Phenylalanine methylester (PME), a lysosomotropic compound can be used to deplete monocytes and myeloid cells from peripheral blood and bone marrow (BM). The potential of PME for purging leukemic cells from BM was investigated using U937 and HL-60 cell lines as models. Optimal purging conditions for U937 cells were determined using an MTT assay (3-4, 5-dimethylthiazol-2, 5-diphenyl tetrazolium ...

Three different antibodies against a human TNF receptor (htr-1, htr-5, and htr-9) have been examined for their binding pattern to U937 cells and ability to mimic TNF-alpha activity in U937 cells, Fs4 fibroblasts, and human endothelial cells. Flow cytometric analysis revealed that htr-5 and htr-9 bound specifically to a TNF receptor on U937 cells that could be blocked by pretreatment with rTNF-a...

A human cell line (U937) can be stimulated to produce a soluble factor (MCF) by either lectin-activated T lymphocytes or their soluble products. In prior studies, we showed that MCF produced by peripheral blood mononuclear cells can increase production of collagenase and prostaglandin E2 by adherent synovial cells obtained from enzymatically dispersed rheumatoid synovium. We show here that peri...

U937 cells have low levels of surface thrombospondin (TSP) under control conditions but express higher levels after treatment for 1 day with 100 nM phorbol myristate acetate (PMA). Increased surface expression is due, in part, to increased biosynthesis. Untreated U937 cells do not adhere to TSP-coated plastic culture dishes but adhere strongly to TSP after stimulation with PMA. Untreated U937 c...

We examined the effect of transforming growth factor-beta (TGF-beta) alone and in combinations with other factors on the growth and differentiation of the human promyelocytic cell line HL60 and the human monoblastic cell line U937. Treatment with TGF-beta alone did not significantly affect growth or differentiation of HL60 cells, while it significantly inhibited proliferation and induced monocy...

Adhesion of leukocytes to endothelial cells in inflammation processes leads to changes of endothelial cell-substrate adhesiveness, and understanding of such changes will provide us with important information of inflammation processes. In this study, we used a noninvasive biosensor system referred to as real-time cell electronic sensor (RT-CES) system to monitor the changes in endothelial cell-s...

Incubation of the human monoblastoid tumor cell line U937 with 5 x 10(-9) M 12-O-tetradecanoylphorbol-13-acetate (TPA) for 3 days was associated with marked morphological and functional changes including adherence of the cells and cessation of proliferation. While growth arrest and the viability of the cells were not influenced, the TPA-induced adherence of U937 cells could be totally blocked b...

Tumor-associated macrophages (TAMs) have been implicated in promoting tumor growth and development. Here we present evidence that demonstrates that co-inoculation of male athymic nude mice with PC-3 prostate cancer cells and U937 promonocytic cells enhances tumor growth and increases tumor angiogenesis. Male athymic nude mice were co-inoculated with PC-3 and U937 cells (control or IL-4 stimulat...

Gamma interferon induced surface expression of interleukin 2 (IL-2) receptors on normal human monocytes and the monocytoid cell lines U937 and HL60. These receptors were detected by anti-IL-2 receptor monoclonal antibodies, and U937 IL-2 receptors were indistinguishable from T lymphocyte IL-2 receptors by immunoprecipitation. Also, U937 IL-2 receptors bound biologically active IL-2. These resul...

Many putative differentiating agents arrest cell growth prior to progression of the cell through differentiation. Vitamin E-succinate is known to be a potent modulator of haematopoietic differentiation as well as an inhibitor of cell growth in vitro and in vivo. In this study, we examined whether vitamin E-succinate could modulate the monocytic differentiation of U937 human monoblasts. Treatmen...