Cyclin D1 and mammary carcinoma

细胞周期蛋白 D1 与乳腺癌

• 批准号: 7007686
• 负责人: John Alan Diehl
• 金额: $ 29.95万
• 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/7007686
• 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(申请人提供)：我研究的长期目标集中在阐明细胞外信号被细胞周期机制感知并调节细胞周期进程的机制。这些信息将提供必要的框架，以阐明生长调节通路在肿瘤中是如何被颠覆的。我们目前的研究集中在生长信号通路如何调节有丝分裂反应的D型细胞周期蛋白，更具体地说，这些通路如何调节活性的、核周期蛋白依赖的激酶的积累。我们的研究表明，在S期，细胞不能从细胞核中去除活性的D1/CDK复合体，从而导致细胞转化，从而强调了阐明调控细胞周期蛋白D1核积聚的机制的重要性。在细胞周期的G1期，细胞周期蛋白D1在细胞核内积聚，以响应有丝分裂的刺激。在S期，细胞周期蛋白D1通过GSK-3β对苏氨酸残基Thr-286的磷酸化进入细胞质。我们已经确定了一个自然存在的细胞周期蛋白D1亚型D1b，它缺乏细胞周期蛋白核输出所必需的关键残基。我们的初步数据表明，该异构体在癌细胞中特异表达，很可能代表典型的细胞周期蛋白D1异构体的致癌变体。此外，在子宫内膜癌中，细胞周期蛋白D1C末端的突变也被报道会破坏细胞周期蛋白D1核输出。我们推测细胞周期蛋白D1b和突变的核细胞周期蛋白D1a亚型是典型细胞周期蛋白D1a的致癌变异，其过度表达直接导致肿瘤的恶性。为了验证这一假设，我们建议：1)确定细胞周期蛋白D1b在乳腺癌中过表达的频率；2)确定构成核的细胞周期蛋白D1b突变体驱动乳腺癌的能力；以及3)确定癌症特异性细胞周期蛋白D1b突变体的特征。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细胞核周期蛋白D1变体D1b在原发人类乳腺癌中的频率，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核细胞周期蛋白D1亚型在体内的致瘤性。最后，我们建议对新发现的细胞周期蛋白D1突变体进行活性的、依赖于CRM1的核输出的能力进行表征。虽然野生型细胞周期蛋白D1在体外或动物模型中的表达不是明显的致癌性，但我的实验室已经证明，构成核的细胞周期蛋白D1亚型具有很强的致癌性。 与癌症有关。这项工作的发现将支持这样一个模型，在该模型中，核周期蛋白D1作为启动癌基因发挥作用，调节其核保留的机制将在癌变过程中成为靶点。与此一致的是，在我们的初步数据中，我们提供了一种新的、构成核的细胞周期蛋白D1亚型的证据，该亚型仅在癌症中表达。本研究将建立细胞周期蛋白D1在乳腺癌中的核滞留与细胞周期蛋白作为致癌蛋白的功能之间的关系。