Targets for selenium in prostate cancer prevention

硒预防前列腺癌的目标

• 批准号: 7147023
• 负责人: JOHN T PINTO
• 金额: $ 31.59万
• 依托单位: WINIFRED MASTERSON BURKE MED RES INST
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-04 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7147023
• 关键词: androgens; cancer prevention; human; model; oxidation reduction reaction; prostate neoplasms; proteins; selenium; transcription factor; yeasts

DESCRIPTION (provided by applicant): This proposal tests the hypothesis that naturally-occurring and synthetic organoselenium compounds (SeC) modify growth of human prostate cancer (CaP) cells by targeting redox sensitive signal proteins and transcription factors thereby regulating proliferative and/or apoptotic responses. Inhibition of cell proliferation and induction of apoptosis are major cancer preventive activities of SeC. Preliminary studies document selective growth inhibitory effects of SeCs utilizing phenotypically similar androgen-responsive (AR+) and - non-responsive (AR-) human LNCaP cells. Proteomic studies reveal that the form of Se and the cell's hormonal status play critical roles in growth inhibition. To test our hypothesis we formulated 3 specific aims. Aim 1 characterizes antiproliferative mechanisms of SeC in AR+ and AR- cells. Studies will compare time and dose-response effects of SeC on cytometric measurements, cell proliferation, apoptotic_processes, and intracellular redox environment. Proteomic analyses will examine expression profiles of selected redox sensitive signal and transcription factors. Aim 2 identifies sites and characterizes the type of interaction between SeC and selected redox signal proteins. Purified or recombinant proteins selected from prolifiterative and apoptotic pathways will be studied to identify occurrences of covalent intra- and intermolecular -S-S- or S- Se conjugates. Immunoprecipitations of similar signal proteins from control and SeC-treated AR+ and AR- cells will be studied. HPLC separation of proteolytic digests followed by MALDI-TOF MS analyses will locate sites of protein modification. In Aim 3, nude mice implanted with AR+ and AR- cells and TRAMP mice are fed diets containing low and high levels of SeC (including selenized yeast). Global expression profiles of redox-sensitive signal proteins as defined in Aim 1 will be determined relative to dietary SeC in these models. Completion of this study will define the molecular targets of SeC at the proteomic level and will identify in AR+ and AR- human prostate cancer cells distinct physiological responses necessary for chemopreventive action. Also, this study aims to determine whether the molecular environment in which Se resides mediates redox sensitive signal and/or transcription factors that regulate proliferative and/or apoptotic processes in CaP. Molecular targets identified in this study will provide relevant biomarkers useful for the on-going SELECT Study that examines selenomethionine for prevention of CaP. Our proposal determines the role of various forms of selenium (natural and synthetic) on protein targets implicated in development of human prostate cancer. The long-term goal of our reseach is to design appropriate dietary strategies for prevention of prostate cancer.

描述（由申请人提供）：该提案测试了以下假设：天然存在和合成的有机硒化合物（SeC）通过靶向氧化还原敏感信号蛋白和转录因子来改变人类前列腺癌（CaP）细胞的生长，从而调节增殖和/或凋亡反应。抑制细胞增殖和诱导细胞凋亡是 SeC 的主要癌症预防活性。初步研究证明 SeCs 利用表型相似的雄激素反应性 (AR+) 和非反应性 (AR-) 人类 LNCaP 细胞具有选择性生长抑制作用。蛋白质组学研究表明，硒的形式和细胞的激素状态在生长抑制中发挥着关键作用。为了检验我们的假设，我们制定了 3 个具体目标。目标 1 描述了 SeC 在 AR+ 和 AR- 细胞中的抗增殖机制。研究将比较 SeC 对细胞计数测量、细胞增殖、细胞凋亡过程和细胞内氧化还原环境的时间和剂量反应影响。蛋白质组学分析将检查选定的氧化还原敏感信号和转录因子的表达谱。目标 2 识别位点并表征 SeC 与选定氧化还原信号蛋白之间相互作用的类型。将研究从增殖和凋亡途径中选择的纯化或重组蛋白，以鉴定共价分子内和分子间-S-S-或S-Se缀合物的出现。将研究来自对照和 SeC 处理的 AR+ 和 AR- 细胞的类似信号蛋白的免疫沉淀。蛋白水解消化物的 HPLC 分离和 MALDI-TOF MS 分析将定位蛋白质修饰位点。在目标 3 中，植入 AR+ 和 AR- 细胞的裸鼠和 TRAMP 小鼠被喂食含有低水平和高水平 SeC（包括硒化酵母）的饮食。目标 1 中定义的氧化还原敏感信号蛋白的整体表达谱将根据这些模型中的饮食 SeC 来确定。这项研究的完成将在蛋白质组水平上确定 SeC 的分子靶标，并将确定 AR+ 和 AR- 人类前列腺癌细胞中化学预防作用所需的不同生理反应。此外，本研究旨在确定 Se 所在的分子环境是否介导调节 CaP 增殖和/或凋亡过程的氧化还原敏感信号和/或转录因子。本研究中确定的分子靶标将为正在进行的 SELECT 研究提供有用的相关生物标志物，该研究检查硒代蛋氨酸是否预防 CaP。我们的建议确定了各种形式的硒（天然和合成）对与人类前列腺癌发展有关的蛋白质靶标的作用。我们研究的长期目标是设计适当的饮食策略来预防前列腺癌。