Phytoestrogens and Cancer

膳食中的植物雌激素(PEs)由于其保护作用而受到相当大的关注。 某些激素依赖型癌症。然而，目前的科学共识是，来自 植物雌激素摄入量的增加是不可预测的，部分原因是对其机制缺乏了解。 在乳腺细胞中的作用。因此，开发乳腺癌细胞中植物雌激素的模型系统是至关重要的。 在调和这些化合物的不利和有益影响的可能性方面采取步骤。潜力 膳食PE可能发挥癌症保护或抗雌激素作用的机制尚不清楚。因此， 阐明这些机制对于了解它们的防癌作用是至关重要的。目前，没有 可以用方法学来区分PE的特定防癌作用和众所周知的 雌激素样作用。因此，为了了解植物雌激素类化合物的分子机制， 对于乳腺癌，我们已经用差异显示RT-PCR鉴定了新的PE反应基因， C DNA代表性差异分析和定量RT-PCR。使用这些方法，我们 已经确定了其中一个基因PE13.1的表达特征，这是以前未知的 由私募股权公司监管。该基因可被染料木素和香豆素选择性激活，但不能被雌二醇激活。 此外，它的表达是PE特异性的，并且依赖雌激素受体(ER)。因此，PE13.1是一种理想的 作为理解饮食雌激素在癌症预防中所起作用的模型的候选人 分子水平。在这项提议中，我们将检验PE13.1表达差异的假设 基因中存在的PE驱动的上游增强子上的活性以及相互作用的结果 有PE/ER复合体。因此，我们将开始阐明PE13.1的调控机制 通过表征PE13.1调节元件(目标1)，特别是PES如何在分子水平表达基因 与内质网结合导致细胞内PE13.1转录激活(目标2)。关键的顺式监管 将通过对PE13.1基因的序列分析来确定元件和反式作用因子， 特别是5‘-侧翼区，并通过将荧光素酶报告结构转入ER阳性 (McF-7ER+)和ER阴性(MDN-ER-)细胞。我们将确定哪个ER亚型负责 PE13.1的转录活性和建立PE13.1表达的差异是否平行于ER的差异 乳腺肿瘤细胞株的研究现状。这些实验将开始提供生物化学模型的基础 从而更好地了解植物雌激素在乳腺癌细胞中的雌激素样作用。

Dietary phytoestrogens (PEs) have been given considerable attention due to their protective role in certain hormone-dependent cancers. However, the current scientific consensus is that the outcome from increased phytoestrogen intake is unpredictable partly due to a poor understanding of their mechanisms of action in breast cells. Thus, developing a model system for phytoestrogens in breast cancer cells is a critical step in reconciling the possibility of both adverse and beneficial effect of these compounds. The potential mechanisms by which dietary PE may exert cancer protective or anti-estrogenic effects are unknown. Thus, elucidation of these mechanisms is essential in understanding their cancer-protective effects. Currently, no methodology is available to distinguish the specific cancer-protective effects of PE from their well-known estrogenic-like effects. Therefore, to understand the molecular mechanisms of phytoestrogenic chemicals in breast cancer, we have identified novel PE-responsive genes using differential display RT-PCR, representational difference analysis of cDNA, and quantitative RT-PCR. Using these methodologies, we have characterized the expression of one of these genes, PE13.1, that has not previously known to be regulated by PE. This gene is selectively activated by genistein and coumestrol but not by estradiol. Furthermore, its expression is PE specific and estrogen receptor (ER) dependent. Thus, PE13.1 is an ideal candidate to use as a model in understanding the role dietary estrogen plays in cancer prevention at the molecular level. In this proposal, we will test the hypothesis that differences in PE13.1 expression result from activity on the PE-driven upstream enhancer present in the gene and from interaction with a PE/ER complex. Therefore, we will begin to elucidate the mechanisms of regulation of the PE13.1 gene at the molecular level by characterizing PE13.1 regulatory elements (aim 1) and, in particular, how PEs in conjunction with the ER lead to PE13.1 transcriptional activation in a cell (aim 2). The key cis-regulatory elements and trans-acting factors will be identified through sequence analysis of the PE13.1 gene, particularly the 5'-flanking region, and through transfection of luciferase reporter constructs into ER-positive (MCF-7 ER+) and ER-negative (MDN-ER-) cells. We will determine which ER subtype is responsible for PE13.1 transcriptional activity and establish if differences in PE13.1 expression parallel differences in ER status in breast tumor cell lines. These experiments will begin to provide a basis of a biochemical model in which to better understand the estrogenic effect of phytoestrogen in breast cancer cells.