The hypomethylating agent Decitabine causes a paradoxical increase in 5-hydroxymethylcytosine in human leukemia cells.
The hypomethylating agent Decitabine causes a paradoxical increase in 5-hydroxymethylcytosine in human leukemia cells.
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DOI：
10.1038/srep09281
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发表时间：
2015-04-22
影响因子：
4.6
通讯作者：
Irudayaraj J
中科院分区：
文献类型：
--
作者：
Chowdhury B;McGovern A;Cui Y;Choudhury SR;Cho IH;Cooper B;Chevassut T;Lossie AC;Irudayaraj J
美国FDA批准的“表观遗传药物”地西他滨通过使DNA低甲基化发挥作用，证明了异常的全基因组DNA甲基化模式在癌症本体论中发挥的关键作用。在急性髓系白血病细胞模型中使用敏感技术，我们证明，虽然地西他滨降低了 5-甲基胞嘧啶 (5mC) 的整体水平，但它导致 5-羟甲基胞嘧啶 (5hmC)、5-甲酰基胞嘧啶 (5fC) 和 5-羧基胞嘧啶 (5caC) 水平反常增加。迄今为止，已知产生 5hmC、5fC 和 5caC 的唯一生物机制（涉及 10-11 易位 (TET) 双加氧酶家族成员对 5mC 的氧化）在 DAC 治疗期间未观察到发生任何改变。使用 DNA 甲基化的多区室模型，我们表明 TET 酶对半甲基化 CpG 二核苷酸的部分选择性可能导致 5hmC 含量的这种变化。此外，我们通过荧光相关光谱法研究了活细胞中 TET1-催化结构域 (CD)-GFP 与 DNA 的结合，并检测到地西他滨处理后 TET1-CD-GFP 的 DNA 结合部分逐渐增加。我们的研究在新发现的 5mC 衍生物的背景下提供了关于 DAC 治疗活性的新见解，并表明 5hmC 有潜力作为监测接受 DAC 的患者临床成功的生物标志物。
The USFDA approved “epigenetic drug”, Decitabine, exerts its effect by hypomethylating DNA, demonstrating the pivotal role aberrant genome-wide DNA methylation patterns play in cancer ontology. Using sensitive technologies in a cellular model of Acute Myeloid Leukemia, we demonstrate that while Decitabine reduces the global levels of 5-methylcytosine (5mC), it results in paradoxical increase of 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) levels. Hitherto, the only biological mechanism known to generate 5hmC, 5fC and 5caC, involving oxidation of 5mC by members of Ten-Eleven-Translocation (TET) dioxygenase family, was not observed to undergo any alteration during DAC treatment. Using a multi-compartmental model of DNA methylation, we show that partial selectivity of TET enzymes for hemi-methylated CpG dinucleotides could lead to such alterations in 5hmC content. Furthermore, we investigated the binding of TET1-catalytic domain (CD)-GFP to DNA by Fluorescent Correlation Spectroscopy in live cells and detected the gradual increase of the DNA bound fraction of TET1-CD-GFP after treatment with Decitabine. Our study provides novel insights on the therapeutic activity of DAC in the backdrop of the newly discovered derivatives of 5mC and suggests that 5hmC has the potential to serve as a biomarker for monitoring the clinical success of patients receiving DAC.