Investigating and modeling MYD88L265P and co-occurring mutations in mature B-cell malignancies

研究和建模 MYD88L265P 和成熟 B 细胞恶性肿瘤中同时发生的突变

• 批准号: 10670435
• 负责人: RUBEN D CARRASCO
• 金额: $ 43.68万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10670435
• 关键词: Accounting; Adaptor Signaling Protein; Animal Model; B lymphoid malignancy; B-Cell Activation; B-Cell Development; B-Cell Lymphomas; B-Cell NonHodgkins Lymphoma; B-Lymphocytes; Binding; Biochemical; Biological Models; CRISPR/Cas technology; Cell Line; Cell model; Chromosome 6; Chromosome Deletion; Clinical; Clinical Engineering; Comparative Study; Correlative Study; DNA Sequence Alteration; Data; Development; Diagnosis; Disease; Disease Progression; Feedback; Frequencies; Gene Mutation; Generations; Genes; Genetic; Genomics; Hematologic Neoplasms; Hematopoietic stem cells; Human; Immunocompetent; Immunotherapy; Incidence; Indolent; Leucine; Lymphoma; Lymphoma cell; Lymphomagenesis; Lymphoproliferative Disorders; Malignant Neoplasms; Malignant lymphoid neoplasm; Mass Spectrum Analysis; Mature B-Lymphocyte; Mediating; Medical; Missense Mutation; Modeling; Molecular; Mus; Mutation; Neoplastic Cell Transformation; Non-Hodgkin' s Lymphoma; Nuclear Translocation; Oncogenes; Oncogenic; Outcome; PRDM1 gene; Pathogenesis; Pathogenicity; Pathologic; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Point Mutation; Positioning Attribute; Predisposition; Prognosis; Proline; Property; Proteins; Proteomics; Repression; Research; Role; Sampling; Side; Signal Transduction; Structure of germinal center of lymph node; System; Testing; Transgenic Mice; Transgenic Organisms; Tumor Suppressor Proteins; Waldenstrom Macroglobulinemia; Work; Writing; activated B cell like; cell type; clinically relevant; cohort; deletion detection; drug sensitivity; effective therapy; improved; in vivo; insight; large cell Diffuse non-Hodgkin' s lymphoma; loss of function; mouse model; mutant; novel; overexpression; p65; pre-clinical; transcriptomics; tumor; tumor-immune system interactions

Project Abstract Non-Hodgkin lymphomas (NHLs) of B-cell type, a heterogenous group of lymphoid malignancies, are among the most common cancers worldwide, accounting for about 4% of all cancers. A dramatic rise in incidence of NHLs worldwide during the past decades has sparked intense research efforts to understand their pathogenesis. Genomics studies have uncovered many novel genomic alterations in NHLs, but these remain to be functionally validated and characterized. Among the most common of the genomic alterations is a missense mutation that results in leucine-to-proline substitution at position 265 in MYD88 (MYD88L265P), an adaptor protein that activates oncogenic NF-κB signaling. The MYD88L265P mutation is exceptionally frequent in lymphoplasmacytic lymphoma (LPL) and activated B-cell type of diffuse large B-cell lymphoma (ABC-DLBCL). While inhibition of MYD88L265P adversely impacts the survival of LPL and ABC-DLBCL cells, its role in lymphoma initiation remains to be clarified. Therefore, to elucidate the lymphomagenic potential of MYD88L265P we generated conditional transgenic mice overexpressing human wild-type (hMYD88WT) or mutant (hMYD88L265P) proteins in activated B-cells. Although abundance of both proteins and p65 NF-κB nuclear translocation was increased in transgenic GC B- cells, we observed that: (i) the MYD88L265P protein differed from the MYD88WT in its stability, ease of aggregation, and downstream activity; (ii) hMYD88WT did not produce detectable phenotypic alterations, but hMYD88L265P promoted with high frequency and long latency, a non-clonal, low-grade B-cell lymphoproliferative disorder resembling human LPL, which occasionally underwent transformation to ABC-DLBCL, suggesting that MYD88L265P is insufficient by itself to drive neoplastic transformation of mature B-cells, and that secondary cooperating genetic alterations are needed. In line with our findings, introduction of MYD88L265P into primary B- cells was recently shown to induce negative feedback mechanisms mediated by TNFAIP3, a negative regulator of NF-κB pathway residing on Chr6q, along with other important tumor suppressors. Notably, Chr6q deletions are observed in almost half of LPL cases with small somatic deletions present in up to 80% of patients with MYD88L265Pmutation and in ABC-DLBCL. Importantly, Chr6q losses are not detected in human MYD88WT LPL patients, indicating that repression of 6q-related signaling is a critical pathogenetic step specifically in MYD88L265P-induced LPL. These results indicate that MYD88L265P possesses unique biochemical and functional properties, and suggest that the hMYD88WT and hMYD88L265P transgenic mice constitute an ideal model system in which to investigate these properties, as well as the secondary cooperating genetic alterations that are necessary to fully develop a clonal LPL phenotype and its eventual progression to ABC-DLBCL. Here we propose to investigate the role of the MYD88L265P mutation, Chr6q deletion (Chr10q in mice) as well as other LPL- associated loss-of-function gene mutations in B-cell development and function as well as the pathogenesis of LPL and ABC-DLBCL, and to develop a preclinical mouse models of LPL and ABC-DLBCL for testing therapies.

项目摘要 B细胞型非霍奇金淋巴瘤(NHL)是一种异质性淋巴系统恶性肿瘤。 全球最常见的癌症，约占所有癌症的4%。非霍奇金淋巴瘤发病率急剧上升 在过去的几十年里，全世界都在进行密集的研究工作，以了解它们的发病机制。 基因组学研究已经在NHL中发现了许多新的基因组改变，但这些改变仍然是功能上的 经过验证和表征。其中最常见的基因组变化是错义突变， 导致MYD88(MYD88L265P)第265位亮氨酸到脯氨酸的替换，MYD88L265P是一种激活连接蛋白 致癌的NF-κB信号转导。MYD88L265P突变在淋巴浆细胞性淋巴瘤中异常常见 弥漫性大B细胞淋巴瘤(ABC-DLBCL)。而对MYD88L265P的抑制 对LPL和ABC-DLBCL细胞的存活产生不利影响，其在淋巴瘤发生中的作用尚不清楚 澄清了。因此，为了阐明MYD88L265P的致淋巴性，我们建立了条件转基因 在激活的B细胞中过表达人类野生型(HMYD88WT)或突变(HMYD88L265P)蛋白的小鼠。 尽管在转基因GC B中，蛋白质和p65 NF-κB核转位的丰度都增加了。 细胞中，我们观察到：(1)MYD88L265P蛋白与MYD88WT蛋白在稳定性、易聚集性、 和下游活性；(Ii)hMYD88WT没有产生可检测到的表型变化，但hMYD88L265P 一种高频率、长潜伏期的非克隆性、低级别B细胞淋巴增生性疾病 与人类LPL相似，偶尔会转化为ABC-DLBCL，表明 MYD88L265P本身不足以推动成熟B细胞的肿瘤性转化，而且继发性 合作进行基因改造是必要的。根据我们的研究结果，将MYD88L265P引入小学B- 最近研究表明，细胞可以通过负调节因子TNFAIP3诱导负反馈机制 与其他重要的肿瘤抑制因子一起存在于KrA-κB途径上。值得注意的是，Chr6q基因的缺失 在几乎一半的LPL病例中观察到，在高达80%的LPL患者中存在微小的体细胞缺失 MYD88L265位点突变和ABC-DLBCL。重要的是，在人类MYD88WT LPL中没有检测到Chr6q丢失 患者，表明抑制6q相关信号是一个关键的致病步骤，特别是在 MYD88L265P诱导的LPL。这些结果表明，MYD88L265P具有独特的生化和功能 HMYD88WT和hMYD88L265P转基因小鼠构成了理想的模型系统 来研究这些特性，以及第二次协同作用的基因改变 完全发育成克隆性LPL表型并最终发展为ABC-DLBCL所必需的。在这里，我们建议 为了研究MYD88L265P突变、chr6q缺失(在小鼠中为chr10q)以及其他LPL-1基因的作用。 B细胞发育和功能相关的功能丧失基因突变及其发病机制 LPL和ABC-DLBCL，并建立临床前LPL和ABC-DLBCL小鼠模型，为临床治疗提供实验依据。