不同靶向药物对EGFR表达异常的非小细胞肺癌细胞系放疗敏感性的影响

Effects of Different Targeted Drugs on Radiosensitivity of Abnormal EGFR Expression in Non-small Cell Lung Cancer Cell Lines

目的 探究不同靶向药物对表皮生长因子受体(epithelial growth factor receptor, EGFR)表达异常的非小细胞肺癌放疗敏感性的影响及其作用机制。方法 选取EGFR过度表达的A549细胞系及EGFR突变的HCC827细胞系,随机均分为空白对照组、放疗组、吉非替尼组、尼妥珠单抗组、放疗+吉非替尼组、放疗+尼妥珠单抗组。尼妥珠单抗组、放疗+尼妥珠单抗组均加入100 μg/ml的尼妥珠单抗溶液,吉非替尼组、放疗+吉非替尼组均加入100 μl浓度为1 μmol/L的吉非替尼溶液,空白对照组及放疗组予以等量的PBS溶液,后放疗组、放疗+尼妥珠单抗组、放疗+吉非替尼组予直线加速器放射处理。利用MTT实验观察细胞增殖情况,采用克隆实验比较细胞放射敏感性,使用流式细胞术分析细胞周期及凋亡情况,采用Western blot检测EGFR、磷酸化EGFR(p-EGFR)及p-Akt表达水平。结果 与放疗组比较,放疗+吉非替尼组、放疗+尼妥珠单抗组能显著抑制A549细胞增殖,升高G0/G1期所占比例,提升细胞凋亡率,差异有统计学意义( P <0.05),而HCC827细胞则无明显改变( P >0.05);A549细胞、HCC827细胞的放疗+吉非替尼组、放疗+尼妥珠单抗组的放疗增敏系数显著高于放疗组( P <0.05);A549细胞放疗+吉非替尼组、放疗+尼妥珠单抗组EGFR、p-EGFR及p-Akt表达水平较放疗组显著降低( P <0.05),但HCC827细胞则无明显改变( P >0.05)。结论 吉非替尼及尼妥珠单抗联合放疗可阻滞A549细胞于G0/G1期,下调EGFR、p-EGFR及p-Akt表达水平,增加细胞放疗敏感性,而对HCC827细胞则无明显影响。

Objective To investigate the effects of different targeted drugs on the radiosensitivity of epidermal growth factor receptor (EGFR) abnormally expressed in non-small cell lung cancer (NSCLC) cell lines and its mechanism of action. Methods NSCLC cell lines A549 with overexpressed EGFR and HCC827 with EGFR mutation were selected and randomly divided into control group, radiotherapy group, gefitinib group, nimotuzumab group, radiotherapy+gefitinib group, and radiotherapy+nimotuzumab group. 100 μg/ml of nimotuzumab solution was added to the nimotuzumab group and radiotherapy+nimotuzumab group, and 100 μl gefitinib solution at a concentration of 1 μmol/L was added to the gefitinib group and radiotherapy+gefitinib group. The blank control group and radiotherapy group were given the same amount of PBS solution, while radiotherapy group, radiotherapy+nimotuzumab group, and radiotherapy+gefitinib group were given radiotherapy linear accelerator. MTT assay was used to observe the proliferation of cells in different groups. The cell radiosensitivity was compared by clone formation assay. The cell cycle and apoptosis were analyzed by flow cytometry. The expression levels of EGFR, p-EGFR and p-Akt were detected by Western blot. Results Compared with radiotherapy group, the proliferation of A549 cells was significantly inhibited in radiotherapy+gefitinib and radiotherapy+nimotuzumab group ( P <0.05), and the proportion of A549 cells in G0/G1 phase and the apoptosis rate were increased, suggesting significant differences ( P <0.05). However, no significant differences were found in HCC827 cells ( P >0.05). The radiosensitivity coefficient of A549 cells and HCC827 cells in radiotherapy+gefitinib and radiotherapy+nimotuzumab groups was significantly higher than that of radiotherapy group ( P <0.05). The expression levels of EGFR, p-EGFR and p-Akt in A549 cells in radiotherapy+gefitinib group and radiotherapy+nimotuzumab group were significantly lower than those in radiotherapy group ( P <0.05), but no significant changes were noted in HCC827 cells ( P >0.05). Conclusion Gefitinib and nimotuzumab combined with radiotherapy can increase the radiosensitivity of A549 cells by blocking A549 cells in G0/G1 phase and down-regulating the expression levels of EGFR, p-EGFR and p-Akt, but they have no significant impact on HCC827 cells.