Role of DNA Double Strand Break Response in Suppression of Thymic Lymphoma

DNA 双链断裂反应在抑制胸腺淋巴瘤中的作用

• 批准号: 8454437
• 负责人: Frederick W. Alt
• 金额: $ 40.76万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 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/8454437
• 关键词: ATM deficient; ATM gene; Address; Affect; Alleles; Am 80; Cell Culture Techniques; Chromosomal translocation; Chromosomes; Chromosomes, Human, Pair 12; Chromosomes, Human, Pair 14; Collaborations; DNA; DNA Double Strand Break; DNA Repair Pathway; DNA Sequence Rearrangement; Development; Double Strand Break Repair; Enhancers; Frequencies; Gene Targeting; Generations; Genes; Genetic Recombination; Genomics; Goals; Human; LMO2 gene; Lead; Location; Lymphomagenesis; Malignant Neoplasms; Malignant lymphoid neoplasm; Measures; Mediating; Modeling; Molecular; Monitor; Mus; Mutant Strains Mice; Mutate; Nature; Nonhomologous DNA End Joining; Oncogenes; Oncogenic; Pathway interactions; Pattern; Population; Process; Protein p53; Proto-Oncogenes; Recurrence; Relative (related person); Research Personnel; Residual state; Role; T-Cell Development; T-Cell Lymphoma; T-Cell Receptor; T-Lymphocyte; Testing; Thymic Lymphoma; Tumor Suppressor Genes; V(D)J Recombination; Work; base; c-myc Genes; comparative genomic hybridization; fusion gene; leukemia/lymphoma; mouse model; novel; prevent; programs; repaired; response; thymocyte; tumor

Immature T cell lymphomas comprise a significant portion of human lymphoid malignancies. Many of these tumors harbor recurrent chromosomal translocations and related aberrations that either activate proto-oncogenes, inactivate tumor suppressor genes, or create novel oncogenic fusion genes. Most oncogenic translocations of human immature T cell lymphomas are thought to occur via errors in the repair of DNA double strand breaks (DSBs) introduced at T cell receptor (TCR) loci during V(D)J recombination and/or general DSBs at other genomic locations. We propose to elucidate functions of the DSB response in suppression of translocations associated with T cell lymphomas and to generate novel mouse models for human T cell lymphoma. We also propose to elucidate molecular mechanisms that underlie recurrent translocations in T cell lymphomas, including how spatial proximity, DSB frequency and DNA repair pathway availability affect translocation patterns. Recurrent chromosome 14 translocations in the vicinity of the TCRa/d locus are found frequently in ATM-deficient mouse thymic lymphomas and similar translocations are found in human T cell lymphomas that have mutated ATM genes. In this regard, we find that a region 10 Mb upstream of the TCRa/d locus is highly amplified on chromosome 14 in most ATM-deficient mouse thymic lymphomas. We propose to fully investigate this recurrent translocation/amplification in ATM-deficient T cell lymphomas i) to elucidate mechanistic aspects, including potential roles of TCRa/d locus V(D)J recombination and TCRa/d enhancers (with Project 2, Harald von Boehmer), ii) to identify target oncogene(s) (with Project 5, Rick Young), and iii) to determine relevance to human T cell lymphomas (with Project 1 Tom Look). For translocations, participating loci on different chromosomes must be broken and must be in close proximity for joining. Thus we propose to test the hypothesis that frequent activation of certain proto-oncogenes via translocation to TCR loci in human, but not mouse, T cell lymphomas may reflect the relative frequency of DNA DSBs and the spatial proximity of target loci. To address this question, we will employ various approaches including 3D FISH and the generation of novel cell culture and mouse models in which DNA breaks are introduced into target T-cell oncogenes during T-cell development. We will also employ these models to test our hypothesis that ATM and its substrates (e.g., H2AX) prevent translocations resulting from aberrant V(D)J recombination by stabilizing TCR locus DSBs introduced during V(D)J recombination. Together, these studies should allow us to address long-standing questions regarding the mechanisms underlying chromosomal translocation targeting in T-ALL and other cancers.

未成熟的T细胞淋巴瘤构成了人类淋巴恶性肿瘤的很大一部分。这些肿瘤中有许多具有复发性的染色体易位和相关的畸变，这些肿瘤要么激活原始基因，灭活肿瘤抑制基因或创建新型的致癌融合基因。人们认为，在V（d）J重组和/或其他基因组位置，在T细胞受体（TCR）基因座引入的DNA双链断裂（TCR）基因座的DNA双链断裂（TCR）基因座的DNA双链断裂（DSB）的误差都会发生。我们建议阐明在 抑制与T细胞淋巴瘤相关的易位，并为人类T细胞淋巴瘤产生新型小鼠模型。我们还建议阐明分子机制，这些机制是T细胞淋巴瘤中复发易位的基础，包括空间接近，DSB频率和DNA修复途径的可用性如何影响易位模式。在ATM缺乏的小鼠胸腺淋巴瘤中经常发现TCRA/D基因座附近的14个复发性染色体易位，并且在具有突变的ATM基因的人T细胞淋巴瘤中发现了类似的易位。在这方面，我们发现在大多数ATM缺乏的小鼠胸腺淋巴瘤中，TCRA/D基因座上游的10 MB区域在14号染色体上被高度扩增。我们建议在ATM缺乏的T细胞淋巴瘤中充分研究这种复发的易位/扩增，以阐明机械方面，包括TCRA/D基因座V（D）J重组和TCRA/D增强剂的潜在作用，与Project 2相关（Harald Von Boehmer），以确定目标5，以及II与人类的toss Oncogene（II）（与Project 5）（s）（S）（s）（s）（S）。淋巴瘤（带有项目1 Tom Look）。对于易位，参与不同染色体的基因座必须被打破，并且必须靠近加入。因此，我们建议测试以下假设：某些原始癌基因通过人类而非小鼠的TCR基因座频繁激活TCR基因座，但T细胞淋巴瘤可能反映了DNA DSB的相对频率和靶基因座的空间接近。为了解决这个问题，我们将采用各种方法，包括3D鱼以及新型细胞培养和小鼠模型的产生，其中在T细胞发育过程中将DNA断裂引入靶标T细胞癌基因。我们还将采用这些模型来测试我们的假设，即ATM及其底物（例如H2AX）通过稳定V（d）J重组期间引入的TCR基因座DSB而导致异常V（d）J重组产生的易位。总之，这些研究应使我们能够解决有关T-All和其他癌症中染色体易位靶向的机制的长期问题。