ROLE OF POLYAMINES IN ESTROGEN FUNCTION IN BREAST CANCER

本提案的总体目标是阐明作用机制 雌激素介导的乳腺癌细胞生长中的多胺。 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 在乳腺癌的起源和发展中的作用以及抗雌激素， 他莫昔芬是治疗一部分人类 乳腺癌 雌激素的作用机制涉及相互作用 一种特殊的细胞内蛋白，雌激素受体 (ER)随后是ER对细胞中特定DNA序列的识别， 基因组 这些序列识别雌激素受体，雌激素反应元件 （EREs），刺激应答基因的转录，DNA合成， 和细胞分裂。 然而，调节这种相互作用的因素， 参与转录的构象改变 雌激素功能的控制是未知的。 我们实验室和其他人的先前研究表明， 多胺在雌激素功能中起重要作用。 我们假设 多胺参与了高亲和力复合物的形成 从而调节乳腺癌细胞的生长。 为了验证这一 假设，我们将量化多胺对ER-ERE的影响 相互作用的平衡结合常数和构象 使用含有ERE的寡核苷酸和质粒改变ERE。 多胺结构特异性将使用同系物和 多胺的衍生物。 多胺和雌激素受体的能力， 通过圆二色性研究ERE中的构象改变 光谱学、酶联免疫吸附测定、凝胶电泳和 通过化学探针检测单链和左手（Z-DNA） 区域内。 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 雌激素反应性乳腺癌细胞系MCF-7。 可能 多胺类似物的加和/协同生长抑制作用将 与他莫昔芬联合研究。 的摄取和机制 多胺类似物的作用将进一步探讨其 改变多胺生物合成酶和抑制细胞周期的能力 进展 对多胺在ER-ERE中作用机制的认识 识别对于理解转录控制至关重要 乳腺癌的基因表达和细胞生长。 该信息 重要的是发展新的战略，用于治疗 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.