Inhibitory effect of combination of cetuximab and irradiation on colorectal carcinoma CL187 cells / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the combination effect of cetuximab and irradiation on colorectal carcinoma CL187 cell line and underlying molecular mechanism.Methods CL187 cells with or without cetuximab treatment were irradiated by 0,4 and 8 Gy X-rays,then cell death percentage was determined by MTT 24 and 48 h post-irradiation.Clone forming assay was used to evaluate the cell reproliferation ability.Cell cycle distribution,apoptosis,and necrosis were analyzed by flow cytometry.Western blot was used to detect the protein expressions of DNA-PKcs,Ku70 and Ku80.Results The cetuximab enhanced the percentage of radiation-induced cell death,while descreased the cloning formation capacity and increased radiosenvtivity (t =-6.14、-6.53,P ＜0.05).The SER of cetuximab on CL187 cell line approached to 1.38.In addition,cetuximab also increased radiation-induced G0/G1 phase arrest (t=-4.64,P＜0.05) and the percentage of apoptosis and necrosis (t=-9.16,P ＜0.05),but it descreased the expression levels of DNA-PKcs,Ku70 and Ku80 proteins.Conclusions The cetuximab treatment might enhance the inhibitory effect of irradiation on colorectal carcinoma CL187 cell line by influencing cell cycle distribution,cell apoptosis,and the expression of DNA repair proteins.