In vitro cytotoxicity of cisplatin combined with carboplatin on osteosarcoma cell line OS-732

Objective To observe the cytotoxicity of cisplatin combined with carboplatin on osteosarcoma cell line OS-732.Methods Using MTT assay,we obtained the mean IC50 of cisplatin and carboplatin for OS-732 cells.The OS-732 cells were incubated with following drugs for 48 or 72h: IC50 of cisplatin,IC50 of carboplatin,and 1/2 IC50 of cisplatin combined with 1/2 IC50 carboplatin.The cytotoxicity of each group was measured with MTT methods.Results The mean IC50 of cisplatin and carboplatin for osteosarcoma OS-732 cells for 48h was 7.6μg/ml and 199.0μg/ml respectively.The mean cytotoxicity index(CI) of 8.0μg/ml cisplatin, 200.0μg/ml carboplatin and 4.0μg/ml cisplatin+100.0μg/ml carboplatin for 48h were (54.7±5.3)%,(56.9±6.3)% and(57.5±5.7)% respectively(P0.05);and those for 72h were (65.7±4.5)%,(69.4±2.2)% and(68.4±3.6)% respectively,the cytotoxicity index increased significantly in groups containing carboplatin.Conclusion The combination of half dose cisplatin with carboplatin appears to be as active as cisplatin or carboplatin alone in full doses in treatment of osteosarcoma OS-732 cells in vitro.