电离辐射克服NSCLC细胞株H1975吉非替尼耐药的体外研究

目的 探讨电离辐射联合吉非替尼对NSCLC耐药株H1975耐药突变、细胞凋亡及相关蛋白表达的影响及其可能机制。方法 实时荧光定量PCR对不同处理组H1975细胞的T790M突变进行相对定量分析；流式细胞仪检测不同处理组H1975细胞的凋亡率；免疫印迹检测不同处理组凋亡相关蛋白的表达水平。结果 2.5 Gy电离辐射组相较于0 Gy对照组，H1975细胞株T790M突变量降为原来的0.67倍，随电离辐射剂量的增高，T790M突变量降低（P＜0.05）；电离辐射联合吉非替尼组的细胞凋亡率为（44.35±8.49）%，相较于单独电离辐射组（21.84±5.62）%或吉非替尼组（17.38±6.78）%明显升高（P＜0.05）；电离辐射联合吉非替尼可诱导H1975细胞中磷酸化表皮生长因子受体（phosphorylated epidermal growth factor receptor, p-EGFR）、磷酸化蛋白激酶B（phosphorylated protein kinase B, p-AKT）蛋白表达水平明显下调。结论 在吉非替尼耐药的NSCLC细胞株H1975中，电离辐射可以克服吉非替尼耐药，与吉非替尼有良好的协同作用。

Ionizing Radiation Overcomes Gefitinib Resistance of Non-small Cell Lung Cancer Cell Line H1975 in vitro

Objective To investigate the effects of ionizing radiation combined with gefitinib on the resistance mutations, apoptosis and expression of apoptosis-related proteins of non-small cell lung cancer(NSCLC) cell line H1975, which had acquired drug resistance, as well as to explore the possible mechanism. Methods The relative quantitation of T790M mutation in H1975 cells treated by different methods was analyzed by real-time PCR. Apoptosis rates in different treatment groups were detected by cytometry (Annexin V-FITC). The expressions of apoptosis-related proteins were detected by Western blot. Results The T790M mutation of H1975 cells in 2.5Gy ionizing radiation group dropped by 0.67 times, compared with 0Gy normal control group; the T790M mutation was reduced as the radiation doses was increased(P＜0.05). The rates of cell apoptosis in ionizing radiation combined with gefitinib group (44.35±8.49)% was statistically higher than those in ionizing radiation group(21.84±5.62)%] and gefitinib group(17.38±6.78)%] (P＜0.05). The expressions of phosphorylated epidermal growth factor receptor(p-EGFR) and phosphorylated protein kinase B(p-AKT) proteins were significantly decreased by the combination of ionizing radiation and gefitinib. Conclusion For NSCLC cell line H1975 with acquired drug-resistance, ionizing radiation could overcome gefitinib-resistance. The combination of ionizing radiation and gefitinib shows a great synergistic effect.