The role of the LZTR1 ubiquitin ligase in stem cells and cancer

LZTR1 泛素连接酶在干细胞和癌症中的作用

• 批准号: 9262886
• 负责人: Antonio Iavarone
• 金额: $ 38.31万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-15 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9262886
• 关键词: Adopted; Applications Grants; BTB/POZ Domain; Biochemical; Biological; Biological Process; Biology; Brain; Brain Neoplasms; Cell model; Cells; Chromosomal translocation; Code; Complex; Copy Number Polymorphism; Cullin Proteins; Data; Data Set; Development; Dissection; Ensure; Event; Foundations; Gene Dosage; Genes; Genetic; Glioblastoma; Glioma; Goals; Growth; Hereditary Disease; Human; Impairment; In Vitro; Individual; Insertional Mutagenesis; Knock-out; Knockout Mice; Ligase; Link; Location; Maintenance; Malignant Neoplasms; Malignant neoplasm of brain; Mass Spectrum Analysis; Mediating; Mitochondria; Modeling; Molecular; Mouse Strains; Mus; Mutation; Nervous system structure; Neurons; Normal Cell; Orphan; Pathogenesis; Play; Point Mutation; Proteins; Proteolysis; Recruitment Activity; Reporting; Role; Salvelinus; Sampling; Set protein; Sleeping Beauty; Specificity; Stem cells; Substrate Domain; Suppressor Genes; System; Technology; Tertiary Protein Structure; Time; Tumor Initiators; Tumor Suppressor Genes; Tumor Suppressor Proteins; Ubiquitin; Validation; Variant; Work; actionable mutation; base; cancer cell; cancer initiation; cullin-3; follow-up; genetic analysis; genetic regulatory protein; in vivo; innovation; loss of function; loss of function mutation; mouse model; multicatalytic endopeptidase complex; nerve stem cell; neurodevelopment; next generation sequencing; novel; novel therapeutic intervention; prevent; protein complex; protein function; public health relevance; scaffold; self-renewal; teration; tumor; tumor growth; tumorigenesis; ubiquitin ligase

 DESCRIPTION (provided by applicant): In the genetic analysis of human cancer, focal gene copy number variation (CNV) and point mutations provide exquisite information on candidate driver genes by pinpointing their exact location. Recently, we conducted a large-scale analysis in which we integrated somatic point mutations and focal CNV information in a single framework to nominate new driver genes implicated in glioblastoma multiforme (GBM), one of the most aggressive types of human cancer. The top-ranking gene that emerged from this analysis is LZTR1, which codes for the substrate adaptor of a Cullin-3 (Cul3) ubiquitin ligase complex for which the substrates still await discovery. In GBM, LZTR1 is targeted by loss-of-function mutations and focal deletions, thus behaving as a new tumor suppressor gene, a notion recently confirmed in other tumors. From a mechanistic standpoint, we have discovered the unexpected capacity of LZTR1 to impair self-renewal and growth of the most aggressive cellular subpopulation in human GBM, the glioma stem cells (GSCs). The central objective of this proposal is to identify and functionally characterize the substrates of the LZTR1 ubiquitin ligase complex and decipher how mechanistically LZTR1 operates to prevent tumor development in normal neural cells. Our overarching hypothesis is that the LZTR1-Cul3 protein complex suppresses tumor growth through the regulated proteolysis of a particular set of substrates. Our preliminary data have already identified and validated a set of proteins with recognized mitochondrial activities as new LZTR1 substrates. Together with our recent observation that LZTR1 localizes at mitochondria, these results are exciting new findings that link alterations of LZTR1 to deregulation of mitochondrial functions in cancer. In Aim 1, the LZTR1 substrates will be comprehensively identified from a novel mass spectrometry-based technology that has already successfully recognized exciting, new substrate candidates of LZTR1. The functional validation of the substrates will be pursued in highly relevant cellular models directly generated from primary human GBM and will be related to the landscape of mutations of LZTR1 discovered in human cancer. In Aim 2, we will determine the normal activity of LZTR1 in the brain and model human GBM harboring inactivating mutations of LZTR1 in a new genetic mouse model in which the LZTR1 gene is conditionally knocked out in the nervous system. We will also use the Sleeping Beauty insertional mutagenesis system to identify the genetic alterations that cooperate with loss of LZTR1 for brain tumorigenesis.

 描述（由申请人提供）：在人类癌症的遗传分析中，焦点基因拷贝数变异（CNV）和点突变通过精确定位候选驱动基因的确切位置，提供了有关候选驱动基因的精确信息。最近，我们进行了一项大规模分析，将体细胞点突变和局灶性 CNV 信息整合到一个框架中，以提名与多形性胶质母细胞瘤 (GBM) 相关的新驱动基因，多形性胶质母细胞瘤 (GBM) 是人类癌症中最具侵袭性的类型之一。该分析中出现的顶级基因是 LZTR1，它编码 Cullin-3 (Cul3) 泛素连接酶复合物的底物接头，该复合物的底物仍有待发现。在 GBM 中，LZTR1 是功能丧失突变和局灶性缺失的靶标，因此表现为一种新的肿瘤抑制基因，这一概念最近在其他肿瘤中得到证实。从机制的角度来看，我们发现 LZTR1 具有意想不到的能力，可以损害人类 GBM 中最具攻击性的细胞亚群——神经胶质瘤干细胞 (GSC) 的自我更新和生长。该提案的核心目标是鉴定 LZTR1 泛素连接酶复合物的底物并对其进行功能表征，并破译 LZTR1 如何在机制上发挥作用来防止正常神经细胞中的肿瘤发展。我们的总体假设是 LZTR1-Cul3 蛋白复合物通过调节一组特定底物的蛋白水解来抑制肿瘤生长。我们的初步数据已经鉴定并验证了一组具有公认的线粒体活性的蛋白质作为新的 LZTR1 底物。加上我们最近观察到 LZTR1 定位于线粒体，这些结果是令人兴奋的新发现，将 LZTR1 的改变与癌症中线粒体功能失调联系起来。在目标 1 中，将通过基于质谱的新型技术全面鉴定 LZTR1 底物，该技术已成功识别出令人兴奋的 LZTR1 新底物候选物。底物的功能验证将在直接从原代人类 GBM 生成的高度相关的细胞模型中进行，并将与人类癌症中发现的 LZTR1 突变情况相关。在目标 2 中，我们将确定大脑中 LZTR1 的正常活性，并在新的遗传小鼠模型中建立含有 LZTR1 失活突变的人类 GBM 模型，其中 LZTR1 基因在神经系统中被条件性敲除。我们还将使用睡美人插入突变系统来识别与 LZTR1 缺失导致脑肿瘤发生相关的基因改变。