【摘要】 本研究探讨急性白血病细胞中抑癌基因TIG1的表达及其甲基化状态。应用实时荧光定量PCR(real-time Quantitative PCR,RT-QT-PCR)的方法,检测53例急性白血病(acute leukemia,AL)患者及20例正常对照者(nomal controls,NC)的TIG1表达情况,并通过甲基化特异性PCR(methylation-sepecific PCR,MS-PCR)检测TIG1基因的甲基化状态。应用去甲基化试剂处理KG-1a、U937和K562细胞株,观察其基因转录水平和甲基化状态之间的关系。结果表明,TIG1 mRNA在NC中高表达,而在AL患者中低表达;AL患者中TIG1的异常甲基化率高达75%(40/53例),而在正常标本中不发生甲基化;在初治AL中,发生甲基化的患者TIG1的表达水平明显低于未甲基化的患者;Kg-1a、U937和K562细胞株TIG1基因启动子CpG岛均存在过甲基化,应用去甲基化试剂处理后,TIG1基因启动子CpG岛甲基化程度降低,TIG1的表达都得到了恢复,并且TIG1的表达随着5-Aza-CdR浓度增加而增高。结论:TIG1基因表达的减少与急性白血病的发病有关,而甲基化是导致TIG1基因转录沉默的重要机制之一。更多还原

【Abstract】 This study was purposed to investigate the expression and methylation status of TIG1 in acute leukemia( AL). The TIG1 expression of 53 cases of AL and 20 cases of normal control( NC) were measured by using real-time quantitative PCR( RT-QT-PCR) and methylation-specific PCR( MS-PCR). The leukemia KG-1a,U937 and K562 cells were treated with 5-Aza-CdR. The results indicated that TIG1 gene expressed at a high level in cases of NC,but expressed at a low level in patients with AL. TIG1 gene was unmethylated in NC,but frequently methylated in AL.Aberrant methylation rate of TIG1 in AL was 75%( 40 /53). The expression of TIG1 in unmethylated patients was higher than that in methylated patients. Hypermethylation of TIG1 promoter CpG islands was detected in all the cell lines. 5-Aza-CdR treatment led to the hypomethylation of TIG1 promoter CpG islands. After the treatment with 5-Aza-CdR of different concentration,the expression of TIG1 was restored,and the effect of 5-Aza-CdR displayed dose-dependency. It is concluded that the reduced expression of TIG1 may play an important role in the pathogenesis of AL,and methylation may be responsible for the decreased transcription of TIG1 gene.更多还原