hDOT1L基因在急性白血病发病机制中的作用及其临床意义

Expression of hDOT1L Gene in Acute Leukemia and Its Clinical Significance

[目的]hDOT1L基因在白血病发病机制中的作用和临床意义,并分析其可能的作用机理,以期揭示白血病治疗的新靶点。[方法]收集和提取非恶性血液病患者和各组白血病患者的骨髓单个核细胞（BMMNC）。RT-PCR检测各组细胞内hDOT1L、HOXA9、HOXA10、MLL-AF10（MLLT10）的m RNA表达水平。应用Western blot法检测各组细胞内hDOT1L蛋白的表达及H3K79双甲基化蛋白表达水平,并检测各组p-MAPK、p-AKT和PI3K蛋白的表达水平。[结果]RT-PCR结果显示,急性髓系白血病（AML）组、急性淋巴细胞白血病（ALL）组及急性白血病复发（AL-relapse）组BMMNC中hDOT1L、HOXA9、HOXA10、MLL-AF10基因在m RNA水平明显高于对照组和急性白血病缓解组（AL-CR组）,且差异显著（P〈0.01）;AML组、ALL组及AL-relapse组组间比较及AL-CR组与对照组比较均无明显差异（P〉0.05）。Western blot检测结果表明,AML组和ALL组及AL-relapse组BMMNC中hDOT1L和H3K79-me2（双甲基）蛋白表达水平及AKT、p-AKT和PI3K蛋白显著高于对照组和AL-CR组,并有统计学意义（P〈0.01）;AML组和ALL组及AL-relapse组之间比较及AL-CR组与对照组比较上述蛋白表达水平均无统计学差异（P〉0.05）。[结论]hDOT1L是一种新型的组蛋白赖氨酸甲基转移酶,它可能通过提高H3K79的甲基化水平,诱导其下游HOXA9、HOXA10、MLL-AF10基因的表达,及影响细胞内其他信号通路参与急性白血病的发生,并与疾病的预后息息相关;阻断此通路可能是治疗白血病的一个新思路。

[Purpose] To investigate the expression of hDOT1 L in acute leukemia and its clinical significance. [Methods] Real time-PCR（RT-PCR） was used to detect the expression levels of intracellular HOXA9,HOXA10,MLL-AF10,and hDOT1 L m RNA in bone marrow mononuclear cells（BMMNC） of 60 acute leukemia patients and 15 non-malignant hematological patients（control group）. Western blot was used to detect the expression levels of hDOT1 L,H3 K79-me2,P-MAPK,p-AKT and PI3 K proteins. [Results] RT-PCR results indicated that the expression levels of HOXA9,HOXA10,MLL-AF10,and hDOT1 L m RNA in acute myeloid leukemia（AML,n=15）, acute lymphoblastic leukemia（ALL,n=15）and acute leukemia relapse（AL-relapse,n=15） patients were higher than those in the control group and complete remission of acute leukemia patients（AL-CR,n=15）（P〈0.01）. There were no significant differences in these genes expression levels between AL-CR patients and the control group（P〉0.05）,and among AML,ALL and AL-relapse groups（P〉0.05）. Western blot results displayed that the expression levels of hDOT1 L,PI3 K,P-MAPK,p-AKT and H3 K79-me2 in AML group,ALL group and AL-relapse group were higher than those in the control group and AL-CR group（P〈0.01）. There were no significant differences in expression levels of those molecules between AL-CR group and control group（P〈0.05）,and among AML,ALL and AL-relapse groups（P〉0.05）. [Conclusion] The study indicates that as a new type of histone lysine methylation transferase,hDOT1 L pathway may be involved in the pathogenesis and prognosis of acute leukemia.