Real-time changes in 1H and 31P NMR spectra of malignant human mammary epithelial cells during treatment with the anti-inflammatory agent indomethacin

Choline metabolites in malignant human mammary epithelial cells (HMECs) are significantly altered compared to normal HMECs. H-1 NMR studies of cell extracts have shown that treatment of malignant HMECs with a nonsteroidal anti-inflammatory agent, indomethacin, results in a distribution of choline compounds more typical of nonmalignant HMECs. To follow the time course of these changes, in this study real-time monitoring of choline compounds of malignant MDA-MB-231 cells was performed during treatment with indomethacin. The contribution of changes in intra- and extracellular pH to changes in choline compounds was also examined. Changes in water-soluble choline phospholipid metabolites, such as phosphocholine (PC), glycerophosphocholine (GPC), and total choline, as well as intracellular pH, were monitored by P-31 and diffusion-weighted H-1 NMR spectroscopy of living cells using an NMR-compatible perfusion system. An accumulation of an decrease of PC, resulting in an increased [GPC]/[PC] ratio, were detected within 2 hr of treatment with 200 muM indomethacin. Since a decreased [GPC]/[PC] ratio is associated with increased malignancy, these data demonstrate that nonspecific cyclooxygenase inhibition by indomethacin alters the choline metabolite profile of malignant cells towards a less malignant phenotype. These changes were not related to alterations of intra- or extracellular pH. (C) 2002 Wiley-Liss, Inc.