PHARMACOLOGY OF NONPOLYGLUTAMATABLE AMINOPTERIN ANALOGS

描述：(申请者摘要)这个项目的总体目标是 在体外和体内进行生物化学和体内外研究 一类超常强效水溶性药物的药理作用模式 非经典二氢叶酸还原酶抑制剂，其活性不 需要多聚谷氨酰胺，而不是依赖多谷氨酰胺。原型成员 这个班级的 N-alpha-(4-amino-4-deoxypteroyl)-N-delta-hemiphthaloyl-L-ornithine(PT523， Nsc-633713)，首次在东风化工厂合成。生化和 第二代PT523类似物的药理性质 作为单独的化学合成补助金的一部分，合成也将被 作为该项目的一部分进行调查，目的是确定是否有 其中可能是比领先者更有吸引力的临床前候选人 化合物。同样要研究的还有一种最近合成的前药衍生物。 PT523的基因被设计成利用“抗体导向酶”的优势 前药治疗“(ADEPT)以减少宿主毒性并改善肿瘤与 宿主选择性。特定目标I(体外研究)：(I)细胞毒性 申请人合成程序中的第二代PT523类似物； 用胸腺嘧啶核苷和/或次黄嘌呤预防细胞毒性； 二氢叶酸还原酶抑制；(Iii)细胞摄取动力学；(Iv) 对细胞还原叶酸库的影响及对抑制和恢复的影响 DNA合成；以及(V)PT523与其他， 非抗叶酸类药物。特异性靶点2(体内研究)：(I)抗肿瘤 PT523等第二代类似物在人异种移植瘤中的活性 肿瘤模型；以及(Ii)对叶酸库减少和DNA合成的影响 肿瘤相对于骨髓和肠道的抑制/恢复。具体目标3 (耐药性研究)：(I)体外产生对人类肿瘤的耐药性 PT523通过不同的选择方案筛选细胞系，并比较 对PT523和MTX达到类似水平的耐药性所需的时间；(Ii) PT523耐药细胞DHFR活性和药物摄取的分析 对这种非多聚谷氨酰胺类药物产生耐药性的可能决定因素；以及 PT523-L-苯丙氨酸体外治疗作用的初步研究 第一个例子是PT523的熟练衍生品。

DESCRIPTION: (Applicant's Abstract) The overall goals of this project are to conduct in vitro and in vivo studies of the biochemical and pharmacological mode of action of a class of unusually potent water-soluble nonclassical dihydrofolate reductase inhibitors whose activity does not require, and is not dependent on, polyglutamation. The prototypical member of this class is N-alpha-(4-amino-4-deoxypteroyl)-N-delta-hemiphthaloyl-L-ornithine (PT523, NSC-633713), which was first synthesized at DFCI. Biochemical and pharmacologic properties of second generation PT523 analogs being synthesized as part of a separate chemical synthesis grant will also be investigated as part of this project with the aim of determining whether any of them may be more attractive preclinical candidates than the lead compound. Also to be studied is a recently synthesized prodrug derivative of PT523 which was designed to take advantage of "antibody directed enzyme prodrug therapy" (ADEPT) to decrease host toxicity and improve tumor versus host selectivity. Specific Aim I (in vitro studies): (i) cytotoxicity of second generation PT523 analogs from the applicant's synthesis program; (ii) prevention of cytotoxicity with thymidine and/or hypoxanthine; (iii) dihydrofolate reductase inhibition; (iii) kinetics of cellular uptake; (iv) effects on cellular reduced folate pools and on inhibition and recovery of DNA synthesis; and (v) synergistic interactions of PT523 with other, non-antifolate drugs. Specific Aim 2 (in vivo studies): (i) antitumor activity of PT523 and other second generation analogs in human xenograft tumor models; and (ii) effects on reduced folate pools and DNA synthesis inhibition/recovery in tumor versus marrow and gut. Specific Aim 3 (resistance studies): (i) in vitro production of resistance in human tumor cell lines by PT523 via different selection protocols, and comparison of the time needed to achieve a similar level of resistance to PT523 and MTX; (ii) analysis of DHFR activity and drug uptake in PT523 resistant cells, the most likely determinants of resistance to this nonpolyglutamatable drug; and iv) pilot in vitro studies on the therapeutic potential of PT523-L-Phe as the first example of an ADEPT derivatives of PT523.