Role of an RNA-Binding Protein in Mammary Carcinogenesis

RNA 结合蛋白在乳腺癌发生中的作用

• 批准号: 7096826
• 负责人: JEFFREY ROSS
• 金额: $ 25.9万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-06 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7096826
• 关键词: RNA binding protein; actin binding protein; breast neoplasms; carcinogenesis; gene environment interaction; gene expression; gene expression profiling; gene induction /repression; genetic susceptibility; genetic translation; genetically modified animals; insulinlike growth factor; laboratory mouse; messenger RNA; microarray technology; neoplastic process; neoplastic transformation; nitrosourea; protooncogene; tetracyclines; tumor suppressor proteins

DESCRIPTION (provided by applicant): This proposal investigates the role of an RNA-binding oncoprotein in mammary tumorigenesis. This protein is located in the cytoplasm and binds to insulin-like growth factor-ll, beta-actin, c-myc, and other mRNAs. We call it the c-myc Coding Region instability Determinant-binding Protein or CRD-BP. because it binds to an instability determinant in the c-myc mRNA coding region. The CRD-BP affects RNA translation, stability, and localization, depending on the RNA to which it binds. It is expressed abundantly in fetal tissues but is repressed shortly after birth. Therefore, it probably has a special role in fetal life. Three findings also link the CRD-BP to breast cancer: (a) The CRD-BP is undetectable in normal breast tissue but is present in ~60 percent of human breast tumors, (b) The CRD-BP gene is amplified in ~30 percent of human breast tumors, (c) The CRD-BP induces mammary adenocarcinomas in female transgenic mice. Three aims use transgenic mice to investigate the pathways of mammary tumor induction by this RNA-binding oncoprotein. Aim I. Determine if CRD-BP expression is required continuously to maintain an existing mammary tumor. Mammary tumors in transgenic mice continue to express the CRD-BP and thus might be CRD-BP- dependent for their survival. To investigate this idea, Aim I exploits a mouse model in which mammary- specific CRD-BP expression is induced by doxycycline (dox), a tetracycline analog. Mammary tumors are expected to arise in dox-treated mice. Aim I then asks: Do these tumors stop growing or regress when dox is withdrawn? Our working hypothesis is that tumors will regress when CRD-BP expression is repressed. Aim II. Use microarray analysis to compare gene expression profiles in non-neoplastic mammary tissues and in purified mammary epithelial cells of mice that do or do not express the CRD-BP. Some CRD- BP-regulated RNAs could play central roles in the induction and maintenance of mammary tumors. Aim III. Determine how genetic and environmental factors contribute to mammary tumorigenesis in CRD-BP-expressing mice. The goal is to assess how the tumor suppressor Ape and the chemical carcinogen N-ethyl-N-nitrosurea (ENU) affect CRD-BP-mediated tumor formation. We predict Ape deficiency and ENU treatment will synergize with the CRD-BP to increase tumor incidence and malignancy. Many of the well-studied oncoproteins are transcription factors or protein kinases. The CRD-BP is an unusual oncoprotein, because it resides in the cytoplasm and binds to RNA. By investigating the oncogenic properties of the CRD-BP, the RNAs it affects in vivo, and its interactions with tumor-inducing genetic and environmental factors, we hope to uncover novel tumorigenesis pathways. REVISED: October 27, 2005 (see Revision Note)

描述（由申请人提供）：该提案研究了 RNA 结合癌蛋白在乳腺肿瘤发生中的作用。该蛋白位于细胞质中，与胰岛素样生长因子-II、β-肌动蛋白、c-myc 和其他 mRNA 结合。我们将其称为 c-myc 编码区不稳定决定因素结合蛋白或 CRD-BP。因为它与 c-myc mRNA 编码区的不稳定决定簇结合。 CRD-BP 影响 RNA 翻译、稳定性和定位，具体取决于其结合的 RNA。它在胎儿组织中大量表达，但在出生后不久就被抑制。因此，它可能在胎儿的生命中具有特殊的作用。三项发现也将 CRD-BP 与乳腺癌联系起来：(a) CRD-BP 在正常乳腺组织中检测不到，但存在于约 60% 的人类乳腺肿瘤中，(b) CRD-BP 基因在约 30% 的人类乳腺肿瘤中扩增，(c) CRD-BP 在雌性转基因小鼠中诱导乳腺癌。三个目标是使用转基因小鼠来研究这种 RNA 结合癌蛋白诱导乳腺肿瘤的途径。目标 I. 确定是否需要持续表达 CRD-BP 来维持现有的乳腺肿瘤。转基因小鼠的乳腺肿瘤继续表达 CRD-BP，因此它们的生存可能依赖于 CRD-BP。为了研究这个想法，Aim I 利用了一种小鼠模型，其中乳腺特异性 CRD-BP 表达是由四环素类似物多西环素 (dox) 诱导的。预计接受 dox 治疗的小鼠会出现乳腺肿瘤。然后我问：当 dox 撤药后，这些肿瘤会停止生长或消退吗？我们的工作假设是，当 CRD-BP 表达受到抑制时，肿瘤将会消退。目标二。使用微阵列分析来比较表达或不表达 CRD-BP 的小鼠非肿瘤性乳腺组织和纯化乳腺上皮细胞中的基因表达谱。一些CRD-BP调节的RNA可能在乳腺肿瘤的诱导和维持中发挥核心作用。目标三。确定遗传和环境因素如何影响 CRD-BP 表达小鼠的乳腺肿瘤发生。目标是评估抑癌基因 Ape 和化学致癌物 N-乙基-N-亚硝基脲 (ENU) 如何影响 CRD-BP 介导的肿瘤形成。我们预测 Ape 缺陷和 ENU 治疗将与 CRD-BP 协同作用，增加肿瘤发生率和恶性肿瘤。许多经过充分研究的癌蛋白是转录因子或蛋白激酶。 CRD-BP 是一种不寻常的癌蛋白，因为它存在于细胞质中并与 RNA 结合。通过研究 CRD-BP 的致癌特性、它在体内影响的 RNA 及其与肿瘤诱导遗传和环境因素的相互作用，我们希望发现新的肿瘤发生途径。 修订日期：2005 年 10 月 27 日（参见修订说明）