VEGF通过MAPK途径上调MC3T3-E1及C2C12细胞中Cbfa1基因的表达

Core binding factor al （Cbfal） up-regulated by VEGF through mitogen-activated protein kinase （MAPK） pathway in MC3T3-E1 and C2C12 cells

目的研究生长因子VEGF对Cbfa1的调节作用及其与MAPK信号传导通路的关系。方法采用瞬时转染技术和RT-PCR方法。结果在MC3T3．E1细胞中，VEGF（1×10^-8～1×10^-6g·L^-1）作用24小时能够增加Cbfa1基因启动子活性，相对荧光素酶活性分别为对照组的1．29（P〈0．05），1．28（P〈0．01）和1．40（P〈0．05）。而加入PD98059（10μmol/L）后不但抑制了Cbfa1基因启动子活性的基础表达，而且完全阻断了VEGF所诱导的Cbfa1基因启动子活性的增加（P〈0．05）。C2C12细胞中不同浓度的VEGF处理组，其相对荧光素酶活性与对照组相比未见显著性差异。MC3T3-E1细胞中，VEGF处理前后，MC3T3-E1细胞中Cbfa1基因mRNA的表达水平未见显著变化。C2C12细胞中，VEGF处理后，第2天和第3天Cbfa1基因mRNA的表达由处理前的32．63±4．41，分别增加至46．56±2．70（P〈0．01）和50．35±5．62（P〈0．05）。PD98059阻断了C2C12细胞中VEGF对Cbfa1基因mRNA表达的上调作用。结论VEGF部分通过MAPK信号传导通路增加MC3T3-E1和C2C12细胞中小鼠Cbfa1基因启动子活性及mRNA的表达。

Objective To study the involvement of the MAPK pathway in Cbfal stimulated by VEGF. Methotis The methods of transient transfeetion and RT-PCR were used. Results MC3T3-E1 cells, VEGF （ 1 ×10^-8～1×10^-6g·L^-1） enhanced the luciferase activity about 1.29 （ P 〈 0. 05 ）, 1.28 （ P 〈 0. 01 ） and 1.40 （ P 〈 0. 05 ） folds respectively compared with that of control group. C2C12 cells, VEGF had no effect on the luciferase activity of p696-Luc. PD98059 （10μmol/L）, a specific inhibitor of MAPK, suppressed basal and completely blocked VEGF-induced expression of Cbfal promoter activity in MC3T3-E1 cells （ P 〈 0. 05 ）. VEGF had no effect on Cbfal mRNA level in MC3T3-E1 cells. Treatment of VEGF resulted in increases in Cbfal gene expression at d2 and d3 （dO： 32.63 ±4.41 vs d2：46.56 ±2. 70, P 〈0. 01 ; d3： 50. 35 ±5.62, P 〈0. 05 in C2C12 cells. PD98059 blocked VEGF-induced Cbfal gene expression in C2C12 cells. Conclusion VEGF could increase the promoter activity in MC3T3-E1 ceils and the expression of murine Cbfal gene in C2C12 cells. And the MAPK pathway is required for VEGF responsiveness.