In Vivo Functional Analysis of Chromosome 7q22 Deletions in Myeloid Malignancies

骨髓恶性肿瘤中染色体 7q22 缺失的体内功能分析

• 批准号: 9924474
• 负责人: KEVIN M. SHANNON
• 金额: $ 33.87万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-22 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9924474
• 关键词: 1 year old; Abnormal Cell; Acute Myelocytic Leukemia; Address; Adolescent; Adult; Aftercare; Alkylating Agents; Blood; CHEK2 gene; CRISPR/Cas technology; Cancer Survivor; Cells; Child; Childhood; Chromosome 7; Chromosome Arm; Chromosome Band; Chromosome Deletion; Chromosome abnormality; Chromosomes; Complex; Cytogenetic Analysis; Cytogenetics; DNA; DNA Damage; DNA sequencing; Data; Defect; Development; Drug resistance; Dysmyelopoietic Syndromes; Engineering; Ethylnitrosourea; Exhibits; Exposure to; Fluorescent in Situ Hybridization; Genes; Genetic; Genetic Transcription; Genetically Engineered Mouse; Genomic DNA; Germ Lines; Growth; Hematologic Neoplasms; Hematological Disease; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Human; Impairment; Inherited; Lymphoid; Malignant - descriptor; Malignant Childhood Neoplasm; Malignant Neoplasms; Modeling; Modernization; Molecular; Monosomy 7; Mouse Strains; Mus; Mutagens; Mutation; Myelogenous; Myeloproliferative disease; Output; Pathogenesis; Patients; Phenotype; Population; Populations at Risk; Predisposition; Radiation therapy; Reagent; Recurrence; Refractory; Resources; Second Primary Cancers; Solid; Specimen; System; Testing; Therapeutic; Treatment Protocols; Tumor Suppressor Genes; Work; aged; cancer genome; cell behavior; chromosome 7 loss; chromosome 7q loss; clinical risk; cohort; genetic analysis; genome-wide; genome-wide analysis; high risk; in vivo; leukemia; leukemic transformation; leukemogenesis; mouse development; mutant; novel; novel therapeutic intervention; reconstitution; response; self-renewal; transcriptome; young adult

ABSTRACT Recurring losses of large chromosomal regions are a hallmark of pediatric and adult cancer genomes that pose exceptional challenges for uncovering how these deletions contribute to malignant growth. Monosomy 7 (-7) and del(7q) (-7/del(7q)) are recurring cytogenetic abnormalities in de novo myeloid malignancies that are strongly associated with cases of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) arising in children and in adolescent/young adult (AYA) patients with inherited cancer predispositions and in those who develop myeloid malignancies after treatment for a primary cancer. Therapy-induced MDS and AML (t-MDS and t-AML) are particularly relevant to the pediatric and AYA population due to modern intensive treatment protocols for many solid cancers, which are frequently curative. As a result, there is a large and growing population of “at risk” pediatric and AYA cancer survivors. Unfortunately, t-MDS/t-AML and other myeloid malignancies with chromosome 7 deletions are highly refractory to current therapies. Extensive cytogenetic and genome wide analysis studies implicate deletions of chromosome band 7q22 in leukemogenesis; however, sequencing studies and transcriptome analysis did not reveal frequent homozygous inactivation of any candidate 7q tumor suppressor gene in myeloid malignancies. These data implicate haploinsufficiency for one or more 7q genes in leukemogenesis, which pose formidable challenges for elucidating the underlying molecular mechanisms. To address this fundamental problem, we deployed chromosome engineering to create 5A3+/del and 5G2+/del mice, which respectively harbor deletions in mouse chromosome bands 5A3 and 5G2. These deletions span ~4 MB of genomic DNA that is syntenic to the most common 7q22 deletions identified in human patients. 5A3+/del hematopoietic stem and progenitor cells (HSPC) exhibit “preleukemic” abnormalities, but these mice do not spontaneously develop MDS or AML. Preliminary studies of 5G2+/del mice also revealed HSPC abnormalities and exposing this strain to N-ethyl-N-nitrosourea (ENU) accelerated the development of hematologic cancer. We will utilize these novel models of 7q22 deletions to pursue the following specific aims: (1) to functionally interrogate hematopoiesis in 5G2+/del and 5A3+/del/5G2+/del mice and to observe cohorts of mice for the development of myeloid malignancies; (2) to investigate the effects of DNA damaging agents on 5A3+/del/5G2+/del HSPC; and, (3) to model the complex genetics of myeloid malignancies with -7/del(7q) by introducing cooperating mutations into 5A3+/del/5G2+/del HSPC and assessing the phenotypic and functional consequences in vivo. Genetically engineered mice that accurately model recurrent chromosome band 7q22 deletions found in human myeloid malignancies are a versatile system for performing functional studies and testing new therapeutic strategies.

摘要 大染色体区域的反复丢失是儿童和成人癌症基因组的标志， 对揭示这些缺失如何导致恶性生长提出了特殊的挑战。单倍体7 (-7)和del（7 q）（-7/del（7 q））是原发性骨髓恶性肿瘤中复发的细胞遗传学异常， 与骨髓增生异常综合征（MDS）和急性髓性白血病（AML）病例密切相关， 在有遗传性癌症倾向的儿童和青少年/年轻成人（AYA）患者中， 在原发性癌症治疗后发生骨髓恶性肿瘤。治疗诱导的骨髓增生异常综合症和急性粒细胞白血病（t-MDS 和t-AML）与儿科和AYA人群特别相关，因为现代强化治疗 许多实体癌的治疗方案，通常是治愈性的。因此，有一个大的和不断增长的 “高危”儿童和AYA癌症幸存者人群。不幸的是，t-MDS/t-AML和其他骨髓性疾病， 具有7号染色体缺失的恶性肿瘤对于目前的治疗是高度难治的。广泛的细胞遗传学 并且全基因组分析研究暗示白血病发生中染色体带7 q22的缺失;然而， 测序研究和转录组分析没有揭示任何基因的频繁纯合失活。 髓系恶性肿瘤中的候选7 q肿瘤抑制基因这些数据暗示了单倍不足， 或更多的7 q基因在白血病发生中的作用，这对阐明潜在的 分子机制为了解决这个根本问题，我们部署了染色体工程， 产生5A 3 +/del和5G 2 +/del小鼠，其分别在小鼠染色体带5A 3和5G 2中具有缺失， 5G2。这些缺失跨越约4 MB的基因组DNA，与最常见的7 q22缺失同线 在人类患者中发现。5A 3 +/del造血干细胞和祖细胞（HSPC）表现出“白血病前期” 这些小鼠不自发地发生MDS或AML。5G 2 +/del小鼠的初步研究 也揭示了HSPC异常，并将该菌株暴露于N-乙基-N-亚硝基脲（ENU）加速了HSPC的生长。 血液癌症的发展。我们将利用这些新的7 q22缺失模型来研究 （1）功能性地研究5G 2 +/del和5A 3 +/del/5G 2 +/del小鼠中的造血作用， 观察小鼠队列的骨髓恶性肿瘤的发展;（2）研究DNA的影响， 对5A 3 +/del/5G 2 +/del HSPC的损伤剂;以及，（3）对骨髓恶性肿瘤的复杂遗传学进行建模 通过向5A 3 +/del/5G 2 +/del HSPC中引入协同突变并评估表型， 和功能性后果。基因工程小鼠，准确地模型复发 在人类骨髓恶性肿瘤中发现的染色体带7 q22缺失是一种多功能系统， 功能研究和测试新的治疗策略。