Recombinant human granulocyte‐macrophage colony‐stimulating factor induces secretion of autoinhibitory monokines by U‐937 cells

Abstract

Colony-stimulating factors are required for survival proliferation, differentiation and functional activation of granulocytes, macrophages and their precursor cells. In the present report, however, we demonstrate antiproliferative activity of recombinant human (rh) granulocyte-macrophage colony-stimulating factor (GM-CSF) on monoblast cell line U-937 and provide evidence for the involvement of tumor necrosis factor alpha TNF-alpha and interleukin 1 beta (IL 1 beta) in its growth inhibitory action. GM-CSF (but not granulocyte CSF, G-CSF or macrophage CSF, M-CSF) suppressed DNA synthesis and self renewal of U-937 cells. Similarly, medium conditioned by U-937 cells in response to GM-CSF (GM-CSF U-937-CM) was able to reduce clonogenicity and [3H]thymidine uptake by U-937 cells. Since neutralization of GM-CSF present in GM-CSF U-937-CM by monoclonal antibody to GM-CSF did not abrogate the autoinhibitory activity present in GM-CSF U-937-CM, we considered the possibility that other soluble molecules are released by U-937 cells upon GM-CSF stimulation. Neutralization by antibodies to IL 1 beta and TNF-alpha suggested that both monokines could be the antiproliferative principle operating in GM-CSF U-937-CM. Moreover, employing IL 1 beta-specific enzyme-linked immunosorbent assay, TNF-alpha specific radioimmunoassay, Northern analysis using a cloned TNF-alpha-specific cDNA and an oligonucleotide probe for IL 1 beta, we demonstrate GM-CSF-inducible IL 1 beta and TNF-alpha gene expression by U-937 cells at the mRNA and protein level. Although M-CSF expression was induced under similar conditions, M-CSF failed to inhibit growth of U-937 cells.

rhG-CSF affects genes involved in mitogen signalling and early gene expression in the ovarian cancer cell line HEY

“…This was not possible with 17% FCS (Spinner et al (1995). In addition, U-937 cells that respond to rhG-CSF treatment (Lindemann et al, 1988) were a good systemic indicator (Fig. 2).…”

“…certainly important parameters for this clinically relevant topic. The presence of wild-type G-CSF receptor does not necessarily mean proliferation of cancer cells since an inhibition of proliferation has been observed for the ovarian cancer cell line NIH: OVCAR-3 (Spinner et al, 1995;Conner et al, 1994) and the leukemic cell line U-937 (Lindemann et al, 1988). Transfection of the murine G-CSF receptor-negative cell line WEHI-3B with wild-type G-CSF receptor causes differentiation of this cell line in response to exogenous G-CSF (Li et al, 1995).…”

“…Two ovarian carcinoma cell lines, BG-1 and SK-OV-3, and the leukemic cell line U-937, which does have G-CSF receptor, were analysed. None of these cell lines showed any G-CSF effect, except that cell division was inhibited by approximately 30% in the cell line U-937 (Lindemann et al, 1988) (Fig. 2).…”

“…After harvesting, cells were counted (CASY 1) and DNA synthesis was measured by BrdU. FIGURE 2 -Different ovarian cancer cell lines (BG-1 and SK-OV-3) and the leukaemic cell line U-937, which possesses G-CSF receptor, the inhibition of which under rhG-CSF was mentioned by Lindemann et al (1988) (control), were exposed to rhG-CSF under the conditions described (48 hr starving in 0.2% serum, further 48 hr exposure to 50 or 200 U rhG-CSF/mL in 0.2% serum). After harvesting, cells were counted with the cell counter CASY 1.…”

Autocrine stimulation of a human lung mesothelioma cell line is mediated through the transforming growth factor alpha/epidermal growth factor receptor mitogenic pathway

“…It has been shown that exogenous TNF-a up-regulates in vitro expression of TNF-a and EGFR in human pancreatic carcinoma cells (Schmiegel et al, 1993). Interestingly, ZL34 cells produce TNF-a (our own observation) as well as granulocyte-macrophage colony-stimulating factor (GM-CSF) (Schmitter et al, 1992), which is known as an activator of TNF-a production (Lindemann et al, 1988). Moreover ZL34 cells secrete interferon-y (our own observation), a cytokine which also enhances TGF-a expression (Hamburger & Pinnamaneni, 1993).…”