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细胞类型的非霍奇金淋巴瘤（NHLS）是一种异源性淋巴性恶性肿瘤，是 全球最常见的癌症，约占所有癌症的4％。 NHL的发生率急剧上升 在过去的几十年中，全球引发了强烈的研究工作，以了解其发病机理。 基因组学研究发现了NHL中许多新的基因组改变，但在功能上仍然是 经过验证和表征。在基因组改变中最常见的是一个错义突变， 在MyD88（MyD88L265p）中的位置265的亮氨酸替代的结果，这是一种激活的衔接蛋白 致癌NF-κB信号传导。 MYD88L265P突变在淋巴质淋巴瘤中异常频繁 （LPL）和活化的B细胞类型的弥漫性大B细胞淋巴瘤（ABC-DLBCL）。虽然抑制MyD88L265p 不利影响LPL和ABC-DLBCL细胞的存活率，其在淋巴瘤倡议中的作用仍然是 澄清。因此，为了阐明MyD88L265p的淋巴细胞势，我们产生了条件转基因 过表达人类野生型（HMYD88WT）或突变体（HMYD88L265P）蛋白的小鼠在活化的B细胞中。 尽管转基因GC B-的蛋白质和p65 NF-κB核转运的抽象增加了 细胞，我们观察到：（i）MyD88L265p蛋白不同于MyD88WT的稳定性，易于聚集， 和下游活动； （ii）HMYD88WT没有产生可检测的表型变化，而是HMYD88L265P 以高频率和长潜伏期促进，是一种非连锁的低级B细胞淋巴结增生剂 类似于人类LPL，偶尔会转换为ABC-DLBCL，这表明 MyD88L265p本身不足以驱动成熟B细胞的肿瘤转化，而该次要 需要进行遗传改变。根据我们的发现，将MYD88L265P引入主要B- 最近显示细胞诱导由TNFAIP3介导的负反馈机制，TNFAIP3是负调节剂 位于CHR6Q上的NF-κB途径以及其他重要的肿瘤补充剂。值得注意的是，CHR6Q删除 在几乎一半 myd88l265pmmon和abc-dlbcl。重要的是，在人MyD88WT LPL中未检测到CHR6Q损失 患者，表明与6Q相关信号的表达是专门在 MYD88L265P引起的LPL。这些结果表明MYD88L265P具有独特的生化和功能性 属性，并建议HMYD88WT和HMYD88L265P转基因小鼠构成理想的模型系统 在其中研究这些特性以及二次合作的遗传改变是 完全开发克隆LPL表型及其最终发展为ABC-DLBCL所必需的。我们在这里提出 为了研究MyD88L265p突变的作用，CHR6Q缺失（小鼠中的CHR10Q）以及其他LPL- B细胞发育和功能中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。