Potential role of interleukin-1 as the trigger for diffuse intravascular coagulation in acute nonlymphoblastic leukemia

Abnormal regulation of coagulation/fibrinolysis in small cell carcinoma of the lung

Components of coagulation and fibrinolysis reactions were identified in situ by immunohistochemical staining in fresh frozen sections of small cell carcinoma of the lung tissue. Tumor cells stained positively for tissue factor, a protein that is capable of activating the extrinsic pathway of coagulation (the components of which have been seen within small cell carcinoma of the lung [SCCL] tissue), and for proteins C and S antigens. Fibrin was seen in a focal distribution at the host-tumor interface, indicating that thrombin had acted upon the fibrinogen found throughout the tumor stroma. Staining with a neoepitope-specific antibody, which does not discriminate between fibrinogen fragment D and fibrin fragment D-dimer, was similar to that of the fibrin antibody. High molecular weight urokinase-type and tissue-type plasminogen activators were seen in vascular endothelium, but neither existed within the tumor. Low molecular weight urokinase was found in rare isolated foci of tumor cells primarily adjacent to areas of necrosis. Plasminogen activator inhibitor-3 occurred in tumor cell cytoplasmic blebs and in necrotic tumor cells, but plasminogen activator inhibitors 1 and 2 were not seen. Our data suggest a mechanism for thrombin generation and fibrin formation within SCCL tissues that could support cell proliferation, stroma formation, and preservation. These features could be conductive to perpetuation of this tumor and conceivably could form the basis of the beneficial effects of antithrombotic therapy seen in SCCL.

Induction of tissue factor by interleukin-2 in acute myelogenous leukemia (AML) cells

We investigated the induction of tissue factor by lymphokines in human monoblastic leukemia cell lines (U937) and leukemic cells from AML (acute myelogenous leukemia) patients. After incubation for 24 h, IL-2 enhanced the intracellular tissue factor 15-fold with U937 cells, and GM-CSF enhanced it 6-fold. In contrast, other lymphokines, such as IL-1-alpha, IL-1-beta, IL-3, IL-4 and G-CSF, did not affect the activity of tissue factor. The leukemic blasts, depleted of T-lymphocytes, taken from five out of 16 AML patients showed a 2.5-14-fold increase in the activity of tissue factor per cell following incubation with 200 u/ml of IL-2 for 72 h. The IL-2 induced tissue factor activity more markedly than GM-CSF. Tissue factor stimulation by IL-2 did not correlate with the expression of the IL-2 receptor, Tac, but correlated well with FAB classification of AML cells. IL-2 responders were found in M4 and M5 subtypes only, but not all M4/M5 leukemias responded to IL-2. These findings indicate that IL-2 can mediate the tissue factor induction in the monocytic type of AML and the effect is not mediated by Tac receptors. This may shed a new light on our understanding of hypercoagulability in acute monoblastic leukemia.

Identification and partial purification of a novel tumor-derived protein that induces tissue factor on cultured human endothelial cells

Conditioned medium of a human bladder carcinoma cell line (J82) was found to induce tissue factor synthesis in cultured human umbilical vein endothelial cells (HUVEC). A protein present in the J82 conditioned medium was partially purified by FPLC using a combination of MONO Q and Superose 6 columns. The bladder carcinoma-derived cytokine (BCDC) exhibited a Mr of 22 kDa by gel permeation HPLC. Polyclonal antibody against either interleukin-1, tumor necrosis factor, or transforming growth factor-beta failed to inhibit the ability of the conditioned medium to induce HUVEC tissue factor activity, suggesting that this tumor cell line secretes a novel cytokine responsible for HUVEC tissue factor induction.

Interleukin 1 as an autocrine growth factor for acute myeloid leukemia cells

Production of interleukin 1 (IL-1) by leukemic cells was studied in 13 cases of acute myeloid leukemia. Intracytoplasmic immunofluorescence studies showed that the cells invariably contained the cytokine. Endogenous labeling studies demonstrated that acute myeloid leukemia cells produced either only the 33-kDa propeptide or both the propeptide and the 17-kDa mature form of IL-1 beta. The 33-kDa propeptide IL-1 alpha was always produced but was less frequently released. Involvement of IL-1 in leukemic cell growth was investigated using two antibodies specific for IL-1 subtypes, which inhibited spontaneous cell proliferation in the six cases studied. After acid treatment of the cells, a surface receptor for IL-1 could be demonstrated, which mediated 125I-labeled IL-1-specific uptake by leukemic cells. Furthermore, recombinant IL-1 alpha or IL-1 beta induced significant cell proliferation in 10 of 12 cases. The above findings were uncorrelated with the cytologic type (French-American-British classification) of leukemia. Our studies suggest that IL-1 may act as an autocrine growth factor in most cases of acute myeloid leukemia.