ROCK II-mediated regulation of centrosome duplication / centrosome amplification

ROCK II 介导的中心体复制/中心体扩增调节

• 批准号: 8115846
• 负责人: KENJI FUKASAWA
• 金额: $ 32.24万
• 依托单位: H. LEE MOFFITT CANCER CTR & RES INST
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8115846
• 关键词: Abbreviations; Affinity; Aneuploidy; Aphidicolin; Binding; CDK2 gene; Cancer Control; Cancer Intervention; Cell Cycle; Cells; Centrioles; Centrosome; Characteristics; Chromosomal Instability; Chromosomal Stability; Chromosome Segregation; Chromosomes; Cyclin E; Defect; Development; Dissection; Event; Fibroblasts; Frequencies; GTP Binding; Generations; Green Fluorescent Proteins; Growth Factor Receptors; Guanine Nucleotide Exchange Factors; Guanosine Triphosphate; Hepatocyte Growth Factor; In Vitro; Location; Malignant - descriptor; Malignant Neoplasms; Mediating; Mitosis; Mitotic; Modeling; Molecular; Monomeric GTP-Binding Proteins; Mus; Mutate; Mutation; NPM1 gene; Oncogene Proteins; Oncogenic; Pathway interactions; Phosphorylation; Phosphotransferases; Play; Proliferating; Protein Tyrosine Kinase; Proteins; Proto-Oncogene Protein c-met; Protocols documentation; Receptor Protein-Tyrosine Kinases; Regulation; Research Project Grants; Research Proposals; Rho-associated kinase; Role; Signal Transduction; Skin; Solid Neoplasm; Substrate Specificity; Transducers; Tumor Suppressor Proteins; base; cancer cell; cell transformation; chromosome loss; daughter cell; genetic regulatory protein; leukemia/lymphoma; malignant phenotype; meetings; mutant; myosin light chain 2; nucleophosmin; physical separation; public health relevance; receptor; red fluorescent protein; rho; tumor; tumor progression

DESCRIPTION (provided by applicant): Chromosome instability (and resulting aneuploidy) has been recognized as a hallmark of cancer cells, and contributes to tumor progression by facilitating the genetic alterations required for acquisition of malignant phenotypes. Numerous studies have shown the frequent occurrence of abnormal amplification of centrosomes (generation of more than two centrosomes) in almost all types of solid tumors and certain types of lymphoma and leukemia, and the strong association between occurrence of centrosome amplification and aneuploidy. The detrimental consequence of centrosome amplification is prominently featured during mitosis: the presence of multiple centrosomes (spindle poles) results in mitotic defects, leading to an increased frequency of chromosome segregation errors. Indeed, centrosome amplification is now widely accepted as one of the major factors that contribute to chromosome instability in cancer. Centrosome amplification is caused primarily by uncontrolled duplication of centrosomes in a single cell cycle. We have recently found that ROCK II (Rho-associated kinase) localizes to centrosomes, and acts as a key regulatory protein for the initiation of centrosome duplication in association with nucleophosmin (NPM/B23). NPM/B23 is one of the major targets of CDK2-cyclin E, which plays a key role in initiating centrosome duplication. CDK2-cyclin E-mediated phosphorylation renders NPM/B23 a higher binding affinity to ROCK II, and ROCK II becomes super- activated by NPM/B23 binding. ROCK II then promotes the initiation of centrosome duplication in a centrosome localization- and kinase activity-dependent manner. ROCK II activation is also controlled by binding to an activated Rho protein (Rho-GTP), a major signal transducer downstream of many growth factor receptors (receptor tyrosine kinases/RTKs). These observations put forward to a model, in which two pathways (CDK2-NPM/B23 pathway and RTK-Rho-ROCK II pathway) converge by the physical interaction between ROCK II and NPM/B23 and super-activation of ROCK II to initiate centrosome duplication. In this research proposal, we will molecularly dissect the how ROCK II is controlled by these cancer-associated proteins to drive centrosome duplication, and how ROCK II controls centrosome duplication through focusing of the protein called LASP1, which we have recently identified as a potential centrosomal target of ROCK II for the initiation of centrosome duplication. Based on the facts that centrosome duplication occurs only in proliferating cells, and centrosome amplification is the major cause of chromosome instability in cancer, centrosome duplication and centrosome amplification can be effective targets for the cancer intervention protocols. Our research proposal that aim to understand the molecular mechanisms of the regulation of centrosome duplication and induction of centrosome amplification will provide vital information on this regard. PUBLIC HEALTH RELEVANCE: Cancer is the result of accumulation of many genetic alterations. Gain or loss of chromosomes (chromosome instability), which occurs frequently in cancer, introduces many genetic alterations simultaneously, hence accelerating tumors to acquire further malignant characteristics. In this research grant application, we will examine the mechanisms of how various oncoproteins and tumor suppressors, which are frequently mutated in cancer, maintain the integrity of chromosomes via controlling the duplication of centrosomes. The centrosome plays a critical role in the accurate segregation of chromosomes to two daughter cells during mitosis. Mutations of those oncoproteins and tumor suppressor proteins result in numeral abnormality of centrosomes, leading to mitotic defects and consequentially destabilization of chromosomes. As centrosome duplication occurs in actively proliferating cells such as cancer cells, centrosome duplication can be an effective target of cancer intervention, and the findings from our proposed studies will provide critical information on the development of superior cancer intervention protocols targeting centrosomes and cancer-associated proteins that control centrosome duplication.

描述(由申请人提供)：染色体不稳定(以及由此产生的非整倍体)已被认为是癌细胞的标志，并通过促进获得恶性表型所需的基因改变而促进肿瘤的进展。大量研究表明，在几乎所有类型的实体肿瘤以及某些类型的淋巴瘤和白血病中，中心体的异常扩增(产生两个以上的中心体)是常见的，并且中心体扩增的发生与非整倍体之间存在很强的相关性。中心体扩增的有害后果在有丝分裂过程中表现得尤为突出：多个中心体(纺锤体极)的存在会导致有丝分裂缺陷，导致染色体分离错误的频率增加。事实上，中心体扩增现在被广泛认为是导致癌症中染色体不稳定的主要因素之一。中心体扩增主要是由单个细胞周期中中心体的不受控制的复制引起的。我们最近发现ROCK II(Rho相关激酶)定位于中心体，并作为与核磷蛋白(NPM/B23)相关的中心体复制启动的关键调节蛋白。NPM/B23是CDK2-Cyclin E的主要靶点之一，在启动中心体复制中起着关键作用。CDK2-Cyclin E介导的磷酸化使NPM/B23与ROCK II具有更高的结合亲和力，并且ROCK II被NPM/B23结合而过度激活。然后，ROCK II以中心体定位和激酶活性依赖的方式促进中心体复制的启动。ROCK II的激活也通过与激活的Rho蛋白(Rho-GTP)结合来控制，Rho-GTP是许多生长因子受体(受体酪氨酸激酶/RTK)下游的主要信号转导分子。这些观察结果提出了一个模型，在该模型中，两条途径(CDK2-NPM/B23途径和RTK-Rho-ROCK II途径)通过ROCK II与NPM/B23之间的物理相互作用和ROCK II的超激活来启动中心体复制。在这个研究方案中，我们将从分子上剖析ROCK II是如何由这些癌症相关蛋白控制来驱动中心体复制的，以及ROCK II是如何通过聚焦名为LASP1的蛋白质来控制中心体复制的，我们最近发现LASP1是ROCK II启动中心体复制的潜在中心体靶点。基于中心体复制只发生在增殖细胞中，中心体扩增是导致肿瘤染色体不稳定的主要原因，中心体复制和中心体扩增可以作为癌症干预方案的有效靶点。我们的研究计划旨在了解中心体复制调控和中心体扩增诱导的分子机制，将提供这方面的重要信息。 与公共卫生相关：癌症是许多基因改变累积的结果。染色体的获得或丢失(染色体不稳定)是癌症中常见的现象，它会同时引起许多基因改变，从而加速肿瘤获得进一步的恶性特征。在这项研究拨款申请中，我们将研究在癌症中频繁突变的各种癌蛋白和肿瘤抑制因子如何通过控制中心体的复制来维持染色体的完整性。在有丝分裂过程中，中心体在染色体准确地分离到两个子细胞中起着关键作用。这些癌蛋白和抑癌蛋白的突变会导致中心体数量的异常，导致有丝分裂缺陷，从而导致染色体的不稳定。由于中心体复制发生在活跃的增殖细胞，如癌细胞，中心体复制可以成为癌症干预的有效靶点，我们拟议的研究结果将为开发针对中心体和控制中心体复制的癌症相关蛋白的更好的癌症干预方案提供关键信息。