Background: Histone deacetylation of tumor suppressor genes such as estrogen receptor alpha (ERα) can induce cancer, which is reversible by epi-drugs such as valproic acid (VPA). The previous result indicated that tamoxifen (TAM) induced apoptosis in hepatocellular carcinoma (HCC). This study was designed to assess the apoptotic and antiproliferative effects of VPA and TAM and also the effect of VPA on ERα gene expression in HCC.
Material and Methods: The cells were treated with various doses of VPA and TAM and the MTT assay, Real-Time RT-PCR, and flow cytometry assay were done to determine viability, ERα gene expression, and apoptosis.
Results: Both agents inhibited viability and induced apoptosis. ERα gene expression was increased by VPA, which in turn increased the apoptotic effect of TAM. The half-maximum inhibitory concentration (IC50) value for VPA and TAM was 5 and 20 μM respectively. VPA inhibited cell growth by 88 % to 38 % at 24 h (P < 0.001) and 76 % to 28 % at 48 h (P < 0.002) and also TAM inhibited by 92 % to 40 % at 24 h (P < 0.006) and 84 % to 32 % at 48 h (P < 0.001). The percentage of VPA- treated apoptotic cells were reduced by about 35 and 43 % (P ˂0.001) and that of TAM-treated 32 and 38 % (P ˂0.001) after 24 and 48 h, respectively.
Conclusion: VPA and TAM can significantly inhibit viability and induce apoptosis and also VPA play a significant role in ERα reactivation.

Background: Hepatocellular carcinoma (HCC), primary liver cancer, is a major health problem and the third most common cause of cancer-related deaths worldwide. Epigenetic modulations are essential for the maintenance of gene expression patterns in mammals. Disruption of these processes can lead to silenced gene and malignant cellular transformation. The current study was designed to compare the effect of curcumin with trichostatin A (TSA) on DNA methyltransferase 1 (DNMT1) gene expression, cell growth inhibition, and apoptosis induction in HCC Hepa 1-6 cell line.
Materials and Methods: Hepatocellular carcinoma Hepa 1-6 cell line  was purchased from the National Cell Bank of Iran-Pasteur Institute,  treated with curcumin (1, 5, 10, 25 and 50 μM) and TSA (0.5, 1, 2.5, 5 and 10 μM), and the MTT assay was performed. Then, flow cytometry assay and Real-Time RT-PCR analysis were performed with curcumin and TSA treatments. Statistical comparisons between groups were performed using ANOVA (one‑way ANOVA) and Turkey test. A significant difference was considered as P < 0.05.
Results: Both treatments showed significant inhibitory and apoptotic effects, besides reducing the expression of DNMT1. The relative expression of DNMT1 gene in the curcumin-treated groups were 0.7 to 0.3 (P <0.001) and in the TSA treated groups were 0.5 to 0.19 (P <0.001).
Conclusion: The curcumin and trichostatin A (TSA) can inhibit cell viability and induce apoptosis somehow through epigenetic modification. The curcumin indicated a more significant apoptotic effect than TSA.

Background: DNA molecule of the eukaryotic cells is found in the form of a nucleoprotein complex named chromatin. Two epigenetic modifications are critical for transcriptional control of genes, including acetylation and DNA methylation. Hypermethylation of tumor suppressor genes is catalyzed by various DNA methyltransferase enzymes (DNMTs), including DNMT1, DNMT2, and DNMT3. The most well characterized DNA demetilating and histone deacetylase inhibitor drugs are 5-aza-2ˈ-deoxycytidine (5-Aza-CdR) and valproic acid (VPA), respectively. The purpose of the current study was to analyze the effects of 5-Aza-CdR and VPA on cell growth, apoptosis, and DNMT1 gene expression in the WCH-17 hepatocellular carcinoma (HCC) cell line.
Materials and Methods: In this descriptive analytical study, MTT assay, flow cytometry assay, and Quantitative Real-Time RT-PCRwere done to evaluate proliferative and apoptotic effects and also gene expression.
Results: Both compounds inhibited the cell growth and induced apoptosis significantly in a dose and time depended fashion. Additionally, 5-Aza-CdR down-regulated DNMT1 gene expression. The relative expression of DNMT1 was 0.40 and 0.20 (P < 0.001) at different times, respectively. The percentage of VPA- treated apoptotic cells were reduced by about 28 and 34 % (P˂0.001) and that of 5-Aza-CdR-treated were reduced by about 34 and 44 % (P˂0.001) after treatment time periods.
Conclusion: In the current study, it was observed that 5-Aza-CdR and VPA could significantly inhibit the growth of WCH-17 cell and played a significant role in apoptosis. It was also found that 5-Aza-CdR could decrease DNMT1 gene expression.

Background: Mammalian cell division is regulated by a complex includes cyclin-dependent kinases (Cdks) and cyclins, Cdk/cyclin complex. The activity of the complex is regulated by Cdk inhibitors (CKIs) compressing CDK4 (INK4) and CDK-interacting protein/kinase inhibitory protein (CIP/KIP) family. Hypermethylation of CKIs has been reported in various cancers. DNA methyltransferase inhibitors (DNMTIs), such as decitabine and 5-aza-2′-deoxycytidine (5-aza-CdR) can reactivate hypermethylated genes. The current study aimed to evaluate the effect of 5-aza-CdR on the expression of p16INK4a, p14ARF, p15INK4b genes, cell viability, and apoptosis in HCC PLC/PRF5 and pancreatic cancer MIA Paca-2 cell lines.
Materials and Methods: In this laboratory trial, both cell lines were treated with 5-aza-CdR (0, 1, 2.5, 5, 10, 15, and 20 μM) to determine cell viability and then with 3 μM to obtain cell apoptosis and relative gene expression. The cell viability, apoptosis, and genes expression were investigated by 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide (MTT) assay, flow cytometry, and Real-Time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), respectively.
Results: 5-aza-CdR indicated significant inhibitory effect with all used concentrations (P = 0.003). The apoptotic effect of 5-aza-CdR on PLC/PRF5 cells in comparison to pancreatic cancer MIA Paca-2 cells was more significant (P= 0.001). Real-time quantitative PCR analysis revealed that treatment with 5-aza-CdR (3 μM) for 24 and 48h up-regulated p16INK4a, p14ARF, p15INK4b genes expression significantly(P=0.040).
Conclusion: Reactivation of p16INK4a, p14ARF, p15INK4b genes by 5-aza-CdR can induce apoptosis and inhibit cell viability in HCC, PLC/PRF5, and pancreatic cancer, MIA Paca-2, cell lines.

The basic unit of chromatin is a nucleosome included an octamer of the four core histones and 147 base pairs of DNA. Posttranslational histones modifications affect chromatin structure resulting in gene expression changes. CpG islands hypermethylation within the gene promoter regions and the deacetylation of histone proteins are the most common epigenetic modifications. The aberrant patterns of methylation localized in normally unmethylated CPG islands mediate chromatin compaction resulting in gene silencing and cancer induction. The current review article aimed to assess and analyze the available literature on the tumor suppressor genes (TSGs) hypermethylation in hepatocellular carcinoma (HCC). For this review article, the suitable studies were obtained by searching PubMed, SCOPUS, NCBI, and Ovid database from 1995 up to September 2018 with the MeSH terms combined with free terms.  A total 1483 Items were identified in SCOPUS (n = 459), PubMed (n = 832), Ovid (n = 118), and other reference sources (n = 74). After the assessment, 73 manuscripts were included in the current study. In total, 13 genes were found to have the most effect on HCC. Therefore, we selected them to evaluate as candidate genes in this cancer. TSGs can affect cell cycle during various stages of the cycle an at the cell cycle checkpoints. The hypermethylation of these genes results in chromatin compaction and TSGs silencing which induces HCC.

Background: Aberrant DNA methylation of the promoter region is one of the most epigenetic changes in numerous cancers. DNA methyltransferase inhibitors (DNMTIs) can revert DNA hypermethylation in tumor suppressor genes (TSGs). The present study was designed to investigate the effect of 5-fluoro-2′-deoxycytidine (FdCyd) on p16INK4a, p14ARF, p15INK4b, and DNA methyltransferase 1, 3a, and 3b genes expression, apoptosis induction, cell growth inhibition in pancreatic cancer AsPC-1 and hepatocellular carcinoma LCL-PI 11 cell lines.
Materials and Methods: The cells were treated with FdCyd at different periods. Then, the MTT assay, cell apoptosis assay, and qRT-PCR were done to determine cell viability, cell apoptosis, and the relative gene expression level respectively.
Results: The FdCyd decreased DNA methyltransferase 1, 3a, and 3b and increased p16INK4a, p14ARF, and p15INK4b genes expression significantly (P<0.001). Besides, LCL-PI 11 cell was more sensitive to FdCyd in comparison to AsPC-1 cell. FdCyd induced significant cell growth inhibition with a dose- and time-dependent manner (P<0.001). The IC50 value of FdCyd was obtained with approximately 1μM. Further, FdCyd induced cell apoptosis significantly as a time-dependent manner. The number of apoptotic cells was significantly increased in all groups. The percentage of apoptotic cells after 24 and 48 h were 13.86 and 29.6 % in AsPC-1 and 21.04 and 41.52 % in LCL-PI 11 cell line respectively (P<0.001).
Conclusion: The FdCyd can reactivate the p16INK4a, p14ARF, and p15INK4b through inhibition of DNA methyltransferase 1, 3a, and 3b gene expression.

Backgrounds: Epigenetic regulation such as DNA methylation plays a major role in chromatin organization and gene transcription. Additionally, histone modification is an epigenetic regulator of chromatin structure and influences chromatin organization and gene expression. The relationship between DNA methyltransferase (DNMTs) expression and promoter methylation of the tumor suppressor genes (TSGs) has been reported in various cancers. Previously, the effect of 5-aza-2'-deoxycytidine (5-AZA-CdR), trichostatin A (TSA), and valproic acid (VPA) was shown on various cancers. This study aimed to investigate the effect of 5'-fluoro-2'-deoxycytidine (FdCyd) and sodium butyrate on the genes of the intrinsic apoptotic pathway, p21, p53, cell viability, and apoptosis in human hepatocellular carcinoma SNU449, SNU475, and SNU368 cell lines.
Materials and Methods: In this lab trial study, the SNU449, SNU475, and SNU368 cells were cultured and treated with 5'-fluoro-2'-deoxycytidine and sodium butyrate. To determine cell viability, cell apoptosis, and the relative gene expression level, MTT assay, flow cytometry assay, and qRT-PCR were done respectively.
Results: 5'-fluoro-2'-deoxycytidine and sodium butyrate changed the expression level of the BAX, BAK, APAF1, Bcl-2, Bcl-xL, p21, and p53 gene (P<0.0001) by which induced cell apoptosis and inhibit cell growth in all three cell lines, SNU449, SNU475, and SNU368. 
Conclusion: Both compounds played their roles through the intrinsic apoptotic pathway to induce cell apoptosis.

Background:  The aberrant and altered patterns of gene expression play an important role in the biology of cancer and tumorigenesis. DNA methylation and histone deacetylation are the most studied epigenetic mechanisms. Histone deacetylase inhibitors (HDACIs) such as valproic acid (VPA) and trichostatin A (TSA) are a group of anticancer compounds for the treatment of solid and hematological cancers. Previously, we reported the effect of two HDACIs, valproic acid (VPA) and TSA, on colon cancer and hepatocellular carcinoma (HCC), respectively. The aim of the current in vitro study is to investigate the effects of TSA on the intrinsic apoptotic pathway, p21/Waf1/Cip1 (p21), p53, and histone deacetylases (HDACs) 1, 2 and 3 in human neuroblastoma LAN-1, glioblastoma GBM-29, HCC SMMC7721, and colon cancer COLO 201 cell lines.
Materials and methods: In this lab-trial study, all three cell lines were seeded at the density of 3 × 105 cells per well and incubated for 24 hours. Then, the cells were treated with TSA based on IC50 values for 24 hours except in the control groups; the control cells were treated with the equal amounts of the DMSO solvent. Subsequently, cell viability, cell apoptosis and gene expression were determined by three techniques including MTT assay, flow cytometry assay, and qRT-PCR.
Results: The result of qRT-PCR indicated that TSA could increase the expression levels of Bid, BimEL, Noxa, p21, and p53 genes and decrease those of Bcl-xL, RIP, Mcl-1, XIAP, HDACs 1, 2 and 3 significantly (P < 0.0001) by which it inhibited cell growth and induced significant cell apoptosis in LAN-1, GBM-29, SMMC7721, and COLO 201 cell lines (p value<0.001).
Conclusion: TSA can affect cell apoptotic via the intrinsic apoptotic pathway in LAN-1, GBM-29, SMMC7721, and COLO 201 cell lines.