Pathogenesis of Malignant Mesothelioma by the Human Polycomb Complex BAP1-ASXL

人多梳复合物 BAP1-ASXL 引起恶性间皮瘤的发病机制

• 批准号: 8788699
• 负责人: FRANK JOSEPH RAUSCHER III
• 金额: $ 52.76万
• 依托单位: RESEARCH INST OF FOX CHASE CAN CTR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8788699
• 关键词: 22q; 3p21; Address; Affect; Asbestos; Asbestos-Related Malignant Mesothelioma; Automobile Driving; BAP1 gene; BRCA1 gene; Binding; Biochemical; Biochemistry; Biology; CDKN2A gene; Cancer Family; Cell Line; Cells; Chromatin; Chromosome Arm; Clinical; Complex; Cutaneous Melanoma; Deubiquitinating Enzyme; Development; Disease; Disease Management; Environmental Exposure; Epigenetic Process; Exposure to; Family; Fiber; Gene Expression Profile; Gene Expression Regulation; Genes; Genetic; Genetic Transcription; Germ-Line Mutation; Health; High-Risk Cancer; Histones; Human; Human Genetics; In Vitro; Incidence; Individual; Inherited; Investigation; Knockout Mice; Laboratories; Link; Malignant Neoplasms; Malignant mesothelioma; Medical; Melanocytic Neoplasm; Mesothelial Cell; Mesothelial Hyperplasia; Mesothelium; Molecular Genetics; Multiprotein Complexes; Mus; Mutate; Mutation; Nature; Neoplasm Metastasis; Non-Small-Cell Lung Carcinoma; Nuclear; Pathogenesis; Pathology; Pathway interactions; Phenotype; Polycomb; Prevention; Proteins; Reporting; Resistance; Risk; Role; Sampling; Seasons; Somatic Mutation; Specimen; Structure; Syndrome; Therapeutic; Tumor Biology; Tumor Suppression; Tumor Suppressor Genes; Tumor Suppressor Proteins; Uveal Melanoma; base; disease phenotype; disorder prevention; enzyme activity; enzyme substrate; epigenetic regulation; genetic analysis; genetic approach; in vivo; insight; mouse model; multidisciplinary; mutant; novel; novel strategies; novel therapeutics; outcome forecast; prognostic; protein complex; reconstitution; response; targeted treatment; tumor; ubiquitin C-terminal hydrolase; ubiquitin isopeptidase

DESCRIPTION (provided by applicant): Malignant mesothelioma (MM) is an aggressive, treatment-resistant cancer linked to asbestos exposure. The genetic basis for MM has historically focused on somatic mutations of CDKN2A and NF2 as key alterations influencing initiation and progression. Very recently, the BAP1 ubiquitin carboxy-terminal hydrolase, first isolated as a Ch. 3p21 tumor suppressor in 1998 (Rauscher Lab), has been strongly implicated as a major player in MM based on genetic analyses. Germline BAP1 mutations were found in two families with a high incidence of MM and other cancers, and somatic BAP1 alterations occurred in MMs, consistent with biallelic inactivation of a tumor suppressor (Testa Lab). Moreover, somatic BAP1 mutations are common in sporadic MMs and in both sporadic and familial uveal melanoma (UM). The genetic and biochemical mechanisms by which BAP1 mutations predispose to MM and UM and how BAP1 interacts genetically with CDKN2A and NF2 to influence MM pathology, prognosis, and therapeutic response are largely unknown. However, the fact that BAP1 encodes a nuclear-localized de-ubiquitinase that binds to ASXL1/2, an obligate polycomb family partner protein that targets histones, strongly suggests a role in epigenetic regulation of gene transcription. Moreover, since binding of BAP1 to ASXL1/2 is required for enzyme activity and tumor suppression, an alternative way to inactivate BAP1 tumor suppressor activity may be to mutate or silence ASXL1/2 genes. To define both the biochemical mechanisms and the genetic interactions among BAP1, ASXL1/2, CDKN2A and NF2 in MM, the Rauscher and Testa Labs have joined forces to pursue the following Specific Aims: 1) Use a direct in vivo genetic approach to determine if heterozygous Bap1-mutant (+/mut) mice are predisposed to the development of various spontaneous tumors, including MM, and accelerate asbestos-induced MM. 2) Use conditional knockout mice to determine if somatic loss of Bap1 alone in the mesothelium is capable of driving mesothelial hyperplasia and/or frank MM, and if somatic Bap1 inactivation combined with loss of Nf2 and Cdkn2a results in more rapid development and/or a more aggressive disease phenotype, with potential prognostic and novel therapeutic implications. 3) Define the spectrum of BAP1 and ASXL1/2 mutations in human MM specimens/cell lines and determine how these mutations affect binding and function of BAP1 in complex with ASXL1/2 and other PR-DUB complex proteins, and define the transcriptome and cellular phenotype which are altered as a consequence of changes (via knockdown and reconstitution) in BAP1 and other PR-DUB components in MM cells. 4) Determine the composition of the native PR-DUB macromolecular protein complexes that contain wild- type BAP1 and ASXL1/2 in mesothelial cells and in BAP1- and/or ASXL1/2-deficient MM cells to compare normal- and tumor-specific subunit structure and the role of these complexes in epigenetic dysregulation. The proposed multipronged studies by two PIs with complementary expertise represent a comprehensive approach to yield novel insights into MM pathogenesis while providing new targets for therapy and prevention.

描述（由申请人提供）：恶性间皮瘤（MM）是一种与石棉暴露有关的侵袭性、治疗抵抗性癌症。MM的遗传基础历来集中在CDKN 2A和NF 2的体细胞突变上，作为影响起始和进展的关键改变。最近，基于遗传分析，BAP 1泛素羧基末端水解酶，首先在1998年作为Ch.3p21肿瘤抑制因子被分离（Rauscher Lab），已经被强烈暗示为MM中的主要参与者。在MM和其他癌症发病率高的两个家族中发现了生殖系BAP 1突变，并且在MM中发生了体细胞BAP 1改变，这与肿瘤抑制因子的双等位基因失活一致（Testa Lab）。此外，体细胞BAP 1突变在散发性葡萄膜黑色素瘤以及散发性和家族性葡萄膜黑色素瘤（UM）中很常见。BAP 1突变易患MM和UM的遗传和生化机制以及BAP 1如何与CDKN 2A和NF 2遗传相互作用以影响MM病理学、预后和治疗反应在很大程度上是未知的。然而，事实上，BAP 1编码一个核定位的去泛素化酶，结合到ASXL 1/2，一个专性polycomb家族伴侣蛋白，靶向组蛋白，强烈表明在基因转录的表观遗传调控的作用。此外，由于BAP 1与ASXL 1/2的结合是酶活性和肿瘤抑制所必需的，因此抑制BAP 1肿瘤抑制活性的替代方法可能是使ASXL 1/2基因突变或沉默。为了确定MM中BAP 1、ASXL 1/2、CDKN 2A和NF 2之间的生化机制和遗传相互作用，Rauscher和Testa实验室联合起来追求以下特定目标：1）使用直接的体内遗传方法来确定杂合Bap 1-突变（+/mut）小鼠是否倾向于发展各种自发性肿瘤，包括MM，并加速石棉诱导的MM。2）使用条件性敲除小鼠确定间皮中单独的Bap 1体细胞丢失是否能够驱动间皮增生和/或明显的MM，以及体细胞Bap 1失活与Nf 2和Cdkn 2a的丢失相结合是否会导致更快的发展和/或更具侵袭性的疾病表型，具有潜在的预后和新的治疗意义。3)定义人MM标本/细胞系中BAP 1和ASXL 1/2突变谱，并确定这些突变如何影响BAP 1与ASXL 1/2和其他PR-DUB复合蛋白的结合和功能，并定义MM细胞中BAP 1和其他PR-DUB组分变化（通过敲低和重建）导致的转录组和细胞表型改变。4)确定间皮细胞和BAP 1和/或ASXL 1/2缺陷型MM细胞中含有野生型BAP 1和ASXL 1/2的天然PR-DUB大分子蛋白复合物的组成，以比较正常和肿瘤特异性亚基结构以及这些复合物在表观遗传失调中的作用。由两名具有互补专业知识的PI进行的拟议多管齐下的研究代表了一种全面的方法，可以对MM发病机制产生新的见解，同时为治疗和预防提供新的靶点。