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目的:研究放射线照射后HEp-2细胞的G2/M期阻滞与细胞分裂周期素(CDC)25A表达的相关性及过表达CDC25A蛋白对细胞周期及凋亡的影响。方法:通过流式细胞仪和Western blot方法检测4Gy X线照射后在不同时间点细胞周期及CDC25A蛋白含量;经脂质体转染pEGFP-N1-CDC25A质粒的HEp-2细胞为CDC25A组,转染pEGFP-N1质粒的为空载对照组,通过实时荧光定量PCR法检测这两组细胞中CDC25A的mRNA含量以鉴定转染效率;通过流式细胞仪检测CDC25A组和空载对照组细胞经4Gy放射线照射后细胞周期和细胞凋亡率;通过MTT法检测两组细胞的存活曲线。结果:放射线照射后G2/M期在细胞周期中的比例与CDC25A蛋白含量成正相关;CDC25A组细胞的CDC25A mRNA含量为空载对照组的15倍;过表达CDC25A联合4Gy放射线照射可废除G1/S关卡阻滞,促进G2/M期聚集和提前进入有丝分裂,可导致细胞凋亡增加和细胞存活率降低。结论:CDC25A的含量与G2/M期的比例正相关,调控CDC25A的表达可影响放射线照射后肿瘤细胞的细胞周期和凋亡水平。
Objective: To investigate the correlation between G2 / M arrest of HEp-2 cells and the expression of 25A of CDC and the effect of CDC25A over-expression on cell cycle and apoptosis. Methods: Cell cycle and CDC25A protein levels at different time points were detected by flow cytometry and Western blotting. HEp-2 cells transfected with pEGFP-N1-CDC25A plasmid by liposome were selected as CDC25A group. The plasmid pEGFP-N1 was transfected into empty vector, and the mRNA expression of CDC25A in both groups was detected by real-time fluorescence quantitative PCR to identify the transfection efficiency. The cells in CDC25A group and control group were detected by flow cytometry through 4Gy The cell cycle and apoptosis rate after irradiation were measured. The survival curves of the two groups of cells were detected by MTT assay. Results: The ratio of G2 / M phase in the cell cycle was positively correlated with the content of CDC25A protein after irradiation. The content of CDC25A mRNA in CDC25A group was 15 times of that in the control group. The over-expression CDC25A combined with 4Gy radiation could abolish G1 / S Level block, promote G2 / M phase aggregation and advance into mitosis, can lead to increased apoptosis and decreased cell viability. Conclusion: The content of CDC25A is positively correlated with the proportion of G2 / M phase. The regulation of CDC25A expression may affect the cell cycle and apoptosis of tumor cells after radiation.