Regulation of FLT3 Signaling in Leukemia

白血病中 FLT3 信号传导的调节

基本信息

批准号：
10718337
负责人：
Wei Tong
金额：
$ 65.63万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
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：
2023-09-01 至 2028-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10718337
关键词：
Acute Myelocytic Leukemia Acyltransferase Binding Biology Breeding Cell Line Cell membrane Chemicals Collaborations Cysteine DNMT3a Disease Endoplasmic Reticulum Enzymes Equilibrium FLT3 gene Genetic Goals Grant Growth Hematopoiesis Hematopoietic stem cells Human Impairment Knock-in Mouse Leukemic Cell Ligands Lipids MAP Kinase Gene Malignant - descriptor Mediating Minor Minority Modeling Modification Molecular Molecular Biology Mus Mutate Mutation Myeloproliferative disease Oncogenic Outcome PI3K/AKT PIK3CG gene Pathway interactions Patients Pharmacology Study Phosphorylation Physiological Post-Translational Protein Processing Prognosis Proliferating Protein Tyrosine Kinase Proteins Proteomics Proto-Oncogene Proteins c-akt Receptor Protein-Tyrosine Kinases Regulation Relapse Role Signal Pathway Signal Transduction Signaling Protein Spatial Distribution Stat5 protein Surface Therapeutic Tyrosine Kinase Inhibitor Ubiquitination Work Xenograft Model Xenograft procedure acute myeloid leukemia cell cell growth clinically relevant clinically significant combinatorial genetic approach in vivo in vivo Model inhibitor innovation insight leukemia leukemogenesis mouse model mutant new therapeutic target novel novel therapeutic intervention novel therapeutics palmitoylation pharmacologic response synergism targeted treatment

项目摘要

Summary The temporal and spatial distribution of signaling proteins is dynamically regulated by post-translational modifications (PTMs). PTMs such as phosphorylation, ubiquitination, or lipid modification dictate protein activities and access to substrates, thereby cellular outcomes. The precise control of signaling pathways is critical to normal hematopoiesis and aberrant signaling leads to malignant transformation of hematopoietic stem and progenitor cells (HSPCs). This application is based on our novel finding that FLT3 (FMS-like tyrosine kinase 3) is palmitoylated and disrupting palmitoylation of oncogenic FLT3 mutants changes their subcellular localization, rewires downstream signaling, and promotes leukemic progression. Internal tandem duplication within FLT3 (FLT3-ITD) is one of the most frequent mutations in acute myeloid leukemia (AML) and correlates with poor prognosis. While wildtype FLT3 receptor tyrosine kinase is activated at the plasma membrane to transduce PI3K/AKT and RAS/MAPK signaling, FLT3-ITD resides in the endoplasmic reticulum (ER) and triggers constitutive STAT5 phosphorylation. Mechanisms underlying this aberrant FLT3-ITD subcellular localization or its impact on leukemogenesis remain poorly understood. We discovered that FLT3-ITD is S-palmitoylated by the ZDHHC6 acyltransferase. Disruption of palmitoylation redirects FLT3-ITD to the plasma membrane and rewires its downstream signaling by activating AKT and ERK pathways in addition to STAT5. Consequently, abrogation of FLT3-ITD palmitoylation via ZDHHC6 depletion promotes FLT3-ITD surface expression, signaling, and increased leukemic progression in xenotransplanted mouse models. Furthermore, we demonstrate that FLT3 proteins are palmitoylated in primary human AML cells. Stabilization of FLT3-ITD palmitoylation by pharmacological inhibition of depalmitoylation synergizes with FLT3 tyrosine kinase inhibitor (TKI) gilteritinib in abrogating the growth of primary FLT3-ITD+ AML cells. The central goal of this grant is to define the molecular basis underlying the regulation of oncogenic FLT3 signaling by palmitoylation and explore its physiological and functional significance in myeloid malignancies. We propose to define roles of ZDHHC6 in FLT3-ITD palmitoylation in vivo in mouse models of myeloproliferative neoplasm (MPN) and AML. We will also identify depalmitoylase(s) for FLT3-ITD that modify FLT3-ITD localization, and activity using combinatorial approaches of targeted and unbiased chemical biology, molecular biology, and genetics. Moreover, we will explore the therapeutic potential of targeting FLT3-ITD depalmitoylation in primary human FLT3-ITD+ AMLs. We will investigate if inhibition of FLT3-ITD depalmitoylase enhances responses to TKI using primary human AML cells as well as patient-derived xenotransplant (PDX) models. These findings provide novel insights into lipid- dependent compartmentalization of FLT3-ITD signaling and suggest targeting depalmitoylation as a new therapeutic strategy to treat FLT3-ITD+ leukemias.

概括信号蛋白的时间和空间分布受翻译后动态调节修改（PTMS）。 PTM，例如磷酸化，泛素化或脂质修饰决定了蛋白质活性并访问底物，从而获得细胞结局。信号通路的精确控制对正常造血和异常信号传导导致造血茎的恶性转化和祖细胞（HSPC）。该应用是基于我们的新发现，即FLT3（FMS样酪氨酸激酶3）被棕榈酰化并破坏致癌的FLT3突变体的棕榈酰化改变了其亚细胞定位，重新布线下游信号传导，并促进白血病进展。 FLT3中的内部串联重复（FLT3-ITD）是急性髓样白血病（AML）中最常见的突变之一，并且与较差预后。而野生型FLT3受体酪氨酸激酶在质膜上激活以传播 PI3K/AKT和RAS/MAPK信号传导，FLT3-ITD位于内质网（ER）和触发器中组成型STAT5磷酸化。这种异常FLT3-ITD亚细胞定位或它对白血病的影响仍然鲜为人知。我们发现flt3-itd是由 ZDHHC6酰基转移酶。棕榈酰化的破坏将FLT3-ITD重定向到质膜和重新布置除STAT5外，通过激活AKT和ERK途径来下游信号传导。因此，废除通过ZDHHC6耗竭的FLT3-ITD棕榈酰化促进FLT3-ITD表面表达，信号传导和异种移植小鼠模型中的白血病进展增加。此外，我们证明了flt3 蛋白质在原代人AML细胞中被棕榈酰。稳定FLT3-ITD棕榈酰化对Depalmitoylation的药理抑制与FLT3酪氨酸激酶抑制剂（TKI）吉尔特替尼在废除原代FLT3-ITD+ AML细胞的生长。该赠款的核心目标是定义分子通过棕榈酰化来调节致癌FLT3信号的基础，并探索其生理和髓样恶性肿瘤的功能意义。我们建议定义ZDHHC6在flt3-itd中的角色骨髓增生性肿瘤（MPN）和AML的小鼠模型中的体内棕榈酰化。我们还将确定用于修改FLT3-ITD定位的FLT3-ITD的deplmitoylase（S），并使用组合方法的活动靶向和无偏的化学生物学，分子生物学和遗传学。而且，我们将探索靶向原代人FLT3-ITD+ AML中靶向FLT3-ITD去氨酰二酰化的治疗潜力。我们将研究抑制FLT3-ITD deplmitoylase是否使用原代人AML细胞增强对TKI的反应以及患者衍生的异种移植（PDX）模型。这些发现为脂质提供了新的见解。 FLT3-ITD信号传导的依赖分室化，并建议将depalmitoylation作为新的治疗FLT3-ITD+白血病的治疗策略。