Possible involvement of RasGRP4 in leukemogenesis
Possible involvement of RasGRP4 in leukemogenesis
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RasGRP4 可能参与白血病发生
DOI：
10.1007/s12185-009-0299-0
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发表时间：
2009
期刊：
影响因子：
2.1
通讯作者：
Kitamura T.
中科院分区：
文献类型：
--
作者：
Watanabe-Okochi N;Oki T;Komeno Y;Kato N;Yuji K;Ono R;Harada Y;Harada H;Hayashi Y;Nakajima H;Nosaka T;Kitaura J;Kitamura T.
现在可以想象，白血病的发生需要两种类型的突变，I类和II类突变。我们先前建立了小鼠骨髓来源的HF 6，一种IL-3依赖性细胞系，其通过II类突变MLL/SEPT 6永生化，并且可以通过I类突变如FLT 3突变体完全转化。为了了解白血病发生的分子机制，特别是骨髓增生异常综合征（MDS）向急性白血病的进展，我们从患者样本中制备cDNA文库，并通过表达克隆对其进行筛选，以检测使HF 6细胞因子不依赖的I类突变。我们从六名患者中的三名患者（MDS/MPD = 1、MDS-RA = 1、MDS/AML = 2、CMMoL/AML = 1和AML-M2 = 1）中鉴定出RasGRP 4（Ras激活剂）为I类突变的候选者。为了研究RasGRP 4在白血病发生中的潜在作用，我们在小鼠骨髓移植（BMT）模型中测试了其体内作用。移植有RasGRP 4转导的原代骨髓细胞的C57 BL/6 J小鼠死于T细胞白血病、髓性白血病或髓性白血病伴T细胞白血病。为了进一步检查I类和II类突变的组合是否加速白血病转化，我们进行了小鼠BMT模型，其中AML 1突变体（S291 fsX 300）和RasGRP 4都被转导到骨髓细胞中。与单独转导RasGRP 4相比，双重转导导致移植小鼠中T细胞白血病的早期发作，但不导致AML的早期发作。因此，我们已经确定RasGRP 4作为一个基因可能参与白血病的发生，并建议RasGRP 4合作与AML 1突变的T细胞白血病的I类突变。
It is now conceivable that leukemogenesis requires two types of mutations, class I and class II mutations. We previously established a mouse bone marrow-derived HF6, an IL-3-dependent cell line, that was immortalized by a class II mutation MLL/SEPT6 and can be fully transformed by class I mutations such as FLT3 mutants. To understand the molecular mechanism of leukemogenesis, particularly progression of myelodysplastic syndrome (MDS) to acute leukemia, we made cDNA libraries from the samples of patients and screened them by expression-cloning to detect class I mutations that render HF6 cells factor-independent. We identified RasGRP4, an activator of Ras, as a candidate for class I mutation from three of six patients (MDS/MPD = 1, MDS-RA = 1, MDS/AML = 2, CMMoL/AML = 1 and AML-M2 = 1). To investigate the potential roles of RasGRP4 in leukemogenesis, we tested its in vivo effect in a mouse bone marrow transplantation (BMT) model. C57BL/6J mice transplanted with RasGRP4-transduced primary bone marrow cells died of T cell leukemia, myeloid leukemia, or myeloid leukemia with T cell leukemia. To further examine if the combination of class I and class II mutations accelerated leukemic transformation, we performed a mouse BMT model in which both AML1 mutant (S291fsX300) and RasGRP4 were transduced into bone marrow cells. The double transduction led to early onset of T cell leukemia but not of AML in the transplanted mice when compared to transduction of RasGRP4 alone. Thus, we have identified RasGRP4 as a gene potentially involved in leukemogenesis and suggest that RasGRP4 cooperates with AML1 mutations in T cell leukemogenesis as a class I mutation.