急性髓系白血病干细胞RIZ1基因启动子甲基化状态研究

A study on the methylation status of RIZ1 gene promoter in acute myeloid leukemia stem cells

目的探讨急性髓系白血病（AML）[除外急性早幼粒细胞性白血病（APL）即非APL]白血病干细胞RIZ1基因启动子甲基化状态与发病的相关性。方法应用流式分选仪提取20例初诊为急性髓系白血病患者CD34^＋CD38^-CD123^＋的干细胞，通过甲基化特异性聚合酶链反应（MSP）检测6例健康者和20例AML（非APL）患者骨髓CD34^＋CD38^-CD123^＋细胞RIZ1基因启动子区域甲基化状态，用实时定量PCR（RT—PCR）检测RIZ1基因的表达情况。结果RIZ1基因在健康者骨髓细胞中呈非甲基化状态，而在40％AML（非APL）患者骨髓CD34^＋CD38^-CD123^＋细胞启动子区域存在甲基化，与健康者比较差异有统计学意义（P〈0．05）。AML患者RIZ1基因mRNA相对表达水平明显低于健康者。结论在大部分AML（非APL）患者白血病干细胞中，RIZ1基因启动子区域发生甲基化，其mRNA表达水平也明显降低。RIZ1基因启动子区域甲基化可能与AML（非APL）的发病相关，其甲基化检测对AML（非APL）的早期诊断具有重要的临床意义。

Objective To explore the correlation between the methylation status of RIZ1 gene promoter in acute myeloid leukemia（ non acute promyelocytic leukemia） stem cells and the onset of AML. Methods Bone marrow stem cells of CD34 ＋ CD38- CD123 ＋ were selected from 20 AML （non APL） patients by flow cytometry and the methylation status of RIZ1 gene promter were detected by MSP in above-mentioned ceils and bone marrow cells of 6 healthy persons. The expression levels of RIZ1 gene was detected by real time polymerase chain reaction（RT-PCR）. Results There was no methylation of RIZ1 gene promoter detected in bone marrow cells of 6 non malignant tumor patients. Methy]ation of RIZ1 gene promoter were found in 40% （8/20） AML CD34＋ CD38- CD123 ^＋ bone marrow cells which were significantly different from non malignant tumor individuals（P 〈0. 05）. The relative expression levesls of RIZ1 mRNA in AML patients were significantly lower than those in healthy persons. Conclusion The high methy]ation of RIZ1 gene promoter occurs in stem cells of AML（ non APL） patients and their mRNA expression level is significantly lower. The methylation of RIZ1 gene promoter probably plays a role in the pathogenesis of AML（non APL） and the test of the methylation of RIZ1 gene promoter has clinical significance in predicting the prognosis of AML（ non APL）.