MicroRNA-23b表观遗传学沉默在t(8;21)急性髓系白血病发病机制的研究

In the analysis of miRNAs' roles in regulation of t(8;21) acute myeloid leukemi(AML), we found that microRNA-23b(miR-23b) had the closely significant correlation with the occurrence and transformation of AML. In order to further investigate the mechanisms of miR-23b involved in AML development, firstly, we would propose for testing miR-23b expression levels and promoter methylation in the bone marrows and cell lines, for the purpose ofanalyzing the expression patterns and the methylation procedures. Furthermore, through reverse analysis of target gene, combined with epegenetics, base on bioinformatics, we would investigate and comfirm the roles of miR-23b suppression to tumors via epigenetic silencing leading to abnoal PI3K/AKT/BCL2 signal pathway, that may be an important mechanism in the occurrence and development of AML. Based on bioinformatics and epigenetics, we would investigate the relationship of miR-23b and t(8;21) AML, that may be provide new insight into understanding the molecular processes required for leukemogenesis and offer possibility of identifying new targets for the development of novel therapeutic approaches to leukemia.

在分析miRNAs对t（8；21）急性髓系白血病（AML）调控机制的研究中，本课题组发现microRNA-23b（miR-23b）与t（8；21）AML的发生、发展有密切联系。为进一步探讨miR-23b参与白血病发生的机制，本课题拟：（1）对临床标本及细胞株进行检测，分析miR-23b在t（8；21）白血病中的表达及其启动子区甲基化水平；（2）通过生物信息学结合靶基因反向分析技术，并以表观遗传学为突破口，分析miR-23b表观遗传学沉默解除了对AML1-ETO以及PI3K/AKT/BCL2的抑制可能是参与t（8；21）白血病发生发展的重要机制。本研究旨在对白血病的发生发展提供新的了解，进而为将来的靶向治疗提供分子理论依据。

为研究miRNA-23b（miR-23b)在t(8;21)白血病发生中的作用以及是否对临床预后有影响，我们首先用去甲基化药物5-azacytidine和Decitabine分别作用于AML1-ETO阳性白血病细胞株KASUMI1以及SKNO1，观察其甲基化水平以及表达式水平的变化；进而通过转染人工合成的功能性miR-23b，观察其作用靶点（AML1-ETO、AKT、BCL2）表达水平的变化，进而通过体内实验进一步论证；同时我们亦选用AML1-ETO阳性以及阴性的急性髓系白血病（AML）临床骨髓标本，进行miR-23b表达水平以及甲基化水平的检测，并观察对临床预后的影响。结果显示去甲基化药物5-azacytidine和Decitabine处理KASUMI1以及SKNO1细胞后，其miR-23b表达水平上调，同时其启动子区甲基化水平下降；转染功能性miR-23b后，AML1-ETO、AKT以及BCL2表达下调；体内试验进一步证实miR-23b可下调AML-ETO、AKT以及BCL2的表达；同时在AML1-ETO阳性以及阴性的骨髓标本中，我们发现miR-23b启动子区甲基化水平可能影响AML1-ETO阳性患者的临床预后，增加其预后差的概率；而miR-23b表示水平对临床预后无影响。综上所述，miR-23b可能通过其启动子区异常甲基化从而解除了对AML1-ETO以及AKT-BCL信号通路的抑制，进而参与白血病的发生；需要进一步实验数据证实此设想。同时miR-23b甲基化水平可能影响t（8；21）白血病患者的预后。