鼻咽癌细胞生物节律及时辰照射观察

目的 探讨鼻咽癌细胞的细胞周期的生物节律和时辰照射对鼻咽癌细胞的作用。方法 体外培养人鼻咽癌细胞CNE-2细胞系,在一天内不同的时间点(4AM、10AM、4PM、10PM)取出培养的细胞,用流式细胞仪检测细胞周期。根据细胞周期曲线一天内G₂/M期的高峰和低谷分别照射鼻咽癌细胞,用微量细胞克隆形成法和平板克隆形成实验观察细胞存活率SF(survival fraction)。结果 各细胞周期在4AM、10AM、4PM、10PM 4个时间点的分布,以单因素方差分析可见随时间变化差异有统计学意义(P < 0.05)。微量细胞克隆形成法和平板克隆形成实验均显示细胞在一天内G₂/M期的高峰和低谷分别照射,细胞存活率均有统计学意义(P < 0.05),在高峰时照射的细胞SF小于低谷时照射。结论 人鼻咽癌CNE-2细胞系的细胞周期随昼夜呈现节律性变化,时辰照射鼻咽癌细胞存活率的差异预示鼻咽癌时辰放疗的优越性。

Circadian Rhythms of Cell Cycle in Human Nasopharyngeal Carcinoma Cell and Chronoradiation

Objective To study the circadian rhythms of cell cycle in human nasopharyngeal carcinoma （NPC） cells and effect of chronoradiation on NPC cells in order to provide necessary data for making clinical chronoradiotherapy schedule of NPC. Methods Single sell suspension was obtained from NPC cell line CNE - 2 cultured in vitro at different times within a day and stained with propidium iodide. The cell cycles were measured by flowcytometry. According to the cell survival curve, NPC cells were irradiated by radiation on the acrophase and nadir of G2/M phase. The cell survival fraction （SF） was examined by microclonogenic and the clonogenic assays. Results One - way ANOVA showed that the proportion of cancer cells in each phase varied according to circadian time with statistical significance （P 〈 0.05 ） ; Both microclonogenic and the clonogenic assays showed that the SF of cells irradiated on the acrophase of G2/M phase was lower than that of cells irradiated on the nadir （ P 〈 0.05）. Conclusion Cell cycle of nasopharyngeal carcinoma cell line CNE - 2 cells might vary according to circadian rhythms. The difference of the survival fraction （SF） of NPC cells irradiated according to circadian rhythms predicted the superiority of chronoradiotherapy.