慢性髓系白血病患者CD34^+ CD38^-细胞水平JunB和CDH13基因启动子区域的甲基化状态研究

Methylation Status of JunB and CDH13 Gene Promoter in CD34^+ CD38^-Chronic Myelogenous Leukemia Cells

慢性髓系白血病(CML)是骨髓造血干细胞恶性增殖的克隆性疾病,在CML患者细胞水平由于JunB和CDH13基因启动子区甲基化而使这2个抑癌基因的表达受损。为了探讨正常人和CML患者CD34+ CD38-细胞水平JunB和CDH13(cadhe rin-13)基因启动子区域甲基化状态及表达水平的差异,应用流式细胞仪分选出CD34+ CD38-细胞,采用甲基化特异性聚合酶链反应(MS-PCR)检测5例正常人和8例CML患者骨髓CD34+ CD38-细胞JunB和CDH13基因启动子区域甲基化状态,用实时定量PCR(RT-PCR)检测JunB和CDH13基因的表达情况。结果表明:JUNB和CDH13基因在正常人骨髓CD34+ CD38-细胞中呈完全性非甲基化状态,CML患者骨髓CD34+ CD38-细胞中JunB和CDH13基因启动子区甲基化比例分别为87.5%(7/8)和50%(4/8),明显高于正常人(p<0.05)。CML患者骨髓CD34+ CD38-细胞中JunB和CDH13基因mRNA相对表达水平与正常人的相比明显降低(2-??CT分别为1/5.21和1/10.63)。结论:在CML患者骨髓CD34+ CD38-细胞中JunB和CDH13基因启动子区域都发生了高度的甲基化,它们的mRNA表达水平也明显降低,JunB和CDH13基因启动子区域甲基化在CML的发病机制中起到一定的作用,甲基化检测对CML的靶向治疗及新的治疗方法具有重要意义。

Chronic myelogenous leukemia（CML） is a clonal myeloproliferative disease of transformed hematopoietic progenitor cells. The expressions of JunB and CDH13 （cadherin-13） gene as tumor suppressor gene were inactivated by promoter methylation in CML patients. This study was purposed to investigate the methylation difference of JunB and CDH13 gene promoter and the expression levels of JunB and CDH13 gene in CD34 ＋ CD38 - cells in CML patients vs normal individuals. CD34 ＋ CD38 - cells from 8 cases of CML and 5 normal individuals were selected by flow cytometry. The methylation status of JunB and CDH13 genes were detected by MS-PCR in selected CD34 ＋ CD38- cells. The expression levels of JunB and CDH13 gene was detected with real time polymerase chain reaction（ RT-PCR）. The results showed that no methylation of JunB and CDH13 gene was detected in CD34 ＋ CD38- cells of 5 normal individuals. Methylations of JunB and CDH13 promoter were found in 87.5 % （ 7/8 ） and 50% （4/8） CML CD34 ＋ CD38 - cells, percentages of which were significantly higher than those in normal individuals. The difference was statistically significant （p 〈0.05）. The relative expression levels of JunB and CDH13 mRNA in CD34 ＋ CD38 cells of CML patients were significantly lower than those in normal individuals （2 ^-△△CT were 1/5.21 and 1/10.63 respectively）. It is concluded that the high methylation of JunB and CDH13 gene promoter occurs in CD34＋ CD38- cells of CML patients, their mRNA expression level is significantly lower, thus the methylation of JunB and CDH13 gene promoter probably plays a role in the pathogenesis of CML and may have clinical significance in predicting prognosis of CML.