Effect Of DNA Methylation Inhibitor Research Articles

Hypermethylated WASF2: tumor suppressive role in head and neck squamous cell carcinoma.

WASF2 regulates actin reorganization during cell migration. WASF2 has been identified as a regulator of the development of gastric cancer, breast cancer, and pancreatic cancer. But its regulatory mechanisms remain unknown. Also, its function was absent in head and neck squamous cell carcinoma (HNSCC). Consequently, we examined the effect of DNA methylation on aberrant WASF2 expression in HNSCC. TNMplot, TIMER, GSEA pathway analysis, and the Kaplan-Meier Plotter database were used to analyze the expression, function, and prognostic value of WASF2, as well as the correlation between WASF2 and infiltrating immune cells in HNSCC or pan-cancer analysis. WASF2 promoter methylation levels and the correlation between WASF2 expression and WASF2 promoter methylation in HNSCC were evaluated using the DNMIVD database. The effect of DNA methylation inhibitor on WASF2 expression was demonstrated in the GEO database. Finally, the TISIDB database determined the relationships between WASF2 methylation, immune cell infiltration, and immune inhibitors. WASF2 was significantly downregulated in HNSCC tissues where WASF2 promoter methylation was elevated. According to the GEO database, treatment with a DNA methylation inhibitor notably restored the mRNA expression of WASF2. WASF2 expression was also a favorable indicator of human papilloma virus (HPV)-positive HNSCC. Its level of promoter methylation had detrimental effects on patient survival. In addition, patients with elevated levels of WASF2 demonstrated active G2/M regulation, TGF-β signaling, Kras signaling, fatty acid metabolism, and p53 pathways. WASF2 was positively associated with tumor-killing immune cells, while WASF2 methylation was positively related to immunosuppressive cells and immune-inhibitors. Hypermethylated WASF2 acted as a tumor suppressor of HNSCC by regulating tumor formation and immune imbalance.

5‑Azacytidine treatment results in nuclear exclusion of DNA methyltransferase‑1, as well as reduced proliferation and invasion in human cytomegalovirus‑infected glioblastoma cells.

Glioblastoma (GBM) is the most aggressive form of brain tumor in adults, with a devastating outcome. Emerging evidence shows that human cytomegalovirus (HCMV) proteins and nucleic acids are present in GBM tissues. DNA methylation is important for the initiation and progression of cancer and is an established host response against invading nucleic acids. The expression and localization of DNA methyltransferase 1 (DNMT‑1) was assessed, and the effects of DNA methylation inhibitor 5‑azacytidine (5AZA) were analyzed in the context of the viral replication, proliferation and invasion capacities of HCMV‑infected GBM U343MG cells. In addition, the expression of various HCMV proteins and DNMT‑1 was examined in GBM tissue specimens obtained from five patients. DNMT‑1 was localized in the nucleus of cells expressing HCMV‑immediate early, whereas in cells expressing HCMV‑glycoprotein gB (gB), extranuclear/cytoplasmic localization was observed. This was also observed in vitro in U343MG cells. In addition, DNMT‑1 was localized to the extranuclear/cytoplasmic space of cells lining blood vessel walls within the GBM tumors. Treatment of infected U343MG cells with 5AZA did not affect viral replication, but reduced cell invasion and proliferation (P=0.05 and P<0.0001, respectively). However, 5AZA treatment of uninfected cells did not affect cell invasion (P=0.09), but proliferation was significantly reduced (P<0.0001). These findings may be of importance in further investigations aimed at using DNA methylation and viral inhibitors in GBM therapy.

Effects of DNA methylation inhibitor 5-Aza-2'-deoxycytidine on biological behavior of esophageal squamous carcinoma cells

Objective To investigate the effects of methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-dC) on biological behavior of esophageal squamous carcinoma cell (ESCC) lines KYSE140 and KYSE150. Methods KYSE140 and KYSE150 cell lines were divided into the blank group, the control group and the experimental group. The cells in the blank group didn't do the treatment, and the cells in the control group were added to DMSO 2 μmol/L, while in the experimental group, cells were treated with different concentration (1, 2, 3 and 4 μmol/L) of 5-Aza-dC which affected respectively at different time (24, 48, 72 and 96 h). Cell proliferation was detected by using methyl thiazolyl tetrazolium (MTT) assay and the optimal drug concentration and time point were selected. Transwell assay was performed to detect the change of cell migration and invasion. Flow cytometry was used to observe the effects of drugs on cell apoptosis and cell cycle. The expression of PARP, Caspase-3, CCNB-1, and CCNE-1 were detected by Western blot. Results MTT result showed that the effective function time of 5-Aza-dC on KYSE140 and KYSE150 was 96 h at the concentration of 4 μmol/L. Under this condition, the cell ability of migration and invasion was decreased significantly. The migrated cell number of KYSE140 and KYSE150 respectively in the blank group, the control group and the experimental group was (193.3±8.6), (184.0±10.4), (61.7±7.1) and (112.0±6.4), (101.3±7.9), (26.3±5.7). The invasive cell number was (47.3±7.3), (38.7±5.1), (8.0±3.9) and (83.3±6.8), (74.7±5.7), (21.0±2.7), respectively. The difference was statistically significant (P <0.05). Flow cytometry revealed that 5-Aza-dC increased the apoptosis of KYSE140 and KYSE150. The apoptosis rate of the blank group, the control group and the experimental group was (2.8±0.3)%, (11.2±0.7)%, (18.6±0.6)% for KYSE140 and (2.7±0.4)%, (9.8±0.4)%, (17.7±0.5)% for KYSE150. Compared with the other two groups, the cell number of G2/M phase in the experimental group was increased remarkably (P < 0.05). PARP and Caspase-3 were sheared evidently and the protein expression of CCNB-1 was up-regulated while the expression of CCNE-1 was down-regulated in the experimental group. Conclusion 5-Aza-dC can inhibit the proliferation and promote apoptosis of ESCC cells. Key words: Esophageal squamous cell carcinoma; DNA Methylation; 5-Aza-2'-deoxycytidine; Apoptosis; Cell cycle

Abstract B053: Characterizing the effects of the DNA methylation inhibitor 5-AZA-CdR during CD8 T cell expansion

Abstract Immune checkpoint blockade therapy has been the most recent advance for achieving durable clinical response of different advanced cancers. However, most patients still remain non-responsive to immunotherapy alone, which suggest the need for combining different cancer therapies. Dual blockade targeting CTLA-4 and PD1/PDL1 pathway have been explored in advance melanoma, renal cell cancer, and NSCLC with promising clinical evidence. Though it is still unclear which sequence of checkpoint blockade therapies is the most effective. Another combinatorial strategy for cancer treatment would be combing epigenetic therapy with immunotherapy. Low doses of the DNA methylation inhibitor (DNMTis), 5-AZA-CdR, on cancer cells has durable anti-tumorigenic effects by inducing cell cycle arrest and immune-modulatory effects that increases their visibility by the immune system. Growing evidence led by our group and others suggest that DNMTis can upregulate immune signalling in cancer cells through viral mimicry and upregulation of tumor associated antigens, highlighting clinical potential to combine with immunotherapy. While the effects of DNMTis have been mostly studied in cancer cells, their effects on the immune system remains vastly unknown specially at clinically relevant low doses. The goal was to study the effects of 5-AZA-CdR on CD8+ T cells due to their inherent cytotoxic functions to recognize and kill pathogen infected cells and tumor cells. Because DNA methylation is a known mechanism by which CD8+ T cells can regulate the transcription of genes encoding for effector cytokines such as IFN-gamma, we hypothesize that treatment of 5-AZA-CdR during CD8+ T cell expansion will allow more permissive transcription of effector cytokines genes, thus conferring enhanced CD8+ T cell effector function. We used human CD8+ T cells expanded with anti-CD3/CD28 beads in the presence or absence of lose dose 5-AZA-CdR. Our results indicate that while low dose 5-AZA-CdR treatment during human CD8+ T cell expansion reduced CD8+ T cell proliferation capacity and increased expression of various T cell inhibitory receptors, functional capacity of CD8+ was improved. Low dose 5-AZA-CdR treatment during human CD8+ T cell expansion conferred higher expression and production of the effector cytokines IFN-gamma and TNF-alpha, and the cytotoxic granules Granzyme B. These observations suggest that treatment with 5-AZA-CdR during CD8+ T cells expansion may enhance their cytotoxic functions. By studying the effects of 5-AZA-CdR on CD8+ T cells, our goal is to use this knowledge generated in here to help elucidate rational combinatorial regimens for epigenetic therapy and immunotherapy. Citation Format: Helen Loo Yau. Characterizing the effects of the DNA methylation inhibitor 5-AZA-CdR during CD8 T cell expansion [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B053.

A New Molecular Mechanism Underlying the Antitumor Effect of DNA Methylation Inhibitors via an Antiviral Immune Response.

Chromatin remodeling mediated by DNA methylation and histone modifications play critical roles in the transcriptional regulation of protein-coding genes, noncoding RNAs such as microRNAs, and endogenous retroviruses (ERVs). Many studies have shown that aberrant DNA methylation and histone modifications are associated with the initiation and progression of various malignancies. Epigenetic silencing of tumor suppressor genes in cancer is generally mediated by DNA hypermethylation of CpG island promoters and histone modifications such as histone deacetylation, methylation of histone H3 lysine 9 (H3K9), and trimethylation of H3K27. Chromatin-modifying drugs such as DNA methylation inhibitors and histone deacetylase inhibitors have clinical promise for cancer therapy. However, details of the mechanisms responsible for the antitumor effects of these drugs have been unclear. Recently, a new molecular mechanism for the antitumor effect of DNA methylation inhibitors has been proposed: induction of interferon-responsive genes via double-stranded RNAs derived from ERVs. We have also confirmed the same effect of DNA demethylation using a 3D culture system for stem cells known as organoid culture. Our findings indicated that DNA demethylation suppresses the proliferation of cancer-initiating cells by inducing an antiviral response, including activation of interferon-responsive genes. Treatment with DNA methylation inhibitors to activate a growth-inhibiting immune response may be an effective therapeutic approach for malignant disorders.

Abstract 2788: Inhibition of DNA methylation suppresses intestinal tumor organoids by inducing an anti-viral response

Abstract Background and Aim It is believed that the anti-tumor effect of DNA methylation inhibitors is mediated by re-activation of epigenetically silenced tumor suppressor genes in cancer cells. However, recent studies have proposed that the major anti-tumor effect of DNA methylation inhibitors is induction of interferon-related genes via dsRNAs-containing endogenous retroviruses. These studies used conventional cancer cell lines, which are maintained in 2D culture condition with serum-containing medium and are considered to be relatively artificial models of cancer cells. Recently, 3D culture system for stem cells known as organoid culture has been developed. Lgr5-positive stem cells form organoids that closely recapitulate the properties of original tissues. To investigate the effect of DNA demethylation on tumor organoids, we have established intestinal tumor organoids from tumors of ApcMin/+ (Min) mice and subjected them to 5-aza-2’-deoxycytidine (5-Aza-CdR) treatment and Dnmt1 knockdown. Methods Min mice were treated with 5-Aza-CdR (1 μg/body weight, n = 12) or PBS (n = 11) by subcutaneous injection weekly from 6 weeks of age. At 21 weeks of age, mice were dissected and number of intestinal polyps was counted. Stem cells were isolated from intestinal tumors of Min mice and maintained by organoid culture. Treatment with 5-Aza-CdR and lentivirus-mediated knockdown of Dnmt1 were performed in organoids derived from intestinal tumors. Expression profiles of genes after treatment with 5-Aza-CdR and Dnmt1-knockdown were analyzed. Results Treatment of Min mice with 5-Aza-CdR significantly reduced the average number of intestinal adenomas from 66 to 44 (male) and from 65 to 47 (female). The average number of large adenomas (≧3mm) in Min mice treated with 5-Aza-CdR was significantly decreased from 24 to11, whereas there was no significant difference in the average number of small adenomas (&amp;lt; 3mm). We successfully established organoids derived from intestinal tumors of Min mice by 3D culture with serum-free medium including epidermal growth factor (EGF) and Noggin. DNA demethylation induced by 5-Aza-CdR treatment and Dnmt1 knockdown significantly reduced the cell proliferation of the tumor organoids. Microarray analyses of the tumor organoids after 5-Aza-CdR treatment and Dnmt1 knockdown revealed that interferon-related genes including interferon regulatory factor 7 (Irf7) were activated by DNA demethylation. Gene ontology and pathway analyses clearly demonstrated that these genes activated by DNA demethylation are involved in the anti-viral response. Conclusions DNA demethylation suppresses the proliferation of intestinal tumor organoids by inducing an anti-viral response including activation of interferon-related genes. These findings suggest that treatment of colon cancers with DNA methylation inhibitors such as 5-Aza-CdR may be an effective therapeutic approach inhibiting cancer stem cells by immune response. Citation Format: Yoshimasa Saito, Kasumi Sakai, Toshihide Muramatsu, Toshiaki Nakaoka, Masaki Kimura, Hidetsugu Saito. Inhibition of DNA methylation suppresses intestinal tumor organoids by inducing an anti-viral response. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2788.

Inhibition of DNA Methylation Suppresses Intestinal Tumor Organoids by Inducing an Anti-Viral Response.

Recent studies have proposed that the major anti-tumor effect of DNA methylation inhibitors is induction of interferon-responsive genes via dsRNAs-containing endogenous retroviruses. Recently, a 3D culture system for stem cells known as organoid culture has been developed. Lgr5-positive stem cells form organoids that closely recapitulate the properties of original tissues. To investigate the effect of DNA demethylation on tumor organoids, we have established organoids from intestinal tumors of ApcMin/+ (Min) mice and subjected them to 5-aza-2′-deoxycytidine (5-Aza-CdR) treatment and Dnmt1 knockdown. DNA demethylation induced by 5-Aza-CdR treatment and Dnmt1 knockdown significantly reduced the cell proliferation of the tumor organoids. Microarray analyses of the tumor organoids after 5-Aza-CdR treatment and Dnmt1 knockdown revealed that interferon-responsive genes were activated by DNA demethylation. Gene ontology and pathway analyses clearly demonstrated that these genes activated by DNA demethylation are involved in the anti-viral response. These findings indicate that DNA demethylation suppresses the proliferation of intestinal tumor organoids by inducing an anti-viral response including activation of interferon-responsive genes. Treatment with DNA methylation inhibitors to activate a growth-inhibiting immune response may be an effective therapeutic approach for colon cancers.

DNA methylation in an engineered heart tissue model of cardiac hypertrophy: common signatures and effects of DNA methylation inhibitors.

DNA methylation affects transcriptional regulation and constitutes a drug target in cancer biology. In cardiac hypertrophy, DNA methylation may control the fetal gene program. We therefore investigated DNA methylation signatures and their dynamics in an in vitro model of cardiac hypertrophy based on engineered heart tissue (EHT). We exposed EHTs from neonatal rat cardiomyocytes to a 12-fold increased afterload (AE) or to phenylephrine (PE 20 µM) and compared DNA methylation signatures to control EHT by pull-down assay and DNA methylation microarray. A 7-day intervention sufficed to induce contractile dysfunction and significantly decrease promoter methylation of hypertrophy-associated upregulated genes such as Nppa (encoding ANP) and Acta1 (α-skeletal actin) in both intervention groups. To evaluate whether pathological consequences of AE are affected by inhibiting de novo DNA methylation we applied AE in the absence and presence of DNA methyltransferase (DNMT) inhibitors: 5-aza-2'-deoxycytidine (aza, 100 µM, nucleosidic inhibitor), RG108 (60 µM, non-nucleosidic) or methylene disalicylic acid (MDSA, 25 µM, non-nucleosidic). Aza had no effect on EHT function, but RG108 and MDSA partially prevented the detrimental consequences of AE on force, contraction and relaxation velocity. RG108 reduced AE-induced Atp2a2 (SERCA2a) promoter methylation. The results provide evidence for dynamic DNA methylation in cardiac hypertrophy and warrant further investigation of the potential of DNA methylation in the treatment of cardiac hypertrophy.

Effects of DNA methylation inhibitors and conventional antidepressants on mice behaviour and brain DNA methylation levels.

Stress increases DNA methylation and decreases the expression of genes involved in neural plasticity, while treatment with DNA methyltransferase inhibitors (DNMTi) increases gene expression and induces antidepressant-like effects in preclinical models. Therefore, the aim of the present work was to further investigate the potential antidepressant-like effect induced by DNMTi by evaluating the behavioural effects induced by associating DNMTi treatment with conventional antidepressant drugs in mice submitted to the forced swimming test (FST). In addition, brain levels of DNA methylation were also investigated. Mice received systemic injections of 5-aza-2'-deoxycytidine (5-AzaD, 0.1, 0.2 mg/kg), RG108 (0.1, 0.2, 0.4 mg/kg), desipramine (DES, 2.5, 5, 10 mg/kg) or fluoxetine (FLX, 5, 10, 20, 30 mg/kg) and were submitted to the FST or to the open field test (OFT). Additional groups received a combination of subeffective doses of 5-AzaD or RG108 (DNMTi) with subeffective doses of DES or FLX (antidepressants). Subeffective doses of RG108 (0.1 mg/kg) or 5-AzaD (0.1 mg/kg) in association with subeffective doses of DES (2.5 mg/kg) or FLX (10 mg/kg) induced significant antidepressant-like effects. Effective doses of RG108 (0.2 mg/kg), 5-AzaD (0.2 mg/kg), DES (10 mg/kg) and FLX (20 mg/kg) atenuated stress-induced changes in DNA methylation levels in the hippocampus and prefrontal cortex. None of the treatments induced locomotor effects in the OFT. These results suggest that DNMTi potentiate the behavioural effects of antidepressant drugs in the FST and that antidepressants, as well as DNMTi, are able to modulate stress-induced changes in DNA methylation in brain regions closely associated with the neurobiology of depression.

The Epigenetic Drug 5-Azacytidine Interferes with Cholesterol and Lipid Metabolism

DNA methylation and histone acetylation inhibitors are widely used to study the role of epigenetic marks in the regulation of gene expression. In addition, several of these molecules are being tested in clinical trials or already in use in the clinic. Antimetabolites, such as the DNA-hypomethylating agent 5-azacytidine (5-AzaC), have been shown to lower malignant progression to acute myeloid leukemia and to prolong survival in patients with myelodysplastic syndromes. Here we examined the effects of DNA methylation inhibitors on the expression of lipid biosynthetic and uptake genes. Our data demonstrate that, independently of DNA methylation, 5-AzaC selectively and very potently reduces expression of key genes involved in cholesterol and lipid metabolism (e.g. PCSK9, HMGCR, and FASN) in all tested cell lines and in vivo in mouse liver. Treatment with 5-AzaC disturbed subcellular cholesterol homeostasis, thereby impeding activation of sterol regulatory element-binding proteins (key regulators of lipid metabolism). Through inhibition of UMP synthase, 5-AzaC also strongly induced expression of 1-acylglycerol-3-phosphate O-acyltransferase 9 (AGPAT9) and promoted triacylglycerol synthesis and cytosolic lipid droplet formation. Remarkably, complete reversal was obtained by the co-addition of either UMP or cytidine. Therefore, this study provides the first evidence that inhibition of the de novo pyrimidine synthesis by 5-AzaC disturbs cholesterol and lipid homeostasis, probably through the glycerolipid biosynthesis pathway, which may contribute mechanistically to its beneficial cytostatic properties.

Quantitative gene analysis of methylation and expression (Q‐GAME) in fresh or fixed cells and tissues

Epigenetic regulation of gene expression by DNA methylation is a central mechanism governing the silencing of tumor suppressor genes in many forms of cancer. Current methods have not proven optimal for the quantitative analysis of DNA methylation and corresponding in situ protein expression within cells in small specimens like skin biopsies. We have overcome this limitation by combining and modifying several techniques: target cell enrichment, DNA micro-isolation, one-step denaturation/bisulphite conversion/in-column desulphonation, specially designed PCR amplification, pyrosequencing and multispectral image analysis. Using this approach optimized for small samples, we can quantify minor alterations in gene methylation and protein expression using minimal amounts of tissue. Comparative studies of fresh and processed cells showed that our method is valid for DNA in both fresh and formalin-fixed, paraffin-embedded specimens. We can measure the effects of DNA methylation inhibitors, administered in vitro or in vivo, on the promoter methylation and protein expression of selected genes in specific cells. This novel approach should prove useful for a wide variety of investigative and clinical applications in dermatology and other specialties where the collection of small, routinely processed biopsy specimens is common. We refer to this method as Q-GAME (quantitative gene analysis of methylation and expression).

Effect of DNA methylation inhibitor on RASSF1A genes expression in non-small cell lung cancer cell line A549 and A549DDP

BackgroundRas association domain family 1A gene (RASSFlA) is a candidate suppressor gene, Lack of RASSF1A expression was found in lung cancer. High DNA methylation at the promoter region is the main reason for inactivating RASSF1A transcription.MethodsIn this study, we examined RASSF1A’s methylation status and its mRNA expression level between non-small cell lung cancer cell line A549 and anti-Cisplatin cell strain A549DDP, Furthermore, methylation of A549DDP was reversed by treatment of 5-Aza-2′ - deoxycytidine (5-Aza-cdR),a DNA methyltransferase inhibitor.ResultsWe found that RASSF1A’s methylation status and its mRNA expression were obvious differences between A549 and A549DDP. 5-Aza-CdR treatment remarkablly reduced cell vability of A549DDP. Moreover, 5-Aza-CdR treatment induced A549DDP cell apoptosis in a dose dependent manner with declining cell percentage in S and G2/M stage, and increasing proportion in G0/G1 stage. Cell motility was blocked in G0/G1 stage. All of A549DDP cells showed unmethylated expression, its high methylation status was reversed in a dose-dependent manner within a certain range.ConclusionsThe abnormal gene methylation status of RASSF1A is a molecular biomarker in lung cancer diagnosis, treatment and prognosis.

Effect of DNA Methylation Inhibitors on the Developmental Competence of Cloned Buffalo (Bubalus bubalis) Embryos.

Effect of DNA Methylation Inhibitors on the Developmental Competence of Cloned Buffalo (Bubalus bubalis) Embryos.

The effect of DNA methylation inhibitor 5-Aza-2′-deoxycytidine on human endometrial stromal cells

Decidualization, the differentiation of endometrial stromal cells is a crucial step for successful implantation of an embryo, development of the placenta and completion of pregnancy to term. Epigenetic mechanisms are thought to be strongly involved in the regulation of processes controlling implantation, placentation, organ formation and foetal growth. Recent studies suggest that decreased DNA methylation facilitates a receptive endometrium. Hence, the aim of this project was to compare the transcriptional profile changes induced by the inhibitor of DNA methylation, 5-Aza-2'-deoxycytidine (AZA) to the transcriptional changes that happen during decidualization. When DNA methylation was inhibited in a human endometrial stromal cell (HESC) line with AZA, it resulted in the fibroblast-like stromal cells being transformed into decidual-like morphology after 9 days. Expression of both prolactin and insulin-like growth factor binding protein-1, the two established decidualization marker genes, were minimally up-regulated by AZA after 10 days of treatment. In a microarray of a three-way experiment between AZA-treated and oestradiol/progestin/cAMP-treated [medroxy-progesterone acetate (MPA)-mix] HESC and the untreated controls, we detected more than 1000 common genes that had a significant difference of expression compared with the controls. AZA-treated cells in the microarray significantly expressed 76 genes in common with the MPA-mix treated cells, and AZA treatment also differentially regulated 148 genes independently to that of MPA-mix treatment. The MPA-mix regulated at least 36 genes in the cell adhesion, extracellular matrix remodelling and RhoGTPase cytoskeletal reorganization pathway; AZA regulated 19 of these genes in common and 15 other RhoGTPase pathway genes. AZA induced some decidualization-like responses of endometrial stromal cells independently of progestins or cAMP, possibly via the cytoskeletal reorganization pathway of the RhoGTPase family.

36 TREATMENT OF PORCINE FETAL FIBROBLASTS WITH DNA METHYLATION INHIBITORS OR HISTONE DEACETYLATION INHIBITORS IMPROVES DEVELOPMENT OF NUCLEAR TRANSFER EMBRYOS

Epigenetic status of the genome of a donor nucleus has an important effect on the developmental potential of cloned embryos produced by somatic cell nuclear transfer (SCNT). DNA methylation inhibitors [such as 5-aza-2′-deoxyctidine (5-aza-dC), zebularine, and RG108] and histone deacetylase inhibitors [such as trichostatin A (TSA), sodium butyrate (NaBu), and scriptaid (SCR)] have been widely used for the alteration of the levels of the epigenetic modification of somatic cells. This study was designed to investigate the DNA methylation status of porcine fetal fibroblast cells treated with TSA or 5-aza-dC and to determine whether treatments with DNA methylation inhibitors or histone deacetylation inhibitors could improve the in vitro development of porcine reconstructed embryos. When the levels of DNA methylation in the PRE-1 sequence (repeat sequence in a euchromatic region) were examined by bisulfite sequencing following treatment of porcine fetal fibroblast cells with TSA or 5-aza-dC for 1 h, DNA methylation was decreased in 5-nm or 50-nm concentrations even if they were not significantly different. To evaluate the effect of DNA methylation inhibitors and histone deacetylation inhibitors on development of porcine nuclear transfer embryos, porcine fetal fibroblast cells were treated with 5 nm of 5-aza-dC, zebularine, or RG108 for 1 h, or with 50 nm of TSA, NaBu, or SCR for 1 h, or treated with both 50 nm TSA and 5 nm 5-aza-dC for 1 h before NT. The reconstructed embryos were electrically fused and cultured in PZM-3 for 6 days. Developmental rates of the reconstructed embryos from donor cells treated with 5-aza-dC, zebularine, or RG-108 to blastocysts significantly increased compared to the control group (21.4, 23.3, and 22.1 v. 12.3%). Blastocyst rates of the reconstructed embryos from donor cells treated with TSA, SCR, and NaBu also were significantly improved compared to the control group (30.0, 23.9, and 22.4 v. 14.5%), and TSA treatment was the highest in blastocyst rates among the treated groups. However, the development rate to the blastocyst stage was not affected when the combination of TSA and 5-aza-dC was treated. In conclusion, treatment of donor cells with DNA methylation inhibitors or histone deacetylase inhibitors improved the subsequent blastocyst development of porcine reconstructed embryos even though combined treatment with both inhibitors had no beneficial effect.

Reactivation of IGFBP7 by DNA demethylation inhibits human colon cancer cell growth in vitro

Background: The insulin-like growth factor binding protein 7 (IGFBP7) gene is regulated by DNA methylation in colon cancer, which was identified in our previous study. In this study, we examined the effects of DNA methylation inhibitor 5-aza-2’-deoxycytidine (5-aza-dC) on IGFBP7 reactivation and cell biological behaviors in vitro to investigate a potential role for 5-aza-dC in treating colorectal cancer. Methods: We examined the effects of 5-aza-dC on reexpression of previously silenced IGFBP7 and its global effects on cell cycle, apoptosis, migration and invasion in three colon cancer cell lines, SW620, HT29 and COLO205. Results: 5-aza-dC treatment showed induction of IGFBP7 transcription in these cancer cells. It consequently led to inhibition of cell growth, cell cycle arrest and apoptosis, suppression of cell migration and invasion in colon cancer cell lines. Conclusion: Our findings indicate that 5-aza-dC may have anticancer function for colon cancer and restoration of IGFBP7 may involve in the biological effects induced by 5-aza-dC in colon cancer cell lines. These data suggest that 5-aza-dC has clinical potential in the treatment of colorectal cancer.