Murine macrophage activation after cisplatin or carboplatin treatment

Murine peritoneal macrophages when treated in vitro with cisplatin (9 micrograms/ml) or carboplatin (50 micrograms/ml) for 2 h are stimulated to form cytoplasmic extensions seeking out tumor cells and establishing cytoplasmic connections; however, no contact is observed with normal cells (fibroblasts and hepatocytes). In addition, cisplatin and carboplatin treatment leads to an increase in the number of lysosomes and their transfer to the tumor cells resulting in lysis (as studied by confocal microscopy). Although calcium seems to be involved in the signalling of macrophage activation, cytosolic calcium does not seem to influence this activation.