Global identification of genes regulated by estrogen signaling and demethylation in MCF-7 breast cancer cells
Global identification of genes regulated by estrogen signaling and demethylation in MCF-7 breast cancer cells
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DOI：
10.1016/j.bbrc.2012.08.007
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发表时间：
2012-09-14
影响因子：
3.1
通讯作者：
Dahlman-Wright, Karin
中科院分区：
文献类型：
--
作者：
Putnik, Milica;Zhao, Chunyan;Dahlman-Wright, Karin
雌激素信号传导和表观遗传修饰，特别是DNA甲基化，参与乳腺癌基因表达的调节。在这里，我们研究了这两种途径之间的潜在调控串扰，通过识别它们的共同靶基因和探索人类MCF-7乳腺癌细胞中的潜在分子机制。基因表达谱显示，大约140个基因的表达受到17 β-雌二醇（E2）和去甲基化剂5-氮杂-2 '-脱氧胞苷（DAC）的影响。基因本体论（GO）分析表明，这些基因参与细胞内信号级联，调节细胞增殖和凋亡。基于先前报道的与乳腺癌的关联、雌激素信号传导和/或DNA甲基化、CpG岛预测和GO分析，我们选择了六个基因（BIG 3、FHL 2、PMAIP 1、BTG 2、CDKN 1A和TGFB 2）用于进一步分析。三苯氧胺逆转E2对所有选定基因表达的影响，表明它们是雌激素受体的直接靶点。此外，DAC治疗以剂量依赖性方式重新激活所有选定基因的表达。启动子CpG岛甲基化状态分析显示，只有BTG 3和FHL 2基因的启动子被甲基化，DAC诱导去甲基化，表明DNA甲基化指导MCF-7细胞中这些基因的阻遏。在进一步分析雌激素信号传导和DNA甲基化之间的潜在相互作用时，E2处理对这些启动子的甲基化状态没有影响。此外，我们表明，ER α招聘发生在FHL 2启动子在E2和DAC独立的方式。总之，我们确定了一组受雌激素信号和DNA甲基化调控的基因。然而，我们的数据并不支持调节基因启动子的雌激素和表观遗传信号传导介质的直接分子相互作用。(C)2012 Elsevier Inc. All rights reserved.
Estrogen signaling and epigenetic modifications, in particular DNA methylation, are involved in regulation of gene expression in breast cancers. Here we investigated a potential regulatory cross-talk between these two pathways by identifying their common target genes and exploring underlying molecular mechanisms in human MCF-7 breast cancer cells. Gene expression profiling revealed that the expression of approximately 140 genes was influenced by both 17 beta-estradiol (E2) and a demethylating agent 5-aza-2'-deoxycytidine (DAC). Gene ontology (GO) analysis suggests that these genes are involved in intracellular signaling cascades, regulation of cell proliferation and apoptosis. Based on previously reported association with breast cancer, estrogen signaling and/or DNA methylation, CpG island prediction and GO analysis, we selected six genes (BIG3, FHL2, PMAIP1, BTG2, CDKN1A and TGFB2) for further analysis. Tamoxifen reverses the effect of E2 on the expression of all selected genes, suggesting that they are direct targets of estrogen receptor. Furthermore, DAC treatment reactivates the expression of all selected genes in a dose-dependent manner. Promoter CpG island methylation status analysis revealed that only the promoters of BTG3 and FHL2 genes are methylated, with DAC inducing demethylation, suggesting DNA methylation directs repression of these genes in MCF-7 cells. In a further analysis of the potential interplay between estrogen signaling and DNA methylation, E2 treatment showed no effect on the methylation status of these promoters. Additionally, we show that the ER alpha recruitment occurs at the FHL2 promoter in an E2- and DAC-independent fashion. In conclusion, we identified a set of genes regulated by both estrogen signaling and DNA methylation. However, our data does not support a direct molecular interplay of mediators of estrogen and epigenetic signaling at promoters of regulated genes. (C) 2012 Elsevier Inc. All rights reserved.