Differences in Phosphate Metabolite Levels in Drug-sensitive and -resistant Human Breast Cancer Cell Lines Determined by ³¹P Magnetic Resonance Spectroscopy¹ Free

³¹P magnetic resonance spectra of perfused human breast cancer cells with the phenotype of pleiotropic drug resistance exhibit striking differences in the levels of phosphate metabolites from the wild-type, drug-sensitive parent cell line. Resistant cells demonstrated elevated levels of phosphocreatine and depressed levels of phosphomonoesters, phosphodiesters, and diphosphodiesters. These differences may reflect significant alterations in the control of bioenergetic metabolism between drug-resistant and -sensitive cells.