Sanaei Masumeh, Kavoosi Fraidoon, Roustazadeh Abazar, Golestan Fatemeh
Research Center for Non-Communicable Diseases, Jahrom University of Medical Sciences, Jahrom, Fars province, Iran.
Student Research Committee, Jahrom University of Medical Sciences, Jahrom, Fars province, Iran.
J Clin Transl Hepatol. 2018 Jun 28;6(2):141-146. doi: 10.14218/JCTH.2018.00002. Epub 2018 Mar 6.
DNA methylation and histone modification are epigenetic modifications essential for normal function of mammalian cells. The processes are mediated by biochemical interactions between DNA methyltransferases (DNMTs) and histone deacetylases. Promoter hypermethylation and deacetylation of tumor suppressor genes play major roles in cancer induction, through transcriptional silencing of these genes. DNA hypermethylation is carried out by a family of DNMTs including DNMT1, DNMT3a and DNMT3b. In hepatocellular carcinoma, a significant positive correlation between over-expression of these genes and cancer induction has been reported. The DNA demethylating agent genistein (GE) has been demonstrated to reduce different cancers. Previously, we reported that GE can induce apoptosis and inhibit proliferation in hepatocellular carcinoma PLC/PRF5 and HepG2 cell lines. Besides, histone deacetylase inhibitors, such as trichostatin A (TSA), were successfully used to inhibit cancer cell growth. The present study was designed to assess the effect of GE in comparison with TSA on DNMT1, DNMT3a and DNMT3b gene expression, cell growth inhibition and apoptosis induction in the HepG2 cell line. Cells were seeded and treated with various doses of GE and TSA. The MTT assay, flow cytometry assay, and real-time RT-PCR were used to determine viability, apoptosis, and DNMT1, DNMT3a and DNMT3b gene expression respectively. Both agents inhibited cell growth, induced apoptosis and reactivated DNMT1, DNMT3a and DNMT3b gene expression. Furthermore, TSA demonstrated a significantly greater apoptotic effect than the other agent, whereas GE improved gene expression more significantly than TSA. Our findings suggest that GE and TSA can significantly inhibit cell growth, induce apoptosis and restore DNMT1, DNMT3a and DNMT3b gene reactivation.
DNA甲基化和组蛋白修饰是哺乳动物细胞正常功能所必需的表观遗传修饰。这些过程由DNA甲基转移酶（DNMTs）和组蛋白脱乙酰酶之间的生化相互作用介导。肿瘤抑制基因的启动子高甲基化和去乙酰化通过这些基因的转录沉默在癌症诱导中起主要作用。DNA高甲基化由包括DNMT1、DNMT3a和DNMT3b在内的DNMT家族进行。在肝细胞癌中，已报道这些基因的过表达与癌症诱导之间存在显著正相关。DNA去甲基化剂染料木黄酮（GE）已被证明可减少不同的癌症。此前，我们报道GE可诱导肝癌PLC/PRF5和HepG2细胞系凋亡并抑制增殖。此外，组蛋白脱乙酰酶抑制剂，如曲古抑菌素A（TSA），已成功用于抑制癌细胞生长。本研究旨在评估GE与TSA相比对HepG2细胞系中DNMT1、DNMT3a和DNMT3b基因表达、细胞生长抑制和凋亡诱导的影响。细胞接种后用不同剂量的GE和TSA处理。MTT法、流式细胞术和实时RT-PCR分别用于测定活力、凋亡以及DNMT1、DNMT3a和DNMT3b基因表达。两种药物均抑制细胞生长、诱导凋亡并重新激活DNMT1、DNMT3a和DNMT3b基因表达。此外，TSA显示出比另一种药物显著更强的凋亡作用，而GE比TSA更显著地改善基因表达。我们的研究结果表明，GE和TSA可显著抑制细胞生长、诱导凋亡并恢复DNMT1、DNMT3a和DNMT3b基因的重新激活。
