31P nuclear magnetic resonance studies of growth inhibition and dexamethasone resistance in human leukemic cells

31P Nuclear magnetic resonance spectra of perchloric acid extracts from wild-type human leukemic CEM-C7 cells and the dexamethasone-resistant CEM-C1 mutant reveal significant differences in concentrations of phospholipid precursors and ATP+, which indicate metabolic differences between these two cell lines. At high cell concentrations the CEM-C7 cells are growth inhibited, which is reflected by low phospholipid precursor levels, indicative of low phospholipid turnover. The CEM-C1 mutant does not exhibit this growth inhibition and has constant phospholipid precursor levels over the same cell concentration range. Dexamethasone causes phospholipid precursor and ATP levels in CEM-C7 to drop after 48 h, but spectra obtained for CEM-C1 cells continue to show high cell viability up to 72 h.