Cyclin D1 and mammary carcinoma

细胞周期蛋白 D1 与乳腺癌

• 批准号: 6851131
• 负责人: John Alan Diehl
• 金额: $ 30.68万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-13 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6851131
• 关键词: RNA interference; biological signal transduction; breast neoplasms; carcinoma; cell growth regulation; cell nucleus; clinical research; cyclin dependent kinase; cyclins; gene expression; gene mutation; genetically modified animals; human subject; immunocytochemistry; laboratory mouse; molecular oncology; neoplasm /cancer genetics; neoplastic process; oncogenes; patient oriented research; phosphorylation; posttranslational modifications; prognosis; protein isoforms; protein localization; protein structure function

DESCRIPTION (provided by applicant): The long-term objective of my research centers on elucidation of the mechanisms whereby extra-cellular signals are sensed by the cell cycle machinery and regulate cell cycle progression. This information will provide the framework necessary to elucidate how growth regulatory pathways are subverted in neoplasia. Our current studies focus on how growth-signaling pathways regulate the mitogenically responsive D-type cyclins and more specifically how these pathways regulate accumulation of an active, nuclear cyclin D1- dependent kinase. The importance of elucidating the mechanisms that regulate nuclear accumulation of cyclin D1 is emphasized by our demonstration that the failure of the cell to remove active D1/CDK complexes from the nucleus during S-phase results in cell transformation. Cyclin D1 accumulates in the nucleus during G1 phase of the cell cycle in response to mitogenic stimulation. During S-phase, cyclin D1 is targeted to the cytoplasm via phosphorylation of the at a single threonyl residue, Thr-286, by GSK-3beta. We have identified a naturally occurring cyclin D1 isoform, D1b, which lacks critical residues necessary for cyclin nuclear export. Our preliminary data indicate that this isoform is specifically expressed in cancer cells and is likely to represent an oncogenic variant of the canonical cyclin D1 isoform. In addition, mutations in the C-terminus of cyclin D1 that will disrupt cyclin D1 nuclear export have been reported in endometrial cancer. We hypothesize that cyclin D1b and mutant nuclear cyclin D1 isoforms are oncogenic variants of canonical cyclin D1 (D1a) whose overexpression contributes directly to neoplastic malignancy. To test this hypothesis, we propose to: 1) Determine the frequency of cyclin D1b overexpression in breast carcinoma; 2) Determine the capacity of cyclin D1 mutants that are constitutively nuclear to drive mammary carcinoma; and 3) Characterize cancer specific cyclin D1 mutants. To accomplish these goals, we will utilize resources here at the University of Pennsylvania to determine the frequency of the nuclear cyclin D1 variant, D1b, in primary human breast cancer and assess its prognostic value. In addition, we will use newly established mouse models to assess the oncogenicity of nuclear cyclin D1 isoforms in vivo. Finally, we propose to characterize newly identified cyclin D1 mutants for their ability to undergo active, CRM1-dependent nuclear export. While expression of wild-type cyclin D1 is not overtly oncogenic in vitro or in animal models, my laboratory has demonstrated that constitutively nuclear cyclin D1 isoforms are strongly oncogenic. Cancer Relevance. Findings from this work would support a model wherein constitutively nuclear cyclin D1 functions as an initiating oncogene and that mechanisms, which regulate its nuclear retention will be targeted during carcinogenesis. Consistent with this, in our preliminary data we provide evidence for a novel, constitutively nuclear cyclin D1 isoform, which is expressed exclusively in cancer. The work proposed herein will establish the relationship between cyclin D1 nuclear retention and the function of cyclin D1 as an oncogenic protein in mammary carcinoma.

描述（由申请人提供）：我的研究中心关于阐明机制的长期目标，从而通过细胞周期机制感知细胞外信号并调节细胞周期的进程。该信息将提供必要的框架，以阐明在肿瘤中如何颠覆生长调节途径。我们目前的研究集中于生长信号途径如何调节有丝分裂响应的D型细胞周期蛋白，更具体地说，这些途径如何调节活性的，核细胞周期蛋白D1-依赖性激酶的积累。我们的证明强调了阐明调节细胞周期蛋白D1核积累的机制的重要性，即在S相过程中，细胞失败从S相中从细胞核中去除活性D1/CDK复合物导致细胞转化。在细胞周期的G1阶段，Cyclin D1响应有丝分裂刺激而积聚在细胞核中。在S期间，通过GSK-3Beta，Cyclin D1通过在单个三苯甲基残基THR-286的磷酸化靶向细胞质。我们已经确定了天然存在的细胞周期蛋白D1同工型D1B，该型缺乏细胞周期蛋白核输出所需的关键残基。我们的初步数据表明，这种同工型在癌细胞中特别表达，并且很可能代表了规范细胞周期蛋白D1同工型的致癌变体。此外，在子宫内膜癌中报道了细胞周期蛋白D1的C末端会破坏细胞周期蛋白D1核输出的突变。我们假设细胞周期蛋白D1B和突变核细​​胞周期蛋白D1同工型是典型的细胞周期蛋白D1（D1A）的致癌变体，其过表达直接导致了肿瘤恶性肿瘤。为了检验这一假设，我们建议：1）确定乳腺癌中细胞周期蛋白D1B过表达的频率； 2）确定组成型核能驱动乳腺癌的细胞周期蛋白D1突变体的能力； 3）表征癌症特异性细胞周期蛋白D1突变体。为了实现这些目标，我们将利用宾夕法尼亚大学的资源来确定原发性人类乳腺癌中核旋风Cyclin D1变体D1B的频率，并评估其预后价值。此外，我们将使用新建立的小鼠模型来评估体内核细胞周期蛋白D1同工型的致癌性。最后，我们建议表征新鉴定的细胞周期蛋白D1突变体的活性，依赖CRM1依赖性核输出的能力。虽然野生型细胞周期蛋白D1的表达在体外或动物模型中并不是公开的致癌性，但我的实验室表明，组成性核细胞周期蛋白D1同工型具有强烈的致癌性。 癌症相关性。这项工作的发现将支持一个模型，其中组成性核细胞周期蛋白D1充当癌基因和该机制，该机制调节其核保留率将在致癌过程中成为目标。与此一致，在我们的初步数据中，我们为一种新型的组成型核细胞周期蛋白D1同工型提供了证据，该型仅在癌症中表达。本文提出的工作将建立Cyclin D1核保留与细胞周期蛋白D1作为乳腺癌中致癌蛋白的功能之间的关系。