Effect of DEX on mitochondrial membrane potential, intracellular metabolites, and PKM2. (A) CLL cells from 8 different patients were cultured with or without DEX. At the indicated times, the cells were stained with DiOC₆(3) to measure mitochondrial membrane potential. Median fluorescence intensities (MFIs) are shown for each sample. (B) Cells (5 × 10⁷) from 5 different CLL patients were cultured for 18 hours in the presence or absence of DEX and then analyzed by 1D ¹H NMR spectroscopy. Averages and standard errors for the 5 samples are shown. Glutamate, alanine, and lactate levels were significantly lowered by DEX, whereas acetate levels were relatively preserved. (C) CLL cells from 9 patients were cultured with or without DEX. After 4 hours, PKM2 mRNA transcripts (relative to HPRT transcripts) were measured by quantitative polymerase chain reaction. (D) After 18 hours of culture, phospho-GR and PKM2 levels were measured in DEX-treated cells from 4 different patients by (upper) immunoblotting and (lower) quantified by densitometry using β-actin as a loading control. PKM2 mRNA and protein were both decreased by DEX. (E) Pyruvate kinase (PK) enzymatic activity in DEX-treated CLL cells from patient 56 after 18 hours, measured as described in Materials and methods. **P < .01; *P < .05.