急性髓系白血病GLIPR1基因甲基化及其表达

目的：检测GLIPR1基因在急性髓系白血病（AML)细胞株和AML患者骨髓细胞中的甲基化状态和表达水平，探讨其表达水平与启动子甲基化的关系。 方法：以5株白血病细胞株， 以及54例治疗前AML患者骨髓、48例急性淋巴细胞胞白血病（ALL）患者骨髓、40例慢性粒细胞白血病（CML）患者骨髓、35例对照骨髓和8例治疗后完全缓解AML患者骨髓为样本，采用RT-PCR检测GLIPR1 mRNA表达水平，采用甲基化特异PCR（MS-PCR）方法检测GLIPR1基因甲基化状态，并对GLIPR1 mRNA表达水平与其甲基化状态进行相关性分析。 结果：GLIPR1基因在AML细胞株中的表达水平低于CML急性变细胞株和ALL细胞株，而前者甲基化水平高于后者。5-aza-2dC处理细胞后，GLIPR1基因在AML细胞株中的表达水平明显上调，而在CML急性变细胞株和ALL细胞株中的表达水平上调不明显。GLIPR1基因在AML骨髓中的表达水平（0.38±0.20）明显低于ALL骨髓（0.76±0.18）、CML骨髓（0.80±0.14）和对照骨髓（0.85±0.12），在完全缓解AML骨髓中的表达水平明显高于治疗前AML骨髓（0.78±0.13 vs. 0.36±0.20）；而ALL和CML骨髓中的表达水平与对照骨髓比较无明显差异(P＞0.05）。GLIPR1基因在AML骨髓的甲基化阳性率(81.5%)明显高于ALL骨髓（37.5%)、CML骨髓（27.5%)和对照骨髓（14.3%)，在完全缓解AML骨髓中的甲基化阳性率明显低于治疗前骨髓(12.5% vs. 75.0%)；而在ALL和CML骨髓中的甲基化阳性率与对照骨髓比较无明显差异(P＞0.05）。GLIPR1基因在AML骨髓中的表达水平与其甲基化呈负相关。结论：GLIPR1基因在AML中表达下调或缺失及启动子甲基化可能是导致GLIPR1基因表达沉默的原因，GLIPR1基因表达和甲基化水平对判断AML患者的疗效有一定意义。

Methylation and expression of glioma pathogenesis-related protein 1 gene in acute myeloid leukemia

ObjectiveTo detect the methylation and expression of glioma pathogenesis-related protein 1(GLIPR1) gene in the acute myeloid leukemia (AML) cell lines and bone marrow cells from AML patients, and to determine the relationship between promoter methylation and expression of GLIPR1.MethodsFive leukemia cell lines, 54 bone marrows from the newly diagnosed AML patients, 48 bone marrows from the acute lymphoblastic leukemia (ALL )patients, 40 bone marrows from the chronic myeloid leukemia (CML) patients,35 bone marrows from control patients, and 8 bone marrows from the complete remission AML patients were collected. RT-PCR and methylation-PCR (MSP) were used to detect the mRNA expression and promoter methylation of GLIPR1, respectively, and the relationship between them was analyzed.ResultsThe level of GLIPR1 mRNA in the AML cell lines was lower than that in the chronic myeloid leukemia (CML) and ALL cell lines, whereas the methylation level of GLIPR1 in the former was higher than that in the latter. The level of GLIPR1 mRNA in the AML cell lines was significantly increased, but had no obvious changes in the CML and ALL cell lines after 5-aza-2dC treatment. The mRNA level of GLIPR1 in the AML bone marrows （0.38±0.20）was obviously lower than that in the ALL bone marrows （0.76±0.18）, CML bone marrows （0.80±0.14）, and control bone marrows（0.85±0.12）. The level of GLIPR1 mRNA in the bone marrows with complete remission AML was obviously higher than that in the AML bone marrows before the treatment (0.78±0.13 vs. 0.36±0.20); but there was no obvious difference between the ALL bone marrows and the control bone marrows, and the CML bone marrows and the control bone marrows (both P＞0.05）. The positive rate of GLIPR1 gene methylation in the AML bone marrows (81.5%) was obviously higher than that in the ALL bone marrows（37.5%), CML bone marrows （27.5%) and the control bone marrows（14.3%). The positive rate of GLIPR1 gene in the bone marrows with complete remission AML was obviously lower than that in the bone marrows before the treatment (12.5% vs. 75.0%), but there was no obvious difference between the ALL bone marrows and between the control bone marrows,and the CML bone marrows and the control bone marrows (both P＞0.05）. There was a negative correlation between the mRNA level and methylation status of GLIPR1 in the AML bone marrows.ConclusionGLIPR1 expression is downregulated or even lost by promoter methylation in AML, and the expression and methylation level of GLIPR1 gene may have some significance in evaluating the curative effect of AML patients.