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目的:观察体外低氧和常氧培养条件下喉癌Hep-2细胞系在放疗前后CD133+细胞比例及生长抑制率的变化,探讨肿瘤干细胞在低氧介导的喉癌放疗抵抗中的作用。方法:体外常氧和低氧环境下培养人喉癌Hep-2细胞,用western blot检测HIF-1α的表达。细胞汇合约80%左右时后分别给予0、5、10、15、20Gy的60 Co照射,检测各组细胞放疗后不同时间细胞生长抑制率和CD133+细胞比例的变化。结果:低氧和常氧条件下,Hep-2细胞放疗后24h细胞增殖抑制率达到高峰,并随放疗剂量的增加而增加。常氧组各个剂量和时间点的生长抑制率均高于低氧组,24h、10Gy时差异最大,有统计学意义(P<0.05)。放疗后CD133+细胞低氧和常氧组均有不同程度的富集,低氧组在各个剂量和时间点的CD133+细胞比例均高于常氧组,24h、10Gy时差异最大,有统计学意义(P<0.05)。结论:喉癌干细胞在低氧介导的喉癌放疗抵抗中有重要作用,并提示阻断低氧因素可能会增强喉癌的放疗敏感性。
OBJECTIVE: To observe the changes of CD133 + cell ratio and growth inhibition rate of Hep-2 laryngeal carcinoma cell lines before and after radiotherapy in hypoxic and normoxic culture in vitro and to explore the role of tumor stem cells in hypoxia-mediated radiotherapy of laryngeal cancer. Methods: Human laryngeal carcinoma Hep-2 cells were cultured under normoxia and hypoxia in vitro. The expression of HIF-1α was detected by western blot. After about 80% confluence, cells were irradiated with 60Co at 0, 5, 10, 15 and 20 Gy respectively, and the changes of cell growth inhibition rate and CD133 + cell ratio were detected at different time after radiotherapy. Results: Under hypoxia and normoxia, the inhibition rate of Hep-2 cells reached the peak 24h after radiotherapy, and increased with the increase of radiotherapy dose. The growth inhibition rate of normoxia group at each dose and time point was higher than that of hypoxia group, with the largest difference at 24h and 10Gy (P <0.05). The percentage of CD133 + cells in hypoxia group was higher than that in normoxia group at each dose and time point after radiotherapy, and there was significant difference between 24h and 10Gy P <0.05). CONCLUSION: Laryngeal carcinoma stem cells play an important role in hypoxia-mediated radiotherapy of laryngeal cancer and suggest that blocking hypoxia may enhance radiosensitivity of laryngeal carcinoma.