SSAT AS A DETERMINANT OF DRUG ACTION

描述：多胺分解代谢酶的诱导 亚精胺/精胺N1-乙酰转移酶（SSAT） 代表了已知最有效的基因反应之一， 抗癌药 这种反应与抗肿瘤活性的关系 和宿主毒性尚未明确确定。 拟议 研究建立在以下观察和发展的基础上， 新酶：a）目前正在进行1期临床试验的多胺类似物 试验（N1，N11 -二乙基去甲精胺（DENSPM）是一种非常有效的诱导剂 B）黑素瘤细胞比其他细胞更响应于SSAT诱导; 大多数其他肿瘤细胞类型; c）生物学相关性表明因果关系 SSAT活性的类似物诱导与体外和体内 肿瘤细胞的生长敏感性; d）肿瘤细胞中的酶的过表达; 转基因动物会引起显著的表型变化， 雌性生殖道; e）SSAT转基因之间的强烈相似性 动物和某些其他转基因生物表明，这种酶在肿瘤中的作用， 促进和f）SSAT基因在小鼠皮肤和黑素瘤细胞中的表达， 12-O-十四烷酰基-13-佛波醇乙酸酯（TPA）可显著增加细胞凋亡。 的 具体目标建议：1）检查SSAT的细胞后果 转染四环素诱导的人黑素瘤细胞中的诱导 SSAT表达系统; 2）研究SSAT基因在转基因中的意义 控制SSAT基因的表达; 3）检查SSAT基因的生理作用。 SSAT在组织功能中使用激活的基因敲除（通过RT-PCR） 与Janne博士的小组（芬兰库奥皮奥）达成协议; 4）利用系统 在目的1-3中开发了研究SSAT在确定抗肿瘤和 对临床相关的多胺拮抗剂的毒性反应; 5） 通过杂交育种实验确定SSAT过表达是否使 动物或多或少倾向于皮肤致癌和6）作为一种机制 与目标5相关，他们建议检查肿瘤促进剂对 SSAT基因的表达及蛋白激酶C的介导作用 TPA和多胺类似物的SSAT诱导。 除了 研究这种不寻常的酶反应的生物学意义， 拟议的研究旨在提供治疗见解， 临床前模型系统，用于促进正在进行的临床和 实验性抗癌疗法的临床前开发 多胺

DESCRIPTION: Induction of the polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT) by certain polyamine analogs represents one of the most potent known gene responses attributable to an anticancer drug. The relationship of this response to antitumor activity and host toxicities has not yet been clearly established. The proposed studies build on the following observations and developments involving this novel enzyme: a) a polyamine analog currently undergoing phase 1 clinical trial (N1, N11 -diethyl-norspermine (DENSPM) is an extremely potent inducer of this enzyme; b) melanoma cells are more responsive to SSAT induction than most other tumor cell types; c) biological correlations suggest a causal linkage between analog induction of SSAT activity and in vitro and in vivo growth sensitivity of tumor cells; d) overexpression of the enzyme in transgenic animals causes striking phenotypic changes involving skin and the female reproductive tract; e) strong similarities between SSAT transgenic animals and certain other transgenics suggest a role for the enzyme in tumor promotion and f) SSAT gene expression in mouse skin and melanoma cells is markedly increased by 12-O-tetradecanoyl-13-phorbol acetate (TPA). The Specific Aims propose: 1) to examine the cellular consequences of SSAT induction in human melanoma cells transfected with a tetracycline-inducible SSAT expression system; 2) to investigate the significance of translational control of SSAT gene expression; 3) to examine the physiological role of SSAT in tissue function using activated gene knock-out (via subcontract agreement with Dr. J. Janne's group Kuopio, Finland); 4) to utilize systems developed in aims 1-3 to study the role of SSAT in determining antitumor and toxicity responses to clinically relevant polyamine antagonists; 5) to determine via cross-breeding experiments whether SSAT overexpression renders animals more or less prone to skin carcinogenesis and 6) as a mechanistic correlate to aim 5, they propose to examine the effects of tumor promters on SSAT gene expression and the possible role of protein kinase C as a mediator of SSAT induction by both TPA and the polyamine analogs. In addition to investigating the biological significance of this unusual enzyme response, the proposed studies are designed to provide therapeutic insights and preclinical model systems for use in facilitating the ongoing clinical and preclinical development of experimental anticancer therapies targeting polyamines.