Variation of choline-substituted lipid metabolism in doxorubicin-resistant leukemia cells

In adriamycin-resistant murine (FLC) and human (K562) leukemia cells, phosphatidylcholine increases and phosphatidylethanolamine decreases compared to adriamycin-sensitive lines. This change is due to an increase in phosphatidylethanolamine methylation. The choline pathway of phosphatidylcholine biosynthesis is also disturbed in resistant cells with a blocking step of CDP-phosphocholine transferase and a decrease in sphingomyelinase activity. These changes in phospholipid metabolism are suggested to be responsible for the changes in membrane fluidity reported previously (Tapiero et al, 1986) for resistant cells.