Molecular biomarkers of selenium chemoprevention

描述(由申请人提供)：之前的人体试验，含硒 酵母菌显示，补硒显著降低了发病率 肺癌、结肠癌和前列腺癌。一项使用癌症的干预试验 作为终点的发病率需要很长时间才能完成，而且成本非常高。 因此，需要替代中间终点或生物标记物来评估 干预的效果。我们在不久的将来的目标是为 乳房试验；一种可行的方法是使用对硒有反应的生物标记物 这与硒化学预防的分子机制有关。 MCF10AT和SUM-190PT人乳腺细胞株将用于建议的 研究。在移植后，MCF 10AT细胞能够发育成 重现人类增生性病变病理的异型增生谱系 乳房疾病。因此，该细胞系为研究提供了一个理想的范例 高危皮损的硒化学预防。Sum-190PT细胞系，在 另一方面，展示了两个已知乳房的放大和过度表达 癌基因：ERBB2和细胞周期蛋白D1。它拥有一种非常独特的基因 接近人类乳腺癌的水平。Aim 1将使用Affymetrix基因芯片 人乳腺细胞中硒敏感生物标志物的体外鉴定 系统。基因表达的时间模式之间的详细关联 具有独特生物学结果的变化将提供重要的洞察力 探讨了硒化学预防的分子机制。信号的调制 基因产物将通过半定量RT-PCR和/或Western进行确认 分析。目的探讨GADD153在人类免疫缺陷中的功能意义。 硒对细胞增殖和诱导细胞凋亡的调控作用。这是一个 根据我们的初步发现进行后续机制研究。AIM 3将验证 人乳腺细胞中最敏感生物标志物的表达 用SCID小鼠建立异种移植模型。配套研究将被设计为 测定硒抑制骨肉瘤病理进展的能力 异种移植(不典型导管增生、导管原位癌、浸润性导管癌 癌症)。这项研究的化学预防部分是一个不可或缺的部分。 生物标记物项目，因为必须评估生物标记物的 生物标记物与乳腺癌预后指标的相关性 保护。目的4研究硒对人体的生物学和免疫功能的影响 治疗大鼠乳腺癌前病变的分子生物学研究 一种致癌物质。目的是扩大我们对这一意义的理解 早期转化细胞克隆抑制在硒保护作用中的作用 癌症。

DESCRIPTION (provided by applicant): A previous human trial with selenized yeast showed that selenium supplementation significantly reduced the incidence of lung, colon and prostate cancers. An intervention trial using cancer morbidity as the endpoint takes a long time to complete and is very costly. Surrogate intermediate endpoints or biomarkers are therefore needed to evaluate the efficacy of intervention. Our goal in the near future is to plan for a breast trial; a viable approach will be to use selenium-responsive biomarkers which are associated with the molecular mechanism of selenium chemoprevention. The MCF10AT and SUM-190PT human breast cell lines will be used for the proposed research. Upon transplantation, the MCF 10AT cells are able to develop a spectrum of dysplasia that recapitulate the pathology of human proliferative breast disease. Thus this cell line provides an ideal paradigm for studying selenium chemoprevention of high-risk lesions. The SUM-190PT cell line, on the other hand, exhibits amplification and over-expression of two known breast cancer oncogenes: erbB2 and cyclin D1. It harbors a genotype which is very close to that of human breast cancer. Aim 1 will use the Affymetrix GeneChip to identify selenium-responsive biomarkers in human breast cells in an in vitro system. A detailed correlation between the temporal pattern of gene expression changes with distinctive biological outcome would provide important insight into the molecular mechanism of selenium chemoprevention. The modulation of gene products will be confirmed by semi-quantitative RT-PCR and/or Western analysis. Aim 2 will investigate the functional significance of GADD153 in selenium control of cell proliferation and induction of apoptosis. This is a follow-up mechanism study based on our preliminary finding. Aim 3 will verify the expression of the most sensitive biomarkers in a human breast cell xenograft model using SCID mice. Companion studies will be designed to determine the ability of selenium to inhibit the pathologic progression of the xenograft (atypical ductal hyperplasia to ductal carcinoma in situ to invasive carcinoma). The chemoprevention component of the research is an integral part of the biomarker project because it is imperative to assess the biological relevance of the biomarkers as prognostic indicators of breast cancer protection. Aim 4 will study the effect of selenium on the biology and molecular biology of premalignant lesions in the mammary gland of rats treated with a carcinogen. The goal is to broaden our understanding of the significance of clonal suppression of early transformed cells in selenium protection of cancer.