摘要目的 研究CDT1基因过表达对辐射诱发基因组不稳定肝细胞凋亡及细胞周期的影响.方法 选择基因组不稳定肝细胞HL-7702,利用慢病毒介导的过表达技术,上调辐射诱发基因组不稳定肝细胞中CDT1基因的表达,通过流式细胞术研究CDT1基因过表达对细胞周期及细胞凋亡的影响;利用实时荧光定量PCR方法,检测CDT1基因上调后p53、ATM、ATR、Bcl-2、Caspase-3基因的表达变化.结果 慢病毒介导的过表达能有效上调HL-7702细胞中CDT1基因的表达(t=15.56,P＜0.05),与阴性对照组相比,CDT1基因的上调能够导致基因组不稳定肝细胞HL-7702凋亡率升高(t=4.19,P＜0.05);CDT1基因的过表达能诱发基因组不稳定肝细胞p53、Bcl-2基因的表达显著下调(t=-4.21、-2.06,P＜0.05),同时,ATM基因上调,ATR和Caspase-3基因下调,但差异均无统计学意义.结论 CDT1基因的过表达通过参与非p53依赖的凋亡途径以及细胞周期检查点适应性对基因组不稳定性进行调控.

abstractsObjective To investigate the effect of CDT1 gene over-expression on the apoptosis and cell cycle distribution in liver cells with a characteristic of genomic instability induced by radiation(GIR).Methods Lentivirus particles were transferred into liver cells of GIR to up-regulate the expression of CDT1 gene.The apoptosis and the cell cycle were detected by flow cytometry (FCM).The expression changes of p53,ATM,ATR,Bcl-2,and Caspase-3 genes were analyzed by real-time fluorescence quantitative PCR.Results CDT1 gene was efficiently increased by the gene transfection(t =15.56,P ＜ 0.05).In the CDT1 over-expressed cells,while the apoptosis ratio was increased (t =4.19,P ＜ 0.05),the expressions of p53 and Bcl-2 gene were decreased (t =-4.21,-2.06,P ＜ 0.05),but the expression of ATM,ATR and Caspase-3 changed with no significant difference compared with control.Conclusions Over-expression of CDT1 could regulate genomic instability through apoptosis pathway and checkpoint independent of p53.