Moderate intracellular ATP reduction does not impair MOLT-3 cell viability and drug response. (A-B) MOLT-3 cells were incubated for 3 hours in standard medium, with oligomycin (10 μg/mL), 2-DG (0.1 mM and 0.3 mM), and in glucose- and serum-free medium (-Glu) in the absence or presence of 1 mM 2-DG. Cells were assessed for intracellular ATP levels using luminometric assay (A) and for apoptosis and necrosis (B) (annexin V/PI staining, percentages of necrotic cells in the upper right quadrant are indicated). (C) MOLT-3 cells were incubated with etoposide (1 μM) in standard medium in the absence or presence of 0.1 mM or 0.3 mM 2-DG. Cells were assessed for p53 protein levels after 3 hours of incubation and for apoptosis (annexin/PI staining) after 6 hours of incubation.