【作者】 喻雄杰；

【导师】 程晶；

【作者基本信息】 华中科技大学 ， 肿瘤学， 2010， 硕士

【摘要】 【目的】研究Cdc25c在人肿瘤细胞低剂量辐射超敏感性发生机制中的作用。【方法】流式细胞术分选计数后,再用克隆形成分析法分析人结肠癌细胞HT29和人宫颈癌细胞Siha在不同剂量辐射后的细胞存活情况,应用诱导修复模型对细胞存活分数进行拟合,验证是否存在HRS/IRR现象;流式细胞术检测人结肠癌细胞HT29和人宫颈癌细胞Siha在不同照射剂量点和时间点下的细胞周期分布情况;免疫印迹法检测人结肠癌细胞HT29和人宫颈癌细胞Siha接受不同剂量照射后磷酸化Cdc25c表达情况。【结果】(1)人结肠癌HT29细胞存在HRS/IRR现象,人宫颈癌Siha细胞不存在HRS/IRR现象。(2)当辐射剂量<0.3 Gy时HT29细胞未发生G2/M期阻滞,Siha细胞出现了G2/M期的阻滞;当辐射剂量≥0.3 Gy时,两种细胞株均存在G2/M期的阻滞,且阻滞程度随照射剂量增加而增加。(3)在照射剂量<0.3 Gy时HT29细胞中磷酸化的Cdc25c不表达,而Siha细胞中可见磷酸化的Cdc25c表达;当照射剂量≥0.3 Gy时两种细胞株中均可见磷酸化的Cdc25c表达,表达活性与辐射剂量呈正相关。【结论】人肿瘤细胞HRS/IRR现象的发生与G2/M期阻滞有关,检查点效应因子Cdc25c在G2/M期阻滞和人肿瘤细胞HRS/IRR的发生中具有重要作用。更多还原

【Abstract】 Objective To study the effect of cdc25c and cell cycle checkpoint on HRS/IRR and the possible mechanism of HRS/IRR in tumor cells.Methods Exponentially growing HT29 cells and Siha cells were irradiated with X-rays at different doses. Cell surviving fractions after irradiating with different radiation doses were measured by the clonogenic survival assay depend on (?)uorescence-activated cell sorter. Cell cycle distribution after irradiating was examined with flow cytometry. The level of Phospho-Cdc25c(216) in cells was detected by Western blot after irradiating.Result HRS/IRR was observed in HT29 cells after low dose irradiating and not observed in Siha cells. The cell cycle distribution of HT29 cells had no change at dose below 0.3Gy. When the radiation dose was beyond 0.3Gy, G2/M phase arrest was observed in HT29 cells. Nevertheless, G2/M phase arrest was observed in Siha cells despite of radiation dose. At the dose less than 0.3Gy, the expression of Phospho- Cdc25C(ser216) was not observed in HT29 cells, but observed in Siha cells. When the dose is greater than 0.3Gy, Phospho-Cdc25c (ser216) was observed both in HT29 cells and in Siha cells.Conclusions The activity of Cdc25c may play an important role in G2/M phase arrest and HRS/IRR.更多还原