delta-Catenin and Cell-Cell Adhesion in Prostate Cancer

描述（由申请人提供）：前列腺癌（CaP）是美国男性中最常见的恶性肿瘤，也是癌症死亡的第二大原因。为了降低显著的发病率和死亡率，预防和治疗CaP的新策略依赖于确定参与这种疾病的特定分子机制。?-连环蛋白是一种独特的含有Armadillo（ARM）结构域的蛋白质，因为它是神经特异性的，主要在大脑中表达。然而，？连环蛋白在前列腺癌中表达增加，从细胞-细胞连接处重新分配E-钙粘蛋白/p120 ctn，并促进CaP细胞生长和侵袭。为了研究这一在很大程度上尚未探索的神经元连环蛋白基因在癌症外周组织中表达的领域，本项目的总体目标是检验以下假设：连环蛋白通过与多种细胞机制相互作用促进CaP形成和进展，所述细胞机制包括细胞-细胞和细胞-基质粘附、细胞生长/存活和侵袭。这项建议有三个具体目标。具体目标1将如何确定？使用CWR 22肿瘤异种移植物及其衍生细胞系，连环蛋白响应于肝细胞生长因子和/或雄激素促进细胞生长/存活和运动。我们将广泛筛选和分析？-连环蛋白诱导的信号分子的改变，通过阵列技术。这些研究将确定癌症的具体途径，连环蛋白参与并将研究它们与？使用蛋白质免疫共沉淀和酵母双杂交分析的连环蛋白。具体目标2将如何确定？连环蛋白与Rho家族小GTP酶相互作用以破坏粘附连接并促进CaP细胞生长/存活和侵袭。我们先来确认一下？-连环蛋白序列负责这一行动。然后，分析了？在Rac-1或E-cadherin结合中有缺陷的连环蛋白RNAi或其突变体将决定GTP-Rac-1/IQGAP-1和E-cadherin/p120 ctn途径之间的相互作用，以揭示对细胞-细胞粘附和细胞生长/存活和侵袭的可能差异调节。我们还将确定？的细胞质积累和核信号传导。由IQGAP-1从E-钙粘蛋白复合物释放的连环蛋白。具体目标3将应用Y311，一种独特的（去磷酸化特异性）单克隆抗体，和定点诱变来确定如何？catenin修饰的发生，以及它们在CaP中的作用。我们也会调查吗？连环蛋白蛋白水解片段及其作为DNA结合蛋白和基因表达的核信号传导的潜力。最后，我们将产生转基因小鼠显示前列腺组织特异性？catenin的表达，在动物水平上解决这些问题。这些研究将？catenin的广泛背景下的生长因子和激酶信号机制相关的钙磷。理解控制的翻译后修饰？连环蛋白的功能将解开机制，连环蛋白在体内调节基因表达并促进CaP。

DESCRIPTION (provided by applicant): Prostate cancer (CaP) is the most common malignancy in men in US and the second leading cause of cancer mortality. To reduce the significant morbidity and mortality, new strategies for CaP prevention and treatment depend on the determination of specific molecular mechanisms involved in this disease. ?-Catenin is a unique armadillo (ARM) domain-containing protein in that it is neural specific and primarily expresses in the brain. However, ?-catenin expression increases in prostatic adenocarcinomas, redistributes E-cadherin/p120ctn from the cell-cell junction, and promotes CaP cell growth and invasion. To investigate this largely unexplored area of neuronal catenin gene expression in peripheral tissues of cancers, the overall goal of this project is to test the hypothesis that ?-catenin promotes CaP formation and progression by interacting with multiple cellular machineries, including cell-cell and cell-matrix adhesion, cell growth/survival, and invasion. There are three specific aims in this proposal. Specific Aim 1 will determine how ?-catenin promotes cell growth/survival and motility in response to the hepatocyte growth factor and/or androgen using CWR22 tumor xenografts and their derived cell lines. We will broadly screen and profile the ?-catenin induced alteration of signaling molecules by array technology. These studies will identify cancer specific pathways that ?-catenin is involved in and will investigate their interactions with ?-catenin using protein co-immunoprecipitation and yeast two-hybrid analyses. Specific Aim 2 will determine how ?-catenin interacts with Rho family small GTPases to disrupt adherens junction and promote CaP cell growth/survival and invasion. We will first identify the ?-catenin sequence responsible for this action. Then, the analyses of ?-catenin RNAi or its mutants that are defective in Rac-1 or E-cadherin binding will determine the interactions between GTP-Rac-1/IQGAP-1 and E-cadherin/p120ctn pathways to reveal possible differential modulations on cell-cell adhesion and cell growth/survival and invasion. We will also determine the cytoplasmic accumulation and nuclear signaling of ?-catenin that is released from E-cadherin complexes by IQGAP-1. Specific Aim 3 will apply Y311, a unique (dePhospho-specific) monoclonal antibody, and site-directed mutagenesis to determine how ?-catenin modifications occur and what are their roles in CaP. We will also investigate ?-catenin proteolytic fragments and their potentials as DNA binding proteins and nuclear signaling for gene expression. Finally, we will generate transgenic mice displaying prostate tissue specific ?-catenin expression to approach these questions at the animal level. These studies will place ?-catenin into the broad context of growth factor and kinase signaling machineries relevant to CaP. Understanding the posttranslational modifications that control ?-catenin functions will unravel mechanisms by which ?-catenin modulates gene expression and promotes CaP in vivo.