Evaluation of the combined cytotoxic activity of TRAIL (1 μg/mL) plus low (1.5 Gy) and high (15 Gy) single-dose IR on erythroleukemic cell lines.

(A) K562, (B) Friend, and (C) HEL erythroleukemic cell lines. Cells were treated with 1 μg/mL TRAIL (for 6, 18, or 24 hours) before IR or IR (3-6 hours) before the addition of 1 μg/mL TRAIL. Viable cells were counted by trypan blue dye exclusion 24 hours after irradiation. Data are expressed as percentage of control (His6-tag peptide-treated) cells and represent the mean ± SD of 5 independent experiments performed in duplicate.