乏氧诱导因子-1α抑制剂YC-1对乏氧脑胶质瘤SHG44细胞株的放射增敏作用

摘要

目的:探讨乏氧诱导因子1α(HIF-1α)抑制剂YC-1对乏氧脑胶质瘤SHG44细胞株的放射增敏作用及其作用机制.方法 选择脑胶质瘤SHG44细胞株,分别在常氧(20％O2)、乏氧(1％O2)12 h和2Ah、乏氧+YC-112 h和24h这5种不同条件下培养,采用Western blot检测HIF-1α的表达水平；细胞克隆形成实验绘制细胞存活曲线以观察其放射敏感性；利用剂量分割法绘制亚致死性损伤修复曲线以观察其修复能力.结果脑胶质瘤SHG44细胞株在乏氧12h和24h与常氧培养相比,HIF-1α的表达水平显著升高,放射敏感性下降,其氧增强比分别为1.22和1.37,进一步统计分析发现其亚致死性损伤修复能力升高,且在间隔8、10、12 h照射时,差异均有统计学意义(均P ＜0.05)；而当在乏氧12h和24h培养的同时加用YC-1时,HIF-1α的表达水平则显著降低,放射敏感性升高,其增强因子均为1.27,进一步统计分析也发现其亚致死性损伤修复显著降低,且在间隔8、10、12 h照射时,差异均有统计学意义(均P＜0.05).结论YC-1能明显提高乏氧脑胶质瘤SHG44细胞株的放射敏感性,其机制可能与YC-1能抑制细胞的亚致死性损伤修复能力有关.%Objective To investigate the radiosensitive effect of hypoxia-inducible factor 1 a (HIF-1α) inhibitor YC-1 on hypoxic glioma SHG44 cell line and its related mechanism. Methods Glioma SHG44 cell line was cultured in normoxic (20% O2), continuous hypoxia (1% O2) for 12 h and 24 h, continuous hypoxia plus YC-1 was performed for 12 h and 24 h, respectively. The expression of HIF-1α was assessed by Western blot. The radiosensitivity was evaluated by the survival curve, and the sublethal damage repair (SLDR) ability was measured by dose-fraction experiment. Results HIF-1α protein levels of glioma SHG44 cells were significantly increased after hypoxic cultures for 12 h and 24 h than those of the corresponding cells cultured in normoxic, while the radiosensitivity was lower. The OER (oxygen-enhancement ratio) of SHG44 cells in hypoxia for 12 h and 24 h were 1.22 and 1.37, respectively. By the further statistical analysis it was found that SLDR ability of glioma SHG44 was increased at hypoxia, and when irradiation was carried one at the interval of 8, 10, 12 h it was statistically significant (P< 0.05). HIF-1α protein levels of glioma SHG44 cells cultured in hypoxia plus YC-1 for 12 h and 24 h were decreased significantly compared to the corresponding cells cultured in hypoxia only, while the radiosensitivity was significantly increased, the EF (enhancement factor) of YC-1 for glioma SHG44 cells at hypoxia for 12 h and 24 h was 1.27. By the further statistical analysis it was also found that SLDR ability was decreased significantly for hypoxic SHG44 cells which was co-cultured with YC-1, and at the interval of 8, 10, 12 h irradiation was statistically significant (P <0.05). Conclusion YC-1 can increase the radiosensitivity of hypoxic glioma SHG44 cell line, and its mechanism is related to SLDR inhibited by YC-1.