目的 探究雷帕霉素通过Fas/FasL信号通路治疗食管癌及放疗增敏的具体机制。方法 采用CCK-8和流式细胞分析评价ECA109细胞的凋亡能力。采用ECA109 sc构建食管癌小鼠瘤体模型。将C57BL/6J小鼠分为对照组、放射组（4 Gy¹³⁷Cs γ射线）、雷帕霉素（雷帕霉素1.5 mg/kg）组、放射+雷帕霉素（4 Gy¹³⁷Cs γ射线+雷帕霉素1.5 mg/kg）组。收集并记录各组小鼠的肿瘤体积及质量、肿瘤抑瘤率及增殖系数，放疗及雷帕霉素对其的增敏影响。采用酶联免疫吸附试剂盒评估肿瘤组织中半胱氨酸蛋白酶3(Caspase-3)、B淋巴细胞瘤-2(Bcl-2)和Bcl-2相关X蛋白（Bax）水平。苏木素–伊红（HE）染色观察小鼠食管癌的病理影响。Western blotting评估Fas/FasL信号通路的激活情况。结果 与放射组相比，放射+雷帕霉素组小鼠肿瘤体积、质量显著减小（P<0.001）。与放射组相比，放射+雷帕霉素组的抑瘤率及生长延迟时间（TGD）显著升高，肿瘤3倍倍增时间（TGT3）显著延长（P<0.05）。放射+雷帕霉素组出现大量肿瘤细胞崩解，间质水肿更明显。与放射组比较，放射+雷帕霉素组Bcl-2表达水平显著降低，Bax、Caspase-3表达水平显著升高（P<0.001）。与放射组比较，放射+雷帕霉素组ECA109细胞活力显著降低（P<0.001）。Fas及FasL的表达在细胞中被抑制后，ECA109细胞活力显著增加，ECA109细胞凋亡率显著降低（P<0.001）。与放射组相比，放射+雷帕霉素组中Fas和FasL蛋白相对表达量显著升高（P<0.001）。结论 雷帕霉素通过Fas/FasL信号通路抑制食管癌肿瘤的进展，该过程能有效地促进食管癌小鼠的放疗增敏。

Objective To explore the specific mechanisms of rapamycin treating esophageal cancer,and sensitizing radiotherapy through the Fas/FasL signaling pathway. Methods The apoptosis ability of ECA109 cells was evaluated using CCK-8 and flow cytometry.The ECA109 mouse model of esophageal cancer was established using ECA109.C57BL/6J mice were divided into control group,radiation group (4 Gy ¹³⁷Cs γ rays),rapamycin group （rapamycin 1.5 mg/kg）,and radiation+rapamycin (4 Gy ¹³⁷Cs γ rays+rapamycin 1.5 mg/kg).The tumor volume and mass,tumor inhibition rate and growth coefficient,the sensitization effect of radiotherapy and rapamycin were recorded.ELISA kits were used to assess levels of Caspase-3,Bcl-2,and Bax in the tumor.Histological changes in the esophageal cancer of mice were observed using HE staining.Western blotting analysis was performed to evaluate the activation of the Fas/FasL signaling pathway. Results Compared with the radiation group,the tumor volume and mass in the radiation+rapamycin group were significantly reduced （P＜0.001）.Compared with the radiation group,the tumor inhibition rate and TGD in the radiotherapy+rapamycin group were significantly increased,and the TGT3 was significantly prolonged （P＜0.05）.In the radiotherapy+rapamycin group,a large number of tumor cells disintegrated,and interstitial edema was more obvious.Compared with the radiation group,the expression levels of Bcl-2 in the radiation+rapamycin group were significantly decreased,while the expression levels of Bax and Caspase-3 were significantly increased （P＜0.001）.Compared with the radiation group,ECA109 cell viability was significantly decreased in the radiation+rapamycin group （P＜0.001）.After the expression of Fas and FasL was inhibited,the viability of ECA109 cells was significantly increased,and the apoptosis rate of ECA109 cells was significantly decreased （P＜0.001）.Compared with the radiation group,the relative expressions of Fas and FasL proteins in the radiation+rapamycin group were significantly increased （P＜0.001）. Conclusion Rapamycin inhibits the progression of esophageal cancer tumor through the Fas/FasL signaling pathway,which effectively promotes the sensitization of esophageal cancer mice to radiotherapy.

R965

江苏省卫生计生委科研课题项目(H2017036)