Fig. 4.

The resveratrol/HDACI regimen induces ROS production, which plays a functional role in lethality. A, U937 cells were incubated with 50 μM resveratrol (RESV) with or without 15 nM LBH-589 (LBH) (left) or 1.5 μM vorinostat (Vor) (right) for the indicated periods, after which intracellular ROS levels were assessed through staining with 2′,7′-dichlorodihydrofluorescein diacetate (a cell-permeable ROS indicator) and flow cytometry. R, resveratrol; L, LBH-589; V, vorinostat. Values represent the mean ± S.D. of triplicate determinations performed on three separate occasions. B and C, U937 cells were treated with 50 μM resveratrol with or without 15 nM LBH-589 or 1.5 μM vorinostat in the absence or presence of 400 μM MnTBAP, after which ROS levels were measured as described for A (B, 6 h) and cell death was determined through 7-aminoactinomycin D staining and flow cytometry (C, 24 h). Veh, vehicle; C, control. Values represent the mean ± S.D. of triplicate determinations performed on three separate occasions. ***, P < 0.001, compared with the same treatment without MnTBAP. D and E, U937 cells were treated for 24 h with 50 μM resveratrol with or without 15 nM LBH-589 or 1.5 μM vorinostat after 1-h pretreatment with 5 μM ML171 (D) or 5 mM sodium azide (Az) (E), after which cell death was determined through 7-aminoactinomycin D staining and flow cytometry.