PHARMACOLOGY OF NONPOLYGLUTAMATABLE AMINOPTERIN ANALOGS

描述：（申请人摘要）本项目的总体目标是 进行体外和体内生物化学研究， 药理作用模式的一类异常有效的水溶性 其活性不 需要并且不依赖于多谷氨酸化。 典型成员 此类的 N-α-（4-氨基-4-脱氧蝶酰基）-N-δ-半邻苯二甲酰基-L-鸟氨酸（PT 523， NSC-633713），其首先在DFCI合成。 生化和 第二代PT 523类似物的药理学性质是 作为单独的化学合成赠款的一部分， 作为该项目的一部分进行调查，目的是确定是否有任何 它们中的一种可能比先导化合物更有吸引力 化合物. 还有待研究的是最近合成的前药衍生物 PT 523的设计利用了“抗体导向酶”的优势， 前体药物治疗”（ADEPT），以减少宿主毒性和改善肿瘤与 寄主选择性 具体目标I（体外研究）：（i） 来自申请人的合成程序的第二代PT 523类似物;（ii） 用胸苷和/或次黄嘌呤预防细胞毒性;（iii） 二氢叶酸还原酶抑制;（iii）细胞摄取的动力学;（iv） 对细胞还原叶酸池的影响以及对 DNA合成;和（v）PT 523与其它， 非抗叶酸药物。 具体目标2（体内研究）：（i）抗肿瘤 PT 523和其他第二代类似物在人异种移植物中的活性 肿瘤模型;和（ii）对还原叶酸库和DNA合成的影响 在肿瘤与骨髓和肠道中的抑制/恢复。 具体目标3 （耐药性研究）：（i）体外产生的人肿瘤耐药性 通过PT 523通过不同的选择方案的细胞系，并比较 达到对PT 523和MTX的相似耐药性水平所需的时间;（ii） PT 523抗性细胞中DHFR活性和药物摄取的分析， 对这种非多聚谷氨酸盐药物的抗性的可能决定因素;和iv） 关于PT 523-L-Phe作为治疗药物的治疗潜力的初步体外研究 PT 523的ADEPT衍生物的第一个实例。

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.