Tartrate-resistant acid phosphatase (TRAcP) is used as a marker for osteoclasts, which are believed to be derived from phagocytic cells or phagocyte stem cell precursors. To further investigate the relationship between monocytic phagocytes and osteoclasts, acid phosphatase (AcP) activity was measured by three different techniques in human peripheral blood monocytes, monocyte-derived macrophages...

Acute Myeloid Leukemia (AML), a cancer of the myeloid line of blood cells, progresses rapidly and is typically fatal within weeks or months if left untreated. Asparaginases are a class of enzymatic anti-leukemia agents that induce apoptosis in leukemia cell lines; however, the role of L-asparaginase in the induction of apoptosis in AML cells has not been investigated. In this study, we investig...

Interactions between the cyclin-dependent kinase inhibitor (CDKI) flavopiridol (FP) and phorbol 12-myristate 13-acetate (PMA) were examined in U937 human leukemia cells in relation to differentiation and apoptosis. Simultaneous, but not sequential, exposure of U937 cells to 100 nM FP and 10 nM PMA significantly increased apoptosis manifested by characteristic morphological features, mitochondri...

Antisera to the naloxone-insensitive receptor for beta-endorphin expressed on the U937 cell line were generated by using the complementary peptide strategy. A nanopeptide complementary to a C-terminal fragment of human beta-endorphin was synthesized as predicted by reading the beta-endorphin antisense mRNA 3' to 5'. By using enzyme-linked immunosorbent assay, rabbit antisera specific for the pe...

ELLS OF THE monocyte/macrophage lineage are considered to be a reservoir of human immunodeficiency virus (HIV). The virus infects these cells without killing them and the cells produce moderate amounts of virus indefinitely.' During the maturation of the cells, HIV replication can be modified.' In particular, HL-60 cells induced to differentiate before infection become permissive for monocytotr...

We have recently described a significant correlation between human immunodeficiency virus-1 (HIV-1) RNA replication and monocyte chemotactic protein-1 (MCP-1) levels in the cerebrospinal fluid (CSF) of individuals with the acquired immunodeficiency syndrome (AIDS) with HIV encephalitis (E). Because local macrophages (microglia) are the cells predominantly infected in the brain, we investigated ...

We have recently demonstrated that bufalin is a new potent inducer of the differentiation of human myeloid leukemia cells. The present work was carried out to examine further the effect of bufalin on the growth and characteristics of human leukemia-derived cell lines U937, Mil. and HL60. At concentrations of 5-10 IIM,bufalin decreased the growth of Mil cells preferentially at the G2 phase and U...

To analyze the activity of the CD11c promoter during myeloid differentiation without the limitations of transient expression systems, we have stably transfected the myeloid U937 cell line with the pCD11C361-Luc plasmid, in which the expression of the firefly luciferase cDNA is driven by the CD11c promoter region -361/+43, previously shown to confer myeloid specificity to reporter genes. The sta...

Glucocorticoids inhibit the proliferation of lymphoid leukemia cells, whereas most myeloid leukemia cells are resistant to glucocorticoids. However, this study showed that glucocorticoids significantly and preferentially inhibited growth of monocytoid leukemia cells in combination with a low concentration of transforming growth factor beta (TGF beta). Combined 1 alpha,25-dihydroxyvitamin D3 and...

Radioiodinated recombinant human interferon-gamma (IFN gamma) bound to human monocytes, U937, and HL60 cells in a specific, saturable, and reversible manner. At 4 degrees C, the different cell types bound 3,000-7,000 molecules of IFN gamma, and binding was of comparable affinity (Ka = 4-12 X 10(8) M-1). No change in the receptor was observed after monocytes differentiated to macrophages or when...