RESUMEN
Objective To evaluate the radiosensitization effect of gemcitabine in human cholangiocarcinoma cells(QBC939)in vitro. Methods The IC10,IC50 and IC90 of gemcitabine in QBC939 cells were determined by clonogenic assay,which were adopted in the following experiments.The cells were divided into five groups:control group,chemotherapy group,radiation group,radiation after chemotherapy(C+R)group and radiation before chemotherapy(R+C)group.The radiation dose ranged from 1 Gy to 10 Gy.The cell survival Curves were fit using two-component equation and the sensitive enhancement ratio(SER)was calculated.Results The IC10,IC50 and IC90 of gemcitabine in QBC939 cells were 0.1 nmol/L(low concentration),11.0 nmol/L(moderate concentration)and 21.5 nmol/L(high concertration),resDectively.Gemcitabine in low concentration radiosensitized the cells at low irradiation dose(≤2 Gy)in R +C group(SERDq=1.52).Gemcitabine in moderate concentration had radiosensitization effect at all irradiation doses in C+R group(SERD0=1.27,SERDq=116.93),and at low irradiation dose(≤2 Gy)in R+C group.Gemcitabine in high concentration had radiosensitization effect at all irradiation doses in both R+C and C+R groups,which was most markedly at low irradiation dose(≤2 Gy)in R+C group(SERDq =323.30). Conclusions Gemeitabine has radiosensitization effect in QBC939 cells,which is based on the optimal scheduling and concentration.