Cisplatin-stimulated murine bone marrow-derived macrophages secrete oncostatin M

Cisplatin (CP), a widely used anticancer drug activates cells of the immune system to a tumoricidal state, and thus functions as a potent biological response modifier. Expression of oncostatin M (OSM), a novel cytokine having a growth regulatory effect, was studied in bone marrow-derived macrophages treated with cisplatin. Supernatants from CP-stimulated macrophages were found to be cytostatic for OSM-sensitive A375 melanoma cells. Immunoblot analysis with anti-OSM antibody revealed that expression of OSM in macrophages upon CP stimulation is a rapid process and within 30 min of CP treatment, a significant amount of OSM is secreted into the culture supernatant. These results therefore indicate that CP can stimulate murine bone marrow-derived macrophages to produce OSM which can be implicated as one of the cytostatic/ cytocidal factors in the antitumour action of cisplatin-stimulated macrophages.