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The molecular mechanisms of leukmogenesis by GATA1

GATA1导致白血病发生的分子机制

基本信息

批准号：
17390295
负责人：
ITO Etsuro
金额：
$ 10.32万
依托单位：
Hirosaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17390295/
关键词：
GATA1 leukemia transcription factor Down syndrome TMD KIT 21番染色体 RUNX1

项目摘要

We performed this study to understand the molecular mechanisms of leukemogenesis by GATA1, and found the following results.1. To clarify the functional differences between GATA1 and GATA1 mutant, we constructed the retroviral expression vector for GATA1/estrogen receptor (ER) fusion protein and transduced a Stem cell factor (SCF)-dependent Down syndrome-associated acute megakaryoblastic leukemia (DS-AMKL) cell line. Conditional activation of both GATA1/ER and GATA1s/ER with Tamoxifen resulted in the growth inhibition and down-regulation of KIT expression.2. We demonstrate the abundant expression of KIT in all transient myeloproliferative disorder (TMD) patients examined. SCF stimulated the proliferation of the blast cells and treatment with the tyrosine kinase inhibitor imatinib suppressed the proliferation effectively in vitro. To investigate the signal cascade downstream from the SCF/KIT pathway, we analyzed a DS-AMKL cell line. SCF activated the RAS/MAPK and PI3K/AKT pathways in this cell line, followed by downregulation of the pro-apoptotic factor BIM and upregulation of the anti-apoptotic factor MCL1. These results suggest the essential role of SCF/KIT signaling in the proliferation of DS-related leukemia.3. The RUNX1 gene is localized to chromosome 21, within the critical region for DS. In this study, we show that GATA1 binds to RUNX1 through its zinc-finger domains, and that the C-finger is indispensable for synergy with RUNX1. All of the patient-specific GATA1 mutants interacted efficiently with RUNX1 and retained their ability to act synergistically with RUNX1 on the megakaryocytic GP1bα promoter, whereas the levels of transcriptional activities were diverse among the mutants. Thus our data indicate that physical interaction and synergy between GATA1 and RUNX1 are retained in DS-AMKL, although it is still possible that increased RUNX1 activity plays a role in the development of leukemia in DS.

本研究旨在了解GATA1致白血病的分子机制，并发现以下结果。为了阐明GATA1和突变体GATA1的功能差异，我们构建了GATA1/雌激素受体(ER)融合蛋白的逆转录病毒表达载体，并转导了依赖于唐氏综合征的急性巨核细胞白血病(DS-AMKL)细胞系。结论：1.三苯氧胺有条件地激活GATA1/ER和GATA1/ER可抑制KIT的生长并下调KIT的表达。我们证明KIT在所有接受检查的一过性骨髓增殖性疾病(TMD)患者中都有丰富的表达。SCF能刺激原始细胞的增殖，酪氨酸激酶抑制剂伊马替尼能有效地抑制体外培养的原始细胞的增殖。为了研究SCF/KIT通路下游的信号级联反应，我们分析了一个DS-AMKL细胞系。SCF激活Ras/MAPK和PI3K/AKT通路，随后下调促凋亡因子BIM，上调抗凋亡因子MCL1。这些结果提示SCF/KIT信号在DS相关白血病的增殖中起重要作用。RUNX1基因定位于21号染色体上，位于DS的关键区域内。在本研究中，我们证明了GATA1通过其锌指结构域与RUNX1结合，而C-Finger对于与RUNX1的协同作用是必不可少的。所有患者特异性的GATA1突变体都与RUNX1有效地相互作用，并保持了它们在巨核细胞GP1bα启动子上与RUNX1协同作用的能力，但不同突变体的转录活性水平不同。因此，我们的数据表明，GATA1和RUNX1之间的物理相互作用和协同作用在DS-AMKL中保留，尽管RUNX1活性增加在DS白血病的发展中仍有可能发挥作用。