Plakoglobin is differentially expressed in alveolar and embryonal rhabdomyosarcoma and is regulated by DNA methylation and histone acetylation
Plakoglobin is differentially expressed in alveolar and embryonal rhabdomyosarcoma and is regulated by DNA methylation and histone acetylation
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DOI：
10.1093/carcin/bgl008
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发表时间：
2006-09-01
期刊：
影响因子：
4.7
通讯作者：
Rosolen, Angelo
中科院分区：
文献类型：
--
作者：
Gastaldi, Tamara;Bonvini, Paolo;Rosolen, Angelo
斑球蛋白（γ-连环蛋白）和 β-连环蛋白是将钙粘蛋白受体与肌动蛋白细胞骨架连接起来的细胞-细胞粘附连接的关键成分。 β-连环蛋白过度表达会诱导细胞增殖和肿瘤形成，而斑珠蛋白则会诱导肿瘤抑制活性。我们研究了斑珠蛋白在肺泡 (ARMS) 和胚胎 (ERMS) 横纹肌肉瘤 (RMS) 细胞系和肿瘤中的表达，发现斑珠蛋白存在于 ERMS 细胞的细胞质和细胞核中，而在 ARMS 中不存在或可检测到极低水平。由于基因沉默可以通过启动子区域的甲基化和/或脱乙酰化来介导，因此我们评估了 DNA 去甲基化剂 5-Aza-2'-脱氧胞苷 (5AzadC) 和组蛋白脱乙酰酶抑制剂曲古抑菌素 A (TSA) 的作用，并获得了在 5AzadC 和 TSA 存在下培养的 ARMS 细胞中斑珠蛋白表达的恢复。通过甲基化特异性 PCR，ARMS 细胞显示位于一个或两个等位基因转录起始位点周围的 CpG 岛中含有甲基化 CpG 二核苷酸，而 ERMS 细胞则不然。此外，我们证明 plakoglobin 基因的启动子区域 (P1-P3) 与 ARMS 细胞 RH4 中的低乙酰化 H4 组蛋白相关，表明 5' CpG 岛的异常 DNA 甲基化和组蛋白脱乙酰化在 plakoglobin 基因沉默中发挥关键作用。这些结果表明斑珠蛋白在 ARMS 和 ERMS 中差异表达，并且其表达取决于基因的甲基化和乙酰化状态。
Plakoglobin (gamma-catenin) and beta-catenin are pivotal components of cell-cell adherent junctions that link cadherin receptors to the actin cytoskeleton. Whereas beta-catenin overexpression induces cell proliferation and tumor formation, plakoglobin induces tumor suppressor activity. We investigated the expression of plakoglobin in alveolar (ARMS) and embryonal (ERMS) rhabdomyosarcoma (RMS) cell lines and tumors, and found that plakoglobin is present both in the cytoplasm and in the nucleus of ERMS cells, whereas it is absent or detectable at extremely low levels in ARMS. As gene silencing can be mediated by methylation and/or deacetylation of promoter regions, we assessed the effects of the DNA demethylating agent 5-Aza-2'-deoxycytidine (5AzadC) and of the histone deacetylase inhibitor Trichostatin A (TSA), and obtained restoration of plakoglobin expression in ARMS cells cultivated in the presence of 5AzadC and TSA. By methylation-specific PCR, ARMS cells were shown to contain methylated CpG dinucleotides in CpG islands located around the transcriptional start site of one or both alleles, whereas ERMS cells did not. Furthermore, we demonstrated that promoter regions (P1-P3) of plakoglobin gene were associated with hypoacetylated H4 histone in ARMS cells RH4, suggesting that aberrant DNA methylation of the 5' CpG island and histone deacetylation play key roles in silencing the plakoglobin gene. These results demonstrate that plakoglobin is differentially expressed in ARMS and ERMS and that its expression depends on the methylation and acetylation status of the gene.