| Abstract: | Disseminated intravascular coagulation (DIC) is a frequent occurrence in acute promyelocytic leukemia (APL), especially after onset of chemotherapy. We have used a human promyelocytic leukemic established cell line (HL-60) and various other human leukemic cells to investigate the effect of cytotoxic drugs on generation of procoagulant activity (PCA). The results indicate that, unlike normal human peripheral blood monocytes and certain other cell types where PCA induction requires active mRNA and protein synthesis, in HL-60 cells, compounds such as actinomycin D, puromycin, and cytosine arabinoside and a variety of other cytotoxic agents, induced generation of a potent PCA. Although different in its mechanism of induction, this HL-60 cell PCA was similar, and may be identical, to mononuclear cell tissue factor. The PCA induction was rapid and preceded the lytic effect of the drugs. It was first detected on the outer cell surface but, following prolonged exposure to the drugs, upon lysis of the cells, it was also found in the extracellular medium. This in vitro effect mimics the development of DIC in patients with APL. The system may, therefore, serve as a model for the study of the cellular and molecular events associated with PCA generation by malignant promyelocytes and DIC occurrence in patients with APL and other malignancies. |
