Glycosphingolipids of K562 cells: a chemical and immunological analysis

The K562 cell line, which was established from a patient with chronic myeloid leukemia in blast crisis, was thought to be myeloid, but recent data indicate that it is an undifferentiated erythroid cell line. We have found that the glycosphingolipid content of these cells differs considerably from that of mature erythrocytes. Globotetraosylceramide, the most abundant glycolipid of mature red cells, was not detected in K562 cells, and neither was globotriaosylceramide. The predominant neutral glycolipids of K562 cells are monohexaosylceramides, which are a mixture of glucosyl- and galactosylceramides, and lactotriaosyl- and lactoneotetraosylceramides were also detected. Secondly, gangliosides which contain N-acetylgalactosamine were much more abundant than those containing N-acetylglucosamine in K562 cells, in contrast to erythrocytes. The most abundant ganglioside of K562 cells, GM2, is present in trace quantities in erythrocytes. A third major difference between these two cells lies in their relative proportions of neutral glycolipids and gangliosides. The molar ratio of neutral glycolipids/gangliosides is approximately 15:1 in erythrocytes and 1:1 in K562 cells. These striking differences between K562 cells and mature erythrocytes indicate that glycolipids may be useful cell surface markers of normal erythrocyte differentiation, and of erythroleukemias.