Role of E6-AP in the Development of Prostate Cancer

描述(由申请人提供) 雄激素是细胞生长和前列腺的重要调节因子 发展。雄激素通过以下途径在靶组织上发挥其生物学作用 一种名为雄激素受体(AR)的细胞内受体蛋白。最近的证据 这表明AR的转录调控需要一组不同的 称为辅活化子的蛋白质。共活化子描绘了一类不断增长的蛋白质 以激素依赖的方式与受体相互作用，并需要 通过受体最大限度地激活基因。人们普遍认为 共激活剂通过充当受体之间的桥梁来增强受体的功能 预起始复合体的DNA结合受体和基础转录因子 还通过提供组蛋白乙酰转移酶活性，HAT，这破坏了 局部抑制性染色质结构并有助于增加 转录活性。最近，我们实验室克隆了与E6相关的 蛋白(E6-AP)，作为包括AR在内的类固醇受体的共激活剂。 E6-AP具有泛素蛋白连接酶活性，而不是HAT活性。我们的 初步观察表明，E6-AP是AR和IS的共同激活剂 在小鼠和人的前列腺癌中都有过表达。来自的初始数据 E6-AP基因敲除小鼠也提示E6-AP在正常 前列腺癌的发育。E6-AP基因敲除小鼠的前列腺 与野生型正常产仔相比，它们更小，体重更轻。 此外，在E6-AP基因敲除的前列腺癌中，P53水平升高。 此外，在E6-AP基因敲除的前列腺中，AR的表达下调。基于 这些初步发现，我们假设E6-AP，一个重要的调节因子 前列腺癌、雄激素受体介导的信号转导途径和细胞 周期控制，在正常的发展中具有重要的功能意义 前列腺癌和前列腺癌。为了更好地理解这一点 E6-AP在正常前列腺发育和前列腺癌发生中的作用 对于前列腺癌，我们提出了以下三个具体目标：a)发展 野生型E6-AP、C833S过表达的动物模型分析 突变体E6-AP(E3泛素蛋白连接酶缺陷突变体)和 前列腺癌中的E6-AP(E6-AP基因敲除，B)，设计和开发 野生型和C833S突变体过表达的体外稳定模型 E6-AP蛋白在前列腺癌细胞系中的表达，以及C)表达分析 前列腺癌活检标本中内源性E6-AP、P53和AR的检测

DESCRIPTION (Provided by the applicant) Androgens are important regulators of cell growth and prostate gland development. Androgens exert their biological effects on target tissues through an intracellular receptor protein named androgen receptor (AR). Recent evidence suggests that transcriptional regulation by AR require a diverse group of proteins termed coactivators. Coactivators portray a growing class of proteins that interact with receptors in a hormone dependent manner and are required for maximal gene activation by the receptors. It is the general belief that coactivators enhance receptor function by acting as a bridge between the DNA-bound receptor and basal transcription factors of the preinitiation complex and also by providing histone acetyl transferase activity, HAT, which disrupts the local repressive chromatin structure and contributes to increase transcriptional activity. Recently, our laboratory has cloned, E6-associated protein (E6-AP), as a coactivator of steroid receptors including that of AR. E6-AP possesses ubiquitin-protein ligase activity, instead of HAT activity. Our preliminary observation suggests that E6-AP act as a coactivator of AR and is overexpressed both in mouse and human prostate tumors. The initial data from E6-AP knockout mice also suggest that E6-AP play a major role in the normal development of prostate gland. The prostate glands of the E6-AP knockout mice are smaller and weigh less compare to that of wild-type normal littermates. Furthermore, p53 levels are elevated in E6-AP knockout prostate glands. Additionally, the AR expression is down in E6-AP knockout prostate. Based on these initial findings, we hypothesize that E6-AP, an important modulator of prostate gland, androgen receptor-mediated signal transduction pathway and cell cycle control, is functionally significant in the development of normal prostate gland and prostate cancer. In order to understand the exact role of E6-AP in the development of normal prostate gland and in the development of prostate tumors, we propose the following three specific aims: A) Development and analysis of animal models for the overexpression of wild type E6-AP, C833S mutant E6-AP (an E3 ubiquitin-protein ligase defective mutant) and loss of E6-AP (E6-AP knockout) in the prostate gland, B), Design and development of stable in vitro models for the overexpression of wild-type and C833S mutant E6-AP proteins in the prostate cancer cell lines, and C) Expression analyses of endogenous E6-AP, p53 and AR in prostate tumor biopsy samples.