低剂量电离辐射预处理对不同肿瘤细胞周期的影响

Effects of Low Priming Dose of Radiation on Cell Cycle Arrest of Tumor Cells Caused by High Dose of Radiation

实验研究了低剂量γ射线预照射对人肝癌细胞系hepG2和人宫颈癌细胞系HeLa的细胞周期进程的影响.结果显示(1)低剂量(5cGy)辐射后,两种细胞的G2/M期细胞短暂累积;(2)低剂量辐射促进肿瘤细胞的生长;(3)高剂量(3Gy)辐射后,hepG2细胞发生G2期阻滞,HeLa细胞发生S期和G2期阻滞;(4)与单纯高剂量照射相比,低剂量辐射预处理后4h,再给予高剂量辐射,可进一步促进hepG2细胞在G2/M期累积,但是预照射对HeLa细胞的周期进程没有明显影响.因此,低剂量辐射预处理对高剂量诱导的细胞周期阻滞的影响依赖于肿瘤细胞的类型.

Effects of low priming dose of radiation on cell cycle progression in hep G2 and HeLa cells have been investigated. For both cell lines, cells in the G2/M phase are accumulated temporarily after 5cGy γ-ray exposing, and the proliferation of tumor cells is significantly promoted by low dose radiation. When exposing to 3Gy γ-ray, only the G2 phase arrest occurred for hep G2 cells, and both S and G2 arrest occurred for HeLa cells. In contrast to treatment with high dose of radiation, when high dose was delivered 4 hr after priming dose, pretreatment facilitates the accumulation of hep G2 cells in G2/M phase, however, pre-treatment does not significantly change the cell cycle progression of HeLa cells. It is concluded that alterations of the cell cycle progression by pretreatment with low dose of radiation are dependent on the type of tumor cell lines.