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Analysis of oncogenic signal transduction and target genes by constitutive active mutations of c-Kit and Flt3

c-Kit和Flt3组成型活性突变分析致癌信号转导和靶基因

基本信息

批准号：
14570977
负责人：
MIZUKI Misao
金额：
$ 2.24万
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：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14570977/
关键词：
receptor tyrosine kinase mutation acute myeloid leukemia transcription factor targeting therapy STAT inhibitor レセプターチロシンキナーゼ白血病シグナル伝達 Pim 転写因子 receptor tyrosine kinase chemotaxis

项目摘要

1. Flt3 mutation specific target genesMicrochip analysis revealed that Flt3 internal tandem duplication (Flt3-ITD) mutation specifically induced STAT3/5 target genes such as pim-2, SOCS3 and CIS. These genes were also induced by constitutive active, c-Kit mutations. Pim-2 was.highly expressed in the leukemic cells form AML patients compared to normal bone marrow cells, which suggested that STAT3/5-pim2 was the common oncogenic signaling pathway in AML. 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.2. Gytoplasmic tyrosine residues involved in the activation and siganl transduction of receptor tyrosine kinasesWe analyzed effects of phenylalanine conversion of 22 tyrosine residues in the cytoplasmic domain of c-Kit of Flt3 on receptor activation, down stream signal transduction and cell function. In the c-Kit kinase domain mutant, Phe-substitution of Tyr719 abolished the binding of p85 PI3-kinase subunit, the kinase activity of receptor itself and the proliferative activity. In the Flt3 kinase domain mutant, Phe-substitution of Tyr845, 892 and 922 suppressed the kinase activity, downstream signal transduction such as Erk1/2 and STAT3/5, factor-independent growth and survival. These results suggested that specific tyrosine residues criticallyregulated the oncogemc acivation of kinase domain muta its of receptor tyrosine kinases.

1. Flt3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。这些基因也被组成型活性c-Kit突变诱导。Pim-2。与正常骨髓细胞相比，STAT3/5-pim2在AML患者的白血病细胞中高表达，这表明STAT3/5-pim2是AML中常见的致癌信号通路。Flt3-ITD可特异性抑制髓细胞特异性转录因子C/EBPalpha和PU.1，提示Flt3-ITD参与了aml的分化阻断。胞质酪氨酸残基参与受体酪氨酸激酶的激活和信号转导我们分析了Flt3 c-Kit胞质区域22个酪氨酸残基苯丙氨酸转化对受体激活、下游信号转导和细胞功能的影响。在c-Kit激酶结构域突变体中，Tyr719的phee取代消除了p85 pi3激酶亚基的结合、受体本身的激酶活性和增殖活性。在Flt3激酶结构域突变体中，Tyr845、892和922的phee替代抑制了激酶活性、下游信号转导如Erk1/2和STAT3/5、不依赖因子的生长和存活。这些结果表明，特定的酪氨酸残基对受体酪氨酸激酶激酶结构域突变的癌基因激活起着关键的调节作用。