低氧条件下γ射线对Hep-2细胞周期、凋亡的影响

The Impact of Hypoxiaon on the Apoptosis and Cell Cycles in Hep-2 Human LKaryngeal Cancer Cell Line Induced by ^(60)Coγ-ray

目的体外建立不同氧供状态下的细胞模型,探讨不同剂量^(60)Coγ射线对喉鳞癌Hep-2细胞周期及凋亡的影响。方法将体外培养的人喉鳞癌Hep-2细胞分为两组:A组(常氧组)、B组(低氧组),两组细胞分别接受1、3、5、10、20、40(Gy)不同剂量^(60)Coγ射线照射,两组分别设0Gy对照组。流式细胞仪检测HIF-1α蛋白表达、细胞凋亡及细胞周期变化;免疫细胞化学检测各组细胞HIF-1α蛋白表达。结果A组Hep-2细胞在接受1～5Gyγ射线照射后,主要发生了G0/G1期阻滞,在接受10～40Gyγ射线照射后,发生了G2/M期阻滞;B组细胞主要发生了G2/M期阻滞。B组0Gy对照组发生了明显的G0/G1期阻滞;A组Hep-2细胞凋亡曲线成抛物线状,凋亡率呈现明显的剂量依赖性,在5Gy处出现最大值41.56±2.25。B组细胞凋亡率同A组相比总体上呈现明显的下调趋势,但不同剂量的γ射线没有对Hep-2细胞的凋亡率产生明显的影响。结论不同剂量^(60)Coγ射线照射会导致常氧条件下Hep-2细胞发生不同周期阻滞,而不同的周期阻滞会对Hep-2细胞的凋亡产生明显的影响。低氧条件下γ射线照射未能导致Hep-2细胞发生明显的凋亡,可能同Hep-2细胞G2/M期阻滞有关,而HIF-1a蛋白的表达上调可能是Hep-2细胞G2/M期阻滞的原因之一。

Objective To establish models of Hep - 2 laryngeal cancer cell line of different oxygen supplying , inves- tigate the impact of hypoxiaon on the apoptosis and cell cycles in Hep - 2 human laryngeal cancer cell line induced by different dosage of γ- ray. Methods The cells were diviced into 2 groups ： group A （normoxia） and group B （hypoxia）. Both of the two group cells are exposured in different dosage of γ- ray which range from 1Gy to 40Gy. Constructinon group （0Gy） was used. Flow cytometry （ FCM ） was used to measure the distribution of cell cycles and the protein levels of HIF - 1 α and to detect cell apoptosis. The protein levels of HIF - 1 α were also determined by immunohistochemistry. Results 1 Gy - 5Gyγ - ray caused G0/G1 cell cycle arrest when 10 - 40Gyγ- ray caused G2/M cell cycle arrest in human Hep- 2 cells in group A .All of the different dosage of γ- ray caused G2/M cell cycle arrest in human Hep - 2 cell in group B, then without exposure of γ - ray （0 Gy） could cause G0/G1 cell cycle arrest in group B. The curve of apoptosis rate in group A show a parabola , The peak was 41.56±2.25 at the point of 5 Gy. Apoptotic rate was related to the dosage of γ- ray in a dosage dependent manner. The apoptosis rate in group B were significantly lower than that in group A. The dose difference of γ- ray have no impact on the apoptosis rate in group B. Conclutions Different dosage of γ- ray could cause different cell cycles arrest in the condition of normoxia. There was an important relationship between eel1 cycle arrest and apoptosis. The descend of the apoptosis rate were related to G2/M cell cycle arrest in the condition of hypoxia and the high expression of HIF - 1 maybe one of these reasons .