FIGURE 1.
The effect of SPE B and G308S on levels of procaspase 8 and caspase 8. A549 cells (2 × 105) were treated with SPE B (20 μg/ml) (A) and G308S (20 μg/ml) (C) for the indicated times or with PBS (control (C)) for 4 h. Total cell lysates were immunoblotted using anti-procaspase 8 and anti-caspase 8 antibodies. β-Actin was an internal control. A quantitative result of procaspase 8 versus β-actin is expressed as the relative ratio (B and D). The ratio of procaspase 8 to β-actin in the control sample is defined as 1, the ratios of each procaspase 8 to β-actin in other time points are compared with control, and their ratios are presented. Results are the mean ± S.E. of three independent experiments. *, p < 0.05.