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: 9067257
• 负责人: Antonio Iavarone
• 金额: $ 38.97万
• 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/9067257
• 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; Health; Hereditary Disease; Human; 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; Sampling; Set protein; Sleeping Beauty; Specificity; Stem cells; Substrate Domain; System; Technology; Time; Tumor Suppressor Genes; Tumor Suppressor Proteins; Ubiquitin; Validation; Work; actionable mutation; base; cancer cell; cancer initiation; cancer stem cell; 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; 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，病灶基因拷贝数变异（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关于候选驱动基因的精确信息。最近，我们进行了一项大规模的分析，在该分析中，我们将体细胞点突变和局灶性CNV信息整合在一个框架中，以提名与多形性胶质母细胞瘤（GBM）有关的新驱动基因，GBM是最具侵袭性的人类癌症类型之一。从该分析中出现的排名最高的基因是LZTR 1，其编码Cullin-3（Cul 3）泛素连接酶复合物的底物接头，其底物仍有待发现。在GBM中，LZTR 1被功能丧失突变和局灶性缺失所靶向，因此表现为新的肿瘤抑制基因，这一概念最近在其他肿瘤中得到证实。从机制的角度来看，我们已经发现了LZTR 1意想不到的能力，以损害自我更新和生长的最具侵略性的细胞亚群在人类GBM，神经胶质瘤干细胞（GSC）。该提案的中心目标是鉴定和功能表征LZTR 1泛素连接酶复合物的底物，并破译LZTR 1如何在正常神经细胞中机制性地防止肿瘤发展。我们的总体假设是LZTR 1-Cul 3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确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LZTR 1底物。加上我们最近观察到LZTR 1定位于线粒体，这些结果是令人兴奋的新发现，将LZTR 1的改变与癌症中线粒体功能的失调联系起来。在目标1中，LZTR 1底物将从一种新的基于质谱的技术中全面鉴定，该技术已经成功地识别出令人兴奋的LZTR 1新底物候选物。底物的功能验证将在直接由原代人GBM产生的高度相关的细胞模型中进行，并且将与在人类癌症中发现的LZTR 1突变的景观相关。在目标2中，我们将确定LZTR 1在大脑中的正常活性，并在新的遗传小鼠模型中建立携带LZTR 1失活突变的人GBM模型，其中LZTR 1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诱变系统来鉴定与LZTR 1缺失合作的遗传改变，以用于脑肿瘤发生。