Effect of cetuximab combined with radiation on the expressions of Ku80 and ATM in CNE-2 nude mice xenograft tumor model / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the effect of cetuximab (C225) combined with radiation on the expressions of Ku80 and ATM in CNE-2 nude mice xenograft tumor model.Methods The CNE2 nude mice xenograft tumor model was established and divided into control group,conventional radiotherapy (CRT) group,simulated intensity modulated radiation therapy (sIMRT) group,C225 group,CRT + C225 group and sIMRT + C225 group with 8 mice in each group.The dose of radiation was 20 Gy,and 1mg C225 per mice in abdominal cavity was applied for the drug treatment.The transcriptional levels of Ku80 and ATM were assayed by RT-PCR and Western blot.Results Compared with control group,the transcriptional and translational levels of Ku80 and ATM in CRT group,sIMRT group,CRT + C225 group and slMRT + C225 group were decreased (P ＜ 0.05).Compared with CRT group,the down-regulation of transcriptional and translational ATM level in sIMRT group was obvious (P ＜ 0.05),and further strengthened in the CRT + C225 group and sIMRT + C225 groups (P ＜0.05),but there was no significant difference of ATM expression between sIMRT + C225 group and CRT group (P ＞ 0.05).Conclusions C225 alone can restrain the transcriptional and translational level of ATM,and the transcriptional and translational level of Ku80 and ATM are also restrained after megadose.ATM is down-regulated by sIMRT but up-regulated by the combination of C225 and radiation.