EXPRESSION OF MEGAKARYOCYTIC AND ERYTHROID PROPERTIES IN HUMAN LEUKEMIC-CELLS

Previous studies have suggested that megakaryocytes and erythrocytes m ap share a common precursor cell. However, studies on the commitment t o erythroid and megakaryocytic lineages have been hampered by the lack of suitable human leukemic cell lines having this kind of bipotential differentiation capability. We investigated the coexpression of megak aryocytic and erythroid markers in human leukemic cell lines as well a s the capability of these cells to further differentiate upon exposure to differentiation-inducing agents. We report that the JK-1 cell line , previously characterized as a typically erythroid cell line with spo ntaneous differentiation to red cells, actually coexpressed. megakaryo cytic cell surface antigens and erythroid spectrins. We also report th at the JK-1 cells could be induced to differentiate along the megakary ocytic lineage by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The other cell lines studied variably expressed megakaryocytic and erythroid antigens, the DAMI and CMK cells predominantly megakary ocytic properties and the T-33 and K562 cells some erythroid markers, whereas the HEL cells expressed markers for both lineages of different iation. Our results suggest that the JK-1 cell line represents an imma ture cell population that has not yet been committed to either of the two lineages of differentiation. The JK-1 cell line might provide a us eful tool for further studies on the transcriptional regulation of ery throid and megakaryocytic phenotypes and for studies on the commitment to these lineages of differentiation. Our results also suggest that t he leukemic cell lines show a considerable plasticity in the expressio n of properties normally specific for distinct lineages of differentia tion.