EGFR和TGF-α在肺癌细胞放疗增敏中的作用

摘要

Objective To study the relationship between epidermal growth factor receptor (EGFR), transforming growth factor-α (TGF-α) and different fractional doses of radiotherapy in lung cancer cells and its possible mechanism. Methods Lung cancer cell line A549 cells were irradiated with conventional fractionation (2Gy/day) and large fractionation (4, 8 Gy/day), DT = 8 Gy. Realtime fluorescence quantitative PCR (QPCR), enzyme-linked immunosorbent assay (ELISA) and Western blotting were used to detect EGFR, TGF-α gene and protein expression in A549 cells, respectively. In addition, the expression of γ-H2 AX was determined by immunofluorescence assay. Results The expression levels of EGFR mRNA and TGF-α mRNA in A549 cells of 4 Gy/day and 8 Gy/day fractionation groups were significantly lower than those of 2 Gy/day fractionation group (P＜0. 05). The expressions of EGFR and TGF-α proteins in A549 cells of 4 Gy/day and 8 Gy/day fractionation groups were significantly lower than those of 2 Gy/day fractionation group (P＜0. 05). Immunofluorescence assay showed that the expression ofγ-H2 AX in A549 cells in 4 Gy/day and 8 Gy/day fractionation groups was significantly higher than that in control group and 2 Gy/day fractionation group. Conclusion The expression of EGFR and TGF-α decreased significantly after high dose fractionated radiotherapy, which increased the sensitivity of A549 cells to radiation.The mechanism may be related to the up-regulation of the expression of histone γ-H2 AX in DNA damage repair.%目的 研究表皮生长因子受体(EGFR)、转化生长因子-α(TGF-α)与肺癌细胞不同放疗分割剂量的关系及可能作用机制.方法 对A549细胞采用常规分割(2 Gy/天)和大分割(4、8 Gy/天)照射,DT=8 Gy,采用实时荧光定量PCR(QPCR)、酶联免疫吸附测定(ELISA)法、Western blotting分别检测A549细胞中EGFR、TGF-α基因和蛋白表达,另采用免疫荧光法测定γ-H2AX表达.结果 4 Gy/天和8 Gy/天分割组A549细胞中EGFR、TGF-αmRNA表达水平均显著低于2 Gy/天组(P＜0. 05); 4 Gy/天和8 Gy/天分割组A549细胞中EGFR、TGF-α蛋白表达均显著低于2 Gy/天组(P＜0. 05).免疫荧光法结果显示,4 Gy/天和8 Gy/天分割组A549细胞中γ-H2AX表达明显高于对照组和2 Gy/天分割组.结论 大剂量分割放疗后EGFR、TGF-α表达明显下调,增加A549细胞对放射线的敏感性,其机制可能与DNA损伤修复组蛋白γ-H2AX表达上调有关.