Epigenetic modifications have been found to play crucial roles in myelodysplastic neoplasm (MDS) progression. Previously, we investigated genome-wide DNA methylation alterations during MDS evolution to acute myeloid leukemia (AML) by next-generation sequencing (NGS). Herein, we further determined the role and clinical implications of an evident methylation change in CpG islands at the SLIT2 promoter identified by NGS. First, increased SLIT2 promoter methylation was validated in 11 paired MDS/AML patients during disease evolution. Additionally, SLIT2 promoter methylation was markedly increased in MDS/AML patients compared with controls and was correlated with poor clinical phenotype and outcome. Interestingly, SLIT2 expression was particularly upregulated in AML patients and was not correlated with SLIT2 promoter methylation. However, the SLIT2-embedded genes SLIT2-IT1 and miR-218 were downregulated in AML patients, which was negatively associated with SLIT2 promoter methylation and further validated by demethylation studies. Functionally, SLIT2-IT1/miR-218 overexpression exhibited antileukemic effects by affecting cell proliferation, apoptosis and colony formation in vitro and in vivo. Mechanistically, SLIT2-IT1 may function as a competing endogenous RNA by sponging miR-3156-3p to regulate BMF expression, whereas miR-218 may directly target HOXA1 in MDS progression. In summary, our findings demonstrate that SLIT2 promoter hypermethylation is associated with disease evolution in MDS and predicts poor prognoses in both MDS and AML. Epigenetic inactivation of SLIT2-IT1/miR-218 by SLIT2 promoter hypermethylation could be a promising therapeutic target in MDS.

已发现表观遗传修饰在骨髓增生异常肿瘤 (MDS) 进展中起关键作用。此前，我们通过下一代测序 (NGS) 研究了 MDS 向急性髓细胞白血病 (AML) 进化过程中的全基因组 DNA 甲基化改变。在这里，我们进一步确定了 NGS 鉴定的SLIT2启动子处 CpG 岛明显甲基化变化的作用和临床意义。首先，在疾病演变过程中，在 11 对 MDS/AML 患者中验证了增加的 SLIT2启动子甲基化。此外，与对照组相比，MDS/AML 患者的SLIT2启动子甲基化显着增加，并且与不良的临床表型和结果相关。有趣的是，SLIT2表达在 AML 患者中特别上调，并且与SLIT2启动子甲基化无关。然而，嵌入 SLIT2的基因SLIT2-IT1和miR-218在 AML 患者中下调，这与SLIT2启动子甲基化呈负相关，并通过去甲基化研究进一步验证。在功能上，SLIT2-IT1 / miR-218过表达通过在体外和体内影响细胞增殖、凋亡和集落形成而表现出抗白血病作用。从机制上讲，SLIT2-IT1可以通过海绵化miR-3156-3p来调节BMF ，从而发挥竞争性内源性 RNA 的作用表达，而miR-218可能在 MDS 进展中直接靶向HOXA1 。总之，我们的研究结果表明，SLIT2启动子高甲基化与 MDS 的疾病演变有关，并预测 MDS 和 AML 的预后不良。SLIT2启动子高甲基化对SLIT2-IT1 / miR-218的表观遗传失活可能是 MDS 中一个有前景的治疗靶点。