ROLE OF POLYAMINES IN ESTROGEN FUNCTION IN BREAST CANCER

这项建议的总体目标是阐明其作用机制 多胺在雌激素介导的乳腺癌细胞生长中的作用。 多胺是存在于所有细胞中的有机阳离子。雌激素起着关键作用 在乳腺癌和一种抗雌激素的发生和发展中的作用， 他莫昔芬是对人类部分亚群最有效的治疗形式 乳腺癌。雌激素的作用机制涉及相互作用 激素对一种特定的细胞内蛋白质雌激素受体的作用 (Er)随后ER对特定DNA序列的识别 基因组。雌激素反应元件对雌激素受体的识别作用 (ERES)，刺激反应基因的转录，DNA合成， 和细胞分裂。然而，调节这种相互作用的因素和 与转录有关的构象变化 雌激素功能的调控尚不清楚。 我们实验室和其他实验室之前的研究表明， 多胺在雌激素功能中起着至关重要的作用。我们假设 多胺参与了高亲和力复合体的形成 与ERE结合，从而调节乳腺癌细胞生长。为了测试这一点 假设，我们将量化多胺对ER-ERE的影响 平衡结合常数和构象的相互作用 ERE的改变，使用寡核苷酸和含有ERE的质粒。 多胺结构特异性将使用同系物和 多胺的衍生物。多胺和内质网的激发能力 将用圆二色谱研究ERE的构象变化 光谱、酶联免疫吸附试验、凝胶电泳法和 通过检测单链和左撇子(Z-DNA)的化学探针 ERE中的区域。不支持ER-ERE的多胺类似物 将在组织培养实验中研究相互作用 雌激素敏感型乳腺癌细胞株MCF-7。可能的 多胺类似物的添加/协同生长抑制作用 与他莫昔芬联合研究。核糖核酸的摄取及其机制 多胺类似物的作用将进一步从它们的作用 改变多胺生物合成酶和抑制细胞周期的能力 进步。 对多胺在ER-ERE中作用机制的认识 识别是理解转录调控的关键 乳腺癌中基因表达和细胞生长的研究。此信息是 对于开发新的治疗策略非常重要 乳腺癌。

The overall goal of this proposal is to elucidate the mechanism of action of polyamines in estrogen-mediated growth of breast cancer cells. Polyamines are organic cations present in all cells. Estrogens play a key role in the origin and progression of breast cancer and an antiestrogen, tamoxifen, is the most effective form of therapy for a subset of human breast cancer. Mechanism of action of estrogen involves the interaction of the hormone to a specific intracellular protein, estrogen receptor (ER) followed by the recognition of ER to specific DNA sequences in the genome. Recognition of ER by these sequences, estrogen response elements (EREs), stimulates the transcription of responsive genes, DNA synthesis, and cell division. However, factors that modulate this interaction and the conformational alterations that are involved in transcriptional control of estrogenic function are not known. Previous studies from our laboratory and others have shown that polyamines play an essential role in estrogenic function. We hypothesize that polyamines are involved in the formation of high affinity complexes with ERE and thus modulate breast cancer cell growth. To test this hypothesis, we will quantity the effects of polyamines on ER-ERE interaction in terms of equilibrium binding constants and conformational alterations of ERE, using oligonucleotides and plasmids containing EREs. Polyamine structural specificity will be examined using homologs and derivatives of polyamines. The ability of polyamines and ER to provoke conformational alterations in ERE will be studied by circular dichroism spectroscopy, enzyme-linked immunosorbent assay, gel electrophoresis, and by chemical probes that detect single-stranded and left-handed (Z-DNA) regions in ERE. Polyamine analogs that do not support ER-ERE interactions will be studied in tissue culture experiments with an estrogen-responsive breast cancer cell line MCF-7. Possible additive/synergistic growth inhibitory effects of polyamine analogs will be studied in combination with tamoxifen. The uptake and mechanism of action of polyamine analogs will be further explored in terms of their ability to alter polyamine biosynthetic enzymes and inhibit cell cycle progression. An understanding of the mechanism of action of polyamines in ER-ERE recognition is critical to the understanding of transcriptional control of gene expression and cell growth in breast cancer. This information is important to the development of novel strategies for the treatment of breast cancer.