Modulation of human lymphoblastoid B cell line by phorbol ester and sphingosine. A 31P-NMR study

Changes in phospholipid and energy metabolism in Epstein-Barr Virus transformed B lymphocytes (EBV-B), induced by phorbol 12,13-dibutyrate (PD) and sphingosine (an inhibitor of protein kinase C), have been evaluated by 31P-NMR spectroscopy. The effects of PD and sphingosine on [3H]thymidine incorporation have also been studied. An increase in phosphorylcholine (PCho) levels has been observed in sphingosine and sphingosine + PD treated cells after 30 min of incubation, whereas no change was observed in lymphocytes incubated with PD during the same period. Extracellular choline levels increased in sphingosine treated cells but decreased in PD treated cells. Hence, a sphingosine-dependent hydrolysis of choline-linked phospholipids is suggested. A time-dependent reduction of PCho observed after 120 min PD incubation is consistent with an increase of the synthesis of choline-linked phospholipids.