Cellular effects of ROS-enhancing, nontoxic compounds. (A) Total
cellular glutathione after treatment with the indicated compounds
(BRD9092, 23.2 μM; BRD56491, 35 μM; BRD5459, 11.7 μM)
was measured in EJ and HeLa cells. (B) BRD9092 and BRD5459, but not
BRD56491, elevate antioxidant response element (ARE) promoter transcription
in a luciferase-based reporter-gene assay in IMR-32 cells. Data are
expressed as mean ± SD, n = 3 (ARE reporter
assay, n = 4). (C–E) Three ROS-enhancing nontoxic
compounds were tested for viability in the presence of a nontoxic
dose (5 μM) of BSO (a glutathione synthesis inhibitor), 200
μM vitamin E, or 5 mM N-acetyl cysteine (NAC)
in EJ cells. ATP values were calculated relative to control wells
lacking the indicated BRD compound but containing BSO and antioxidant
when applicable. All treatments were nontoxic individually (Supporting Figure 4). (F) Pairing of BRD5459
(2.9 μM) or BRD9092 (11.6 μM) with BSO (5 μM) leads
to enhanced depletion of glutathione. All data are expressed as mean
± SD, n = 3.