自噬对人肺腺癌A549细胞放疗敏感性的影响

背景与目的放射治疗是肺癌最重要的治疗手段之一，然而却因放疗抵抗极易导致肿瘤的复发和转移。放疗可诱导肿瘤细胞自噬发生，最新研究也报道，自噬可能与DNA损伤修复过程相关。本研究旨在探讨通过雷帕霉素上调A549细胞自噬，能否增加细胞放疗敏感性，其过程是否与DNA损伤修复过程相关。方法以人肺腺癌A549细胞作为实验对象，实验设对照组（N）、单纯放疗组（IR）、雷帕霉素联合放疗组（R+ARPA）。采用Western blot检测γ-H2AX蛋白质、Rad51蛋白质、Ku70/80蛋白质、p62蛋白质、LC3蛋白质表达；电镜检测自噬体形成；细胞克隆形成实验检测细胞存活分数（survival fraction, SF）值。结果与单纯放疗组相比，放疗联合雷帕霉素组自噬活性增加，且Rad51、Ku80蛋白质表达减少，细胞增殖能力下降。结论通过雷帕霉素上调自噬可增加肺癌细胞放疗敏感性，其机制可能与抑制DNA损伤修复过程相关。

Role of Autophagy in the Radiosensitivity of Human Lung Adenocarcinoma A549 Cells

Background and objective Radiotherapy is an important treatment for lung cancer. The poor prognosis of lung cancer is largely caused by the high recurrence rate and metastasis of the tumor. Autophagy, which can be induced by radiotherapy, might be associated with DNA repair. The aim of this study is to investigate whether activating autophagy us-ing rapamycin can enhance the radiosensitivity of lung cancer cells and clarify the association of autophagy with DNA repair. Methods The human adenocarcinoma A549 cell line was selected as the experimental subject. The specimens were divided into three groups: control (N), radiation (R), and Rapamycin and radiation (R+ARPA). hTe protein levels of γ-H2AX, Rad51, Ku70/Ku80, p62, and LC3 were determined by Western blot. Autophagosome was observed under a transmission electron microscope, and SF was determined by colony formation assay.Results Compared with group R, the activity of autophagy and the protein expression levels of Rad51 and Ku70/80 were remarkably increased in group R+ARPA.ConclusionhTe radiosensitivity of lung cancer can be promoted by activating autophagy via treatment with Rapamycin, and the process may be associated with DNA repair.