Epigenetic Regulation of Cancer Stem Cell Genes in Triple-Negative Breast Cancer
Epigenetic Regulation of Cancer Stem Cell Genes in Triple-Negative Breast Cancer
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DOI：
10.1016/j.ajpath.2012.03.019
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发表时间：
2012-07-01
影响因子：
6
通讯作者：
Hoon, Dave S. B.
中科院分区：
文献类型：
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作者：
Kagara, Naofumi;Huynh, Kelly T.;Hoon, Dave S. B.
在侵袭性肿瘤中可以看到特定的乳腺癌干细胞(BCSCs)的表达，但它们的调控尚不清楚。表观遗传学改变影响基因表达，并与乳腺癌的进展有关。我们假设启动子甲基化调节特定的BCSC相关基因[CD44，CD133，CD24，MSH1(别名，Musashi-1)和ALDH1]，并且这种表观遗传学特征可以识别侵袭性亚型，如三阴性乳腺癌(TNBC)。用MassARRAY EpiTYPER测序进行甲基化分析，除ALDH1外，在BCSC基因的启动子区域有丰富的CpG位点。用5-氮杂-2‘-脱氧胞苷处理4个TN和5个非TNBC细胞系筛选这些位点。在CD44、CD133和Musashi-1中发现了CpG位点甲基化与mRNA表达之间最显著的负相关的调控位点，但CD24没有发现。对91例美国癌症联合委员会I-III期原发性乳腺癌肿瘤中CD44、CD133和Musashi-1的甲基化进行了评估，与非TNBC相比，这些位点的甲基化程度显著降低。甲基化水平最高和最低的原发肿瘤的MC染色显示，在低甲基化的标本中染色最强，表明低甲基化导致基因激活。我们证明甲基化是调节CD44、CD133和Musashi-1的重要机制，并且基因低甲基化与TNBC相关。评估BCSC基因的表观遗传学变化可能为TNBC提供更准确的分类，并可作为潜在的治疗靶点。(Am J Pathol2012,181：257-267；http://dx.doi.org/10.1016/j.ajpath.2012.03.019)
Expression of specific breast cancer stem cells (BCSCs) is seen in aggressive tumors, but their regulation is unclear. Epigenetic changes influence gene expression and are implicated in breast cancer progression. We hypothesized that promoter methylation regulates specific BCSC-related genes [CD44,CD133,CD24, MSH1 (alias, Musashi-1), and ALDH1] and that this epigenetic profile can identify aggressive subtypes, such as triple-negative breast cancer (TNBC). Methylation analysis was performed using MassARRAY EpiTYPER sequencing; CpG-rich sites were identified in the promoter regions of BCSC genes, except ALDH1. These sites were screened by treatment with 5-aza-2'-deoxycytidine in four TN and five non-TNBC cell lines. The specific regulatory CpG site demonstrating the most significant inverse correlation between CpG site methylation and mRNA expression was identified for CD44, CD133, and Musashi-1, but not for CD24. Methylation of CD44,CD133, and Musashi-1 was evaluated in 91 American Joint Committee on Cancer stage I to III primary breast cancer tumors, and these sites were significantly hypomethylated in TNBC versus non-TNBC. The MC staining of primary tumors with the highest and lowest methylation levels revealed the strongest staining in hypomethylated specimens, suggesting that hypomethylation leads to gene activation. We demonstrate that methylation is a significant mechanism regulating CD44, CD133, and Musashi-1, and that gene hypomethylation correlates with TNBC. Assessment of epigenetic changes in BCSC genes may provide a more accurate classification of TNBC and could be developed as potential therapeutic targets. (Am J Pathol 2012, 181:257-267; http://dx.doi.org/10.1016/j.ajpath.2012.03.019)