CISPLATIN-STIMULATED MURINE BONE-MARROW-DERIVED MACROPHAGES SECRETE ONCOSTATIN-M

Cisplatin (CP), a widely used anticancer drug activates cells of the i mmune system to a tumoricidal state, and thus functions as a potent bi ological 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-stim ulated macrophages were found to be cytostatic for OSM-sensitive A375 melanoma cells. Immunoblot analysis with anti-OSM antibody revealed th at expression of OSM in macrophages upon CP stimulation is a rapid pro cess and within 30 min of CP treatment, a significant amount of OSM is secreted into the culture supernatant. These results therefore indica te that CP can stimulate murine bone marrow-derived macrophages to pro duce OSM which can be implicated as one of the cytostatic/cytocidal fa ctors in the antitumour action of cisplatin-stimulated macrophages.