Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung, Taiwan.
J Cell Biochem. 2011 Oct;112(10):3044-53. doi: 10.1002/jcb.23229.
Vorinostat (suberoylanilide hydroxamic acid), a class of histone deacetylase inhibitors, represents an emerging class of anticancer agents currently progressing in clinical trials. It causes cell growth inhibition, differentiation, and apoptosis of many tumor types in vitro and in vivo. Recently, it was reported that hTERT is one of the targets for cancer therapy in cancer cells. Telomerase repeat amplification protocol assay was used to analyze the expression of hTERT after vorinostat treatment in the A549 lung cancer cells. Vorinostat inhibited telomerase activity by reducing the expression of human telomerase reverse transcriptase (hTERT) in A549 human lung cancer cells. The epigenetic regulation mechanism is responsible for the repression of hTERT by vorinostat, analyzed through the methylation-specific PCR and bisulfite sequencing of the hTERT promoter. Vorinostat induced the demethylation of site-specific CpGs on the promoter region of hTERT, which was caused by the down-regulation of DNA methyltransferases. DNA methyltransferases (DNMT1 and DNMT3b) were also decreased in vorinostat-treated A549 cancer cells. Furthermore, chromatin immunoprecipitation analysis of the hTERT promoter revealed that vorinostat decreased the level of inactive chromatin markers dimethyl-H3K9, and the declined binding of DNMT1 and DNMT3b were associated. The novel insights showed that vorinostat down-regulated telomerase via epigenetic alteration in lung cancer to vorinostat-mediated cancer-specific therapies.
伏立诺他（琥珀酰亚胺基羟肟酸），是一类组蛋白去乙酰化酶抑制剂，属于当前在临床试验中不断进展的新兴抗癌药物类别。它在体外和体内能抑制多种肿瘤类型的细胞生长、分化和凋亡。最近，有报道称 hTERT 是癌症治疗的一个靶点。端粒重复扩增协议检测法用于分析伏立诺他处理 A549 肺癌细胞后 hTERT 的表达。伏立诺他通过降低 A549 人肺癌细胞中人端粒酶逆转录酶（hTERT）的表达来抑制端粒酶活性。通过 hTERT 启动子的甲基化特异性 PCR 和亚硫酸氢盐测序分析，发现表观遗传调控机制负责伏立诺他对 hTERT 的抑制。伏立诺他诱导 hTERT 启动子上特定 CpG 位点的去甲基化，这是由 DNA 甲基转移酶的下调引起的。伏立诺他处理的 A549 癌细胞中，DNA 甲基转移酶（DNMT1 和 DNMT3b）也减少了。此外，hTERT 启动子的染色质免疫沉淀分析显示，伏立诺他降低了非活性染色质标记物二甲基化 H3K9 的水平，并且 DNMT1 和 DNMT3b 的下降结合相关。这些新的见解表明，伏立诺他通过肺癌中的表观遗传改变下调端粒酶，从而实现伏立诺他介导的癌症特异性治疗。
