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.

概括信号蛋白的时空分布受翻译后动态调控修饰（PTM）。磷酸化、泛素化或脂质修饰等 PTM 决定蛋白质活性和获得底物，从而产生细胞结果。信号通路的精确控制对于正常的造血功能和异常的信号传导导致造血干细胞的恶性转化祖细胞（HSPC）。该应用基于我们的新发现：FLT3（FMS 样酪氨酸激酶 3）是棕榈酰化的，破坏致癌 FLT3 突变体的棕榈酰化会改变其亚细胞定位，重新连接下游信号，并促进白血病进展。 FLT3 内的内部串联重复 (FLT3-ITD) 是急性髓系白血病 (AML) 中最常见的突变之一，与不良预后相关预后。而野生型 FLT3 受体酪氨酸激酶在质膜上被激活以转导 PI3K/AKT 和 RAS/MAPK 信号传导，FLT3-ITD 驻留在内质网 (ER) 中并触发 STAT5 组成型磷酸化。这种异常 FLT3-ITD 亚细胞定位的潜在机制或它对白血病发生的影响仍知之甚少。我们发现 FLT3-ITD 被 S-棕榈酰化 ZDHHC6 酰基转移酶。棕榈酰化的破坏将 FLT3-ITD 重定向至质膜并重新布线除 STAT5 外，还通过激活 AKT 和 ERK 途径来调节其下游信号传导。因此，废除通过 ZDHHC6 耗竭实现 FLT3-ITD 棕榈酰化可促进 FLT3-ITD 表面表达、信号转导和异种移植小鼠模型中白血病进展加快。此外，我们证明 FLT3 蛋白质在原代人 AML 细胞中被棕榈酰化。 FLT3-ITD 棕榈酰化的稳定化去棕榈酰化的药理学抑制与 FLT3 酪氨酸激酶抑制剂 (TKI) gilteritinib 协同作用抑制原代 FLT3-ITD+ AML 细胞的生长。这笔赠款的中心目标是定义分子棕榈酰化调节致癌 FLT3 信号传导的基础，并探讨其生理和作用髓系恶性肿瘤中的功能意义。我们建议定义 ZDHHC6 在 FLT3-ITD 中的作用骨髓增生性肿瘤 (MPN) 和 AML 小鼠模型体内棕榈酰化。我们还将确定使用组合方法修改 FLT3-ITD 定位和活性的 FLT3-ITD 去棕榈酰化酶有针对性且公正的化学生物学、分子生物学和遗传学。此外，我们将探索靶向 FLT3-ITD 去棕榈酰化在原发性人类 FLT3-ITD+ AML 中的治疗潜力。我们将使用原代人 AML 细胞研究抑制 FLT3-ITD 去棕榈酰化酶是否增强对 TKI 的反应以及患者来源的异种移植（PDX）模型。这些发现为脂类提供了新的见解 FLT3-ITD 信号传导的依赖性区室化并建议将去棕榈酰化作为一种新的治疗 FLT3-ITD+ 白血病的治疗策略。