Retinoic acid targets DNA-methyltransferases and histone deacetylases during APL blast differentiation in vitro and in vivo
Retinoic acid targets DNA-methyltransferases and histone deacetylases during APL blast differentiation in vitro and in vivo
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DOI：
10.1038/sj.onc.1208286
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发表时间：
2005-03-10
期刊：
影响因子：
8
通讯作者：
Nervi, C
中科院分区：
文献类型：
--
作者：
Fazi, F;Travaglini, L;Nervi, C
急性早幼粒细胞白血病（PML）-视黄酸受体α（RAR α）融合产物在视黄酸（RA）靶向启动子上募集组蛋白脱乙酰酶（HDAC）和DNA甲基转移酶（DNMT）活性，导致其沉默和分化阻断。RA治疗诱导表观遗传modi。阳离子在其靶位点和恢复APL原始细胞的髓样分化。使用RA敏感和RA耐药APL细胞系和原代母细胞，我们解决了RA靶启动子RAR β 2的异常甲基化状态的功能相关性和RA逆转甲基化的机制。RA降低DNMT的表达和活性，这与RAR β 2启动子/外显子1上特定位点的去甲基化以及APL母细胞在体外和体内的分化能力有关。这些事件均未发生在含有配体结合缺陷的PML-RAR α的RA耐药APL细胞系中。HDAC和DNMT途径对APL细胞对RA的反应的具体贡献也通过用TSA和/或5-氮杂胞苷抑制这些酶活性来测试。在RA应答和RA耐药APL母细胞中，TSA和5-氮杂胞苷诱导RA靶位点染色质状态的特异性变化，增加RA对启动子活性、内源性RA靶基因表达和分化的影响。这些结果扩展了染色质靶向治疗APL和RA耐药白血病的基本原理。
The acute promyelocytic leukemia (PML)-retinoic acid receptor alpha (RAR alpha) fusion product recruits histone deacetylase ( HDAC) and DNA methyltransferase (DNMT) activities on retinoic acid (RA)-target promoters causing their silencing and differentiation block. RA treatment induces epigenetic modi. cations at its target loci and restores myeloid differentiation of APL blasts. Using RA-sensitive and RA-resistant APL cell lines and primary blasts, we addressed the functional relevance of the aberrant methylation status at the RA-target promoter RAR beta 2 and the mechanism by which methylation is reversed by RA. RA decreased DNMT expression and activity, which correlated with demethylation at specific sites on RAR beta 2 promoter/exon-1, and the ability of APL blasts to differentiate in vitro and in vivo. None of these events occurred in an RA-resistant APL cell line containing a PML-RAR alpha defective for ligand binding. The specific contribution of the HDAC and DNMT pathways to the response of APL cells to RA was also tested by inhibiting these enzymatic activities with TSA and/or 5-azacytidine. In RA-responsive and RA-resistant APL blasts, TSA and 5-azacytidine induced specific changes on the chromatin state at RA-target sites, increased the RA effect on promoter activity, endogenous RA-target gene expression and differentiation. These results extend the rationale for chromatin-targeted treatment in APL and RA-resistant leukemias.