Changes in isoenzyme patterns expressed by the erythroleukemia cell lines K-562 and HEL after induction of differentiation.

Stable human leukemia-lymphoma cell lines provide model systems to study the processes involved in leukemic and normal cell differentiation [10]. Leukemic cells, arrested at a certain stage of differentiation, can be triggered to differentiate to functionally and morphologically more mature cells [7]. Both "fresh" leukemic cells and cells maintained in long-term culture are sensitive to in vitro induction of differentiation. Furthermore, cell differentiation is a novel concept in the treatment of acute leukemias and several substances such as low dose Ara-C and the physiologic compound retinoic acid have been shown to act as differentiating agents in vivo [7]. Two human erythroleukemia cell lines, K-562 [8] and HEL [9], were used to study the effects of 12-0-tetradecanoylphorbol13-acetate (TP A) and of a differentiation inducing factor-(DIF)-containing medium for induction of differentiation.