ROLE OF POLYAMINES IN ESTROGEN FUNCTION IN BREAST CANCER

这项建议的目标是理解自然发生的 多胺与雌激素在乳腺癌中的作用。一种组合 组织培养、物理化学和重组DNA技术将成为 用来实现这一目标。两个激素反应细胞系(MCF-7和 T-47D)和两个激素不敏感细胞系(BT-20和MDA-MB-231)，均为 人类乳腺癌起源的基因，将用于这项研究。雌激素 多胺生物合成酶鸟氨酸脱羧酶的刺激作用 (ODC)将通过测量ODC和多胺的水平作为 雌激素的给药功能。银杏叶提取物的抗增殖作用 ODC抑制剂α-二氟甲基鸟氨酸(DFMO)将在 与抗雌激素在激素反应细胞系和与 顺铂、阿霉素及其类似物对激素不敏感细胞的作用。 多胺在雌激素诱导的细胞生长中的作用将通过 ODC的合成与DNA、RNA和特异性 雌激素诱导蛋白，如24和52K蛋白。 为了了解多胺作用的分子机制 论雌激素的作用、雌激素的稳定和活化 受体(ER)的研究将通过密度梯度分析、DNA-纤维素 竞争分析和配体解离速率 多胺及其衍生物。Er与右旋B-DNA的结合 将对左撇子Z-DNA进行检查，以深入了解其影响 多胺诱导的DNA在ER-DNA上的构象转变 互动。这些研究将得到内质网地图的补充 在多胺存在的情况下，DNA上的结合位点。在分子层面 雌激素对人乳腺癌中ODC基因的调控作用 用人ODC基因进行研究。核转录分析，斑点印迹 分析，Northern转移和S1核酸酶分析将进行 了解ODC在激素反应和转录调控中的作用 激素反应迟钝的细胞系。这些研究产生的结果 将促进我们对激素调节基因表达的了解 乳腺癌。这些研究还将为以下方面提供重要信息 多胺类药物治疗新方法的研究进展 抑制剂与抗雌激素/抗肿瘤药物联合使用。

The goal of this proposal is to understand the role of naturally occurring polyamines in the function of estrogens in breast cancer. A combination of tissue culture, physico-chemical and recombinant DNA techniques will be used to achieve this goal. Two hormone-responsive cell lines (MCF-7 and T-47D) and two hormone-unresponsive cell lines (BT-20 and MDA-MB-231), all of human breast cancer origin, will be used for this study. The estrogenic stimulation of a polyamine biosynthetic enzyme, ornithine decarboxylase (ODC) will be studied by measuring the levels of ODC and polyamines as a function of estrogen administration. The antiproliferative effect of the ODC inhibitor, Alpha-difluromethylornithine (DFMO) will be examined in combination with antiestrogens on hormone responsive cell lines and with cisplatin, adriamycin, and their analogs on hormone-unresponsive cells. The role of polyamines on estrogen induced cell growth will be studied by correlating the synthesis of ODC with that of DNA, RNA and specific estrogen-induced proteins, such as 24 and 52K proteins. In order to understand the molecular mechanism of the action of polyamines on estrogen function, the stabilization and activation of estrogen receptors (ER) will be studied by density gradient analysis, DNA-cellulose competition assay and ligand dissociation rate in the presence of polyamines, and their derivatives. ER binding to the right-handed B-DNA and the left-handed Z-DNA will be examined to gain insight into the effect of polyamine-induced conformational transitions of DNA on ER-DNA interactions. These studies will be complemented by a mapping of the ER binding sites on DNA in the presence of polyamines. At the molecular level, the regulation of ODC gene by estrogen in human breast cancer will be studied using human ODC cDNA. Nuclear transcription assays, dot-blot analysis, Northern transfer and S1 nuclease analysis will be carried out to understand the transcriptional regulation of ODC in hormone-responsive and hormone-unresponsive cell lines. The results generated from these studies will advance our knowledge of the hormonal regulation of gene expression in breast cancer. These studies will also provide significant information for the development of novel therapeutic approaches involving polyamine inhibitors in combination with antiestrogens/antitumor drugs.