Fialova Barbora, Luzna Petra, Gursky Jan, Langova Katerina, Kolar Zdenek, Trtkova Katerina Smesny
Department of Clinical and Molecular Pathology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic.
Institute of Molecular and Translational Medicine, Palacky University Olomouc and University Hospital, Olomouc, Czech Republic.
Oncol Rep. 2016 Oct;36(4):2365-74. doi: 10.3892/or.2016.5000. Epub 2016 Aug 3.
The androgen receptor (AR) plays an essential role in the development and progression of prostate cancer. Castration-resistant prostate cancer (CRPC) is a consequence of androgen deprivation therapy. Unchecked CRPC followed by metastasis is lethal. Some CRPCs show decreased AR gene expression due to epigenetic mechanisms such as DNA methylation and histone deacetylation. The aim of this study was to epigenetically modulate the methylated state of the AR gene leading to targeted demethylation and AR gene expression in androgen-independent human prostate cancer DU145 cell line, representing the CRPC model with very low or undetectable AR levels. The cell treatment was based on single and combined applications of two epigenetic inhibitors, sodium butyrate (NaB) as histone deacetylases inhibitor and 5'-Aza-2'-deoxycytidine (Aza-dC) as DNA methyltransferases inhibitor. We found that the Aza-dC in combination with NaB may help reduce the toxicity of higher NaB concentrations in cancer cells. In normal RWPE-1 cells and even stronger in cancer DU145 cells, the combined treatment induced both AR gene expression on the mRNA level and increased histone H4 acetylation in AR gene promoter. Also activation and maintenance of G2/M cell cycle arrest and better survival in normal RWPE-1 cells compared to cancer DU145 cells were observed after the treatments. These results imply the selective toxicity effect of both inhibitors used and their potentially more effective combined use in the epigenetic therapy of prostate cancer patients.
雄激素受体（AR）在前列腺癌的发生和发展中起着至关重要的作用。去势抵抗性前列腺癌（CRPC）是雄激素剥夺治疗的结果。未经控制的CRPC随后发生转移是致命的。一些CRPC由于DNA甲基化和组蛋白去乙酰化等表观遗传机制而表现出AR基因表达降低。本研究的目的是通过表观遗传调控AR基因的甲基化状态，在雄激素非依赖性人前列腺癌DU145细胞系中实现靶向去甲基化和AR基因表达，该细胞系代表了AR水平极低或无法检测到的CRPC模型。细胞处理基于两种表观遗传抑制剂的单独和联合应用，丁酸钠（NaB）作为组蛋白去乙酰化酶抑制剂，5'-氮杂-2'-脱氧胞苷（Aza-dC）作为DNA甲基转移酶抑制剂。我们发现Aza-dC与NaB联合使用可能有助于降低癌细胞中较高NaB浓度的毒性。在正常RWPE-1细胞中，联合处理在mRNA水平上诱导了AR基因表达，并增加了AR基因启动子中的组蛋白H4乙酰化，在癌症DU145细胞中这种诱导作用更强。处理后还观察到正常RWPE-1细胞与癌症DU145细胞相比，G2/M细胞周期停滞的激活和维持以及更好的存活率。这些结果表明所使用的两种抑制剂具有选择性毒性作用，以及它们在前列腺癌患者的表观遗传治疗中潜在更有效的联合使用。
