Fig. 1
Effects of METH and chemotherapeutic drugs on GBM cells viability. a U-118 cells were exposed to increasing METH concentrations (0.01–1,000 μM) for 48 h and cell viability significantly decreased at drug concentrations ≥650 μM. The results are expressed as mean % of control + SEM, n = 12. b, c Cells were treated for 48 h with increasing concentrations of (b) DOX or (c) MTX alone and in the presence of METH (1 μM). Data are expressed as mean ± SEM and were fitted to a sigmoid function for IC50 calculation; n = 15–18. d, e Cells were treated for 48 h with different concentrations of (d) TMZ alone or (e) in combination with METH (1 μM). Data shown are expressed as mean + SEM, n = 9. *p < 0.05, ***p < 0.001, significantly different when compared to the control using one-way ANOVA followed by Dunnett’s multiple comparison test. The values are available in Supplementary Table 1