Fig. 1

Effect of serum on neurosphere formation and the expression of stem cell markers in glioblastoma stem cells. a Glioblastoma stem cells (GSC11 and GBM3752) formed neurospheres in serum-free medium supplemented with epidermal growth factor and basic fibroblast growth factor. Exposure of the cells to serum (5 % FBS) for 3 days led to a loss of neurosphere formation in both clones. b Western blot analysis of CD133 in GSC11 cells before and after exposure to serum for 1, 3, and 7 days. c Flow cytometry analysis of CD133 expression in GSC11 cells before and after exposure to serum for 7 days. The right panel shows quantitation of the percentage of CD133⁺ cells before and after GSC11 cells were exposed to serum for 1, 3, and 7 days; *P < 0.05. d Expression of SOX2, Olig2, and Notch1 mRNA in GSC11 cells before and after exposure to serum for 3 days. Expression of mRNA was measured by quantitative reverse transcription-polymerase chain reaction. **P < 0.001. e Effect of serum on protein expression of stem cell markers SOX2 and Olig2 and differentiation marker ANXA1. GSC11 cells were exposed to 5 % FBS for 1, 3, and 7 days as indicated. SOX2, Olig2, ANXA1 were detected by Western blot analysis. Cont control, D day, FBS fetal bovine serum, GBM glioblastoma multiforme, GSC glioma stem cell, PI