FIG 4.

Azaserine treatment decreases reduced glutathione but increases superoxide and oxidized glutathione. (A and B) The concentration of total glutathione in untreated H-RasG12V-transformed STAT3 wild-type or STAT3^−/− MEFs was measured by flow cytometry of monochlorobimane-stained cells (A), and reduced and oxidized glutathione abundance was measured by the GSH/GSSG glo luciferase assay (B). (C and D) Reduced (C) and oxidized (D) glutathione concentrations were determined after 24 h of treatment with 1 μM azaserine. (E) The production of reactive oxygen species was determined using specific probes for superoxide (DHE), mitochondrial superoxide (mitoSOX), or cytosolic hydroxyl peroxyl radicals (DCFDA) by flow cytometry. Data plotted are the means ± 1 standard deviation from three independent experiments. Statistical significance was determined using the Student t test. *, P < 0.05; **, P < 0.01.