氟达拉滨联合不同电离辐射对肾癌细胞系786-O杀伤效果观察

目的 比较氟达拉滨(FA)联用不同电离辐射对肾癌细胞系786-O的DNA双链损伤作用异同和药物放射增敏效应。方法 FA联用X射线、重离子处理786-O细胞,流式细胞术检测γH₂AX细胞分数和周期分布,中性彗星电泳法检测细胞DNA双链损伤程度,克隆形成法比较不同处理对细胞存活影响。单因素方差分析或Dunnet’s t检验比较组间差异。结果 与单纯给药和单纯照射相比,FA联合不同电离辐射可增强细胞DNA双链损伤程度,表现为γH₂AX水平均显著提高(P=0.007、0.001);重离子联用则可将细胞周期阻滞在放射敏感时相G₂+M期(P=0.020、0.060),并显著增加G₂+M期γH₂AX表达量(P=0.000、0.000);彗星电泳表明DNA亚致死性损伤随着药物与射线的联合应用而显著增加(P=0.030、0.020;0.020、0.030);FA可降低放射后细胞克隆形成率(P=0.000、0.030;0.001、0.040)。结论 FA增强X射线和重离子束的放射效应具有不同特点,其增强重离子束的放射杀伤作用尤为明显。

Cellular response to fludarabine treatment in combination with different ionizing radiation in renal carcinoma 786-O cells

Objective To investigate DNA double-strand breaks and radiosensitization in renal carcinoma 786-O cells induced by fludarabine (FA) combined with different ionizing radiations.Methods The 786-O cells were exposed to FA combined with X-ray or heavy ion beam irradiation.Flow cytometry was used to evaluate the percentage of γH2AX-positive cells and cell cycle.The neutral comet assay was used to detect DNA double-strand breaks.The colony-forming assay was used to evaluate the effects of different treatments on cell survival.Comparison between groups was made by one-way analysis of variance or Dunnet' s t test.Results Compared with FA alone or irradiation alone,FA combined with different ionizing radiations increased DNA double-strand breaks as shown by significantly increased levels of γH2AX (P=0.007,0.001);FA combined with heavy ion beam irradiation lead to a cell cycle block at the radiosensitive G2/M phase and significantly increased the expression of γH2AX in the G2/M phase (P=0.000,0.000);the neutral comet assay revealed that FA combined with irradiation significantly increased DNA sublethal damage (P=0.020,0.060);FA significantly reduced the colony-forming rate after irradiation (P=0.000,0.030;0.001,0.040).Conclusions FA enhances the effects induced by X-ray and heavy ion beam irradiation with different properties.Particularly,FA substantially enhances the cell death induced by heavy ion beam irradiation.