IGF-I、GM-CSF和EGF通过MAPK途径上调MC3T3-E1及C2C12细胞中核心结合因子α1的表达

摘要

AIM: To study the regulating function and mechanism of insulin-like growth factor-I (IGF-I), granulocyte-macrophage colony-stimulating factor (GM-CSF), and epidermal growth factor (EGF) on murine core binding factor αl (Cbfal) gene expression. METHODS: Luciferase reporter gene method and RT-PCR technique were used to examine the effects of these growth factors on the promoter activity and mRNA expression of Cbfal gene in MC3T3-E1 and C2C12 cells. RESULTS: IGF-I (from 1 nmol/L to 1 μmol/L), GM-CSF (100 nmol/L), and EGF (1μmol/L) increased thc luciferase expression in MC3T3-E1 cells (P＜0.05). And mitogen-activated protein kinase (MAPK) inhibitor, PD 98059 (10 μmol/L), completely blocked IGF-1, GM-CSF, and EGF-induced expression of Cbfal promoter activity (P＜0.01). In C2C12 cells, IGF-I (from 1 nmol/L to 10 μmol/L), GM-CSF (100 nmol/L and 1 μmol/L), and EGF (100 nmol/L) enhanced the expression of luciferase reporter plasmid driven by mCbfal promoter (P＜0.05). Addition of PD 98059 also blocked the stimulatory effects of these growth factors on Cbfal promoter activity (P＜0.01). Moreover, Cbfal mRNA expression was significantly increased after treatment with IGF-I (1 nmol/L, 100 nmol/L), GM-CSF (100 nmol/L, 1 μmol/L), and EGF (1 μmol/L, 100 nmol/L) in MC3T3-E1 and C2C12 cells, respectively (P＜0.05). These stimulatory effects of IGF-I, GM-CSF, and EGF on Cbfal mRNA expression were abolished by PD 98059. CONCLUSION: IGF-I, GM-CSF, and EGF could increase thc promoter activity and the mRNA expression of murine Cbfal gene in MC3T3-E1 and C2C12 cells. These stimulatory effects might be mediated by activating the intracellular MAPK-dependent signaling pathway.%目的:研究生长因子胰岛素样生长因子-Ⅰ(IGF-Ⅰ)、巨噬-粒细胞集落刺激因子(GM-CSF)和表皮生长因子(EGF)对核心结合因子α1(Cbfα1)的调节作用及其与有丝分裂原激活蛋白激酶(MAPK)信号转导通路的关系.方法:采用报告基因方法和RT-PCR技术检测Cbfα1基因启动子活性及mRNA表达的变化.结果:在MC3T3-E1细胞中,IGF-Ⅰ(1 nmol/L-1μmol/L)、GM-CSF(100 nmol/L)和EGF(1 μmol/L)作用24小时能够增加Cbfα1基因启动子活性(P＜0.05).加入PD98059(10 μmol/L)后不但抑制了Cbfα1基因启动子活性的基础表达,而且完全阻断了IGF-1、GM-CSF和EGF所诱导的Cbfα1基因启动子活性的增加(P＜0.01).在C2C12细胞中得到了类似结果.另外,MC3T3-E1和C2C12细胞分别经IGF-Ⅰ(1,100 nmol/L)、GM-CSF(100 nmol/L,1 μmol/L)和EGF(1μmol/L,100 nmol/L)处理后均使Cbfα1基因mRNA表达水平提高(P＜0.05).而加入PD98059可抑制上述因子的刺激作用.结论:IGF-Ⅰ、GM-CSF和EGF能够刺激MC3T3-E1和C2C12细胞中小鼠Cbfα1基因启动子活性及mRNA的表达,此作用可能经MAPK信号传导通路介导.