Association of Oxidative Stress with Realgar-Induced Differentiation in Human Leukemia HL-60 Cells

Background: Realgar (arsenic sulfide, As 4 S 4) has been shown to have clinical efficacy in patients with newly diagnosed and relapsed acute promyelocytic leukemia. Mechanistic studies have demonstrated that realgar is able to induce cell differentiation. Methods: The oxidative stress in the realgar-induced differentiation was examined with human leukemia HL-60 cells. Cell differentiation was evaluated by the expression of cell surface antigen CD11b and nitroblue tetrazolium assay. The activities of catalase and superoxide dismutase were measured spectrophotometrically. Flow cytometry was used to assess cell cycle distribution and apoptosis, the cellular level of reactive oxygen species (ROS) and glutathione, as well as mitochondrial transmembrane potential (MTP). Results: The realgar-induced differentiation was enhanced by hydrogen peroxide, and preceded with drastic changes in ROS and catalase, as well as small changes in superoxide dismutase and the reduced form of glutathione. MTP values at 24 h were in linear proportion to the CD11b expression at 48 h when no apoptosis was observed. Conclusion: Oxidative stress and stress-related MTP decrease are associated with realgar-induced differentiation in HL-60 cells. Copyright (C) 2009 S. Karger AG, Basel