heparitin-sulfate and Leukemia--Monocytic--Acute

We have previously shown that heparin and heparan sulfate stimulate the growth of human erythroleukemia cells in vitro in the presence of serum or plasma. To determine whether heparin and other glycosaminoglycans (GAGs) are involved in the growth of leukemia cells, effects of GAGs on the growth of three leukemia cell lines expressing different phenotypes, the HEL, HL60 and U937 cell lines were studied using both plasma clot and serum-free agar systems. The cells were cultured with different doses of six GAGs: hyaluronic acid, chondroitin sulfate, dermatan sulfate, keratan sulfate, heparin and heparan sulfate. It was found that, in serum-free agar system, no GAG was able to stimulate (HEL) cell growth. In contrast, when serum-containing culture systems were used, all six GAGs promoted colony formation of HL60 and U937 cells. In addition, all GAGs, except keratan sulfate, stimulated the growth of HEL cells. The findings suggest that the GAGs may play an indirect role in enhancing leukemia cell proliferation by different mechanisms.

Topics: Cell Division; Chondroitin; Culture Media; Dermatan Sulfate; Glycosaminoglycans; Heparin; Heparitin Sulfate; Humans; Hyaluronic Acid; Keratan Sulfate; Leukemia; Leukemia, Monocytic, Acute; Leukemia, Promyelocytic, Acute; Tumor Cells, Cultured

Human promyelocytic (HL-60) and monoblast-like (U-937) leukemia cell lines were tested for expression of an endoglycosidase (heparanase) capable of degrading heparan sulfate (HS) side chains in the subendothelial extracellular matrix (ECM). Heparanase activity has been previously shown to be expressed by activated lymphocytes and macrophages and by highly metastatic tumor cells, in correlation with their ability to invade blood vessels and extracellular matrices. Incubation of HL-60 and U-937 cells with sulfate-labeled ECM in the presence of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) resulted in heparanase-mediated release of heparan sulfate degradation products. This degradation was inhibited by heparin, stimulated by plasminogen and not expressed by cells treated with retinoic acid or dimethylsulfoxide and undergoing neutrophilic differentiation. Heparanase activity was not detected in media conditioned by HL-60 and U-937 cells but was found in their cell lysates, regardless of whether or not the cells were exposed to TPA. These findings imply that TPA-induced differentiation of human myeloid leukemic cells to macrophage-like cells, but not to neutrophilic granulocytes, is associated with expression on the cell surface of a preformed heparanase activity. The enzyme may serve as a marker for human cell differentiation into macrophages, allowing the differentiating cells to traverse the vascular compartment and reach their target sites.

Topics: Cell Line; Extracellular Matrix; Glucuronidase; Glycosaminoglycans; Glycoside Hydrolases; Heparitin Sulfate; Humans; Leukemia, Monocytic, Acute; Leukemia, Promyelocytic, Acute; Molecular Weight; Plasminogen; Tetradecanoylphorbol Acetate

An 8-month-old male with acute monoblastic leukemia died during induction chemotherapy of severe bleeding refractory to repeated infusions of platelets and clotting factors. A heparin effect was suggested by prothrombin time (PT) of 26 seconds, partial thromboplastin time (PTT) of 94 seconds, thrombin time 240 seconds, and reptilase time 18.4 seconds, with a fibrinogen of 88 mg/dl. Both plasma mixed with the patient's urine and the patient's plasma had their thrombin times corrected toward normal by both PF4 and protamine. Synergism of the anticoagulant with antithrombin III was demonstrated not only by enhanced inhibition of thrombin but also by an increased rate of formation of thrombin--antithrombin III complexes in the presence of the anticoagulant, which was eliminated by preincubation with heparinase. Since the anticoagulant activity was not found in the blasts themselves, it is presumed that the anticoagulant is heparin/heparan liberated from the endothelial lining by products of the cell destruction secondary to chemotherapy.

Topics: Acute Disease; Blood Coagulation; Drug-Related Side Effects and Adverse Reactions; Heparin; Heparitin Sulfate; Humans; Infant; Leukemia, Monocytic, Acute; Male