), whereas their membrane transport characteristics in different cells will be determined in collaboration with Dr. G. Jansen (Free University Hospital, Amsterdam). In addition, where such studies are indicated, compounds will be co-crystallized with FPGS and the crystals analyzed by X-ray crystallography to obtain critical information about how FPGS inhibitors bind to the active site. The crystallographic studies will be part of an ongoing collaboration with Dr. V. Cody (Hauptman-Wood Medical Research Institute, Buffalo). It is hoped that these interactive studies may ultimately lead to development of a therapeutic agent based on the exploitation of qualitative or quantitative differences in binding specificity which are thought to exist between/among FPGS isoforms in tumor and nontumor tissues, and which may also be present, in principle, at the level of membrane transport. In addition to the binding and uptake assays, the new compounds derived from this project will be tested for the ability to inhibit growth of cultured tumor cells, with the hope of identifying one or more promising candidates for scaled up synthesis and further preclinical development.