Mechanisms of growth, survival and transformation mediated by KIT and FLT3

KIT 和 FLT3 介导的生长、存活和转化机制

基本信息

批准号：
13671063
负责人：
KURATSUNE Hirohiko
金额：
$ 2.5万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13671063/
关键词：
Receptor tyrosine kinase mutation Acute myeloid leukemia chemotaixs Targeting therapy STAT inhibitor receptor tyrosine kinase acute myeloid leukemia targeting therapy KIT PI3-K STI571 AG1296

项目摘要

l. Cytoplasmic tyrosine residues involved in KIT-signal transductionWe analyzed effects of phenylalanine conversion of 22 tyrosine residues in the cytoplasmic domain on KIT-mediated cell function. In the wild type KIT, although the proliferation and survival was not affected by these Tyr->Phe conversions, the conversions of Tyr 567, 569, or 719 suppressed the cell migration mediated by KIT/SCF interaction. Tyr567 activated Src family kinase, p38 MAPkinase, which induced Ca2+ influx and the subsequent activation of Erk. Tyr 719 activated PI3-kinase, which induced Ca2+ influx. Both pathways synergistically induced the cell migration. In the constitutively active KIT mutant of kinase domain, Phe conversion of Tyr 719 abolished the kinase activity and the proliferative activity, which suggested that Tyr 719 and associated PI3-kinase is critical for kinase and transforming activity.2. Targeting inhibition of constitutive active KITTyrosine kinase inhibitors, STI571 and AG1296 suppressed the kinase activity of juxtamembrane domain KIT mutant more effectively than wild type. In contrast, kinase domain mutant resisted to these inhibitors, even though in combination. Therefore, the sensitivity to the inhibitor differs dependent on the type of mutant.3. FIt3 mutation specific target genes Microchip analysis revealed that Flt3 internal tandem duplication (Flt3-ITD) mutation specifically induced STAT3/5 target genes such as pim-2, SOCS3 and CIS. Flt3-ITD specifically suppressed myeloid-specific transcription factors such as C/EBPalpha and Pu. 1, which suggested that Flt3-ITD is involved in the differentiation block in AML.

湖参与 KIT 信号转导的细胞质酪氨酸残基我们分析了细胞质结构域中 22 个酪氨酸残基的苯丙氨酸转化对 KIT 介导的细胞功能的影响。在野生型KIT中，尽管增殖和存活不受这些Tyr->Phe转化的影响，但Tyr 567、569或719的转化抑制了KIT/SCF相互作用介导的细胞迁移。 Tyr567 激活 Src 家族激酶 p38 MAPkinase，诱导 Ca2+ 流入并随后激活 Erk。 Tyr 719 激活 PI3 激酶，诱导 Ca2+ 流入。两种途径协同诱导细胞迁移。在激酶结构域组成型活性KIT突变体中，Tyr 719的Phe转化消除了激酶活性和增殖活性，这表明Tyr 719和相关的PI3激酶对于激酶和转化活性至关重要。2．组成型活性 KITT 酪氨酸激酶抑制剂的靶向抑制，STI571 和 AG1296 比野生型更有效地抑制近膜结构域 KIT 突变体的激酶活性。相反，激酶结构域突变体对这些抑制剂具有抵抗力，即使是组合使用。因此，对抑制剂的敏感性根据突变体的类型而不同。3． FIt3突变特异性靶基因 Microchip分析显示，Flt3内部串联重复（Flt3-ITD）突变特异性诱导STAT3/5靶基因，如pim-2、SOCS3和CIS。 Flt3-ITD 特异性抑制骨髓特异性转录因子，例如 C/EBPα 和 Pu。图 1 表明 Flt3-ITD 参与 AML 的分化阻断。