Cooperation of SF3B1 mutations and ATM deletions in the pathogenesis of chronic lymphocytic leukemia

项目摘要 世界范围内的测序工作已经确定了与疾病相关的复发性新遗传病变 进展，推断的共同共同出现的模式，以及响应于 慢性淋巴细胞白血病的治疗尽管有丰富的可用遗传信息，这些分析 都依赖于统计推断，因此限制了将基因型与表型联系起来的可能性。目前， 了解高频遗传病变的功能以及它们如何与它们的共同发生 导致CLL起始和进展的突变不可用。在本提案中，我们旨在了解如何 CLL中两种最常见的遗传性病变（SF 3B 1突变和ATM缺失）在机制上影响 CLL启动和进展，总体目标是了解CLL生物学，产生新的鼠 模型，并找到治疗这些病变的CLL的新策略。 该建议基于我们的发现，突变的Sf 3b 1与Atm缺失的共表达导致了 在低表达率下，在血液、骨髓和脾脏中克隆特异性CD 19 + CD 5 + B细胞的发育， 老龄（18个月）小鼠，其可通过体内传代繁殖。有趣的是，全基因组测序 来自小鼠CLL的DNA显示了反复的染色体扩增，表明染色体不稳定性， 在具有Sf 3b 1突变和Atm缺失的小鼠中促成CLL的机制。我们现建议 研究SF 3B 1突变通过RNA剪接相关的R- 环的形成，而ATM缺失通过减少R-环相关的 DNA损伤修复（Aim 1）。我们进一步假设R环形成的调节有助于 CLL的加速度（目标2）。因此，靶向RNA剪接和DNA损伤反应检查点是 可能为具有这些病变的CLL提供合成的细胞毒性（目的3）。完成拟议工作将 创建一个基本的基础来解释剪接因子突变如何影响基因组的不稳定性， 有助于肿瘤发生，并为在SF 3B 1和CLL患者中设计新型临床试验提供理论基础。 突变和ATM缺失。

Project Summary World-wide sequencing efforts have identified recurrent novel genetic lesions associated with disease progression, inferred patterns of common co-occurrence, and characterized clonal evolution in response to treatments in chronic lymphocytic leukemia. Despite the wealth of available genetic information, these analyses all rely on statistical inference, thus limiting the possibility to link the genotype to the phenotype. Currently, understanding functions of high frequency genetic lesions and how they cooperate with their co-occurring mutations to cause CLL initiation and progression are not available. In this proposal, we aim to understand how two of the most recurrent genetic lesions in CLL (SF3B1 mutations and ATM deletions) mechanistically impact CLL initiation and progression with the overarching goal to understand CLL biology, generate novel murine model, and find new strategies for treating CLL with these lesions. This proposal is based on our finding that co-expression of mutated Sf3b1 with Atm deletion resulted in the development of clonal pathognomonic CD19+CD5+ B cells in blood, marrow and spleen at low penetrance in aged (18 months) mice, that can be propagated by in vivo passaging. Interestingly, whole-genome sequencing of DNA from murine CLL revealed recurrent chromosome amplifications, suggesting chromosome instability as a mechanism contributing to CLL in the mice with Sf3b1 mutation and Atm deletion. We now propose to investigate the hypothesis that SF3B1 mutations promote genomic instability through RNA splicing related R- loop formation while ATM deletion further augment genomic instability through decreasing R-loop associated DNA damage repair (Aim 1). We further hypothesize that modulation of the R-loop formation is contributing to the acceleration of CLL (Aim 2). Thus, targeting both RNA splicing and DNA damage response checkpoints are likely to provide synthetic cytotoxicity for CLLs with these lesions (Aim 3). Completion of the proposed work will create a fundamental foundation to explain how splicing factor mutations impact genomic instability and contribute to oncogenesis, and provide rationale for designing novel clinical trials in CLL patients with both SF3B1 mutations and ATM deletions.