IRF8 and lymphomagenesis

IRF8 和淋巴瘤发生

基本信息

批准号：
9898227
负责人：
Ricardo C Aguiar
金额：
--
依托单位：
SOUTH TEXAS VETERANS HEALTH CARE SYSTEM
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-04-01 至 2021-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9898227
关键词：
Address Adult Affect Agreement Animal Model Apoptosis B Cell Proliferation B cell differentiation B lymphoid malignancy B-Cell Development B-Cell Lymphomas B-Lymphocytes BCL2 gene BCL6 gene Balkans Biological Biology Biopsy Blood Cells CD19 gene Cell Line Chemical Exposure Chromosomal translocation Clinical Complex DNA Data Deletion Mutation Development Diagnosis Disease Early Diagnosis Ectopic Expression Emu species Enhancers Enzymes Epigenetic Process Family Fostering Functional disorder Gene Fusion Genes Genetic Genetic Transcription Genomics Goals Human IFN consensus sequence binding protein IGH@ gene cluster Immune Immuno-Chemotherapy Immunoglobulin Somatic Hypermutation In Vitro Incidence Infectious Agent Interferons Knowledge Lesion Link Lymphoma Lymphomagenesis MLL2 gene Maintenance Malignant - descriptor Malignant Neoplasms Malignant lymphoid neoplasm Maps Massive Parallel Sequencing Mature B-Lymphocyte Military Personnel Modeling Mus Mutate Mutation Oncogenes Oncogenic Other Genetics PAX5 gene PRDM1 gene Pathogenesis Pathway interactions Patients Phenotype Physiological Point Mutation Population Process Proteins Reaction Reporting Research Resistance Risk Role Secondary to Somatic Mutation Structure of germinal center of lymph node Testing Therapeutic Transgenic Organisms Tumor Suppressor Genes Tumor Suppressor Proteins Variant Veterans Vietnam Western World activation-induced cytidine deaminase cancer type gain of function histone methyltransferase in vivo large cell Diffuse non-Hodgkin&apos s lymphoma member mouse model mutant next generation sequencing novel novel marker plasma cell differentiation pressure programs trait transcription factor tumor

项目摘要

The advent of massive parallel sequencing highlighted the genetic complexity of cancer, and unveiled the putative contribution of several unsuspected genes to the process of malignant transformation. These advances also indicated a need for the systematic examination of newly-found mutant genes as to determine whether they truly contribute to cancer pathogenesis, or simply represent innocuous variants irrelevant to the observed phenotype. Diffuse large B cell lymphoma (DLBCL), the most common lymphoid malignancy in adults, is curable in only ~60% of cases. This clinical challenge is associated with the disease’s complex genetics, which include disruption of epigenetic modifiers, constitutive activation of the NF-κB pathway, and deregulation of B cell relevant transcription factors. The latter, can derive from chromosomal translocation, genomic amplification/deletions and somatic mutations. Recently, we developed an IGH-targeted capture/sequencing strategy and discovered novel aberrant gene fusions in DLBCL including the juxtaposing of IRF8 (interferon regulatory factor 8) to the IGH locus, t(14;16)(q32;q24), a prototypical model of transcription factor deregulation in B cell lymphomas. Independently, IRF8 was found to be somatically mutated in ~10% of DLBCL biopsies. Interestingly, close to 50% of the IRF8-mutant DLBCLs also have mutations in KMT2D, a histone methyltransferase that when inactivated enhances the lymphomagenic potential of other genetic lesions. IRF8, a member of the interferon family of transcription factors, is expressed in the germinal center (GC) where it directly influences the expression of several key regulators of the GC reaction, including BCL6, AICDA and PRDM1. The central objective of this proposal is to test the hypothesis that IRF8 is a bona fide oncogene in DLBCL, which can be deregulated by chromosomal translocation and somatic mutations. To advance this concept, we found that ectopic expression of IRF8 in DLBCL cell lines promotes a lymphomagenic profile characterized by induction of BCL6 and AICDA, suppression of PRDM1 and resistance to apoptosis. In addition, we generated preliminary data to show that the missense IRF8 mutants found in DLBCL are all gain-of-function. Lastly, we created a mouse with B cell restricted transgenic expression of Irf8. Building on our preliminary data, and on the availability of this novel animal model, we propose to address the following specific aims: 1) Determine the mechanism for Irf8 lymphomagenesis in a mouse model that mimics the IGH/IRF8 fusion found in human DLBCL; 2) Characterize in vivo the pro-lymphoma cooperation between the oncogenic Irf8 and the tumor suppressor Kmt2d; 3) Define the functional consequences of the somatic IRF8 mutations found in DLBCL. When this project is completed, we will show that IRF8 functions as an oncogene that cooperates with KMT2D loss for the development of DLBCL. We also expect to mechanistically link IRF8’s lymphomagenesis to the deregulation of BCL6, AICDA and PRDM1.

大规模并行测序的出现凸显了癌症的遗传复杂性，并揭示了一些未被怀疑的基因对恶性转化过程的推定贡献。进展还表明需要对新发现的突变基因进行系统检查以确定它们是否真正有助于癌症发病机制，或者只是代表与癌症无关的无害变异观察到的表型是弥漫性大 B 细胞淋巴瘤 (DLBCL)，最常见的淋巴恶性肿瘤。成人中，只有约 60% 的病例可以治愈，这一临床挑战与该疾病的复杂性有关。遗传学，包括表观遗传修饰因子的破坏、NF-κB 通路的组成型激活，以及 B 细胞相关转录因子的失调可能源自染色体易位，最近，我们开发了一种针对 IGH 的基因组扩增/缺失和体细胞突变。捕获/测序策略并在 DLBCL 中发现了新的异常基因融合，包括并置 IRF8（干扰素调节因子 8）与 IGH 基因座 t(14;16)(q32;q24) 的转录原型模型独立地，IRF8 被发现在约 10% 的 B 细胞淋巴瘤中发生体细胞突变。匿名 DLBCL 活检显示，接近 50% 的 IRF8 突变 DLBCL 也有 KMT2D 突变，KMT2D 是一种突变。组蛋白甲基转移酶失活后会增强其他遗传基因的淋巴瘤形成潜力 IRF8 是转录因子干扰素家族的成员，在生发中心表达。 (GC)，它直接影响 GC 反应的几个关键调节因子的表达，包括 BCL6， AICDA 和 PRDM1 该提案的中心目标是检验 IRF8 是否真实的假设。 DLBCL 中的癌基因，可通过染色体易位和体细胞突变而失调。推进这一概念，我们发现 DLBCL 细胞系中 IRF8 的异位表达促进了淋巴瘤发生特征为 BCL6 和 AICDA 的诱导、PRDM1 的抑制和耐药性此外，我们生成的初步数据表明，IRF8 错义突变体存在于细胞凋亡中。 DLBCL 都是功能获得性的。最后，我们创建了 B 细胞限制性 Irf8 转基因表达的小鼠。基于我们的初步数据以及这种新型动物模型的可用性，我们建议解决以下具体目标：1) 确定模拟小鼠模型中 Irf8 淋巴瘤发生的机制在人类 DLBCL 中发现的 IGH/IRF8 融合体；2) 表征两者之间的促淋巴瘤协同作用；致癌 Irf8 和肿瘤抑制因子 Kmt2d 3) 定义体细胞的功能后果；在 DLBCL 中发现 IRF8 突变。当这个项目完成时，我们将证明 IRF8 具有作为 DLBCL 的功能。我们也期望与 KMT2D 损失机制合作发展 DLBCL。将 IRF8 的淋巴瘤发生与 BCL6、AICDA 和 PRDM1 的失调联系起来。