Activation of cytokine production and adhesion molecule expression on THP-1 myelomonocytic cells by macrophage colony-stimulating factor in combination with interferon-gamma.
THP-1 myelomonocytic leukemia cells cultured with either macrophage colony-stimulating factor (M-CSF) or interferon-gamma (IFN-gamma) alone produce, at best, only low levels of interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha). However, combinations of the two factors resulted in at least 3- to 20-fold greater amounts of IL-1 beta and TNF-alpha than would have been predicted by additive mechanisms. This enhanced cytokine production was observed when M-CSF and IFN-gamma were added simultaneously or when M-CSF was added 24 h after addition of IFN-gamma to the cells. Similar results were obtained with fresh human peripheral blood cells treated with IFN-gamma + M-CSF. Cycloheximide treatment of the cultures containing M-CSF and IFN-gamma inhibited the production of IL-1 beta and TNF-alpha. Northern blotting studies revealed no effect of IFN-gamma alone on IL-1 beta or TNF-alpha mRNA production. IL-1 beta and TNF-alpha mRNA expression was observed at 2 and 6 h after treatment with M-CSF or IFN-gamma + M-CSF. Higher TNF-alpha mRNA expression was observed at 2 and 6 h after treatment with IFN-gamma + M-CSF, and higher IL-1 beta mRNA expression was observed at 2 h after treatment with IFN-gamma + M-CSF compared with mRNA levels observed for cells cultured only with M-CSF. These results suggest that the augmented cytokine production resulting from treatments with combinations of M-CSF and IFN-gamma occurs due to increased cytokine mRNA and increased cytokine protein synthesis. In addition to up-regulating cytokines, combinations of IFN-gamma and M-CSF resulted in augmented cell surface expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. This was accompanied by morphological and functional changes that included plastic adherence, extensive homotypic aggregation, and a macrophage-like appearance. These phenotypic changes and enhancements in cytokine expression and cell surface molecule expression may be related to activation of monocytic cells to become cytotoxic effectors by M-CSF and IFN-gamma combinations. In vitro cytotoxicity against A-375 melanoma cells was greatest for cultures that contained M-CSF and IFN-gamma in combination.
Kimball
E S
ES
Oncology and Endocrinology Research, Janssen Research Foundation, Spring House, Pennsylvania 19477-0776, USA.
Kovacs
E
E
Clark
M C
MC
Schneider
C R
CR
D003513:Cycloheximide / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D007111:Immunity, Cellular; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007371:Interferon-gamma / Q000008:administration & dosage*; D007375:Interleukin-1 / Q000008:administration & dosage*; D007948:Leukemia, Monocytic, Acute / Q000378:metabolism*; D016173:Macrophage Colony-Stimulating Factor / Q000008:administration & dosage; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
D007375:Interleukin-1; D011500:Protein Synthesis Inhibitors; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D016173:Macrophage Colony-Stimulating Factor; D007371:Interferon-gamma; D003513:Cycloheximide