The effect of oxaplatin on enhancing radiosensitivity in human hepatocellular carcinoma cell line HepG2 / 中华放射肿瘤学杂志

ABSTRACT

Objective To explore the effect of oxaliplatin ( OXA) on enhancing radiosensitivity in human hepatocellular carcinoma cell line HepG2 . Methods 50% inhibition concentration ( IC50 ) of HepG2 cells treated with OXA was measured by using MTT method at 6, 12, 24, 48 hours. Then clone formation assay was applied to obtain sensitizing enhancement ratio ( SER) of OXA combing IR, according to the survival fraction of three groups 10?14 days after treatmentsplacebo?treated group ( C) ,radiation group ( IR, single dose of 1 Gy,2 Gy,4 Gy,6 Gy,8 Gy,10 Gy) and IR synchronizing OXA group ( IR+3 mg/L OXA) . The proportions of cell apoptosis were analyzed using flow cytometry at 24 hours after treatment. At last, we semi?quantitative tested the expression of extracellular regulated protein kinase 1/2 ( ERK 1/2 ) and DNA damage repair protein Ku?70 of the C,IR and IR+OXA groups. Statistical analysis was performed by T test. Results The IC50 of OXA on HepG2 cells is 54?4 mg/L at 6 hours,29?1 mg/L at 12 hours,17?8 mg/L at 24 hours and 10?5 mg/L at 48 hours.3 mg/L was selected in clone formation assay at which 80?90% HepG2 cells survived at 24 hours. The SER ( SF2 ) is calculated as 1?59. Flow cytometry showed the proportion of survival cells in IR+OXA group is significantly lower than those of IR group ( P=0?005) ,OXA group ( P=0?008) and C group ( P=0?001) . The expressions of ERK 1/2 were inhibited in IR and IR+OXA groups compared by that of control group. But the expression of ERK 1/2 in IR group showed increasing after 48 hours which was higher than that of IR+OXA group. For Ku?70,the changes of expression were similar with that of ERK 1/2. Conclusion Oxaliplatin presented enhancing radiosensitivity in human hepatocellular carcinoma cell line HepG2 in vitro.