Induction of megakaryocytic characteristics in human leukemic cell line K562: polyploidy, inducers, and secretion of mitogenic activity.

Because of the rarity of megakaryocytes in the bone marrow, a cell line inducible for megakaryocytic characteristics provides a valuable model for study. When cultured with phorbol esters, the human multipotent hematopoietic leukemic cell line K562 can be induced to develop many megakaryocytic characteristics, viz. increased cell size, reduced growth rate, megakaryocytic antigens, and expression of the sis proto-oncogene, the structural gene for the B-chain of platelet-derived growth factor. Further aspects of this process are here presented. First, it induces the release of mitogenic activity into the medium. Second, phorbol dibutyrate induces polyploidy, a feature of normal megakaryocyte development. Third, mezerein and teleocidin, nonphorbol ester tumor promotors, also induce development of multinuclearity and polyploidy.