Abstract:

Objective To explore the radiosensitivity of C225(cetuximab)，an anti-epithelial growth factor receptor monoclonal antibody,which combined with irradiation against  lung adenocarcinoma cell line SPC-A-1,and  provide theoretical basis for clinical combined treatment in non-small lung cancer. Methods SPC-A-1 were cultivated in vitro for 6 passages,and the SPC-A-1 in logarithmic growth phase were seleted for experiment.The SPC-A-1 were divided into control group(PBS),irradiation group(4 Gy),C225 group(100 nmol·L^-1) and irradiation+C225 group(4 Gy+100 nmol·L^-1).The apoptosis of SPC-A-1 was observed by fluorescence microscope after Hoechst 33258 staining.SPC-A-1 were treated  with different doses of 6-MV X-Rays including 0,2,4 and 8 Gy alone
 or together with C225(100 nmol·L^-1),72 h after irradiation, the cells were divided into irradiation group and experimental group(irradiation+C22),the  apototic rate was detected  by flow cytometry (FCM).SPC-Ａ-1 were divided into control group(PBS),C225 group(100 nmol·L^-1),irradiation group(8 Gy) and irradiation+C225 group (8 Gy+100 nmol·L^-1), 48 h after irradiation, the  cell cycle was determined by FCM.   Results A
fter staining by Hoechst 33258,the number of apoptotic cells in irradiation+C225 group was significantly higher than those in  irradiation  group and C225 group.In apoptosis experiment,the apoptotic rate in experimental group was higher than that in irradiation group(P<0.05).The cell cycle analysis showed that compared with control group,the number of cells  in G0+G1 phase was increased in  C225 group(P<0.05),the number of cells in  G0+G1 and G2+M phrases in  irradiation+C225 group was increased(P<0.05),the number of cells in S phrase
 of  three groups was decreased(P<0.05). Conclusion The mechanism of  radiosensitivity enhancement of C225 to SPC-A-1 may be related to  arresting   G0+G1 phases and inducing apoptosis.

Key words: epithelial growth factor receptor monoclonal antibody;SPC-A-1 cell line;radiation therapy；radiosensitivity