Phosphorus-31 nuclear magnetic resonance spectroscopy of human retinoblastoma cells: correlations with metabolic indices

Abstract

The 31P nuclear magnetic resonance spectrum of cultured human Y-79 retinoblastoma cells was obtained at 121 MHz on intact cells trapped in agarose threads. The spectrum was dominated by monoester peaks, which varied in relative concentration from preparation to preparation. Resonances from phosphocreatine, phosphodiesters and diphosphodiesters also exhibited variability relative to ATP. The main monoester was identified as phosphorylcholine by 31P-NMR of perchloric acid extracts. It was determined that the changes in monoester concentration correlated with feeding pattern. Phosphorus spectra of cells 1,2 and 3 days post feeding showed a 40% decrese in the relative concentration of phosphorylcholine concentration over the 3 day period. Phosphocreatine, phosphodiesters and diphosphodiesters increased relative to ATP during the same period. Growth curve experiments and oxygen consumption measurements indicated that the decrease in phosphorylcholine correlated with a decrease in cellular growth and oxygen consumption. We conclude that monoester concentration may be a useful indicator of nutritional status in these cells and possibly in intact tumors.