Effect of 2-DG treatment on prednisolone-induced cytotoxicity in primary ALL cells. Cell survival curves representing in vitro prednisolone responsiveness, in prednisolone-resistant ALL patients (top panel), -intermediate patients (middle panel), and -sensitive patients (bottom panel) as assessed by the MTT assay. Concentrations 2-DG varied from 0.2 mM to 2 mM (▼), depending on the patient sample sensitivity. To visualize the synergy, the survival of cells treated with prednisolone and 2-DG was corrected for the toxic effect of 2-DG given as single drug (set at 100%). Cells treated only with prednisolone served as controls (■). A representative experiment is shown; data are presented as means plus or minus SD (n = 3).