Phytoestrogens and Cancer

植物雌激素与癌症

• 批准号: 7059833
• 负责人: Wesley George Gray
• 金额: $ 18.1万
• 依托单位: SOUTHERN UNIV A&M COL BATON ROUGE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7059833
• 关键词: alpha benzopyrone; breast neoplasms; cancer prevention; cell line; dietary constituent; estrogen receptors; flavonoids; gel mobility shift assay; gene expression; genetic regulatory element; genetic transcription; genistein; hormone regulation /control mechanism; hormone related neoplasm /cancer; intermolecular interaction; luciferin monooxygenase; molecular cloning; molecular genetics; neoplasm /cancer genetics; neoplastic cell; nucleic acid sequence; nutrition aspect of cancer; nutrition related tag; phytoestrogens; tissue /cell culture; transcription factor

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.

膳食植物雌激素（PE）由于其在以下方面的保护作用而受到相当大的关注： 某些依赖癌症的癌症。然而，目前的科学共识是， 植物雌激素摄入量的增加是不可预测的，部分原因是对它们的作用机制缺乏了解。 在乳腺细胞中的作用。因此，开发一个乳腺癌细胞中植物雌激素的模型系统是一个关键， 协调这些化合物的不利和有益作用的可能性的步骤。的潜在 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，在本发明中， 阐明这些机制对于理解它们的癌症保护作用至关重要。当前没有任何 一种方法可用于区分PE的特定癌症保护作用与其众所周知的 雌激素样作用因此，为了了解植物雌激素化学物质的分子机制， 乳腺癌，我们已经确定了新的PE反应基因，使用差异显示RT-PCR， cDNA的代表性差异分析和定量RT-PCR。使用这些方法，我们 已经表征了这些基因之一PE13.1的表达，该基因以前不知道是 由PE监管。该基因被染料木黄酮和香豆雌酚选择性激活，但不被雌二醇激活。 此外，它的表达是PE特异性的和雌激素受体（ER）依赖性的。因此，PE 13.1是理想的 候选人作为一个模型，在理解饮食雌激素在癌症预防中的作用， 分子水平。在这个提议中，我们将检验PE13.1表达的差异 这是由于基因中存在的PE驱动的上游增强子的活性以及 具有PE/ER综合体。因此，我们将开始阐明PE 13.1的调节机制。 通过表征PE13.1调控元件（目的1），特别是如何在分子水平上研究PE基因 与ER结合导致细胞中的PE 13.1转录激活（目的2）。关键的顺式调节 元件和反式作用因子将通过PE 13.1基因的序列分析来鉴定， 特别是5 ′-侧翼区，并通过将荧光素酶报告基因构建体转染到ER阳性细胞中， （MCF-7 ER+）和ER阴性（MDN-ER-）细胞。我们将确定哪种ER亚型负责 PE13.1转录活性，并确定PE13.1表达的差异是否与ER表达的差异平行。 乳腺肿瘤细胞系的状态。这些实验将开始提供一个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。