中文摘要：

目的探讨白血病细胞ZO-1基因的表达、甲基化情况及其与白血病发生的相关性。方法应用基因组限制性酶切扫描（RLGS）技术自白血病小鼠标本中钓取ZO-1基因，用甲基化PCR方法检测白血病细胞系Molt4、HL-60、K562细胞及白血病患者原代白血病细胞及正常人外周血单个核细胞ZO-1基因甲基化水平，用RT—PCR方法检测ZO-1基因表达水平，并对高表达ZO-1基因的K562细胞进行小干扰RNA（siRNA）靶向干扰，然后用Northern blot方法验证ZO-1基因抑制效率，用CCK-8检测细胞增殖情况，膜联蛋白V（Annexin V）和碘化丙锭（PI）双染色法观察细胞凋亡率及细胞周期。结果采用RLGS技术从白血病小鼠标本中成功钓取ZO-1基因。原代白血病细胞及Molt4、HL-60细胞ZO-1基因呈高甲基化状态，ZO-1基因表达水平较正常人外周血细胞明显下降或不表达。正常人外周血单个核细胞ZO-1基因不发生甲基化，ZO-1基因高表达。K562细胞高表达ZO-1基因，未见ZO-1基因甲基化；去甲基化药物可以诱导Molt4及HL-60细胞重新表达ZO-1基因。经ZO-1小干扰RNA干预的K562细胞ZO-1基因的表达明显降低，但并不影响细胞的增殖及凋亡。结论绝大多数急性白血病细胞中ZO-1基因呈高甲基化状态，表达明显降低，ZO-1基因是一个白血病相关基因。其在K562细胞中高表达的意义尚不明确。

英文摘要：

Objective To explore ZO-1 gene expression and methylation in leukemia cells and the involvement of ZO-1 gene in leukemogenesis. Methods Restriction landmark genomie scanning（RLGS） was used to identify new leukemia related gene, and methylation specific PCR（MSP） for ZO-1 methylation status. ZO-1 specific siRNA was designed and prepared by in vitro transcription and transfeeted into K562 cells, the transfeeted cells were euhured for 48 hours before harvesting. The effect of ZO-1 siRNA was monitored by Northern blot. Cellular proliferation capacity was assayed by CCK-8, cell apoptosis by Annexin V- fluorescencein isothioeyanate （FITC） assay, and cell cycle by phosphatidylinositol （PI）. Results The intensified spots in RLGS gel were subjected to bioinformatics analysis and one of the candidate spots was proved to be ZO-1 gene. In fresh leukemia cells, Molt4 cells and HL-60 cells, ZO-1 was hypermethylated, causing it reduced or silenced. ZO-1 gene was highly expressed with no methylation in normal peripheral blood MNC and K.562 cells. There was a good correlation between promoter methylation and the gene silence. The silenced gene can be re-activated by demethylation treatment with 5-AZA-dC in most leukemia cell lines. RNA interference for ZO-1 gene in K562 cells did not interfere with cell proliferation, cell cycle and apoptosis. Conclusion ZO-1 gene methylation might be involved in the tumorigenesis of acute leukemia.