Cyclin A Function in Stem Cells and in Neoplasia

细胞周期蛋白 A 在干细胞和肿瘤形成中的功能

基本信息

批准号：
9264990
负责人：
Peter Sicinski
金额：
$ 45.12万
依托单位：
DANA-FARBER CANCER INST
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-01 至 2019-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9264990
关键词：
ATP Synthesis Pathway Ablation Acute Address Affect Alleles Animals Antibodies Apoptosis Binding Proteins Breast Cancer Cell Bypass CCNE1 gene CDC2 Protein Kinase Cell Compartmentation Cell Cycle Cell Cycle Progression Cell Proliferation Cell physiology Cells Characteristics Cultured Cells Cyclin A Cyclin B Cyclin D1 Cyclins DNA Damage DNA Sequence DNA biosynthesis Dependence Development Embryo Employee Strikes Fibroblasts Funding Genes Genetic Materials Hematopoietic stem cells Human In Vitro Knock-in Knock-out Knockout Mice MYC gene Maintenance Malignant Neoplasms Mass Spectrum Analysis Mitosis Molecular Molecular Analysis Mouse Mammary Tumor Virus Mus Neoplasms Normal Cell Nuclear Envelope Null Lymphocytes Oncogenic Pathway interactions Peptides Phosphorylation Phosphotransferases Play Process Proliferating Proteins Role S Phase Signal Transduction Stem cells System Testing Testis Tumor Initiators analog c-myc Genes cancer stem cell cancer therapy cancer type cell type cyclin A1 cyclin A2 embryonic stem cell follow-up homologous recombination implantation in vivo male malignant breast neoplasm neoplastic cell novel overexpression protein function public health relevance senescence stem-like cell therapeutic target tumor initiation tumor progression tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): A-type cyclins (cyclins A1 and A2) belong to the core cell cycle machinery. Cyclin A1 is expressed in the testes in the male germline, whereas cyclin A2 is ubiquitously expressed in all proliferating cells. Cyclin A2, together with its catalytic partners Cdk1 and Cdk2 is thought to drive S-phase progression by phosphorylating key proteins involved in DNA replication. In addition, cyclin A2 was postulated to play a role in entry of cells into mitosis, by regulating nuclear envelope breakdown and accumulation of cyclin B. It has been assumed that cyclin A represents an essential protein which is required for proliferation of all cell types. Consistent with this notion, cyclin A2-/- mice die shortly after implantation. Cyclin A2 is frequently overexpressed in different human cancer types. Moreover, this cyclin was postulated to represent a cell cycle recipient of c-Myc driven oncogenic pathways. Collectively, these observations suggest that cyclin A2 might represent an attractive therapeutic target in human neoplasia. However, the notion that cyclin A2 is essential for proliferation of all cell types has discouraged exploring this possibility. Duing the last funding period, we used conditional cyclin A knockout mice (cyclin A1-/-A2F/F) to bypass the embryonic lethality of cyclin A-null animals, and to test the requirement for cyclin A function at later stages of development. We found that cyclin A is dispensable for proliferation of several cell types. Our molecular analyses of fibroblasts revealed that A-type and E-type cyclins play redundant functions in cell cycle progression. We demonstrated that combined ablation of all A- and E-cyclins blocked proliferation of cyclin E1-/-E2-/-A1-/-A2�/� fibroblasts. In contrast, we observed that A-cyclins play an essential function in hematopoietic stem cells and in embryonic stem (ES) cells. Intriguingly, we observed that ES cells express relatively lower levels of cyclin E, which might explain their dependence on cyclin A. Alternatively, cyclin A may play a molecularly distinct role in stem cells, which cannot be carried out by E-cyclins. The molecular basis of the dependence of stem cells on cyclin A function remains unknown, and will be studied in this application in Aims 1 and 2. Lastly, in Aim 3 we will use conditional cyclin A knockout mice to test whether cyclin A is required for initiation and maintenance of c-Myc-driven breast cancers. The specific Aims are as follows: Specific Aim 1. To determine whether cyclin A plays a unique function in stem cells, and to elucidate the exact cellular mechanism in which cyclin A plays a rate-limiting role. Specific Aim 2. To determine the molecular function of cyclin A-Cdk1 in stem cells. Specific Aim 3. To test the requirement for cyclin A function in Myc-driven breast cancers.

描述（由应用程序提供）：A型细胞周期蛋白（Cyclins A1和A2）属于核心细胞周期机械。 Cyclin A1在男性种系的测试中表达，而细胞周期蛋白A2在所有增殖细胞中均普遍表达。 Cyclin A2及其催化伴侣CDK1和CDK2被认为通过磷酸化参与DNA复制的关键蛋白来驱动S期进展。此外，假定细胞周期蛋白A2在入口中发挥作用通过控制核包膜分解和细胞周期蛋白B的积累，细胞进入有丝分裂。已经假定细胞周期蛋白A代表了所有细胞类型所必需的必需蛋白质。与这个概念一致，植入后不久，细胞周期蛋白A2 - / - 小鼠死亡。 Cyclin A2经常在不同的人类癌症类型。此外，该细胞周期蛋白被发布以代表C-MYC驱动的致癌途径的细胞周期接受者。总的来说，这些观察结果表明Cyclin A2可能代表了人类肿瘤中有吸引力的治疗靶标。但是，Cyclin A2对于所有细胞类型的扩散至关重要的观念使人们不鼓励探索这种可能性。由于最后的融资期，我们使用条件细胞周期蛋白A基因敲除小鼠（Cyclin A1 - / - A2F/F）绕过了细胞周期蛋白A-Null动物的胚胎致死性，并测试了晚期发育阶段Cyclin a功能的需求。我们发现，细胞周期蛋白A是可用于增殖的几种细胞类型。我们对成纤维细胞的分子分析表明，A型和E型细胞周期蛋白在细胞周期进程中起冗余功能。我们证明了所有A-和e-Cyclin的结合消融都阻止了细胞周期蛋白E1 - / - E2 - / - A1 - / - A2-A2/�成纤维细胞的增殖。相比之下，我们观察到A-胞霉素在造血干细胞和胚胎（ES）细胞中起着重要的作用。有趣的是，我们观察到ES细胞表现出相对较低的细胞周期蛋白E水平，这可能解释了它们对细胞周期蛋白A的依赖。可替代地，细胞周期蛋白A可能在干细胞中起分子独特的作用，而这些作用不能由E-Cyclins进行。干细胞对细胞周期蛋白A功能的依赖性的分子基础尚不清楚，并将在AIMS 1和2中进行研究。最后，在AIM 3中，我们将使用条件细胞周期蛋白A基因敲除小鼠来测试Cyclin A是否需要用于启动和维持C-Myc-c-Myc驱动的乳腺癌。具体目的如下：特定目的1。确定细胞周期蛋白在干细胞中是否起着独特的功能，并阐明细胞周期蛋白A起限速作用的确切细胞机制。具体目标2。确定干细胞中细胞周期蛋白A-CDK1的分子功能。特定目的3。测试在MYC驱动的乳腺癌中对细胞周期蛋白A功能的需求。