Role of BCL11B in lineage ambiguous leukemia

BCL11B 在谱系不明性白血病中的作用

基本信息

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
项目类别：
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

项目摘要

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.

项目概要谱系不明确的急性白血病 (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骨髓和 T 淋巴谱系相关的标记物，这使选择变得复杂的治疗。此外，ALAL 的基因组、分子和细胞基础仍然模糊，阻碍了我们的能力以确定更相关和量身定制的治疗策略。我最近发现了一个新的基因组改变特定于 T/骨髓 MPAL 和 ETP-ALL 病例的子集，即非编码结构变异异常激活非 T 谱系细胞中的 T 细胞转录因子基因 BCL11B。其中大部分病例 (81%) 存在 FLT3 酪氨酸激酶激活突变（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。我的初步数据表明异位 BCL11B 表达足以驱动胸腺外池中表型 T 细胞的形成人类 CD34+ 造血干细胞和祖细胞 (HSPC)。然而，HSPC 是一种高度异质的具有不同干细胞能力和谱系定型程度的细胞群，并且它仍然未知某个亚群是否最容易发生 BCL11B 诱导的谱系偏差，或者如何发生 BCL11B转录活性破坏不同的HSPC基因调控程序，导致谱系模糊表型。该提案的目标是定义异位 BCL11B 表达的机制破坏造血分化以驱动 ALAL 的发育。为了实现这一目标，目标 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 BCL11B/FLT3-ITD 驱动谱系倾斜的能力。目标 2 将补充这种基于细胞表型的测定使用单细胞 RNA-seq 来识别伴随变化的基因表达变化谱不同来源细胞的分化潜力和谱系偏向。我也会使用急性蛋白质降解识别直接 BCL11B 靶基因的技术，这些基因将为 BCL11B 控制的转录网络提供信息我将在未来的独立研究中进行调查。总的来说，这些实验将阐明确定致癌 BCL11B 活性的起源细胞并识别 BCL11B 控制的转录网络。在独立阶段（目标3），我将研究BCL11B致癌活性的分子机制提名新的治疗靶点。我将首先通过识别 BCL11B 如何改变染色质调控来研究染色质状态和转录因子占用的变化。然后我将使用新的鼠标模型来筛选表观遗传调控因子对 BCL11B 致癌活性至关重要。这些目标代表了阐明 ALAL 的细胞和分子基础，将为我提供新知识、技术专长、并合作建立一个以高危白血病基因调控为中心的研究计划。