Role of a new polyomavirus in Merkel cell carcinoma

一种新的多瘤病毒在默克尔细胞癌中的作用

• 批准号: 8215839
• 负责人: PATRICK S. MOORE
• 金额: $ 42.28万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-13 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8215839
• 关键词: Affinity Chromatography; Antibodies; Antigen Targeting; Binding; Binding Proteins; Biological Assay; Biological Models; Blood Cells; Breeding; C-terminal; Cell Line; Cells; Cercopithecus pygerythrus; Detection; Enhancers; Epidemiology; Fluorescent in Situ Hybridization; Gene Expression; Generations; Genome; Germany; Health; Human; Immunoblotting; Immunoprecipitation; In Vitro; Insertional Mutagenesis; Introns; Japan; Knockout Mice; Learning; Luciferases; Malignant Epithelial Cell; Malignant Neoplasms; Mechanoreceptor Cell; Merkel Cells; Merkel cell carcinoma; Mus; Mutation; N-terminal; Oncogene Proteins; PTPRG gene; Patients; Pattern; Persons; Plasmids; Play; Polyomavirus; Polyomavirus Infections; Population; Preclinical Drug Evaluation; Prevention; Production; Protein Binding Domain; Protein C; Protein Tyrosine Phosphatase; Proteins; Proteomics; Reporter; Retinoblastoma Protein; Rodent; Role; Signal Transduction; Simian virus 40; Site; Skin Cancer; Soft Agar Assay; Southern Blotting; Transgenic Mice; Tumor Suppressor Proteins; Tumor-Derived; Viral Tumor Antigens; Virus; Virus Diseases; Virus Integration; advanced disease; carcinogenesis; cell transformation; novel; receptor; research study; tumor; tumorigenesis

DESCRIPTION (provided by applicant): We have recently discovered a new human polyomavirus monoclonally-integrated into human Merkel cell carcinomas (MCC) that we call Merkel cell polyomavirus (MCPyV). MCC is a rare neuroectodermal cancer suspected to be caused by a viral infection because of its unusual epidemiology. It is the most aggressive skin cancer and only 50% of patients with advanced disease survive 9 months or longer. MCPyV has a 5.4 kbase genome closely related to murine and African green monkey lymphotropic polyomaviruses (MuPyV and LPyV, respectively). MCPyV is distantly related to SV40 and the four known human polyomaviruses. Human serosurveys show that 15-30% of populations from the US, Japan and Germany have cross-reactive antibodies to LPV which may actually represent reactivity to MCPyV infection. We find similar MCPyV infection rates using direct detection of MCPyV genome from peripheral blood cells. If confirmed, these findings suggest that over a billion persons have been exposed to MCPyV infections worldwide. Southern blotting shows that MCPyV is integrated into MCC genome at different sites in a somatic and monoclonal pattern. One cellular integration site has been defined as the receptor-type protein tyrosine phosphatase-gamma (PTPRG) intron 1. MCPyV also expresses a highly conserved T antigen in tumors. The N-terminus of MCPyV encodes transformation-associated DnaJ and LXCXE pocket protein-binding domains. All tumor- derived MCPyV T antigens, however, possess T antigen mutations that eliminate T antigen origin binding and/or plasmid replication functions. These functions are not needed to maintain integrated virus, suggesting that MCC arises in at least two steps: first, MCPyV integrates into the host genome; second, truncation mutations arise allowing expression of N-terminal transforming domains, but eliminating deleterious C- terminal domains. MCPyV may play a role in tumorigenesis through insertional mutagenesis, expression of T antigen or both. Our proposal seeks to understand these mechanisms for transformation and oncogenesis by 1) identifying additional cell integration sites, 2) analyzing T antigen transforming functions in rodent cells and in cell signaling assays, 3) performing cell-wide proteomic analysis following T antigen expression, 4) identifying novel cellular T antigen direct interactors and 5) generating transgenic mice with MCPyV T antigen expression targeted to Merkel mechanoreceptor cells. Through this systematic approach we anticipate we will learn how this new virus contributes to human carcinogenesis. PUBLIC HEALTH RELEVANCE: This proposal seeks to understand how Merkel cell virus (MCV) contributes to human cancers. MCV has been found as an integrated virus in Merkel cell carcinoma where it expresses T antigen, an oncoprotein that has been well-characterized from closely-related viruses. This proposal will investigate similarities and differences between MCV T antigen and T antigen from other viruses as well as dysregulation of cellular proteins from MCV integration and T antigen expression. Finally, we seek to generate a model system for MCV tumorigenesis that will be useful for drug screening and prevention.

描述（由申请人提供）：我们最近发现了一种单克隆整合到人默克尔细胞癌（MCC）中的新的人多瘤病毒，我们称之为默克尔细胞多瘤病毒（MCPyV）。 MCC 是一种罕见的神经外胚层癌，由于其不寻常的流行病学，怀疑是由病毒感染引起的。它是最具侵袭性的皮肤癌，只有 50% 的晚期患者能存活 9 个月或更长时间。 MCPyV 具有 5.4 kbase 基因组，与鼠类和非洲绿猴嗜淋巴细胞多瘤病毒（分别为 MuPyV 和 LPyV）密切相关。 MCPyV 与 SV40 和四种已知的人类多瘤病毒有远亲关系。人类血清调查显示，美国、日本和德国 15-30% 的人群具有 LPV 交叉反应性抗体，这实际上可能代表对 MCPyV 感染的反应性。通过直接检测外周血细胞中的 MCPyV 基因组，我们发现类似的 MCPyV 感染率。如果得到证实，这些发现表明全世界有超过 10 亿人接触过 MCPyV 感染。 Southern 印迹显示 MCPyV 以体细胞和单克隆模式整合到 MCC 基因组的不同位点。一个细胞整合位点被定义为受体型蛋白酪氨酸磷酸酶-γ (PTPRG) 内含子 1。MCPyV 还在肿瘤中表达高度保守的 T 抗原。 MCPyV 的 N 末端编码转化相关的 DnaJ 和 LXCXE 口袋蛋白结合域。然而，所有肿瘤来源的 MCPyV T 抗原都具有消除 T 抗原起点结合和/或质粒复制功能的 T 抗原突变。这些功能并不是维持病毒整合所必需的，这表明MCC至少分两个步骤产生：首先，MCPyV整合到宿主基因组中；其次，出现截短突变，允许表达 N 端转化结构域，但消除有害的 C 端结构域。 MCPyV 可能通过插入诱变、T 抗原表达或两者在肿瘤发生中发挥作用。我们的提案旨在通过以下方式了解这些转化和肿瘤发生机制：1) 识别其他细胞整合位点，2) 分析啮齿动物细胞和细胞信号转导测定中的 T 抗原转化功能，3) 在 T 抗原表达后进行全细胞蛋白质组分析，4 ) 鉴定新型细胞 T 抗原直接相互作用物，以及 5) 生成针对 Merkel 机械感受器细胞表达 MCPyV T 抗原的转基因小鼠。通过这种系统方法，我们预计将了解这种新病毒如何导致人类致癌。公共健康相关性：该提案旨在了解默克尔细胞病毒 (MCV) 如何导致人类癌症。 MCV 被发现是默克尔细胞癌中的一种整合病毒，它表达 T 抗原，这是一种癌蛋白，已从密切相关的病毒中得到了很好的表征。该提案将研究 MCV T 抗原与其他病毒 T 抗原之间的异同，以及 MCV 整合和 T 抗原表达引起的细胞蛋白失调。最后，我们寻求建立一个 MCV 肿瘤发生的模型系统，这将有助于药物筛选和预防。