KIT signaling regulates MITF expression through miRNAs in normal and malignant mast cell proliferation
KIT signaling regulates MITF expression through miRNAs in normal and malignant mast cell proliferation
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DOI：
10.1182/blood-2010-07-293548
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发表时间：
2011-03-31
期刊：
影响因子：
20.3
通讯作者：
Takemoto, Clifford M.
中科院分区：
文献类型：
--
作者：
Lee, Youl-Nam;Brandal, Stephanie;Takemoto, Clifford M.
在大多数系统性肥大细胞增多症患者中发现酪氨酸激酶受体（KIT）密码子D816的激活突变。我们发现转录因子，小眼相关转录因子（MITF），在10例系统性肥大细胞增多症和激活c-KIT突变患者中的9例骨髓活检中高度表达。在原代肥大细胞和转化肥大细胞中，我们发现KIT信号显著上调MITF蛋白。我们通过敲低MITF的sh-RNA来抑制集落形成单位，证明MITF是增殖性表型所必需的。此外，组成型活性KIT不能恢复原代mitf缺陷肥大细胞的生长。MITF mRNA水平不随KIT信号而显著改变，提示转录后调控。肥大细胞阵列筛选发现KIT信号调控的候选mirna。我们发现miR-539和miR-381被KIT信号下调，它们通过MITF 3'-非翻译区保守的miRNA结合位点抑制MITF的表达。这些mirna的强制表达抑制了MITF蛋白，抑制了肥大细胞增生细胞系的集落形成能力。这项工作证明了由mirna介导的2个关键肥大细胞因子KIT和MITF之间的新调控途径；该通路的失调可能导致肥大细胞异常增殖和恶性肥大细胞疾病。(血。2011;117 (13):3629 - 3640)
Activating mutations in codon D816 of the tyrosine kinase receptor, KIT, are found in the majority of patients with systemic mastocytosis. We found that the transcription factor, microphthalmia-associated transcription factor (MITF), is highly expressed in bone marrow biopsies from 9 of 10 patients with systemic mastocytosis and activating c-KIT mutations. In primary and transformed mast cells, we show that KIT signaling markedly up-regulates MITF protein. We demonstrate that MITF is required for the proliferative phenotype by inhibiting colony-forming units with sh-RNA knockdown of MITF. Furthermore, constitutively active KIT does not restore growth of primary MITF-deficient mast cells. MITF mRNA levels do not change significantly with KIT signaling, suggesting posttran-scriptional regulation. An array screen from mast cells identified candidate miRNAs regulated by KIT signaling. We found that miR-539 and miR-381 are down-regulated by KIT signaling and they repressed MITF expression through con-served miRNA binding sites in the MITF 3'-untranslated region. Forced expression of these miRNAs suppressed MITF protein and inhibited colony-forming capacity of mastocytosis cell lines. This work demonstrates a novel regulatory pathway between 2 critical mast cell factors, KIT and MITF, mediated by miRNAs; dysregulation of this pathway may contribute to abnormal mast cell proliferation and malignant mast cell diseases. (Blood. 2011;117(13):3629-3640)