The Role of Shp2 Phosphatase Activity in FLT3-ITD+ Acute Myeloid Leukemia

Shp2 磷酸酶活性在 FLT3-ITD 急性髓系白血病中的作用

• 批准号: 9112779
• 负责人: Briana Richine
• 金额: $ 1.42万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2016-05-06
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9112779
• 关键词: Ablation; Acute Myelocytic Leukemia; Address; Adult; Amino Acids; Blood Cells; Bone Marrow; C3H/HeJ Mouse; Cell Proliferation; Cells; Child; Complex; Development; Diagnosis; Dominant-Negative Mutation; Evaluation; FLT3 gene; Genetic; Goals; Hematologic Neoplasms; Hematopoietic; Human; Lead; Leukemic Cell; Link; Malignant Neoplasms; Mediator of activation protein; Modeling; Molecular; Mus; Mutate; Mutation; Myeloproliferative disease; Patients; Phenylalanine; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Protein Dephosphorylation; Protein Tyrosine Kinase; Protein Tyrosine Phosphatase; Proteins; Publishing; Reporting; Role; Sampling; Site; Staging; Stat5 protein; Testing; Transplantation; Tyrosine; Work; base; in vitro Assay; in vivo; in vivo Model; inhibitor/antagonist; innovation; interest; leukemia; leukemogenesis; mutant; novel; novel strategies; outcome forecast; overexpression; preclinical study; prevent; progenitor; protein complex; public health relevance; receptor; src-Family Kinases; therapeutic target

 DESCRIPTION (provided by applicant): Acute myeloid leukemia (AML) is a cancer of the bone marrow in which hyperproliferative blood cell progenitors are arrested in an early stage of development. Unfortunately, there is only a 20% cure rate for AML at 5 years post-diagnosis. Internal tandem duplications, the addition of several amino acids into the juxtamembrane domain of the FLT3 receptor (FLT3-ITDs), are found in approximately 30% of AML in both adults and children, and confer a poor prognosis. The protein tyrosine phosphatase, Shp2, is commonly overexpressed in AML, and we have previously found that it is constitutively associated with FLT3-ITD and that its genetic ablation reduces FLT3-ITD-stimulated cell hyperproliferation and STAT5 hyperactivation. Recently published studies from our lab suggest that a major site of Shp2 function is at FLT3-ITD tyrosine (Y) residue 599. However, the mechanism of how Shp2 works at FLT3-ITD to promote leukemogenesis is unknown. Based on the findings that both Src kinase and Syk kinase have been shown to interact with STAT5, that both kinases depend on Tyr599 for physical interaction with FLT3, and that Shp2 dephosphorylation of Src enhances its kinase activity, our over-riding hypothesis is that the duplicated Tyr599 on N51-FLT3-ITD permits increased Shp2 recruitment, allowing Shp2 to dephosphorylate, and thus activate Src, leading to Syk and STAT5 hyperactivation, thereby promoting leukemogenesis. To address this hypothesis, we will utilize FLT3-ITD constructs bearing mutation of Y599 to phenylalanine (F) and express dominant negative constructs of Shp2 phosphatase, Src kinase, and Lyn kinase to dissect the molecular mechanism linking Shp2 phosphatase activity with Syk kinase activity. Additionally, we will perform pre-clinical studies using pharmacologic inhibitors of Shp2 phosphatase and Syk kinase in primary AML cell proliferation assays in vitro and in a murine in vivo model of FLT3-ITD-induced leukemia. These studies are timely and innovative, as we will determine if inhibition of an activating tyrosine phosphatase (Shp2) cooperates with inhibition of activating tyrosine kinase (Syk), as a novel approach to therapy for AML.

 描述（由申请人提供）：急性髓性白血病（AML）是一种骨髓癌症，其中过度增殖的血细胞祖细胞在发育的早期阶段被阻止。不幸的是，AML在诊断后5年的治愈率仅为20%。在成人和儿童中约30%的AML中发现了内部串联重复，即在FLT 3受体（FLT 3-ITD）的质膜结构域中添加几个氨基酸，并导致预后不良。蛋白酪氨酸磷酸酶Shp 2通常在AML中过表达，我们以前发现它与FLT 3-ITD组成性相关，并且其基因消融可减少FLT 3-ITD刺激的细胞过度增殖和STAT 5过度活化。我们实验室最近发表的研究表明，Shp 2功能的主要位点位于FLT 3-ITD酪氨酸（Y）残基599。然而，Shp 2如何在FLT 3-ITD处起作用以促进白血病发生的机制尚不清楚。基于Src激酶和Syk激酶都已显示与STAT 5相互作用，这两种激酶都依赖于Tyr 599与FLT 3的物理相互作用，以及Src的Shp 2去磷酸化增强其激酶活性的发现，我们的首要假设是N51-FLT 3-ITD上的重复Tyr 599允许增加的Shp 2募集，允许Shp 2去磷酸化，从而激活Src，导致Syk和STAT 5过度活化，从而促进白血病发生。为了解决这一假设，我们将利用携带Y 599突变为苯丙氨酸（F）的FLT 3-ITD构建体，并表达Shp 2磷酸酶、Src激酶和林恩激酶的显性阴性构建体，以剖析将Shp 2磷酸酶活性与Syk激酶活性联系起来的分子机制。此外，我们将在体外原代AML细胞增殖试验和FLT 3-ITD诱导白血病的小鼠体内模型中使用Shp 2磷酸酶和Syk激酶的药理学抑制剂进行临床前研究。这些研究是及时的和创新的，因为我们将确定抑制激活酪氨酸磷酸酶（Shp 2）是否与抑制激活酪氨酸激酶（Syk）合作，作为AML治疗的新方法。