[Effects of cisplatin on cultured glioma cells]

Cytotoxic and cytokinetic effects of Cisplatin (cisdiamminedichloroplatinum) on cultured human and rat glioma cells (KY and C6) were studied both in vitro and in vivo. The cytotoxic or cytostatic effect was evaluated by either colony formation assay or inhibition rate of cell growth. The cytokinetic effects were analyzed by DNA histogram using a flow cytometer. It was found that the cytotoxic effect of Cisplatin on the cultured glioma cells was dose-dependent, and that human KY cells and rat C6 cells had similar sensitivity to Cisplatin. Within 24 hours after treatment of KY cells with Cisplatin, a time-dependent effect was observed, but the cytotoxic effect of Cisplatin in the medium decreased rapidly. Investigation of chronological changes in the DNA histogram of KY cells treated with 0.2 microgram/ml Cisplatin revealed that cell-cycle progression was delayed in the S-phase and blocked at the S-G2 + M boundary 18 hours later. KY tumors subcutaneously transplanted into nude mice were treated with intraperitoneal injection of 3 mg/kg/day Cisplatin for 10 days and the tumors markedly regressed by 65% of their wet weight.