The role of the SF3B1 splicing factor in chronic lymphocytic leukemia

SF3B1剪接因子在慢性淋巴细胞白血病中的作用

• 批准号: 8417317
• 负责人: Catherine Ju-Ying Wu
• 金额: $ 41.38万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8417317
• 关键词: ATM gene; Adult; Affect; Alleles; Automobile Driving; B Cell Proliferation; B-Lymphocytes; Biology; CD19 gene; Catalytic Domain; Cell Cycle; Cell Line; Cell Lineage; Cell Survival; Cell physiology; Cells; Cellular biology; Chromosome abnormality; Chronic Lymphocytic Leukemia; Clinical; Collaborations; Complement; DNA Damage; DNA Repair; DNA Sequence; Data; Development; Disease; Dysmyelopoietic Syndromes; Employee Strikes; Event; Frequencies; Gene Expression Profile; Gene Targeting; Generations; Genes; Genetic; Hematologic Neoplasms; Hematopoietic Neoplasms; Heterogeneity; Human; Indolent; Infection; Inflammation; Introns; Investigation; Kinetics; Knock-in Mouse; Knock-out; Knowledge; Large-Scale Sequencing; Length; Link; Malignant Neoplasms; Mediating; Messenger RNA; Methods; Modeling; Molecular; Monitor; Mouse Strains; Mus; Mutate; Mutation; Nucleic Acids; Oncogenes; Oncogenic; Organ; PTPRC gene; Pathogenesis; Pathway interactions; Patients; Pattern; Physical Chemistry; Process; Prognostic Factor; Prognostic Marker; Proteins; RNA; RNA Sequences; RNA Splicing; RNA-Protein Interaction; Recurrence; Resistance; Role; Sampling; Signal Transduction; Silent Mutation; Spliceosomes; System; Technology; Testing; Transgenic Organisms; U2 Small Nuclear Ribonucleoprotein; Variant; aggressive therapy; base; cell behavior; chromosome 13q loss; deep sequencing; del(11q); exome sequencing; genetic manipulation; improved; in vivo; inhibitor/antagonist; insight; leukemia; leukemogenesis; mRNA Precursor; mouse model; mutant; new therapeutic target; notch protein; novel; outcome forecast; protein complex; protein protein interaction; public health relevance; repository; response; tool; transcriptome sequencing

DESCRIPTION (provided by applicant): Through large-scale DNA sequencing, we recently identified the core spliceosome factor, SF3B1, as a novel cancer gene in chronic lymphocytic leukemia (CLL). SF3B1 functions in the catalytic core of the U2 small nuclear ribonucleoprotein (U2 snRNP), an essential RNA-protein complex involved in pre-mRNA splicing. Several features of this new cancer gene make it a high priority for investigation. First, SF3B1 is mutated at a high frequency in CLL, with all mutations localizing to a discrete gene region, and with half recurrent at K700E. Second, mutation in SF3B1 is significantly associated with del(11q), a cytogenetic abnormality associated with aggressive disease, and yet, is an independent predictive marker of poor prognosis. Third, CLL samples with SF3B1 mutation demonstrate altered pre-mRNA splicing in known spliceosome target genes compared to samples with wildtype SF3B1. Finally, SF3B1-K700E was recently identified as a recurring mutation in myelodysplasia. Mutations in SF3B1 and modulation of RNA splicing are likely to represent a novel oncogenic process across hematologic malignancies and preferentially in aggressive forms of CLL. Our hypothesis is that mutated SF3B1 generates mis-spliced pre-mRNAs, encoding proteins that promote leukemogenesis. Our strategy for functionally linking SF3B1 mutation and CLL pathogenesis is to first define the effects of SF3B1 mutation on survival and proliferation of B cells, and on other pathways that we recently identified as critical to CLL (inflammation, Notch1 and Wnt signaling, DNA damage/repair) (Aim 1). Second, we will identify the mechanism by which these changes in cellular function are mediated (Aim 2). Since SF3B1 is essential for RNA splicing, we will examine the effects of SF3B1 mutation on critical protein-protein and protein-RNA interactions within the spliceosome, and use RNA sequencing to globally identify the novel splice variants generated by SF3B1 mutation. Understanding of the critical cellular processes affected by SF3B1 mutation (per Aim 1) will prioritize the candidate splice variants to be functionally validated as crucial to promoting CLL. Because SF3B1 mutation appears to function in a cell lineage specific context, we will carry out all studies in B cell lines or primary normal B cells; into which mutated or wildtype SF3B1 is introduced using novel biomolecule delivery or infection methods that our group has pioneered. Additionally, we will validate our findings using CLL samples naturally harboring SF3B1 mutations. Third, to definitively establish the role of SF3B1 mutation in driving CLL, we are generating a transgenic conditional knock-in SF3B1-K700E mouse (Aim 3). We will examine these mice for in vivo evidence of lymphohematopoietic accumulation of clonal B cells when SF3B1-K700E expression is restricted to CD19+ B cells alone or in combination with other CLL-generating genetic alterations. The proposed studies are anticipated to provide critical insights into a novel splicing mechanism underlying CLL (with implications for other blood cancers) that are expected to contribute to improved strategies to treat this incurable disease, especially given the development of spliceosome inhibitors.

描述（由申请人提供）：通过大规模的DNA测序，我们最近将核心剪接体因子SF3B1确定为慢性淋巴细胞性白血病（CLL）中的一种新型癌症基因。 SF3B1在U2小核核糖核蛋白（U2 SNRNP）的催化核中起作用，这是一种参与MRNA剪接的必需RNA蛋白复合物。这个新的癌症基因的几个特征使其成为研究的高度优先级。首先，SF3B1在CLL中以高频突变，所有突变都定位于离散基因区域，并且在K700E时复发一半。其次，SF3B1中的突变与DEL（11q）显着相关，DEL（11q）是一种与侵袭性疾病相关的细胞遗传学异常，但是预后不良的独立预测标志。第三，与Wildtype SF3B1的样品相比，具有SF3B1突变的CLL样品在已知的剪接体靶基因中显示出MRNA剪接的改变。最后，最近将SF3B1-K700E鉴定为骨髓增生性突变。 SF3B1中的突变和RNA剪接的调节可能代表了血液系统恶性肿瘤的新型致癌过程，并优先以侵略性的CLL形式。我们的假设是突变的SF3B1会产生错误的pre pre mRNA，编码促进白血病发生的蛋白质。我们在功能上连接SF3B1突变和CLL发病机理的策略首先定义SF3B1突变对B细胞存活和B细胞增殖的影响，以及我们最近确定为CLL至关重要的其他途径（炎症，Notch1和Wnt Nntch1和Wnt信号，DNA信号，DNA损害/修复）（AIM 1）。其次，我们将确定细胞功能中介导的这些变化的机制（AIM 2）。由于SF3B1对于RNA剪接是必不可少的，因此我们将研究SF3B1突变对剪接体内临界蛋白 - 蛋白质和蛋白RNA相互作用的影响，并使用RNA测序在全球范围内识别由SF3B1突变产生的新型剪接变体。了解受SF3B1突变影响的临界细胞过程（每个目标1）将优先考虑候选剪接变体，该变体在功能上对促进CLL至关重要。由于SF3B1突变似乎在细胞谱系特定的环境中起作用，因此我们将在B中进行所有研究 细胞系或原发性B细胞；使用我们小组已经开创的新型生物分子递送或感染方法引入突变或野生型SF3B1。此外，我们将使用自然含有SF3B1突变的CLL样品来验证我们的发现。第三，为了确定建立SF3B1突变在驾驶CLL中的作用，我们正在生成转基因条件敲击SF3B1-K700E小鼠（AIM 3）。当SF3B1-K700E表达仅限于CD19+ B细胞或与其他CLL生成的遗传改变时，我们将检查这些小鼠的体内证据表明克隆B细胞的淋巴细胞体积累。预计拟议的研究将为新颖的研究提供关键的见解 CLL的剪接机制（对其他血液癌的影响）预计将有助于改善治疗这种无法治愈的疾病的策略，尤其是考虑到剪接体抑制剂的发展。