Figure 1. Neither apoptosis nor necroptosis is involved in OP-A-induced cell death in various glioma cells.

(A, B) Cells were treated with the indicated concentrations of OP-A for 24 h. (A) Cellular viability was assessed using calcein-AM and EthD-1. Data represent the means ± SD (n = 7). One-way ANOVA and Bonferroni’s post hoc test. ^*P < 0.01, ^**P < 0.001 vs. untreated control. IC₅₀s were calculated using GraphPad Prism. (B) Phase-contrast microscopy. Bar 20 μm. (C, D) Cells were pretreated with z-VAD-fmk (C) or necrostatin-1 (D) for 30 min and further treated with the indicated concentrations of OP-A for 24 h. Cellular viability was assessed using calcein-AM and EthD-1. Data represent the means ± SD (n = 7). One-way ANOVA and Bonferroni’s post hoc test. ^*P < 0.001 vs. untreated control.