Expression of core binding factor alpha1 up-regulated by IGF-I, GM-CSF, and EGF through MAPK pathway in MC3T3-E1 and...

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 alpha1 (Cbfalpha1) gene expression.

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 Cbfalpha1 gene in MC3T3-E1 and C2C12 cells.

IGF-I (from 1 nmol/L to 1 micromol/L), GM-CSF (100 nmol/L), and EGF (1 micromol/L) increased the luciferase expression in MC3T3-E1 cells (P<0.05). And mitogen-activated protein kinase (MAPK) inhibitor, PD 98059 (10 micromol/L), completely blocked IGF-1, GM-CSF, and EGF-induced expression of Cbfa1 promoter activity (P<0.01). In C2C12 cells, IGF-I (from 1 nmol/L to 10 micromol/L), GM-CSF (100 nmol/L and 1 micromol/L), and EGF (100 nmol/L) enhanced the expression of luciferase reporter plasmid driven by mCbfalpha1 promoter (P<0.05). Addition of PD 98059 also blocked the stimulatory effects of these growth factors on Cbfalpha1 promoter activity (P<0.01). Moreover, Cbfalpha1 mRNA expression was significantly increased after treatment with IGF-I (1 nmol/L, 100 nmol/L), GM-CSF (100 nmol/L, 1 micromol/L), and EGF (1 micromol/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 Cbfalpha1 mRNA expression were abolished by PD 98059.

IGF-I, GM-CSF, and EGF could increase the promoter activity and the mRNA expression of murine Cbfalpha1 gene in MC3T3-E1 and C2C12 cells. These stimulatory effects might be mediated by activating the intracellular MAPK-dependent signaling pathway.