自噬对口腔鳞状细胞癌CAL-27和KB细胞放疗敏感性的影响及其机制

目的：利用自噬抑制剂联合放射疗法作用于口腔鳞状细胞癌CAL-27和KB细胞，探讨自噬对口腔癌放射治疗敏感性的影响及其作用机制。方法：选择人口腔鳞状细胞癌CAL-27和KB细胞，分为对照组、氯喹（CQ）组、3-甲基腺嘌呤（3-MA）组、放射组（IR组）及联合放射组（CQ+IR组和3-MA+IR组）。应用MTT法检测细胞生存率，采用免疫荧光法激光共聚焦显微镜观察CAL-27细胞自噬水平（即LC3Ⅱ免疫荧光强度），Western blotting法检测自噬相关蛋白LC3和beclin-1表达水平，AnnexinV/PI双染色流式细胞仪检测细胞凋亡率。结果：与IR组比较，联合放射组细胞生存率明显降低（P < 0.05）。IR组细胞自噬水平明显高于对照组、CQ组、3-MA组和联合放射组（P < 0.05）。IR 组LC3和beclin-1蛋白表达水平明显高于对照组和联合放射组（P < 0.05）。与对照组比较，IR组和联合放射组细胞凋亡率明显升高（P < 0.05）；与IR组比较，联合放射组细胞凋亡率也明显升高（P < 0.05）。结论：放射疗法可以诱导口腔鳞状细胞癌细胞自噬水平升高。自噬抑制剂可以通过对口腔鳞状细胞癌细胞的增殖抑制及促凋亡作用，提高其对放射治疗的敏感性。

Influence of antophagy in radiation sensitivities of oral squamous cell carcinoma CAL-27 and KB cells and its mechanisms

Objective: To use autophagy inhibitors combined with radiation to treat the oral squamous cell carcinoma CAL-27 and KB cells,and to explore the influence of autophagy in the oral cancer radiation sensitivity and its mechanisms. Methods:The human oral squamous cell carcinoma CAL-27 and KB cells were divided into control group,CQ group,3-MA group,IR group,CQ+IR group,and 3-MA+IR group. The survival rate was detected by MTT method and the autophagy of CAL-27 cells was observed by immunofluorescence method and laser scanning confocal microscope.The expression levels of LC3 and beclin-1 were detected by Western blotting method. The apoptotic rate was determined by flow cytometry with Annexin Ⅴ/PI doulde staining. Results:Compared with IR group,the survival rates in 3-MA + IR and CQ+ IR groups were signifcantly decreased (P < 0.05 ).The autophagy levels of cells in IR group were significantly higher than those in control group, CQ group, 3-MA group,CQ+IR group,and 3-MA+IR group (P <0.05).The expression levels of LC3 and beclin-1 proteins in IR group were significantly higher than those in control group,CQ+ IR group,and 3-MA+ IR group (P < 0.05). The apoptotic rates in IR,3-MA+ IR,and CQ+ IR groups were markedly higher than those in control group. Compared with IR group,the apoptotic rates in CQ+IR and 3-MA+IR groups were significantly increased (P <0.05).Conclusion:Radiotherapy can induce the increase of autophagy level of oral squamous cell carcinoma cells. Inhibiors of autophagy can increase the radio-sensitivity of oral squamous cell carcinoma cells by inhibiting the proliferation and inducing the apoptosis.