甘草素通过影响鼻咽癌CNE-2 细胞的自噬增强其放疗敏感性

摘要] 目的：探讨甘草素（licorice）对鼻咽癌CNE-2 细胞放疗增敏的影响及其作用机制。方法：体外培养构建放射抵抗性的鼻咽癌细胞株CNE-2-RR。MTT细胞实验检测不同浓度的甘草素对鼻咽癌细胞增殖活性的影响，透射电镜检测甘草素处理鼻咽癌细胞后自噬体的变化情况，Western blotting 检测甘草素对鼻咽癌细胞自噬蛋白水平的影响，彗星实验检测不同组鼻咽癌细胞DNA损伤修复情况，流式细胞术检测鼻咽癌细胞株凋亡率的变化。结果：成功构建放射抵抗细胞株CNE-2-RR，20 mmol/L甘草素对鼻咽癌细胞的最高抑制率为（58.86±5.02）%。甘草素处理鼻咽癌CNE-2-RR细胞后胞内自噬体数量增加，线粒体和细胞核形态异常；细胞中自噬体蛋白LC3-II 水平升高、LC3-I 水平降低（P<0.05）；甘草素作用CNE-2-RR细胞后彗星尾距长度大于对照组，表明对DNA损伤修复能力明显降低。甘草素作用导致CNE-2-RR细胞的凋亡率明显增加（P<0.05）。结论：甘草素通过影响鼻咽癌CNE-2-RR细胞的自噬行为及DNA修复能力增强其对放疗的敏感性。

Licorice enhances radio-sensitivity of nasopharyngeal carcinoma CNE-2 cells by affecting autophagy

Abstract] Objective: To investigate the effect of licorice on radio-sensitization of nasopharyngeal carcinoma CNE-2 cells and its mechanism. Methods: The radio-resistant nasopharyngeal carcinoma cell line (CNE-2-RR) was constructed and cultured in vitro. MTT assay was used to detect the effect of different concentrations of licorice on the proliferation activity of nasopharyngeal carcinoma cells.The changes of autophagosome in CNE-2-RR cells after licorice treatment were observed by transmission electron microscopy (TEM).Western blotting was used to detect the effect of licorice on the level of autophagy protein in CNE-2-RR cells. Single cell gel electrophoresis (comet assay) was used to detect the DNA damage and repair of different groups of CNE-2-RR cells. Flow cytometry was used to detect the apoptosis rate of CNE-2-RR cell line. Results: Low-radiation resistant CNE-2-RR cell line was successfully constructed;MTT assay showed that 20 mmol/L licorice exhibited highest inhibition on CNE-2-RR cells (58.86 ± 5.02)%. Transmission electron microscopy showed increased autophagicbody and abnormal mitochondria and nuclei morphology in CNE-2-RR cells after treatment.Western blotting showed that autophagic protein LC3-II level was increased and LC3-I level was decreased in CNE-2-RR cells (P <0.05). The results of single cell gel electrophoresis showed that the length of comet tail distance of CNE-2-RR cells after licorice treatment was higher than that of the control group (P<0.05), indicating weakened repair ability of DNA damage. Conclusion: Licorice enhances the radio-sensitivity of CNE-2-RR cells by influencing autophagy and DNA repair ability.