Radiosensitivity Mechanism Of Oxaliplatin On The Pancreatic Cancer Cell Line Panc-1

Objective To explore the radio-sensitivity enhancement effect of Oxaliplatin on the Pancreatic cancer Cell Line Panc-1in vitro and initially disclosure its mechanism and providing the evidence to improving clinical diagnosis and treatment of tumor by chemo-radiotherapy.Method (1)MTT was adopted to detect the sensitivity of Panc-1cell to Oxaliplatin with different dose(0.5.1.3.125.6.25.12.5.25.50.100.200.300.500μg/ml) to determine the medicine concentration to IC50.(The cells were randomized into three groups,Blank control group,control group and drug-group),MTT assay was also used to measure Oxaliplatin’s effect on cell radio-sensitivity.(The cells were treated in vitro with no-treatment,different doses of radiation alone(2.4.6.8Gy)and radiation combined with Oxaliplatin administrated).(2)The cloning experiments assay was performed to determine the radiation-sensitizing effect of Oxaliplatin on Panc-1cells with the concentration of less than20%IC50(4μg/ml.8μg/ml),"Multi-target single hit survival model"(SF=1-(1-e-D/D0)N) was used for dealing with data,then built the cell surviving curve.(3)Analyzing the distribution of cell cycle and apoptosis by flow cytometry(FCM).(4)Detecting the expressions of apoptosis-associated gene proteins:survivin by immunocytochemical technique.(In methods (2),(3),(4):The cells were treated in vitro with no-treatment, different doses of radiation alone(2、4、6、8Gy),Oxaliplatin (4μg/ml、8μg/ml) alone and radiation combined with Oxaliplatin administrated.)Statistical analysis was performed by SPSS17.0.Results (1)Inhibition of cell proliferation seemed more dependent on the dose and the time. In48h,IC50is44.639μg/ml.(2)The value of D0、Dq、SF2in group of radiation combined with Oxaliplatin was obviously Lower than that of radiation alone group.(3)Cell cycle analysis showed that the cell population in G2/M phase was increased and in G0/G1phase was decreased,the percent of apoptosis cells was apparently increased(P<0.05vs control).(4) The Panc-1cell expression of survivin was down-regulated in48hours by IHC(P<0.05vs control).Conclusion1.Oxaliplatin could obviously enhance the radiosensitivity of Panc-1cells.2.The cell expression of survivin was down-regulated, which may be one of mechanism for Oxaliplatin to be the radiation-sensitizing agents.