HUMAN LEUKEMIA FOLYPOLYGLUTAMATE SYNTHETASE INHIBITORS

细胞中还原型叶酸辅酶的保留和功能取决于 这些叶酸的聚（γ-谷氨酰）衍生物的形成。 通过突变删除它们的合成是致命的，除非所有终产物 叶酸代谢（胸苷，型黄嘌呤，Gly，Vet）提供给 细胞 负责合成聚谷氨酸的酶， 因此，叶酰聚谷氨酸合成酶（FPGS）是一个有吸引力的新靶点。 抗折剂 根据令人鼓舞的初步研究，一系列新的 含有鸟氨酸和相关氨基的针对FPGS的抗叶酸剂 将合成和研究酸而不是谷氨酸。 化合物 将作为FPGS抑制剂进行测试，以及 其他关键的叶酸酶，以及它们的作用机制。 其细胞毒性 对MTX敏感和耐药的淋巴细胞和野生型的作用和机制 型非淋巴样人白血病细胞系。 活动 对后一种类型将特别感兴趣，因为患者 非淋巴细胞白血病患者对MTX具有内在耐药性。 这些 研究还将确定细胞毒性与细胞毒性之间是否存在相关性， 和在细胞中或用分离的酶测量的FPGS抑制。 叶酸缺乏和补充的聚谷氨酸合成、周转和外排 人类白血病细胞系目前正在使用MTX作为模型进行比较 因为它也使用FPGS。 利用这个实验系统，我们希望 阐明细胞内叶酸库在调节 聚谷氨酸合成 同样的系统将允许我们检查 FPGS抑制剂对细胞内聚谷氨酸合成的影响 叶酸库的存在和不存在。 这个系统还可以揭示 叶酸库和抑制剂之间有趣的相互作用， 影响聚谷氨酸合成。 FPGS抑制剂也将用于聚谷氨酸盐的基础研究。 例如，第一次， 在没有连续合成的情况下聚谷氨酸盐将是可能的。

Retention and function of reduced folate coenzymes in cells is dependent on the formation of poly (Gamma-glutamyl) derivatives of these folates. Deletion of their synthesis by mutation is lethal unless all end products of folate metabolism (thymidine, typoxanthine, Gly, Vet) are supplied to cells. The enzyme responsible for synthesis of polyglutamates, folylpolyglutamate synthetase (FPGS), is thus an attractive target for new antifols. Based on encouraging preliminary studies, a series of new antifolates directed against FPGS which contain ornithine and related amino acids instead of glutamate will be synthesized and investigated. Compounds will be tested as FPGS inhibitors, as well as inhibitors and substrates of other key folate enzymes, and their mechanism examined. Their cytotoxic effects and mechanism on both MTX-sensitive and resistant lymphoid and wild type nonlymphoid human leukemia cell lines will be determined. Activity against the latter type will be of particular interest because patients with nonlymphoid leukemia are intrinsically resistant to MTX. These studies will also determine if there is a correlation between cytotoxicity and FPGS inhibition as measured in cells or with the isolated enzyme. Polygluamate synthesis, turnover, and efflux in folate-depleted and replete human leukemia cell lines are currently being compared using MTX as a model since it also utilizes FPGS. Using this experimental system, we hope to elucidate the role of the intracellular folate pool in regulation of polyglutamate synthesis. This same system will allow us to examine the effects of FPGS inhibitors on polyglutamate synthesis intracellularly in the presence and absence of the folate pool. This system may also uncover interesting interactions between the folate pool and inhibitor which may affect polyglutamate synthesis. FPGS inhibitors will also be useful in basic studies on polyglutamates. For example, for the first time, measurement of degradation of polyglutamates in the absence of continued synthesis will be possible.