Ecd as a regulator of cell cycle and breast oncogenesis

Ecd 作为细胞周期和乳腺肿瘤发生的调节剂

基本信息

批准号：
8775947
负责人：
VIMLA BAND
金额：
$ 4.94万
依托单位：
UNIVERSITY OF NEBRASKA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-03-01 至 2016-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8775947
关键词：
Acinus organ component Address Adult Animal Model Area Breast Breast Cancer Cell Breast Epithelial Cells Cancer Biology Cancer cell line Cell Aging Cell Cycle Cell Cycle Progression Cell Cycle Proteins Cell Cycle Regulation Cell Proliferation Cell model Cells Cellular biology Complex Cyclin-Dependent Kinase Inhibitor Cyclin-Dependent Kinases Cyclins Disease Drosophila genus E2F transcription factors Ectopic Expression Embryo Embryonic Development Ensure Family Fibroblasts Gene Targeting Genetic Transcription Goals Growth HPV-High Risk Homeostasis Human Immunohistochemistry In Vitro Lead Maintenance Malignant Neoplasms Mammary Gland Parenchyma Mammary Neoplasms Mammary Tumorigenesis Mammary gland Modeling Mus Mutation Noninfiltrating Intraductal Carcinoma Oncogene ErbB2 Oncogenes Oncogenic Organ Orthologous Gene Outcome Pathway interactions Phenotype Phosphorylation Protein Family Proteins Publishing Regulation Research Retinoblastoma Retinoblastoma Protein Role S Phase Testing Tissues Transgenic Mice Viral Oncogene Work base cancer cell ductal breast carcinoma in vivo innovation malignant breast neoplasm novel overexpression prevent public health relevance senescence therapeutic target transcription factor tumor initiation tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): Precisely regulated cell proliferation is essential for embryonic development as well as homeostasis in adult organs and tissues, whereas uncontrolled cell proliferation is a hallmark of cancer. Thus, elucidating how the cell cycle machinery is controlled is an important area of research in cancer cell biology. A large body of evidence has established a basic paradigm of the control of cell cycle progression involving the Retinoblastoma (Rb) protein family in conjunction with the E2F family of transcription factors. During G0/G1, interaction of hypo-phosphorylated Rb proteins with E2Fs prevents the transcription of E2F target genes. Cyclin-CDK complexes generated during cell cycle progression hyper-phosphorylate Rb, leading to release of Rb from E2Fs; this allows E2F target gene transcription and cell cycle progression. We have identified the mammalian ortholog of Drosophila ecdysoneless (Ecd) protein as a novel and essential regulator of Rb-E2F-dependent cell cycle progression. Loss of Ecd retards the separation of Rb from E2F, arrests cells at G1/S boundary and prevents cell cycle progression. These findings have led to a new model that represents a fundamental shift in the Rb-E2F-dependent cell cycle control paradigm. Notably, Ecd is overexpressed in breast cancer cell lines as well as in ductal carcinoma in situ and infiltrating ductal carcinomas of the breast. Notably, Ecd overexpression produced two opposite phenotypes: p53-dependent senescence in fibroblasts, compared to rapid transit through cell cycle in immortal human mammary epithelial cells (hMECs) that lack p16; and co-overexpression of Ecd with activated Ras induced a dramatic hyper-proliferation and aberrant branching of hMECs in three-dimensional culture. These features are reminiscent of senescence induced by oncogenes, such as Ras. These findings lead us to hypothesize that Ecd is a novel and essential component of Rb-E2F-dependent control of cell cycle progression, and alterations in the levels and/or function of Ecd contribute to oncogenic transformation. Here, we will address these hypotheses using unique and innovative cellular and animal models established by our team. We will examine the structural basis of the role of Ecd in cell cycle progression and its regulation. We will characterize Ecd-induced cellular senescence. We will analyze the consequences of Ecd overexpression in promoting mammary oncogenesis in vitro and in vivo using inducible transgenic mice. Finally, we will determine if Ecd is essential for mammary tumor initiation, progression and maintenance driven by a human breast cancer-relevant oncogene ErbB2 using mammary-specific deletion of Ecd in Ecd-floxed mice. A successful outcome of our studies will elucidate the role of a novel cell cycle control regulator in breast cancer with broad implications for oncogenesis in human cancer, and could help establish Ecd as a potential therapeutic target in cancer.

描述（由申请人提供）：精确调节的细胞增殖对于胚胎发育以及成体器官和组织的稳态至关重要，而不受控制的细胞增殖是癌症的标志。因此，阐明细胞周期机制是如何控制的是癌细胞生物学研究的一个重要领域。大量证据已经建立了细胞周期进程控制的基本范式，涉及视网膜母细胞瘤 (Rb) 蛋白家族与转录因子 E2F 家族的结合。在 G0/G1 期间，低磷酸化的 Rb 蛋白与 E2F 相互作用，阻止 E2F 靶基因的转录。细胞周期进程中产生的细胞周期蛋白-CDK 复合物使 Rb 过度磷酸化，导致 E2F 释放 Rb；这允许 E2F 靶基因转录和细胞周期进展。我们已经确定果蝇无蜕皮激素 (Ecd) 蛋白的哺乳动物直系同源物是 Rb-E2F 依赖性细胞周期进程的新型重要调节因子。 Ecd 的缺失会延迟 Rb 与 E2F 的分离，使细胞停滞在 G1/S 边界并阻止细胞周期进展。这些发现催生了一种新模型，它代表了 Rb-E2F 依赖性细胞周期控制范式的根本转变。值得注意的是，Ecd 在乳腺癌细胞系以及乳腺导管原位癌和浸润性导管癌中过度表达。值得注意的是，Ecd 过度表达产生了两种相反的表型：成纤维细胞中 p53 依赖性衰老，而缺乏 p16 的永生人乳腺上皮细胞 (hMEC) 则快速经历细胞周期； Ecd 与激活的 Ras 的共过表达诱导了三维培养中 hMEC 的急剧过度增殖和异常分支。这些特征让人想起由 Ras 等癌基因诱导的衰老。这些发现使我们推测 Ecd 是 Rb-E2F 依赖性细胞周期进程控制的一个新颖且重要的组成部分，并且 Ecd 水平和/或功能的改变有助于致癌转化。在这里，我们将使用我们团队建立的独特且创新的细胞和动物模型来解决这些假设。我们将研究 Ecd 在细胞周期进程及其调节中的作用的结构基础。我们将描述 Ecd 诱导的细胞衰老的特征。我们将使用诱导型转基因小鼠在体外和体内分析 Ecd 过度表达对促进乳腺肿瘤发生的影响。最后，我们将在 Ecd-floxed 小鼠中使用乳腺特异性删除 Ecd 来确定 Ecd 是否对于人类乳腺癌相关癌基因 ErbB2 驱动的乳腺肿瘤的发生、进展和维持至关重要。我们研究的成功结果将阐明新型细胞周期控制调节剂在乳腺癌中的作用，对人类癌症的发生具有广泛的影响，并有助于将 Ecd 确立为癌症的潜在治疗靶点。