Figure 1

HHT sensitizes cancer cells for TRAIL-induced necroptosis. (A) Cells were treated with TRAIL with or without pretreatment of 50 μM zVAD-fmk to induce cell death in the absence of any additional sensitizers. (B) Cells were pretreated with 50 μM zVAD-fmk in combination with 0.01, 0.1, 1, and 10 μM of HHT or 0.36, 3.56, 7.12, 17.79 and 35.59 μM CHX (corresponding to 0.1, 1, 2, 5 and 10 μg/ml) for one hour before 100 ng/ml of TRAIL were added. (C) Cells were stimulated with optimized concentrations of HHT (red arrows in (B)) in a time course experiment to monitor the cytotoxic effects of HHT alone. Loss of membrane integrity (after 24 h for panels A and B, as indicated for panel C) was measured as a marker for cell death by flow cytometric detection of PI-positive cells. Each measurement represents the means of two independent experiments with three parallel determinations each, error bars indicate the corresponding standard deviations (SDs). Red arrows indicate concentrations used for further experiments.