造血系统肿瘤WT1基因启动子区域DNA甲基化及其调控的研究

目的 应用聚合酶链反应（PCR）的实验方法研究白血病细胞系中WT1基因启动了区域的DNA甲基化水平，及其与WT1基因表达的关系。方法 ①采用RT-PCR技术及甲基化特异性PCR（Methylation-spectific PCR，MSP）技术检测8226、HL-60、Jurkat、KG-1及Raji等血液系统肿瘤细胞系中WT1基因mRNA表达水平及其启动子区域的DNA甲基化状态；②以5-杂氮脱氧胞嘧啶（5-aza-CdR）对U937细胞系进行去甲基化处理，并观察WT1基因表达水平的改变。结果 ①HL-60、K562、KG-1、NB4及SHI-1细胞系中WT1表达水平高，而8226、Jurkat、Raji、U266和U937细胞系WT1表达水平则极低，同时检测到在8226、Jurkat、Raji、U266和U937这5个细胞系存和WT1基因启动子区域DNA高甲基化；②经去甲基化处理后，U937细胞系的WT1基因表达水平较未处理者上升，同时伴随着WT1启动子区域DNA甲基化水平的下降和未甲基化水平的升高。结论 WT1基因启动子区域DNA高甲基化是抑制其表达的机制之一。

Study on DNA methylation status of WT1 gene in its promoter region in hematologic malignancy cell lines

OBJECTIVE: To study the DNA methylation status of WT1 gene promoter region in hematologic malignancy cell lines and its correlation with WT1 gene expression. METHODS: 1. RT-PCR and methylation-specific PCR were performed for detecting WT1 gene expression and DNA methylation status in its promoter region in 8226, HL-60, Jurkat, K562, KG-1, NB4, Raji, SHI-1, U266 and U937 cell lines. 2. Treatment of U937 cells with 5-aza-CdR, a demethylation inducing agent and the changes in WT1 gene expression level and its promoter region methylation status were determined. RESULTS: 1. HL-60, K562, KG-1, NB4 and SHI-1 cells showed higher levels while 8226, Jurkat, Raji, U266 and U937 cells showed extremely low levels of WT1 expression. DNA hypermethylation in WT1 gene promoter region was identified in 8226, Jurkat, Raji, U266 and U937 cells. 2. The WT1 gene expression in U937 was enhanced after treatment with 5-aza-CdR accompanied with the decrease of methylated and the increase of unmethylated levels in its promoter region. CONCLUSION: Modulation of the DNA methylation status in WT1 promoter region is one of the epigenetic mechanisms for regulating its expression.