Department of Pediatric Surgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, People's Republic of China.
Anticancer Drugs. 2012 Nov;23(10):1054-66. doi: 10.1097/CAD.0b013e32835739dd.
Epigenetic aberrations and a CpG island methylator phenotype are associated with poor outcome in children with neuroblastoma (NB). Previously, we have shown that valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, exerts antitumor effects in an NB xenograft model. However, the underlying antitumor molecular mechanisms are largely unknown. In this study, we examined the role of HDAC in cell proliferation, cell cycle progression, gene expression patterns, and epigenome in NB. Cell proliferation, cell cycle progression, caspase activity, RNA and protein expression, quantitative methylation, and global DNA methylation were examined in NBL-W-N and LA1-55n NB cell lines. Our studies showed that inhibition of HDAC decreased NB proliferation, and induced caspase activity and G1 growth arrest. Expression patterns of cancer-related genes were modulated by VPA. The expression of THBS1, CASP8, SPARC, CDKN1A, HIC1, CDKN1B, and HIN1 was upregulated, and that of MYCN and TIG1 was downregulated. HDAC inhibition decreased methylation levels of THBS1 and RASSF1A promoters. Inhibition of HDAC increased acetylation of histone 4 and overall DNA methylation levels. Our studies showed that inhibition of HDAC blocked cell proliferation and cell cycle progression in relation to alteration in cancer-related genes, increased overall DNA methylation, and decreased methylation of tumor suppressor genes. Further studies examining the antitumor effects of VPA in NB are warranted.
表观遗传异常和 CpG 岛甲基化表型与神经母细胞瘤（NB）患儿的不良预后相关。此前，我们已经表明，组蛋白去乙酰化酶（HDAC）抑制剂丙戊酸（VPA）在 NB 异种移植模型中具有抗肿瘤作用。然而，其潜在的抗肿瘤分子机制在很大程度上尚不清楚。在这项研究中，我们研究了 HDAC 在 NB 中的细胞增殖、细胞周期进展、基因表达模式和表观基因组中的作用。在 NBL-W-N 和 LA1-55n NB 细胞系中检查了细胞增殖、细胞周期进展、半胱天冬酶活性、RNA 和蛋白质表达、定量甲基化和全基因组甲基化。我们的研究表明，HDAC 抑制降低了 NB 的增殖，并诱导了半胱天冬酶活性和 G1 生长停滞。VPA 调节了与癌症相关的基因表达模式。THBS1、CASP8、SPARC、CDKN1A、HIC1、CDKN1B 和 HIN1 的表达上调，而 MYCN 和 TIG1 的表达下调。HDAC 抑制降低了 THBS1 和 RASSF1A 启动子的甲基化水平。抑制 HDAC 增加了组蛋白 4 的乙酰化和整体 DNA 甲基化水平。我们的研究表明，抑制 HDAC 阻断了细胞增殖和细胞周期进展，与改变癌症相关基因、增加整体 DNA 甲基化和降低肿瘤抑制基因的甲基化有关。进一步研究 VPA 在 NB 中的抗肿瘤作用是必要的。
