Inhibition of radiation-induced EGFR nuclear import by C225 (Cetuximab) suppresses DNA-PK activity
Inhibition of radiation-induced EGFR nuclear import by C225 (Cetuximab) suppresses DNA-PK activity
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DOI：
10.1016/j.radonc.2005.06.022
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发表时间：
2005-08-01
影响因子：
5.7
通讯作者：
Rodemann, HP
中科院分区：
文献类型：
--
作者：
Dittmann, K;Mayer, C;Rodemann, HP
背景与目的：抑制EGFR功能可诱导肿瘤细胞产生放射增敏作用。我们研究的目的是确定抗 EGFR 抗体 C225（西妥昔单抗）治疗后放射增敏的可能分子机制。 材料和方法：在人类支气管癌 (A549) 细胞系和乳腺腺瘤细胞 (MDA MB 231) 中测定 C225 对放射反应的影响。应用蛋白质印迹、免疫沉淀和激酶测定分析了照射后 C225 对 EGFR 功能的分子影响。通过照射后 24 小时定量 γ-H2AX 阳性病灶来检测对 DNA 修复的影响。结果：EGFR 特异性抗体 C225 在 A549 和 MDA MB 231 细胞中诱导放射增敏。 A549 的放射增敏作用与辐射诱导的 EGFR 转运至细胞核的阻断有关，并将 EGFR 与 DNA 依赖性蛋白激酶 (DNA-PK) 的复合物固定在细胞质中。结果，辐射诱导的 DNA-PK 激活被废除，而这一过程对于辐射暴露后的 DNA 修复至关重要。同样，C225 处理增加了 A549 和 MDA MB 231 细胞中照射 24 小时后 γ-H2AX 阳性灶的残留量。结论：我们的结果表明，照射诱导的 DNA-PK 激活（对于 DNA 修复至关重要）可能会因使用抗 EGFR 抗体 C225 而受到特别阻碍。该过程与放射增敏有关。 (C) 2005 爱思唯尔爱尔兰有限公司
Background and purpose: Inhibition of EGFR-function can induce radiosensitization in tumor cells. Purpose of our investigation was to identify the possible molecular mechanism of radiosensitization following treatment with anti-EGFR-antibody C225 (Cetuximab).Materials and methods: The effect of C225 on radiation response was determined in human cell lines of bronchial carcinoma (A549) and breast adenoma cells (MDA MB 231). The molecular effects of C225 on EGFR-function after irradiation were analyzed applying western blotting, immune-precipitation and kinase assays. Effects on DNA-repair were detected by quantification of gamma-H2AX positive foci 24 h after irradiation.Results: The EGFR specific antibody C225 induced radiosensitization in A549 and also in MDA MB 231 cells. Radiosensitization in A549 was associated with blockage of radiation-induced EGFR transport into the nucleus, and immobilized the complex of EGFR with DNA-dependent protein kinase (DNA-PK) in the cytoplasm. As a consequence radiation-induced DNA-PK activation was abolished, a process that is essential for DNA-repair after radiation exposure. Likewise C225 treatment increased the residual amount of gamma-H2AX-positive foci 24 h after irradiation in A549 and in MDA MB 231 cells.Conclusions: Our results suggest that irradiation induced DNA-PK activation-essential for DNA repair-may be hampered specifically by use of the anti-EGFR-antibody C225. This process is associated with radiosensitization. (C) 2005 Elsevier Ireland Ltd.