[Changes of fibrinolytic activity of human HL60 acute leukemia cells responses to chemically induced differentiation].

The fibrinolytic activity of human acute leukemia HL 60 and K 562 cells was studied by the (I25)I-fibrin plate method. The treatment of this cell lines with chemical inducers of differentiation such as Dimethyl sulfoxide (DMSO), 12-0-tetradodecanoilphorbol 13-acetate (TPA), and retinoic acid was found in some instance to affect such fibrinolytic activity. Increased activity was found during the myeloid differentiation induced by retinoic acid of HL 60, while the DMSO, another inducer of myeloid differentiation, and TPA, an inducer of macrophagic differentiation, both produced a decreased of the lytic activity. In the treatment with retinoic acid of th K 562 cells, which do not differentiate by such compound, we failed to show an increase of the fibrinolytic activity. Our data suggest that changes of the fibrinolytic activity of HL 60 are related to the process of differentiation.