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: 10501718
• 负责人: RUBEN D CARRASCO
• 金额: $ 43.37万
• 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/10501718
• 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; Genomics; Hematologic Neoplasms; Hematopoietic stem cells; Human; Immunocompetent; Immunotherapy; Incidence; Indolent; Lead; 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; 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 Genes; Tumor Suppressor Proteins; Waldenstrom Macroglobulinemia; Work; base; cell type; clinically relevant; cohort; 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）是一组异质性淋巴恶性肿瘤， 是全球最常见的癌症，约占所有癌症的4%。NHL发病率急剧上升 在过去的几十年里，世界范围内的疾病引发了深入的研究工作，以了解其发病机制。 基因组学研究已经发现了许多新的NHL基因组改变，但这些改变仍然是功能性的。 验证和表征。其中最常见的基因组改变是错义突变， 导致MYD 88（MYD 88 L265 P）中第265位的亮氨酸取代为脯氨酸，MYD 88是一种激活 致癌NF-κB信号传导。MYD 88 L265 P突变在淋巴浆细胞性淋巴瘤中异常常见 (LPL)和活化B细胞型弥漫性大B细胞淋巴瘤（ABC-DLBCL）。而MYD 88 L265 P的抑制 不利地影响LPL和ABC-DLBCL细胞的存活，其在淋巴瘤起始中的作用仍有待进一步研究。 明确了因此，为了阐明MYD 88 L265 P的淋巴瘤发生潜力，我们产生了条件性转基因MYD 88 L265 P。 在活化的B细胞中过表达人野生型（hMYD 88 WT）或突变体（hMYD 88 L265 P）蛋白的小鼠。 虽然转基因GC B-1细胞中这两种蛋白的丰度和p65 NF-κB核转位的丰度都增加了，但在转基因GC B-1细胞中，p65 NF-κB核转位的丰度和p65 NF-κB核转位的丰度都增加了，而在转基因GC B-1细胞中，p65 NF-κ B核转位的丰度和p65 NF-κB核转位的丰度都增加了。 我们观察到：（i）MYD 88 L265 P蛋白在其稳定性，易于聚集， （ii）hMYD 88 WT不产生可检测的表型改变，但hMYD 88 L265 P 以高频率和长潜伏期促进，一种非克隆性、低度B细胞淋巴增生性疾病 类似于人LPL，其偶尔经历向ABC-DLBCL的转化，这表明， MYD 88 L265 P本身不足以驱动成熟B细胞的肿瘤转化，并且其继发性肿瘤转化是不可能的。 需要进行基因改造。与我们的发现一致，将MYD 88 L265 P引入原代B- 细胞最近显示出诱导由TNFAIP 3介导的负反馈机制，TNFAIP 3是一种负调节因子 NF-κB通路位于Chr 6 q上，沿着与其他重要的肿瘤抑制因子。值得注意的是，Chr 6 q缺失 在几乎一半的LPL病例中观察到，高达80%的LPL患者存在小的体细胞缺失， MYD 88 L265 P突变和ABC-DLBCL。重要的是，在人MYD 88 WT LPL中未检测到Chr 6 q丢失 患者，表明6 q相关信号的抑制是一个关键的发病步骤，特别是在 MYD 88 L265 P诱导的LPL。这些结果表明MYD 88 L265 P具有独特的生化和功能 hMYD 88 L265 P和hMYD 88 WT转基因小鼠是一种理想的转基因小鼠模型 研究这些特性，以及次要的协同遗传改变， 这是完全发展克隆LPL表型及其最终进展为ABC-DLBCL所必需的。在这里我们建议 研究MYD 88 L265 P突变、Chr 6 q缺失（小鼠中为Chr 10 q）以及其他LPL- B细胞发育和功能相关的功能丧失基因突变以及 LPL和ABC-DLBCL，并开发用于测试疗法的LPL和ABC-DLBCL的临床前小鼠模型。