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对靶组织发挥其生物学作用： 一种名为雄激素受体（AR）的细胞内受体蛋白。最近的证据 表明AR的转录调控需要一组不同的 蛋白质称为coactivators。辅激活因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， 最大程度地激活基因。人们普遍认为， 辅活化剂通过充当受体与受体之间的桥梁来增强受体功能。 前起始复合体的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， 局部抑制性染色质结构，并有助于增加 转录活性最近，我们的实验室克隆了E6相关的 蛋白（E6-AP），作为类固醇受体（包括AR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 初步观察表明，E6-AP作为AR的共激活因子， 在小鼠和人前列腺肿瘤中均过表达。最初的数据来自 E6-AP基因敲除小鼠也表明E6-AP在正常的免疫反应中起主要作用。 前列腺的发育E6-AP基因敲除小鼠的前列腺 与野生型正常同窝仔相比更小且重量更轻。 此外，p53水平在E6-AP敲除的前列腺中升高。 此外，AR表达在E6-AP敲除前列腺中下降。基于 根据这些初步发现，我们假设E6-AP，一种重要的 前列腺，雄激素受体介导的信号转导通路和细胞 周期控制，在正常发育中具有重要的功能意义， 前列腺和前列腺癌。为了理解 E6-AP在正常前列腺发育和前列腺增生中的作用 前列腺肿瘤，我们提出以下三个具体目标： 和野生型E6-AP、C833 S过表达的动物模型的分析 突变体E6-AP（E3泛素-蛋白连接酶缺陷突变体）和缺失 前列腺中的E6-AP（E6-AP敲除），B）， 野生型和C833 S突变体过表达的稳定体外模型 前列腺癌细胞系中E6-AP蛋白的表达分析，和 内源性E6-AP、p53和AR。

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.