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 癌症化学预防药物诱导2相反应的意义。非同寻常的 各种化学制剂可以保护动物免受多种不同类型的 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 增强转录)第二阶段，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，从而提高细胞的存活率。其中大多数都是 保护性基因是通过一种常见的增强子，即抗氧化反应元件(ARE)诱导的，由 与转录因子Nrf2的相互作用。NRF2又被抑制因子Keap1隔离，抑制因子Keap1 调节Nrf2在细胞中的命运。在这个项目中，我们试图使用分子、遗传和化学方法 为了验证Keapl是激活Nrf2依赖的药物的主要传感器的假设 细胞保护基因。目标1旨在表征化合物的结构性质和反应动力学 以及在体外和活细胞中Keap1-Nrf2相互作用的时空动力学。 荧光共振能量转移光谱。次级AIMS将调查下游 Keap1-Nrf2激活的后果。目标2将定义这一途径在调节氧化中的作用 通过使用野生型、Nrf2干扰、Keap1干扰的模型在体外和体内应激 以及双基因敲除细胞和小鼠。目标3将使用这些遗传模型来探索药效学 一类特别有效的化学预防药物三萜类的作用，并评估中枢 Nrf2在他们的行动中的作用。目标4将描述Nrf2信号与其他通路的相互作用 影响顺应性反应，影响细胞命运。尤其是芳烃的交叉调节 将探讨受体和Notch信号通路以及反式激活的功能后果 评估过了。这些研究将坚定地确立诱导第二阶段反应在 化学预防。对化学预防药物与Keapl AS相互作用机制的认识 前哨传感器，从而促进信号通过Nrf2诱导细胞生存基因，将促进 识别和利用更具选择性的化合物，并提高其在人体内的有效性。

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.