Nutrients and Prostate Cancer Prevention

描述（由申请人提供）：背景：流行病学研究继续支持这样一个前提，即增加葱属蔬菜（如大蒜）的消费可能有助于预防某些类型的癌症，包括前列腺癌。最近的研究表明，人前列腺癌细胞以及转基因小鼠前列腺腺癌衍生的细胞系（转基因腺癌小鼠前列腺; TRAMP-C1细胞系）对大蒜衍生的有机硫化合物（OSC）二烯丙基三硫化物（DATS）的生长抑制高度敏感。有趣的是，正常前列腺上皮细胞系（PrEC，Clonetics）的活力受到DATS的影响最小，即使在对前列腺癌细胞具有高度细胞毒性的浓度下。这些结果是令人鼓舞的，因为选择性杀死癌细胞是潜在的癌症预防/治疗剂的高度期望的性质。目的/假设：驱动该项目的基本假设是，DATS提高细胞内活性氧（ROS）水平，随后激活INK和半胱天冬酶。细胞凋亡途径的激活导致DATS的化学预防功效。具体目标：本课题的具体目的是研究（1）DATS是否通过线粒体电子传递链增加ROS的产生或通过谷胱甘肽过氧化物酶/谷胱甘肽还原酶系统减少ROS的消除来提高细胞内ROS水平，（2）氧化还原调节蛋白如硫氧还蛋白（TRX）和谷氧还蛋白（GRX）是否识别DAT诱导的氧化应激并激活ASK 1-MEK-JNK-1。Bim-Bax信号转导通路;（3）内源性和外源性caspase通路是否参与DATS诱导的细胞凋亡。研究设计：在拟议的研究中，第一个目标将使用荧光分光光度计测量细胞内ROS水平。第二个目的是利用生物化学方法研究ASK 1-MEK-JNK信号转导通路。第三个目标将使用药理学和分子遗传学方法来减弱caspase的活性/表达。相关性：我们相信，这项研究的成功结果将支持DATS的发展和临床应用的化学预防人类前列腺癌。

DESCRIPTION (provided by applicant): Background: Epidemiological studies continue to support the premise that increased consumption of allium vegetables, such as garlic, may be protective against the risk of certain types of cancers including prostate cancer. Recent studies have revealed that human prostate cancer cells as well as a cell line derived from prostate adenocarcinoma of a transgenic mouse (transgenic adenocarcinoma mouse prostate; TRAMP-C1 cell line) are highly sensitive to growth inhibition by diallyl trisulfide (DATS), a garlic-derived organosulfur compound (OSC). Interestingly, viability of a normal prostate epithelial cell line (PrEC, Clonetics) was minimally affected by DATS even at concentrations that were highly cytotoxic to the prostate cancer cells. These results are encouraging since selective killing of cancer cells is a highly desirable property of potential cancer preventive/therapeutic agents. Objective/Hypothesis: The underlying hypothesis driving this project is that DATS elevates the intracellular level of reactive oxygen species (ROS) and subsequently activates INK and caspases. The activation of the apoptotic pathway leads to the chemopreventive efficacy of DATS. Specific Aims: The specific aims of this project are to examine (1) whether DATS elevates the intracellular level of ROS by either increasing production of ROS through the mitochondrial electron transport chain or decreasing elimination of ROS through the glutathione peroxidase/glutathione reductase system, (2) whether redox-regulatory proteins such as thioredoxin (TRX) and glutaredoxin (GRX) recognize DATS-induced oxidative stress and activate the ASKl-MEK-JNK-Bim-Bax signal transduction pathway, and (3) whether intrinsic and extrinsic caspase pathways are involved in DATS- induced apoptotic death. Study design: In the proposed studies, the first aim will use a spectrofluorometer to measure the intracellular level of ROS. The second aim will be use of biochemical assays to investigate the ASK1-MEK-JNK signal transduction pathway. The third aim will use pharmacological and molecular genetic approaches to attenuate the activity/expression of caspase. Relevance: We believe that the successful outcome of this study will support the development and clinical application of DATS for the chemoprevention of human prostate cancer.