Role of BCL11B in lineage ambiguous leukemia

BCL11B 在谱系不明性白血病中的作用

• 批准号: 10807886
• 负责人: Lindsey Montefiori
• 金额: $ 13.62万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-20 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10807886
• 关键词: Acute; Acute Lymphocytic Leukemia; Acute leukemia; Binding; Biological; Biological Assay; CD34 gene; CRISPR/Cas technology; Cell Lineage; Cells; Child; Chromatin; Clinical; Code; Collaborations; Complement; Coupled; DNA Sequence Alteration; Data; Development; Diagnostic; Disease; Dissection; Early identification; Enhancers; Epigenetic Process; Exhibits; Experimental Models; FLT3 gene; Face; Frequencies; Future; Gene Expression; Gene Expression Alteration; Gene Expression Profile; Gene Expression Regulation; Genes; Genetic Transcription; Genomics; Goals; Hematopoietic; Hematopoietic stem cells; Human; Immunophenotyping; In Vitro; Knock-out; Knowledge; Lymphoid; Malignant Childhood Neoplasm; Molecular; Mutate; Mutation; Myelogenous; Myeloid Cells; Oncogenes; Oncogenic; Output; Pathway interactions; Phase; Phenotype; Population; Population Heterogeneity; Protein Tyrosine Kinase; Proteins; Receptor Protein-Tyrosine Kinases; Regulation; Regulator Genes; Research; Role; T-Cell Activation; T-Lymphocyte; Technical Expertise; Techniques; Technology; Therapeutic; Thymus Gland; Training; Treatment Failure; Tumor Suppressor Proteins; Untranslated RNA; Variant; Viral; Work; cell stroma; cell type; disorder risk; experimental study; fusion gene; gene regulatory network; hematopoietic differentiation; high risk; innovation; leukemia; leukemic transformation; mRNA sequencing; mouse model; new therapeutic target; permissiveness; post-doctoral training; pre-doctoral; progenitor; programs; protein degradation; protein expression; self-renewal; single-cell RNA sequencing; stem; stem cells; stemness; targeted treatment; transcription factor; treatment strategy

PROJECT SUMMARY Acute leukemias of ambiguous lineage (ALAL) are high-risk leukemia subtypes and include mixed phenotype acute leukemia (MPAL) and early T cell precursor acute lymphoblastic leukemia (ETP-ALL). These leukemias commonly express markers associated with both the myeloid and T lymphoid lineages which complicates choice of therapy. Moreover, the genomic, molecular, and cellular basis of ALAL remains obscure and hinders our ability to identify more relevant and tailored therapeutic strategies. I recently discovered a new genomic alteration that is specific to a subset of T/myeloid MPAL and ETP-ALL cases, namely noncoding structural variations that aberrantly activate the T cell transcription factor gene BCL11B in a non-T lineage cell of origin. Most of these cases (81%) harbored activating mutations (e.g. internal tandem duplication, ITD) in the FLT3 tyrosine kinase receptor gene, suggesting functional cooperation between these alterations. This discovery enables faithful experimental modeling of the earliest stages of ALAL development. My preliminary data demonstrated that ectopic BCL11B expression is sufficient to drive formation of phenotypic T cells from a pool of extra-thymic human CD34+ hematopoietic stem and progenitor cells (HSPCs). However, HSPCs are a highly heterogeneous population of cells with different stemness capacities and degrees of lineage commitment, and it remains unknown whether a certain subpopulation is most permissive to BCL11B-induced lineage skewing or how BCL11B transcriptional activity disrupts different HSPC gene regulatory programs to drive the lineage ambiguous phenotype. The goal of this proposal is to define the mechanisms by which ectopic BCL11B expression corrupts hematopoietic differentiation to drive development of ALAL. To accomplish this, Aim 1 will use a single cell in vitro differentiation assay to determine how the developmental state of the cell of origin impacts the ability of BCL11B/FLT3-ITD to drive lineage skewing. Aim 2 will complement this cell phenotype-based assay with single cell RNA-seq to identify the spectrum of gene expression changes that accompany changes in differentiation potential and lineage skewing of different cells of origin. I will also use acute protein degradation techniques to identify direct BCL11B target genes which will inform on BCL11B-controlled transcription networks that I will investigate in my future independent research. Collectively, these experiments will clarify the role of the cell of origin in dictating oncogenic BCL11B activity and identify BCL11B-controlled transcription networks. In the independent phase (Aim 3), I will investigate the molecular mechanism of BCL11B oncogenic activity to nominate new therapeutic targets. I will first investigate how BCL11B alters chromatin regulation by identifying changes in chromatin state and transcription factor occupancy. I will then use a new mouse model to screen for epigenetic regulators critical for oncogenic BCL11B activity. These aims represent the first steps in elucidating the cellular and molecular underpinnings of ALAL and will equip me with new knowledge, technical expertise, and collaborations to establish a research program centered on the gene regulatory control of high-risk leukemia.

项目摘要 谱系不清的急性白血病（ALAL）是高危白血病亚型，包括混合表型 急性白血病（MPAL）和早期T细胞前体急性淋巴细胞白血病（ETP-ALL）。这些白血病 通常表达与髓系和T淋巴系相关的标记物，这使得选择复杂化 心理治疗此外，ALAL的基因组、分子和细胞基础仍然不清楚，阻碍了我们研究ALAL的能力。 以确定更相关和定制的治疗策略。我最近发现了一个新的基因组变异， 特异于T/髓系MPAL和ETP-ALL病例的一个子集，即非编码结构变异， 异常激活非T谱系细胞来源的T细胞转录因子基因BCL 11 B。大多数这些 例（81%）在FLT 3酪氨酸激酶中存在激活突变（例如内部串联重复，ITD） 受体基因，表明这些改变之间的功能合作。这一发现使忠实的 ALAL发展最早阶段的实验模型。我的初步数据显示， 异位BCL 11B表达足以驱动胸腺外T细胞库形成表型T细胞。 人CD 34+造血干细胞和祖细胞（HSPC）。然而，HSPC是高度异质的， 具有不同的干细胞能力和谱系承诺程度的细胞群体，并且它仍然存在 不知道某个亚群是否最允许BCL 11B诱导的谱系偏斜或如何 BCL 11B转录活性破坏不同的HSPC基因调控程序，以驱动谱系模糊 表型本研究的目的是明确异位BCL 11 B表达的机制， 破坏造血分化以驱动ALAL的发展。为了实现这一点，Aim 1将使用 单细胞体外分化测定，以确定起源细胞的发育状态如何影响细胞的分化。 BCL 11B/FLT 3-ITD驱动谱系偏斜的能力。Aim 2将补充这种基于细胞表型的检测 用单细胞RNA-seq来鉴定伴随着基因表达变化的基因表达谱， 分化潜力和不同起源细胞的谱系偏斜。我还会用急性蛋白质降解 鉴定直接BCL 11B靶基因的技术，这些基因将在BCL 11B控制的转录网络中提供信息 我将在未来的独立研究中进行调查。总的来说，这些实验将阐明 在决定致癌BCL 11B活性和鉴定BCL 11B控制的转录网络中的起源细胞。 在独立阶段（目标3），我将研究BCL 11 B致癌活性的分子机制， 提名新的治疗靶点。我将首先研究BCL 11B如何改变染色质调节， 染色质状态和转录因子占有率的变化。然后，我将使用新的鼠标模型来筛选 表观遗传调节因子对致癌BCL 11B活性至关重要。这些目标代表了阐明 ALAL的细胞和分子基础，并将为我提供新的知识，技术专长， 并合作建立以高危白血病基因调控为中心的研究项目。