BMP-2 promoted glioma cell proliferation via regulation of BMP/Smad and BMP/MAPK pathway

Abstract

Objective To investigate the BMP-2 expression in glioma cell lines and its promotive role and mechanism of proliferation in glioma cells. Methods Subculture of five glioma cell lines including U8vIII, U87, T98G, LN229 and U373, Semi-quantitative PCR was performed to analyze BMP-2, BMP-2 receptors (BMPR1A, BMPR1B and Alk-2) and Smad1 expression in these glioma cell lines. MTS assay was used to investigate the glioma cell proliferation with BMP-2 (0, 25, 50, 100, 250 and 500 ng/ml) treatment. Western blot was performed to detect activation of canonical BMP pathway (BMP/Smad pathway) and non-canonical BMP pathway (BMP/MAPK pathway) under BMP-2 treatment with different doses and timepoints. At last, the expression of BMP pathway downstream genes cyclin B, cyclin D1, p27 and p21 were explored at 0, 4, 8, 16 or 24 h posttreatment of BMP-2 (100 ng/ml). Results The expression of BMP-2, its receptors and Smad1 were significantly different among five glioma cell lines (P<0.01). The MTS assay showed that BMP-2 promoted U87 cell proliferation. It reached the maximum level when the BMP-2 concentration reached 100-250 ng/ml. The Western blot results revealed that BMP-2 activated phosphorylated Smad1/5/8, p38, JNK and ERK in dose and time dependent manners (P<0.01). The expression levels of BMP pathway downstream genes cyclin B and cyclin D1 were higher compared to those of control (P<0.01). However, the levels of p27 and p21 were lower (P<0.01). Conclusions BMP-2 could promote glioma cell proliferation via regulation of BMP/Smad and BMP/MAPK pathway. Key words: Glioma; Bone morphogenetic protein 2; Mitogen-activated protein kinases; Smad proteins