GO-203–induced disruption of redox balance and death is reversed by NAC. (A) MOLM-14 cells were left untreated, and treated with 5μM GO-203 or 5μM CP-2 each day for 3 days. The GO-203–treated cells were also incubated concurrently with 5mM NAC. The cells were analyzed for GSH and hydrogen peroxide levels (A). The results are expressed as GSH levels/10⁶ cells (mean ± SD of 3 determinations) (A, left) and relative hydrogen peroxide levels (mean ± SD of 3 determinations) compared with that obtained with control cells (A, right). The cells were also stained with PI/annexin V (B). The results are expressed as the percentage of cells (mean ± SD of 3 determinations) with late apoptosis/necrosis (B). (C-D) MV4-11 (C) and AML patient 1 (D) cells were left untreated, and treated with 5μM GO-203 or 5μM CP-2 each day for 3 (C) and 4 (D) days. The GO-203–treated cells were also incubated in the presence of 5mM NAC. The cells were stained with PI/annexin V. The results are expressed as the percentage of cells (mean ± SD of 3 determinations) with late apoptosis/necrosis.