GSTA2-mediated intracellular ROS removal positively-affects the proliferation of AML cells. (A) Intracellular ROS content was measured by a luminometer in MV4-11 cells transduced with control (sh_Luc.) or with RUNX1 shRNAs (sh_Rx1_moderate and sh_Rx1_profound) in the presence of 3 μM of doxycycline for 48 h. Values are normalized to those of control vector-transduced cells (n = 3). (B) Intracellular ROS content was measured in MV4-11 cells transduced with lentivirus encoding shRNA targeting Luciferase (sh_Luc.) or shRNAs against GSTA2 (sh_GSTA2 1 or sh_GSTA2 2) with or without simultaneous transduction of shRNA-targeting RUNX1 (sh_Rx1_moderate) in the presence of 3 μM of doxycycline for 48 hours. Values are normalized to those of control vector-transduced cells (n = 3). (C) Intracellular ROS content was measured in MV4-11 cells treated with β-lapachone at 100 to 200 nM or DMSO for 24 h (n = 3). (D) The number of cells with S + G₂/M-phase DNA content was determined in MV4-11 cells, as in panel C. Twenty-four hours after treatment, cells were harvested and subjected to flow cytometric analysis (n = 3). (E) Intracellular ROS amount was measured in MV4-11 cells transduced with lentivirus-expressing GSTA2 or control. Cells were incubated with 3 μM of doxycycline for 48 h, then harvested and subjected to flow cytometric analysis (n = 3). (F) Graphic showing the interaction of RUNX, GST, ROS, and their effect on the cell cycle progression in AML cells. RUNX modulate the expression of GSTA2 in AML cells and subsequently reduce intracellular ROS accumulations, which in turn promote the cell cycle advancement and contribute to the propagation of the disease. Data are mean ± SEM values. *P < .05, by 2-tailed Student t test; **P < .01; ***P < .001. GSH, glutathione.