GO-203 induces cardiolipin oxidation and loss of the mitochondrial transmembrane potential. (A-B) U266 (A) and RPMI8226 (B) 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 in the presence of 5mM NAC for the last 2 days. The cells were then incubated with 50nM NAO for 30 minutes and analyzed by flow cytometry (left). The percentage of positive cells is included in the panels. The results are expressed as the percentage of positive cells (mean ± SD of 3 determinations; right). (C-D) U266 (C) and RPMI8226 (D) cells were left untreated, and treated with 5μM GO-203 or 5μM CP-2 each day for 3 days. The cells were incubated with rhodamine 123 and analyzed by flow cytometry (left). The results are expressed as the percentage ΔΨm (mean ± SD of 3 determinations) compared with that obtained for the control (right).