title: An in vitro study on the mechanisms of coagulation activation in acute myelogenous leukemia (AML): role of tissue factor regulation by cytotoxic drugs and GM-CSF.
abstract: AML patients may suffer from a disseminated coagulopathy, which can aggravate a pre-existing bleeding tendency due to thrombocytopenia and platelet dysfunction. The cellular and molecular mechanisms underlying this coagulopathy, however, are not completely understood. Indeed, the broad and increasing therapeutic use of cytotoxic drugs and growth factors is likely to contribute to the complexity of hemostatic abnormalities encountered in this hematologic malignancy. The nature of coagulation activation in AML was therefore investigated in vitro using the human leukemic cell line, HL60. Tissue factor (TF) was almost entirely located on the cell surface and bound factor VIIa, but only 15-25% of this TF was primarily functionally active. Treatment with increasing concentrations of daunorubicin or cytosine-beta-D-arabinofuranoside, two cytotoxic drugs commonly used in AML therapy, induced apoptosis and secondary necrosis of HL60 cells and resulted in marked decryption of TF PCA independent of de novo protein synthesis. This PCA-modulating effect was concomitant with and functionally dependent on the exposure of phosphatidylserine on the outer membrane leaflet. Similar observations were made in analogous ex vivo studies on patient-derived myeloblasts. Incubation of HL60 cells with GM-CSF, a cytokine expressed in the bone marrow microenvironment and used as an adjunct to AML treatment, evoked a cellular response, which included both enhanced TF production and release of VEGF-A and uPA into the culture medium. We conclude that both decryption of pre-formed TF PCA by chemotherapeutic drugs and de novo induction of TF by cytokines such as GM-CSF can regulate the pro-coagulant phenotype of HL60 cells in vitro.
authors.affiliation: Clinical and Research Laboratories, Florida Hospital Cancer Institute, Orlando, Florida 32804, USA. florian.langer@flhosp.org
authors.forename: Florian
authors.initials: F
authors.lastname: Langer
authors.forename: Ali
authors.initials: A
authors.lastname: Amirkhosravi
authors.forename: Sonja
authors.initials: S
authors.lastname: Loges
authors.forename: Todd
authors.initials: T
authors.lastname: Meyer
authors.forename: Barbara
authors.initials: B
authors.lastname: Eifrig
authors.forename: Dieter K
authors.initials: DK
authors.lastname: Hossfeld
authors.forename: Walter
authors.initials: W
authors.lastname: Fiedler
authors.forename: John L
authors.initials: JL
authors.lastname: Francis
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D001773:Blood Cells / Q000473:pathology; D001777:Blood Coagulation; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D003561:Cytarabine / Q000494:pharmacology; D003630:Daunorubicin / Q000494:pharmacology; D042381:Granulocyte Precursor Cells / Q000187:drug effects / Q000473:pathology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D007948:Leukemia, Monocytic, Acute / Q000097:blood / Q000473:pathology; D015470:Leukemia, Myeloid, Acute / Q000097:blood* / Q000473:pathology; D015479:Leukemia, Myelomonocytic, Acute / Q000097:blood / Q000473:pathology; D013925:Thromboplastin / Q000096:biosynthesis / Q000187:drug effects* / Q000502:physiology
chemical_list: D000970:Antineoplastic Agents; D003561:Cytarabine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013925:Thromboplastin; D003630:Daunorubicin