POLYAMINE ANALOG AND INHIBITOR REGULATION OF CELL CYCLE

细胞周期调控发现的治疗潜力刚刚被认识到，虽然它们为开发新的和新颖的抗癌剂提供了明确的机会，但它们更直接的潜力在于改善现有药物的使用。DNA损伤剂是从这个角度研究药物的一个明显例子。根据最近的研究结果，我们认为，本实验室的积极参与，目前正在进行临床评价的两个多胺拮抗剂开发，以前未实现的潜力，作为细胞周期调控途径的调制器。这种信念是基于我们最近的观察，即多胺类似物N1，N11-二乙基去甲精胺（DENSPM）和多胺酶抑制剂CGP-48664有效地激活p53，p21，Rb途径并诱导含有野生型p53的MALME-3 M人黑素瘤细胞中的G1细胞周期停滞.在含有突变的p53的SK-MEL-28黑色素瘤细胞中，DENSPM诱导快速和大量的凋亡反应。这些发现代表了多胺和细胞周期调节机制之间的第一个联系。 拟议的研究将调查这些发现在人类黑色素瘤细胞系中的治疗和生物学意义。这种疾病的重点是基于黑素瘤在临床前系统中对这些药物的相对高敏感性;在II期临床试验中黑素瘤的靶向以及黑素瘤在p53表达水平和突变频率方面倾向于与其他实体瘤不同的事实。 因此，以下具体目的提出：（1）检查负责多胺类似物和抑制剂诱导MALME-3 M黑素瘤细胞中G1期阻滞的细胞周期调节途径，最初集中于p53和p21的贡献;（2）鉴定负责多胺类似物诱导SK-MEL- 28细胞凋亡的效应物;（3）研究负责类似物和底物诱导的生长停滞和细胞凋亡的多胺相关起始事件;（4）确认体外发生的特异性类似物和底物诱导的效应也发生在体内。这是我们的信念，了解细胞周期调控事件的两个多胺拮抗剂将有助于合理地部署作为抗癌剂和/或化学预防剂，并在同一时间，提供新的见解如何公认的多胺的要求细胞生长接口与复杂的途径，控制细胞周期的进展和凋亡。

The therapeutic potential of cell cycle regulatory discoveries is just being realized and while they provide clear opportunity for the development of new and novel anticancer agents, their more immediate potential resides in improving the use of existing drugs. DNA-damaging agents are an obvious example of drugs being investigated from this perspective. On the basis of recent findings, we believe that two polyamine antagonists developed with the active involvement of this laboratory and currently undergoing clinical evaluation, have previously unrealized potential as modulators of cell cycle regulatory pathways. This belief is predicated on our recent observation that the polyamine analog N1, N11-diethylnorspermine (DENSPM) and the polyamine enzyme inhibitor CGP-48664 potently activate the p53, p21, Rb pathway and induce G1 cell cycle arrest in MALME-3M human melanoma cells containing wild- type p53. In SK-MEL-28 melanoma cells containing mutated p53, DENSPM induces a rapid and massive apoptotic response. The findings represent the first linkage between polyamines and the cell cycle regulatory machinery. The proposed studies will investigate the therapeutic and biological significance of these findings in human melanoma cell lines. This disease-focus is based on relative high sensitivity of melanoma to these agents in preclinical systems; the targeting of melanoma in Phase II clinical trials and the fact that melanoma tends to differ from other solid tumors with respect to p53 expression levels and mutation frequency. Thus, the following Specific Aims propose: (1) to examine the cell cycle regulatory pathways responsible for polyamine analog and inhibitor induction of G1 arrest in MALME-3M melanoma cells, focusing initially on the contribution of p53 and p21; (2) to identify the effectors responsible for polyamine analog induction of apoptosis in SK-MEL- 28 cells; (3) to investigate the polyamine-related initiating event(s) responsible for analog- and inhibitor-induced growth arrest and apoptosis; and (4) to confirm that specific analog- and inhibitor-induced effects that occur in vitro also occur in vivo. It is our belief that an understanding of cell cycle regulatory events by the two polyamine antagonists will contribute rationally to their deployment as anticancer agents and/or chemopreventive agents and at the same time, provide new insights into how the well-recognized polyamine requirement for cell growth interfaces with the complex pathways that control cell cycle progression and apoptosis.