EFFECTORS OF POLYAMINE POOL MAINTENANCE

我们最近提出，细胞内多胺库是 通过自我平衡复合物小心地维持在一个狭窄的范围内 由三个效应器系统组成，所有这些效应器系统都是快速响应的， 速率限制其特定活性，特定于多胺， 受细胞内多胺库的敏感调节。 的效应器 包括酶鸟氨酸脱羧酶（ODC）和S- 腺苷甲硫氨酸脱羧酶（SAMDC）控制多胺 控制摄取的推定转运蛋白;和 乙酰化酶亚精胺/精胺N1乙酰转移酶（SSAT） 其具有多功能的潜力， 转换、装订、出口和目录。 这个概念已经证明 可用于解释多胺类似物的细胞效应， 抑制剂和预测其用于抗癌的有效性 战略布局 在此，我们建议利用最近开发的探针， 研究尚未解决的和治疗相关的生物系统 每个效应器的各个方面，以更好地了解其功能 和/或调节，并更好地定义其与多胺的关系 体内平衡 该计划的具体目标是：（1）光亲和 标记和鉴定涉及的质膜蛋白 多胺结合和转运;（2）克隆多胺结合和转运的cDNA。 用于研究分子机制的转运蛋白 多胺对多胺转运和生长的潜在调节 刺激;（3）开发一组细胞系变体， 多胺生物合成酶，用于进一步确定 酶和其他稳态效应物之间的相互关系; (4)研究SSAT和SSAT诱导在多胺 代谢多胺稳态和细胞生理学 并通过用SSAT mRNA定向的反义核酸阻断表达， （d）开发2-氟鸟氨酸作为用于检测寡核苷酸的HPLC标记物。 监测通过多胺池的代谢通量， 研究多胺稳态的方法学。 预计各国 这些研究将为多胺库的研究提供新的信息 稳态;它作为一个概念的有效性;它对至少两个 多胺导向剂（起源于本实验室），现在 接近临床试验和适应症，它可能是更多的 在未来的药物设计中被有效地利用和/或靶向。

We have recently proposed that intracellular polyamine pools are carefully maintained within a narrow range via a homeostatic complex comprised of three effector systems all of which are rapidly responsive, rate limiting for their specified activity, specific for polyamines and sensitively regulated by intracellular polyamine pools. The effectors include the enzymes ornithine decarboxylase (ODC) and S- adenosylmethionine decarboxylase (SAMDC) which control polyamine biosynthesis; a putative transporter protein which controls uptake; and the acetylating enzyme spermidine/spermine N1 acetyltransferase (SSAT) which has the multifunctional potential to control polyamine back- conversion, binding, export and catabolism. The concept has proven useful in interpreting cellular effects of polyamine analogs and inhibitors and in predicting the effectiveness of their use in anticancer strategies. Herein, we proposed to utilize recently developed probes and biological systems to study unresolved and therapeutically relevant aspects of each effector in an attempt to better understand its function and/or regulation and to better define its relationship to polyamine homeostasis. The Specific Aims of the program are (1) photoaffinity labelling, and identification of plasma membrane protein(s) involved in polyamine binding and transport; (2) cloning the cDNA(s) for the transporter protein(s) for use in studying the molecular mechanisms underlying regulation of the polyamine transport by polyamines and growth stimuli; (3) to develop a panel of cell line variants which overproduce polyamine biosynthetic enzymes for use in further defining the regulatory interrelationships between the enzymes and other homeostatic effectors; (4) to study the significance of SSAT and SSAT induction in polyamine metabolism polyamine homeostasis and cellular physiology by transfecting and by blocking expression with SSAT mRNA-directed antisense oligonucleotide; (d) to develop 2-fluoroornithine as a HPLC marker for monitoring metabolic flux through the polyamine pools and to use this methodology to studying polyamine homeostasis. It is anticipated that these studies will provide novel information relevant to polyamine pool homeostasis; its validity as a concept; its implications to at least two polyamine-directed agents (with origins in this laboratory) which are now approaching clinical trial and indications by which it might be more effectively exploited and/or targeted in future drug design.