ROLE OF ENZYME INDUCTION IN CANCER CHEMOPREVENTION

拟议研究的总体目标是评估潜在的机制和功能 癌症化学预防剂诱导2期反应的意义。一个非凡 各种化学试剂保护动物免受许多不同类型的肿瘤的影响。 致癌物质。这些化学保护剂中的许多通过选择性地诱导（通过诱导）细胞增殖来发挥其抗癌作用。 增强转录）第2阶段，抗氧化和抗炎基因，用于解毒 生物分子破坏形式的亲电体和氧化剂，从而增强细胞存活。大多数这些 保护性基因是通过一个共同的增强子，抗氧化反应元件（ARE）， 与转录因子Nrf 2的相互作用。反过来，Nrf 2被阻遏物Keapl隔离， 调节Nrf 2在细胞中的命运。在这个项目中，我们寻求使用分子，遗传和化学方法 为了检验Keapl是激活Nrf 2依赖性神经递质的试剂的主要传感器的假设， 细胞保护基因目的1是为了表征的结构性质和反应动力学 Keapl，以及Keapl-Nrf 2在体外和活细胞中相互作用的时空动力学， 荧光共振能量转移光谱法Subequent aims将调查下游 Keapl-Nrf 2激活的后果。目的2将定义该通路在调节氧化应激中的作用。 通过使用采用野生型、Nrf 2破坏的、Keap 1破坏的 和双敲除细胞和小鼠。目的3将使用这些遗传模型来探索药效学 作用的一个非常有效的一类化学预防剂，三萜类化合物，并评估中央 NRF 2在其行为中的作用。目的4将描述Nrf 2信号传导与其他途径的相互作用 影响适应性反应从而影响细胞命运。特别地，芳基烃的交叉调节 受体和Notch信号通路将被探测和反式激活的功能后果 评估。这些研究将坚定地确立诱导2期应答的作用， 化学预防了解化学预防剂与Keapl相互作用的机制， 一个前哨传感器，从而促进信号传导的Nrf 2诱导细胞存活基因，将促进 鉴定和利用更具选择性的化合物，并提高其对人体的有效性。

The overall goals of the proposed studies are to assess the underlying mechanisms and the functional significance of induction of the phase 2 response by cancer chemopreventive agents. An extraordinary variety of chemical agents protect animals against the neoplastic effects of many different types of carcinogens. Many of these chemoprotectors exert their anticarcinogenic effects by selectively inducing (by enhanced transcription) phase 2, antioxidative and anti-inflammatory genes that serve to detoxify the biomolecule damaging forms of electrophiles and oxidants, thereby enhancing cell survival. Most of these protective genes are induced through a common enhancer, the Antioxidant Response Element (ARE), by interactions with the transcription factor Nrf2. Nrf2, in turn, is sequestered by the represser Keapl, which regulates the fate of Nrf2 in cells. In this project we seek to use molecular, genetic and chemical approaches to test the hypothesis that Keapl is the major sensor for agents that activate the Nrf2-dependent cytoprotective genes. Aim 1 is designed to characterize the structural properties and reaction kinetics of Keapl, as well as the spatio-temporal dynamics of Keapl-Nrf2 interactions in vitro and in living cells by fluorescence resonance energy transfer spectroscopy. Subequent aims will investigate the downstream consequences of Keapl-Nrf2 activation. Aim 2 will define the role of this pathway in modulating oxidative stress in vitro and in vivo through the use of models employing wild-type, Nrf2-disrupted, Keapl-disrupted and double knockout cells and mice. Aim 3 will use these genetic models to probe the pharmacodynamic action of a exceptionally potent class of chemopreventive agents, triterpenoids, and to assess the central role of Nrf2 in their actions. Aim 4 will characterize the interactions of Nrf2 signaling with other pathways affecting adpative responses affecting cell fate. In particular, cross regulation of the aryl hydrocarbon receptor and the Notch signaling pathways will be probed and functional consequences of transactivation assessed. These studies will firmly establish the role of induction of the phase 2 response in chemoprevention. Knowledge of the mechanisms by which chemopreventive agents interact with Keapl as a sentinel sensor, thereby facilitating signaling by Nrf2 for induction of cell survival genes, will facilitate the identification and utilization of more selective compounds and enhance their effectiveness in humans.