Regulation of Lymphocyte Proliferation and Replicative Capacity

淋巴细胞增殖和复制能力的调节

基本信息

批准号：
9343566
负责人：
RICHARD J. HODES
金额：
$ 66.16万
依托单位：
DIVISION OF BASIC SCIENCES - NCI
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/9343566
关键词：
ATM gene ATM wt Allele Affect Age Aggressive Clinical Course Antibodies Aplastic Anemia Ataxia Telangiectasia Ataxia Telangiectasia Patients B lymphoid malignancy B-Cell Lymphomas B-Lymphocytes B-Lymphoma Development BCL10 gene Biology Breeding CD3E gene Categories Cell Lineage Cell Proliferation Cell Survival Cell division Cell physiology Cells Chromosomal Instability Chromosome Structures Chromosomes, Human, Pair 18 Clinical Collaborations Competence Complex DNA Double Strand Break Defect Dependence Development Disease Disease model Dyskeratosis Congenita Enzymes Epigenetic Process Family Frequencies Gene Expression Gene Expression Profiling Genes Genetic Genetic Engineering Genetically Engineered Mouse Histologic Human Immune Immunoglobulin M Immunologic Surveillance In Vitro Incidence Knock-out Knockout Mice Laboratories Length Link Lymphocyte Lymphoid Lymphoma Lymphomagenesis Malignant - descriptor Malignant Neoplasms Malignant lymphoid neoplasm Mediating Modeling Molecular Profiling Mucosa- associated lymphoid tissue lymphoma translocation protein-1 Mus Mutation NF-kappa B National Heart, Lung, and Blood Institute Normal Cell Oncogenic Outcome Outcome Study PTEN gene Pathogenesis Pathway interactions Phosphoric Monoester Hydrolases Phosphotransferases Play Predisposition Protein p53 Protein-Serine-Threonine Kinases Proteins Proto-Oncogene Proteins c-akt Pulmonary Fibrosis RNA-Directed DNA Polymerase Recurrence Regulation Reporting Ribonucleoproteins Role Signal Pathway Signal Transduction Somatic Cell Structure of germinal center of lymph node Study models T-Cell Lymphoma T-Cell Transformation T-Lymphocyte TP53 gene Telomerase Telomerase RNA Component Telomere Length Maintenance Telomere Maintenance Testing Therapeutic Intervention Thymic Lymphoma Thymocyte Development ataxia telangiectasia mutated protein cancer cell early onset gene product genome integrity human disease in vivo inhibitor/antagonist insight large cell Diffuse non-Hodgkin&apos s lymphoma lymphocyte proliferation mouse model non-genetic offspring prevent recombinase telomere tumor tumorigenesis

项目摘要

Telomeres are unique terminal chromosomal structures that shorten with cell division in vitro and with increased age in vivo in human somatic cells. Telomerase, a ribonucleoprotein enzyme that is capable of synthesizing telomeric repeats, is expressed in germline and malignant cells and is absent in most normal human somatic cells. However, we demonstrated that telomerase is in fact highly regulated during development and activation of mouse and human lymphocytes. Expression of the two genes encoding the necessary and sufficient components of telomerase, RNA template (TR) and reverse transcriptase catalytic component (TERT), was found to be regulated during lymphocyte development and activation. Our studies of genetically engineered knockout mice have demonstrated that, in addition to the defect in telomere length maintenance observed in complete homozygous knockouts for either of the telomerase components, there is a deficiency in telomere maintenance in mice that are heterozygous for inactivation of one copy of either telomerase component. This phenomenon, termed haplo-insufficiency, has recently been observed in an increasing number of clinical entities, including dyskeratosis congenita, aplastic anemia, and pulmonary fibrosis, resulting from mutation and inactivation of telomerase components or related genes. In collaboration with the laboratory of Dr. Neal Young (NHLBI), we have assessed the impact of parental haplo-insufficiency for telomere maintenance on the telomere length and function of genetically normal or abnormal offspring in these affected families. The outcome of studies in mice and humans demonstrated that inheritance of telomere length is not determined by species-specific homeostatic mechanisms, but appears to be determined largely by stochastic factors. Cell survival and proliferation are also regulated by the p53 tumor suppressor molecule. Although the function of p53 in preventing malignant transformation and tumorigenesis is well established, there is much less understanding of the role of p53 in normal cell function. Ataxia-telangiectasia mutated (ATM) is a kinase that plays a central role in maintaining genomic integrity. In both humans and mice, ATM deficiency is associated with an increased incidence of lymphoid cancers that are primarily T cell in origin. We asked if ATM plays a more general role in preventing non-T cell malignancies by breeding mice that were both ATM- and T cell-deficient. This model removes T cells as targets for lymphomagenesis as well as eliminating T cell-dependent immune surveillance. These mice exclusively develop early onset IgM+ B cell lymphomas that histologically and genetically resemble the activated B cell-like (ABC) subset of human diffuse large B cell lymphomas (DLBCL). Tumors express clonal as well as emerging IghV hypermutation, and express AID, but B lymphoma development is independent of AID, occurring at equal frequency in AID knockout mice. Lymphomas express high levels of MHCII and costimulatory molecules, are highly stimulatory to T cells in vitro, and grow in vivo in T-deficient but not T cell-intact hosts, pointing to a role of immune surveillance in preventing emergence of these B cell malignancies. These ATM-deficient lymphomas show considerable chromosomal instability with a recurrent amplification of a 4.48Mb region on chromosome 18 (MMU18), orthologous to a region amplified in some cases of human ABC-DLBCL, and containing Malt1 in the region of highest amplification. Importantly, these lymphomas also depend on NF-kB, MALT1, and BCR signaling for survival. Gene expression analysis revealed strong similarities between these mouse lymphomas and human ABC-DLBCL. This study reveals that ATM is required to prevent the development of B cell lymphomas that model human ABC-DLBCL and identifies an unappreciated role of T cells in preventing the emergence of these tumors. Studies now in progress are further characterizing the pathways that mediate transformation of the T cell thymic lymphomas originally described in ATM-deficient mice. We had previously reported that thymic T cell lymphomas develop in mice that are deficient in RAG-1 or RAG-2 recombinase in addition to ATM deficiency. These findings contrast to the absence of T cell lymphomas in mice double deficient in ATM and CD3e. This suggests the possibility that CD3e-containing complex, independent of rearranged TCR gene products, is required for lymphomagenesis. The ability to induce dramatic expansion of RAG-deficient thymocyte development by in vivo treatment with anti-CD3e antibody, demonstrated the potential for such function. Additional studies now in progress are testing the requirement for components of the prototypic TCR/pre-TCR signal pathways, such as LAT, in development of lymphomas. The requirements for survival and proliferation of ATM-deficient T cell lymphomas have in fact not been fully elucidated. We have therefore initiated studies of the genetic and epigenetic changes in these lymphomas, and their dependence on defined signaling pathways. Initial findings have included a universal defect in the phosphatase PTEN, through genetic/non-genetic mechanisms that vary from tumor to tumor. Consistent with loss of PTEN activity, we have observed activation of the AKT pathway and concomitant susceptibility of lymphomas to inhibitors of AKT activity. These findings will inform the underlying biology of T cell transformation with potential relevance to clinical approaches to human T cell malignancies.

端粒是独特的末端染色体结构，随着人体体细胞细胞的体内年龄增长而随着细胞分裂而缩短。端粒酶是能够合成端粒重复序列的核糖核蛋白酶，在种系和恶性细胞中表达，在大多数正常的人类体细胞细胞中不存在。但是，我们证明端粒酶实际上在小鼠和人淋巴细胞的发育和激活过程中受到了高度调节。在淋巴细胞发育和激活期间，发现编码端粒酶，RNA模板（TR）和逆转录酶催化成分（TERT）的必要成分的两个基因的表达。我们对基因工程敲除小鼠的研究表明，除了在端粒酶组件的完全纯合敲除中观察到的端粒长度维护缺陷外，小鼠的端粒维持缺乏，它们是杂合的，它们是远程合并的一种远程触点组件的副本副本的副本。最近在越来越多的临床实体中观察到了这种现象，称为单倍症，包括脑膜化症状和相关基因的突变和灭活型临床实体，包括兴奋性脑膜炎，性障碍性贫血和肺纤维化。通过与NEAL YOUNG博士（NHLBI）的实验室合作，我们评估了父母单倍不使您对端粒维持的影响对这些受影响家庭的基因正常或异常后代的端粒长度和功能。小鼠和人类研究的结果表明，端粒长度的遗传不是由物种特异性稳态机制决定的，而是在很大程度上取决于随机因素。细胞存活和增殖也受p53肿瘤分子的调节。尽管p53在预防恶性转化和肿瘤发生方面的功能已经很好地确定，但对p53在正常细胞功能中的作用的了解要少得多。共济失调 - 凝血症突变（ATM）是一种激酶，在维持基因组完整性中起着核心作用。在人类和小鼠中，ATM缺乏症与主要是T细胞起源的淋巴样癌的发生率增加有关。我们询问ATM是否通过育种ATM缺陷和T细胞的小鼠来预防非T细胞恶性肿瘤中起着更普遍的作用。该模型去除T细胞作为淋巴作用的靶标，并消除T细胞依赖性免疫监测。这些小鼠专门发展了组织学和遗传上类似于活化的B细胞样（ABC）的早期发作IgM+ B细胞淋巴瘤，该淋巴类（ABC）的人体弥漫性大B细胞淋巴瘤（DLBCL）。肿瘤表达克隆以及出现的IGHV超誉和明确的辅助，但是B淋巴瘤的发育与AID无关，在AID基因敲除小鼠中出现在相等的频率下。淋巴瘤表达高水平的MHCII和共刺激分子，在体外对T细胞高度刺激性，并且在T缺陷型但不具有T细胞单直体宿主体内生长，这表明免疫监测在防止这些B细胞恶性肿瘤中出现中的作用。这些ATM缺陷型淋巴瘤显示出相当大的染色体不稳定性，并在18染色体上的4.48Mb区域（MMU18）复发，在某些情况下与人类ABC-DLBCL扩增的区域直系同源，并且在最高扩增的区域中包含MALT1。重要的是，这些淋巴瘤还取决于NF-KB，MALT1和BCR信号的生存。基因表达分析表明，这些小鼠淋巴瘤与人ABC-DLBCL之间的相似性很强。这项研究表明，需要ATM来防止B细胞淋巴瘤的发展，该B细胞淋巴瘤对人类ABC-DLBCL进行了模拟，并确定T细胞在防止这些肿瘤出现中的不受欢迎的作用。现在正在进行的研究进一步表征了介导最初在ATM缺陷小鼠中描述的T细胞胸腺淋巴瘤转化的途径。我们以前曾报道过，除了ATM缺乏外，胸腺T细胞淋巴瘤在RAG-1或RAG-2重物组织酶不足的小鼠中发展。这些发现与在ATM和CD3E中双重缺陷的小鼠中缺乏T细胞淋巴瘤形成鲜明对比。这表明淋巴细胞化需要含CD3E的复合物，独立于重排的TCR基因产物。通过在体内用抗CD3E抗体进行体内处理，诱导抹布缺陷胸腺细胞发育的急剧扩张的能力证明了这种功能的潜力。现在正在进行的其他研究正在测试对淋巴瘤开发中原型TCR/PER-TCR信号途径（例如LAT）组件的需求。实际上，ATM缺陷型T细胞淋巴瘤生存和增殖的要求实际上尚未完全阐明。因此，我们已经开始研究这些淋巴瘤中遗传和表观遗传学变化及其对确定信号通路的依赖。最初的发现包括磷酸酶PTEN中的普遍缺陷，通过遗传/非遗传机制因肿瘤而异。与PTEN活性的丧失一致，我们观察到AKT途径的激活以及淋巴瘤对AKT活性抑制剂的易感性。这些发现将为T细胞转化的潜在生物学提供与人类T细胞恶性肿瘤的临床方法相关的潜在生物学。