表皮生长因子受体单克隆抗体C225对肺鳞癌细胞系放射增敏作用研究

RadiosensiUzation of C225 on human non-small cell lung cancer cell line H-520

目的观察表皮生长因子受体单克隆抗体C225与^60Coγ线对人肺鳞癌细胞系（H-520）的杀伤作用，探讨C225联合照射治疗非小细胞肺癌的可行性。方法细胞成克隆实验中单纯照射（对照组）和照射＋100nmol／L C225组（实验组）给予0、1、2、4、6、8、10Gy照射，培养10d后计数〉／50个细胞克隆。采用多靶单击模型进行数据处理，拟合细胞存活曲线，计算增敏比（D0值比）。细胞凋亡实验均照射0、2、4、8Gy后继续培养72h，收集细胞，流式细胞仪检测细胞凋亡。细胞周期检测设对照组（不处理）、C225组（100nmol／L）、照射组（8Gy照射）和C225联合照射组（100nmol／L C225＋8Gy），照后48h收集细胞，流式细胞仪检测周期分布。结果细胞克隆存活实验结果表明，扣除C225毒性影响后实验组存活分数比对照组低（F=6．36，P〈0．05），增敏比为1．35。细胞凋亡实验结果显示，C225组4个剂量点凋亡百分率分别为13．75％±0．83％、25．12％±1．60％、46．12％±2．60％、50．51％±4．06％，对照组的分别为5．56％±0．62％、13．86％±0．80％、25．36％±1．02％、29．89％±2．09％（F=4．72，P〈0．05）。细胞周期分布显示100nmol／L C225可使细胞阻滞于G0＋G1期，单纯照射阻滞于G2＋M期，两者联合后同时出现G0＋G1、G2＋M期阻滞，三者均使S期细胞比例下降。结论C225对H-520细胞具有放射增敏作用，其机制可能与细胞G0＋G1期阻滞和诱发凋亡有关；结果为临床上二者联合治疗非小细胞肺癌提供了理论基础。

Objective To investigate the efficacy of C225 （cetuximab）, a chimeric human-mouse anti-epithelial growth factor receptor monoclonal antibody, combined with ^60 Co gamma irradiation against human non-small cell lung cancer cell line H-520. Methods H-520 cells were treated either with different dose of ^60Co irradiation（ 1,2,4,6,8 and 10 Gy） alone or together with C225 （ 100 nmol/L）. Colony forming capacity was determined to create the survival curve 10 days after the treatment. Cells in different groups were harvested 72 hours after irradiation for apoptosis analysis or 48 hours after irradiation for cell cycle analysis by flow cytometry assay. Results The clone number in combinational treatment group was less than that in irradiation only group, which suggested that the cell survival rate in the combinational treatment group was significantly decreased comparing with irradiation only group（ F = 6.36, P 〈 0.05 ）. The sensitizing enhance rate（SER） was 1.35. The percentage of apoptotic H-520 cells was 5.56% ± 0.62% , 13.86% ± 0.80% ,25.36% ± 1.02% and 29.89% ±2.09% ,respectively in 0,2,4 and 8 Gy irradiation alone groups, which were significantly lower than 13.75% ±0.83% ,25.12% ± 1.60% ,46.12% ± 2.60% and 50.51% ± 4.06%, respectively in irradiation combined with C225 treatment groups （ F = 4.72, P 〈 0.05 ）. The cell cycle analysis showed that cells arrested in G0 ＋ G1 phases for C225 treatment,in G2 ＋ M phases for ^60Co irradiation,and in both G0 ＋ G1 and G2 ＋ M phases for C225 in combination with ^60Co irradiation. Conclusions C225 has radiosensitizing effects on H-520 cells, which may through the enhancement of ^60 Co irradiation-induced cell death and cell cycle arrest. This study provides a supportive evidence for clinical treatment in non-small cell lung cancer.