Multiple differentiation programs in K562 erythroleukemia cells and their regulation.

The chronic myeloid leukemia-derived cell line K562 expresses, in its uninduced state, notable erythroid features. However, in addition to the presence of well-characterized "erythroid-specific" molecules, such as hemoglobin and glycophorin A, there is increasing evidence of both granulopoietic and megakaryocytic differentiation in this cell line. In this chapter we have further characterized erythroid and nonerythroid features in order to investigate the range of differentiation programs expressed by uninduced K562 cells. Also we have extended these observations by attempting to manipulate the expression of the different lineage-specific components of the phenotype of the K562 cell line in induction experiments. The aim of these studies was to attempt to determine the extent and significance of multipotentiality in K562. The relationship of our findings on the phenotype of K562 to the nature of multipotent hemopoietic stem cells and their differentiated progeny in normal and malignant hemopoiesis is discussed.