Hypermethylated ITGA8 Facilitate Bladder Cancer Cell Proliferation and Metastasis

DNA methylation plays a vital role during the development of tumorigenesis. The purpose of this study is to identify candidate DNA methylation drivers during progression of bladder cancer (BLCA). The methylation spectrum in bladder cancer tissues was detected by CHARM analysis, and methylated ITGA8 was selected for further study due to its low expression. Methylation levels in BLCA tissues and cells were detected with methylated-specific PCR (MSP), while mRNA expression and methylation of ITGA8 were detected by qRT-PCR and MSP. After treatment with 5-Aza-dC (DNA methylation inhibitor), the proliferation, migration, and invasion abilities of BLCA cells were determined by MTT, wound healing, and transwell assays, respectively. Flow cytometric analysis was performed to evaluate any variance in the cell cycle. In addition, the effect of demethylated ITGA8 on BLCA tumor growth was verified with an in vivo xenograft tumor model. Based on the methylation profiling of BLCA, ITGA8 was identified to be hypermethylated. ITGA8 methylation levels in BLCA tissues and cells were upregulated, and 5-Aza-dC significantly suppressed ITGA8 methylation levels and increased ITGA8 mRNA expression. Furthermore, after treatment with 5-Aza-dC, the propagation, migration, and invasiveness of the cancer cells were inhibited, and more cancer cells were arrested at the G0/G1 phase. In vivo assays further demonstrated that 5-Aza-dC could impede BLCA tumor growth by repressing methylation levels of ITGA8 and increasing ITGA8 mRNA expression. Hypermethylated ITGA8 facilitated BLCA progression, and 5-Aza-dC treatment inhibited BLCA cell propagation and metastasis by decreasing methylation levels of ITGA8 and inducing cell cycle arrest.

5-Aza-2'-Deoxycytidine Alters the Methylation Profile of Bortezomib-Resistant U266 Multiple Myeloma Cells and Affects Their Proliferative Potential

Multiple myeloma (MM) is a plasma cell malignancy that accounts for 1% of all cancers and is the second-most-common hematological neoplasm. Bortezomib (BTZ) is a proteasome inhibitor widely implemented in the treatment of MM alone or in combination with other agents. The development of resistance to chemotherapy is one of the greatest challenges of modern oncology. Therefore, it is crucial to discover and implement new adjuvant therapies that can bypass therapeutic resistance. In this paper, we investigated the in vitro effect of methylation inhibitor 5-Aza-2'-deoxycytidine on the proliferative potential of MM cells and the development of resistance to BTZ. We demonstrate that alterations in the DNA methylation profile are associated with BTZ resistance. Moreover, the addition of methylation inhibitor 5-Aza-2'-deoxycytidine to BTZ-resistant MM cells led to a reduction in the proliferation of the BTZ-resistant phenotype, resulting in the restoration of sensitivity to BTZ. However, further in vitro and ex vivo studies are required before adjuvant therapy can be incorporated into existing treatment regimens.

Epigenetic PPARγ preservation attenuates temporomandibular joint osteoarthritis

OBJECTIVE

Previous studies have demonstrated that PPARγ deficiency is associated with osteoarthritis in the knee joint. However, whether epigenetic PPARγ dysregulation has any effect on temporomandibular joint osteoarthritis (TMJOA) is unknown. This study aims to determine the role and mechanism of epigenetic PPARγ dysregulation in TMJOA.

METHODS

Partial TMJ discectomy was performed to induce TMJOA in rat. Primary condylar chondrocytes were isolated, and TNF-α-induced inflammatory condition was created in vitro. The expressions of PPARγ and DNA methyltransferase were investigated in vivo and in vitro. The association of PPARγ and DNA methylation was further studied by treating chondrocytes with DNA demethylation agent 5-Aza-2'-deoxycytidine (5Aza) and transfecting with siRNA of DNA methyltransferase (DNMT)1 and DNMT3a, and the methylation level of PPARγ promoter was evaluated by Bisulfite-sequencing PCR. The chondroprotective effects of 5Aza were explored in vitro and in vivo.

RESULTS

PPARγ suppression and upregulated DNMT1/DNMT3a expression exist in TMJOA cartilage in vivo and primary condylar chondrocytes under TNF-α-induced inflammatory conditions in vitro. DNMT1 and DNMT3a elevation contributes to PPARγ-promoter hypermethylation in TMJ chondrocytes under TNF-α-induced inflammation conditions. DNA demethylation intervention by 5Aza protects chondrocytes from inflammation response in vitro. Mechanistically, 5Aza reversed the hypermethylation of the PPARγ promoter and subsequently resulted in PPARγ restoration and decreased expression of cartilage-catabolic factors in chondrocytes. Rat TMJOA model revealed that 5Aza, by reversing PPARγ suppression, effectively attenuated cartilage degeneration and stabilized cartilage homeostasis by balancing anabolic factor and catabolic factor expression.

CONCLUSION

Epigenetic PPARγ suppression may play a causal role in TMJOA pathogenesis, which can be alleviated by DNA demethylation with 5Aza treatment. This study provides new insights into the pathogenic mechanism and therapeutic strategy of TMJOA.

The Methylation Inhibitor 5-Aza-2'-Deoxycytidine Induces Genome-Wide Hypomethylation in Rice

DNA methylation is a conserved epigenetic modification which is vital for regulating gene expression and maintaining genome stability in both mammals and plants. Homozygous mutation of rice methyltransferase 1 (met1) gene can cause host death in rice, making it difficult to obtain plant material needed for hypomethylation research. To circumvent this challenge, the methylation inhibitor, 5-Aza-2'-deoxycytidine (AzaD), is used as a cytosine nucleoside analogue to reduce genome wide hypomethylation and is widely used in hypomethylation research. However, how AzaD affects plant methylation profiles at the genome scale is largely unknown. Here, we treated rice seedlings with AzaD and compared the AzaD treatment with osmet1-2 mutants, illustrating that there are similar CG hypomethylation and distribution throughout the whole genome. Along with global methylation loss class I transposable elements (TEs) which are farther from genes compared with class II TEs, were more significantly activated, and the RNA-directed DNA Methylation (RdDM) pathway was activated in specific genomic regions to compensate for severe CG loss. Overall, our results suggest that AzaD is an effective DNA methylation inhibitor that can influence genome wide methylation and cause a series of epigenetic variations.

Short communication: Effects of in-ovo injection of endocrine disruptors and methyltransferase inhibitor on quail growth and egg-laying performances

Early experiences, including prenatal environment, are known to influence a wide variety of mechanisms involved in the phenotype elaboration. We investigated the effect of the addition of endocrine disruptors or of a methyltransferase inhibitor during the embryonic development of quails from different genetic backgrounds (four different quail lines) on their growth and egg-laying performances. Fifty-four pairs of parents per line were used and fertilised eggs from each pair were randomly divided into five groups: a control group without any injection, an injected control group treated by injection into the egg of sesame oil, and three groups treated by injection of Genistein, Bisphenol A or 5-Aza-2'-deoxycytidine. All quails were individually weighed at 8, 21, 36 and 78 days. The age at first egg laid and the number of eggs laid were recorded. These analyses revealed a significant impact of the treatment on growth but no influence on the egg-laying traits. All three molecules significantly affected at least one of the analysed growth traits. In conclusion, we showed that the injection of endocrine disruptors or DNA methyltransferase inhibitor into the egg had significant effects on quail development; these effects were specific to each treatment, but no interaction between line and treatment was observed.

Evaluation of the Antitumor Immune Response Following Photofrin-Based PDT in Combination with the Epigenetic Agent 5-Aza-2'-Deoxycytidine

Photofrin-based photodynamic therapy (PDT) is approved for clinical use by the US Food and Drug Administration and the European Medicines Agency and is among the most widely used photosensitizer for the treatment of cancer. It was broadly reported that both the innate and the adaptive arms of immune response can be activated by PDT and play a critical role in the anticancer outcome of this treatment. PDT leads to the induction of acute local inflammation that includes leukocyte infiltration as well as increased activation and production of pro-inflammatory factors and cytokines. These events can lead to the development of systemic and specific antitumor immune response. Combining Photofrin-PDT with the epigenetic agent 5-aza-2'-deoxycytidine results in potentiated antitumor effects in vivo. Understanding the molecular mechanisms underlying this phenomenon would be invaluable for clinical development of this therapeutic approach. This chapter describes a detailed protocol allowing evaluation of specific antitumor immune response induced by PDT.

The Differential Antitumor Activity of 5-Aza-2'-deoxycytidine in Prostate Cancer DU145, 22RV1, and LNCaP Cells

DNA methylation is a DNA methyltransferase-mediated epigenetic modification affecting gene expression. This process is involved in the initiation and development of malignant disease. 5-Aza-2'-deoxycytidine (5-Aza), a classic DNA methyltransferase inhibitor, possesses antitumor proliferation activity. However, whether 5-Aza induces cytotoxicity in solid tumors warrants further investigated. In this study, human prostate cancer (CaP) cells were treated with 5-Aza and subjected to cell viability and cytotoxicity analysis. Reverse transcription-polymerase chain reaction and methylation-specific polymerase chain reaction assay were utilized to test the gene expression and methylation status of the p53 and p21 gene promoters. The results showed that 5-Aza differentially inhibited spontaneous proliferation, arrested the cell cycle at S phase in DU145, at G1 phase in 22RV1 and LNCaP cells, and G2 phase in normal RWPE-1 cells, as well as induced the expression of phospho-H2A.X and tumor suppressive mammary serine protease inhibitor (maspin) in all three types of CaP cells. 5-Aza also increased p53 and p21 transcription through promoter demethylation, and decreased the expression of oncogene c-Myc in 22RV1 and LNCaP cells. Western blotting analysis showed that the poly (ADP-ribose) polymerase cleavage was detected in DU145 and 22RV1 cells. Moreover, there were no significant changes in p53, p21 and c-Myc expression in DU145 cells following treatment with 5-Aza. Thus, in responsible for its apoptotic induction and DNA damage, the mechanism of the antitumor activities of 5-Aza may involve in an increase of tumor suppressive maspin, upregulation of wild type p53-mediated p21 expression and a decrease of oncogene c-Myc level in 22RV1 and LNCaP cells, and enhancing the tumor suppressive maspin expression in DU145 cells. These results enriched our understanding of the multifaceted antitumor activity of 5-Aza, and provided the expression basis of biomarkers for its possible clinical application in prostate cancer.

LRWD1 expression is regulated through DNA methylation in human testicular embryonal carcinoma cells

BACKGROUND

Sperm growth and maturation are correlated with the expression levels of Leucine-rich repeat and WD repeat-containing protein 1 (LRWD1), a widely expressed protein in the human testicles. The decrease in LRWD1 cellular level was linked to the reduction in cell growth and mitosis and the rise in cell microtubule atrophy rates. Since DNA methylation has a major regulatory role in gene expression, this study aimed at exploring the effect of the modulation of DNA methylation on LRWD1 expression levels.

RESULTS

The results revealed the presence of a CpG island up of 298 bps (- 253 ~ + 45) upon LRWD1 promoter in NT2/D1 cells. The hypermethylation of the LRWD1 promoter was linked to a reduction in the transcription activity in NT2/D1 cells, as indicated by luciferase reporter assay. The methylation activator, floxuridine, confirmed the decrease in the LRWD1 promoter transcriptional activity. On the other hand, 5-Aza-2'-deoxycytidine (5-Aza-dc, methylation inhibitor), significantly augmented LRWD1 promoter activity and the expression levels of mRNA and proteins. Furthermore, DNA methylation status of LRWD1 promoter in human sperm genomic DNA samples was analyzed. The results indicated that methylation of LRWD1 promoter was correlated to sperm activity.

CONCLUSIONS

Thus, the regulation of LRWD1 expression is correlated with the methylation status of LRWD1 promoter, which played a significant role in the modulation of spermatogenesis, sperm motility, and vitality. Based on these results, the methylation status of LRWD1 promoter may serve as a novel molecular diagnostic marker or a therapeutic target in males' infertility.

MiR-320a is associated with cisplatin resistance in lung adenocarcinoma and its clinical value in non-small cell lung cancer: A comprehensive analysis based on microarray data

BACKGROUND

Currently, the main treatment for non-small cell lung cancer (NSCLC) is surgery and chemotherapy. Although major progress has been made in targeted treatment and immunotherapy, the survival rates for this disease are still low and associated with resistance to chemotherapy. Previous studies have shown that histone acetylation and microRNAs (miRNAs) might play an important role in chemotherapy resistance. The aim of this study was to identify candidate miRNAs related to cisplatin (DDP) resistance in lung adenocarcinoma.

METHODS

We used 5-aza-2'-deoxycytidine and trichostatin A to reverse the drug resistance of A549/DDP cells in vitro, and miRNA expression profiling was performed by microarrays to identify candidate miRNAs. In addition, we investigated the correlations between miR-320a expression and clinical characteristics through data collected from Gene Expression Omnibus (GEO) microarrays, and The Cancer Genome Atlas (TCGA) to determine the clinical role of miR-320a in lung adenocarcinoma. Furthermore, we investigated the biological function of miR-320a. TargetScanHuman, PicTar2005 and miRanda v5.1. were used to predict the target genes of miR-320a; then, the function of these genes were suggested from the enrichment of GO categories items and KEGG analyses.

RESULTS

Treatment with 5-Aza-dc significantly inhibited cellular proliferation, and increased apoptosis in the A549/DDP cells compared with the untreated cells. TSA did not reverse cisplatin resistance. MiR-320a was up-regulated during reversal of cisplatin resistance. The lung adenocarcinoma groups had a significantly lower level of miR-320a expression than the control groups. For the bioinformatics analyses, we found some target genes involved in cell cycle progression, tumor progression, the MAPK signaling pathway, and the ErbB signaling pathway. The promising target genes were highly enriched in various pathways in cancer.

CONCLUSIONS

The current study confirmed miR-320a was up-regulated during the revering of cisplatin resistance. The results of bioinformatics analyses may present a new method for investigating the pathogenesis of lung adenocarcinoma.

The impact of DNA demethylation on the upregulation of the NRN1 and TNFAIP3 genes associated with advanced gastric cancer

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. Very few therapeutic options are currently available in this neoplasia. The use of 5-Aza-2'-deoxycytidine (5-AZAdC) was approved for the treatment of myelodysplastic syndromes, and this drug can treat solid tumours at low doses. Epigenetic manipulation of GC cell lines is a useful tool to better understand gene expression regulatory mechanisms for clinical applications. Therefore, we compared the gene expression profile of 5-AZAdC-treated and untreated GC cell lines by a microarray assay. Among the genes identified in this analysis, we selected NRN1 and TNFAIP3 to be evaluated for gene expression by RT-qPCR and DNA methylation by bisulfite DNA next-generation sequencing in 43 and 52 pairs of GC and adjacent non-neoplastic tissue samples, respectively. We identified 83 candidate genes modulated by DNA methylation in GC cell lines. Increased expression of NRN1 and TNFAIP3 was associated with advanced tumours (P < 0.05). We showed that increased NRN1 and TNFAIP3 expression seems to be regulated by DNA demethylation in GC samples: inverse correlations between the mRNA and DNA methylation levels in the promoter of NRN1 (P < 0.05) and the intron of TNFAIP3 (P < 0.05) were detected. Reduced NRN1 promoter methylation was associated with III/IV TNM stage tumours (P = 0.03) and the presence of Helicobacter pylori infection (P = 0.02). The identification of demethylated activated genes in GC may be useful in clinical practice, stratifying patients who are less likely to benefit from 5-AZAdC-based therapies. KEY MESSAGES: Higher expression of NRN1 and TNFAIP3 is associated with advanced gastric cancer (GC). NRN1 promoter hypomethylation contributes to gene upregulation in advanced GC. TNFAIP3 intronic-specific CpG site demethylation contributes to gene upregulation in GC. These findings may be useful to stratify GC patients who are less likely to benefit from DNA demethylating-based therapies.

5-Aza-2'-deoxycytidine increases hypoxia tolerance-dependent autophagy in mouse neuronal cells by initiating the TSC1/mTOR pathway

BACKGROUND

Our previous study found that 5-Aza-2'-deoxycytidine (5-Aza-CdR) can repress the expression and activity of protein serine/threonine phosphatase-1γ (PP1γ) in mouse hippocampus. It is well known that PP1γ regulates cell metabolism, which is related to hypoxia/ischaemia tolerance. It has been reported that it can also induce autophagy in cancer cells. Autophagy is important for maintaining cellular homeostasis associated with metabolism. In this study, we examined whether 5-Aza-CdR increases hypoxia tolerance-dependent autophagy by initiating the TSC1/mTOR/autophagy signalling pathway in neuronal cells.

METHODS

5-Aza-CdR was either administered to mice via intracerebroventricular injection (i.c.v) or added to cultured hippocampal-derived neuronal cell line (HT22 cell) in the medium for cell culture. The hypoxia tolerance of mice was measured by hypoxia tolerance time and Perl's iron stain. The mRNA and protein expression levels of tuberous sclerosis complex 1 (TSC1), mammalian target of rapamycin (mTOR) and autophagy marker light chain 3 (LC3) were measured by real-time PCR and western blot. The p-mTOR and p-p70S6k proteins were used as markers for mTOR activity. In addition, the role of autophagy was determined by correlating its intensity with hypoxia tolerance in a time-dependent manner. At the same time, the involvement of the TSC1/mTOR pathway in autophagy was also examined through transfection with TSC1 (hamartin) plasmid.

RESULTS

5-Aza-CdR was revealed to increase hypoxia tolerance and induce autophagy, accompanied by an increase in mRNA and protein expression levels of TSC1, reduction in p-mTOR (Ser2448) and p-p70S6k (Thr389) protein levels, and an increase in the ratio of LC3-II/LC3-I in both mouse hippocampus and hippocampal-derived neuronal cell line (HT22). The fluorescence intensity of hamartin was enhanced in the hippocampus of mice exposed to 5-Aza-CdR. Moreover, HT22 cells that over-expressed TSC1 showed more autophagy.

CONCLUSIONS

5-Aza-CdR can increase hypoxia tolerance by inducing autophagy by initiating the TSC1/mTOR pathway.

Myeloid leukemia with high EVI1 expression is sensitive to 5-aza-2'-deoxycytidine by targeting miR-9

PURPOSE

High expression of ecotropic viral integration site 1 (EVI1) has been associated with a poor prognosis in leukemia patients, but the underlying mechanism remains unclear. Aberrant expression of microRNAs plays critical roles in leukemia development. MiR-9 is a putative potential target of EVI1. We have investigated the regulating mechanism of miR-9 by EVI1 in leukemia cells.

METHODS

We first examined the relationship between miR-9 and EVI1 expression levels in nine leukemia cell lines by RT-PCR. Then we forced high expression of EVI1 in UoCM1 and K562 cells to confirm the downregulation of miR-9 by EVI1. Methylation of the miR-9 promoter region was detected by DNA bisulfite sequencing. We treated the EVI1-overexpressing cells with the hypomethylating agent 5-aza-2'-deoxycytidine (5-AZA) to reverse EVI1-induced hypermethylation of miR-9.

RESULTS

EVI1 and miR-9 expression was negative related. Forced expression of EVI1 downregulated miR-9 by inducing hypermethylation of the miR-9 promoter. 5-AZA reversed high EVI1-induced hypermethylation of the miR-9 promoter and restored the expression of miR-9. 5-AZA induced extensive apoptosis and inhibited proliferation through cell cycle arrest in EVI1-overexpressing leukemia cells.

CONCLUSIONS

Our results suggest that EVI1 may be involved in leukemia cell proliferation and apoptosis via the regulation of miR-9 promoter methylation. 5-AZA may represent a promising therapeutic option for EVI1-high leukemia patients.

5-Aza Exposure Improves Reprogramming Process Through Embryoid Body Formation in Human Gingival Stem Cells

Embryoid bodies (EBs) are three-dimensional aggregates formed by pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells. They are used as an in vitro model to evaluate early extraembryonic tissue formation and differentiation process. In the adult organisms, cell differentiation is controlled and realized through the epigenetic regulation of gene expression, which consists of various mechanisms including DNA methylation. One demethylating agent is represented by 5-Azacytidine (5-Aza), considered able to induce epigenetic changes through gene derepression. Human gingival mesenchymal stem cells (hGMSCs), an easily accessible stem cells population, migrated from neural crest. They are particularly apt as an in vitro study model in regenerative medicine and in systemic diseases. The ability of 5-Aza treatment to induce hGMSCs toward a dedifferentiation stage and in particular versus EBs formation was investigated. For this purpose hGMSCs were treated for 48 h with 5-Aza (5 μM). After treatment, hGMSCs are organized as round 3D structures (EBs-hGMSCs). At light and transmission electron microscopy, the cells at the periphery of EBs-hGMSCs appear elongated, while ribbon-shaped cells and smaller cells with irregular shape surrounded by extracellular matrix were present in the center. By RT-PCR, EBs-hGMSCs expressed specific transcription markers related to the three germ layers as MAP-2, PAX-6 (ectoderm), MSX-1, Flk-1 (mesoderm), GATA-4, and GATA-6 (endoderm). Moreover, in EB-hGMSCs the overexpression of DNMT1 and ACH3 other than the down regulation of p21 was detectable. Immunofluorescence staining also showed a positivity for specific etodermal and mesodermal markers. In conclusion, 5-Aza was able to induce the direct conversion of adult hGMSCs into cells of three embryonic lineages: endoderm, ectoderm, and mesoderm, suggesting their possible application in autologous cell therapy for clinical organ repair.

Epigenetic silencing of SFRP5 promotes the metastasis and invasion of chondrosarcoma by expression inhibition and Wnt signaling pathway activation

BACKGROUD/AIMS

Abnormal activation of the Wnt/β-catenin signaling, which may be antagonized by the members of secreted frizzled-related proteins family (SFRPs), is implicated in tumor occurrence and development. However, the function of SFRP5 relating to Wnt/β-catenin pathway in chondrosarcoma is not clear yet. This study was undertaken to investigate the potential role of SFRP5 promoter methylation in chondrosarcoma metastasis and invasion through activating canonical Wnt signaling pathway.

METHODS AND RESULTS

The results demonstrated that SFRP5 promoter was hypermethylated and SFRP5 expression was significantly reduced in chondrosarcoma cell lines at the mRNA and protein levels. The canonical Wnt/β-catenin signaling was observably activated with β-catenin stabilization by dephosphorylation and translocation into the nuclear. 5-Aza-2'-deoxycytidine (5-Aza-dC), the DNA methyltransferase inhibitor, significantly inhibited the proliferation of chondrosarcoma cells by cell cycle arrest through repressing the methylation of SFRP5 and promoting its expression. Both 5-Aza-dC treatment and SFRP5 overexpression could significantly inhibited the metastasis and invasion of chondrosarcoma cells by inactivating Wnt/β-catenin signaling pathway and promoting chondrosarcoma cells mesenchymal-epithelial transition (MET). 5-Aza-dC also inhibited the xenograft growth and lung metastasis of chondrosarcoma cells in vivo via suppressing SFRP5 promotor methylation, inactivating Wnt/β-catenin pathway and inducing epithelial markers expression.

CONCLUSION

All of our results revealed the epigenetic silencing of SFRP5 by promoter methylation plays pivotal roles in chondrosarcoma development and metastasis through SFRP5/Wnt/β-catenin signaling axis. Modulation of their levels may serve as potential targets and diagnostic tools for novel therapeutic strategies of chondrosarcoma.

Retinoic acid-induced 2 (RAI2) is a novel tumor suppressor, and promoter region methylation of RAI2 is a poor prognostic marker in colorectal cancer

Background

Reduced expression of retinoic acid-induced 2 (RAI2) was found in breast cancer. The regulation and function of RAI2 in human colorectal cancer (CRC) remain unclear.

Methods

Eight CRC cell lines and 237 cases of primary CRC were analyzed. Methylation-specific PCR (MSP), flow cytometry, xenograft mouse model, and shRNA technique were employed.

Results

RAI2 was completely methylated in RKO, LOVO, and HCT116 cells; partially methylated in HT29 cells; and unmethylated in SW480, SW620, DLD1, and DKO cells. RAI2 was methylated in 53.6% (127/237) of primary colorectal cancer. Methylation of RAI2 was significantly associated with gender (P < 0.001), TNM stage (P < 0.001), and lymph node metastasis (P < 0.001). Analyzing by the Kaplan-Meier method, methylation of RAI2 was significantly associated with poor 5-year overall survival (OS) (P = 0.0035) and 5-year relapse-free survival (RFS) (P = 0.0062). According to Cox proportional hazards model analysis, RAI2 methylation was an independent poor prognostic marker for 5-year OS (P = 0.002) and poor 5-year RFS (P = 0.022). RAI2 suppressed cell proliferation, migration, and invasion and induced cell apoptosis in CRC. In addition, RAI2 inhibited AKT signaling in CRC cells and suppressed human CRC cell xenograft growth in mice.

Conclusion

RAI2 is frequently methylated in human CRC, and the expression of RAI2 is regulated by promoter region methylation. Methylation of RAI2 is an independent poor prognostic marker of CRC. RAI2 suppresses CRC cell growth both in vitro and in vivo. RAI2 suppresses CRC by inhibiting AKT signaling.

Integrated data analysis identifies potential inducers and pathways during the endothelial differentiation of bone-marrow stromal cells by DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine

Bone-Marrow Stromal Cells (BMSCs)-derived vascular endothelial cells (VECs) is regarded as an important therapeutic strategy for spinal cord injury, disc degeneration, cerebral ischemic disease and diabetes. The change in DNA methylation level is essential for stem cell differentiation. However, the DNA methylation related mechanisms underlying the endothelial differentiation of BMSCs are not well understood. In this study, DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-aza-dC) significantly elevated the endothelial markers expression (CD31/PECAM1, CD105/ENG, eNOS and VE-cadherin), as well as promoted the capacity of angiogenesis on Matrigel. The result of Alexa 488-Ac-LDL uptake assay indicated that the differentiation ratio of BMSCs into VECs was 68.7% in 5-azaz-dC induced differentiation. And then we screened differentiation inducers with altered expression patterns and DNA methylation levels in four important families (VEGF, ANG, FGF and ETS). By integrating these data, five endothelial differentiation inducers (VEGFA, ANGPT2, FGF2, FGF9 and ETS1) which were directly upregulated by 5-aza-dC and five indirect factors (FGF1, FGF3, ETS2, ETV1 and ETV4) were identified. These data suggested that 5-aza-dC is an excellent chemical molecule for BMSCs differentiation into functional VECs and also provided essential clues for DNA methylation related signaling during 5-aza-dC induced endothelial differentiation of BMSCs.

Effects of 5-Aza-2'-deoxycytidine (decitabine) on gene expression

5-Aza-2'-deoxycytidine (AzaD), also known as Decitabine, is a deoxycytidine analog that is typically used to activate methylated and silenced genes by promoter demethylation. However, a survey of the scientific literature indicates that promoter demethylation may not be the only (or, indeed, the major) mechanism by which AzaD affects gene expression. Regulation of gene expression by AzaD can occur in several ways, including some that are independent of DNA demethylation. Results from several studies indicate that the effect of AzaD on gene expression is highly context-dependent and can differ for the same gene under different environmental settings. This may, in part, be due to the nature of the silencing mechanism(s) involved - DNA methylation, repressive histone modifications, or a combination of both. The varied effects of AzaD on such context-dependent regulation of gene expression may underlie some of the diverse responses exhibited by patients undergoing AzaD therapy. In this review, we describe the salient properties of AzaD with particular emphasis on its diverse effects on gene expression, aspects that have barely been discussed in most reviews of this interesting drug.

5-Aza-2'-deoxycytidine protects against emphysema in mice via suppressing p16Ink4a expression in lung tissue

Background

There is a growing realization that COPD, or at least emphysema, involves several processes presenting in aging and cellular senescence. Endothelial progenitor cells (EPCs) contribute to neovascularization and play an important role in the development of COPD. The gene for p16^Ink4a is a major dominant senescence one. The aim of the present study was to observe changes in lung function, histomorphology of lung tissue, and expression of p16^Ink4a in lung tissue and bone marrow-derived EPCs in emphysematous mice induced by cigarette-smoke extract (CSE), and further to search for a potential candidate agent protecting against emphysema induced by CSE.

Materials and methods

An animal emphysema model was induced by intraperitoneal injection of CSE. 5-Aza-2′-deoxycytidine (5-Aza-CdR) was administered to the emphysematous mice. Lung function and histomorphology of lung tissue were measured. The p16^Ink4a protein and mRNA in EPCs and lung tissues were detected using Western blotting and quantitative reverse-transcription polymerase chain reaction, respectively.

Results

CSE induced emphysema with increased p16^Ink4a expression in lung tissue and bone marrow-derived EPCs. 5-Aza-CdR partly protected against emphysema, especially in the lung-morphology profile, and partly protest against the overexpression of p16^Ink4a in EPCs and lung tissue induced by CSE.

Conclusion

5-Aza-CdR partly protected against emphysema in mice via suppressing p16^Ink4a expression in EPCs and lung tissue.

5-Aza-2'-deoxycytidine induces human Tenon's capsule fibroblasts differentiation and fibrosis by up-regulating TGF-β type I receptor

The principle reason of high failure rate of glaucoma filtration surgery is the loss of filtration function caused by postoperative scar formation. We investigated the effects of 5-aza-2'-deoxycytidine (5-Aza-dc), a DNA methyltransferases inhibitor, on human Tenon's capsule fibroblasts (HTFs) differentiation and fibrosis and its mechanism of action, especially in relation to transforming growth factor (TGF)-β1 signaling. TGF-β1 was used to induce differentiation of cultured HTFs. 5-Aza-dc suppressed DNA methyltransferases (DNMTs) activity 6 h after treatment with a course corresponding to that of TGF-β1-induced reduction of DNMT activity without affecting cell viability as measured by Cell Counting Kit-8 assay. 5-Aza-dc also reduced DNMT1 and DNMT3a protein expression from 24 to 48 h. HTFs migration evaluated by scratch-wound assay were significantly increased 24 h after 5-Aza-dc treatment, a time course similar to that of TGF-β1. Treatment with 5-Aza-dc significantly increased the mRNA and protein levels of α-smooth muscle actin (α-SMA), collagen-1A1 (Col1A1), fibronectin (FN) and TGF-β type I receptor (TGFβRI). Furthermore, the effects of 5-Aza-dc on DNMT activity suppression, cell migration, and fibrosis were all reversed by a TGFβRI inhibitor- SB-431542. Meanwhile, knockdown of DNMT1 upregulated TGFβRI expression and had the same fibrosis-inducing effect in HTFs, which was also inhibited by SB-431542. Thus, the results indicate that DNA hypomethylation induces HTFs differentiation and fibrosis through up-regulation of TGFβRI. DNA methylation status plays an important role in subconjunctival wound healing.

Determinants of orofacial clefting I: Effects of 5-Aza-2'-deoxycytidine on cellular processes and gene expression during development of the first branchial arch

In this study, we identify gene targets and cellular events mediating the teratogenic action(s) of 5-Aza-2'-deoxycytidine (AzaD), an inhibitor of DNA methylation, on secondary palate development. Exposure of pregnant mice (on gestation day (GD) 9.5) to AzaD for 12h resulted in the complete penetrance of cleft palate (CP) in fetuses. Analysis of cells of the embryonic first branchial arch (1-BA), in fetuses exposed to AzaD, revealed: 1) significant alteration in expression of genes encoding several morphogenetic factors, cell cycle inhibitors and regulators of apoptosis; 2) a decrease in cell proliferation; and, 3) an increase in apoptosis. Pyrosequencing of selected genes, displaying pronounced differential expression in AzaD-exposed 1-BAs, failed to reveal significant alterations in CpG methylation levels in their putative promoters or gene bodies. CpG methylation analysis suggested that the effects of AzaD on gene expression were likely indirect.

Inhibition of DNA methyltransferases regulates cocaine self-administration by rats: a genome-wide DNA methylation study

DNA methylation is a major epigenetic process which regulates the accessibility of genes to the transcriptional machinery. In the present study, we investigated whether modifying the global DNA methylation pattern in the brain would alter cocaine intake by rats, using the cocaine self-administration test. The data indicate that treatment of rats with the DNA methyltransferase inhibitors 5-aza-2'-deoxycytidine (dAZA) and zebularine enhanced the reinforcing properties of cocaine. To obtain some insights about the underlying neurobiological mechanisms, a genome-wide methylation analysis was undertaken in the prefrontal cortex of rats self-administering cocaine and treated with or without dAZA. The study identified nearly 189 000 differentially methylated regions (DMRs), about half of them were located inside gene bodies, while only 9% of DMRs were found in the promoter regions of genes. About 99% of methylation changes occurred outside CpG islands. Gene expression studies confirmed the inverse correlation usually observed between increased methylation and transcriptional activation when methylation occurs in the gene promoter. This inverse correlation was not observed when methylation took place inside gene bodies. Using the literature-based Ingenuity Pathway Analysis, we explored how the differentially methylated genes were related. The analysis showed that increase in cocaine intake by rats in response to DNA methyltransferase inhibitors underlies plasticity mechanisms which mainly concern axonal growth and synaptogenesis as well as spine remodeling. Together with the Akt/PI3K pathway, the Rho-GTPase family was found to be involved in the plasticity underlying the effect of dAZA on the observed behavioral changes.

Simultaneous quantitative determination of 5-aza-2'-deoxycytidine genomic incorporation and DNA demethylation by liquid chromatography tandem mass spectrometry as exposure-response measures of nucleoside analog DNA methyltransferase inhibitors

The epigenetic and anti-cancer activities of the nucleoside analog DNA methyltransferase (DNMT) inhibitors decitabine (5-aza-2'-deoxycytidine, DAC), azacitidine, and guadecitabine are thought to require cellular uptake, metabolism to 5-aza-2'-deoxycytidine triphosphate, and incorporation into DNA. This genomic incorporation can then lead to trapping and degradation of DNMT enzymes, and ultimately, passive loss of DNA methylation. To facilitate measurement of critical exposure-response relationships of nucleoside analog DNMT inhibitors, a sensitive and reliable method was developed to simultaneously quantitate 5-aza-2'-deoxycytidine genomic incorporation and genomic 5-methylcytosine content using LC-MS/MS. Genomic DNA was extracted and digested into single nucleosides. Chromatographic separation was achieved with a Thermo Hyperpcarb porous graphite column (100mm×2.1mm, 5μm) and isocratic elution with a 10mM ammonium acetate:acetonitrile with 0.1% formic acid (70:30, v/v) mobile phase over a 5min total analytical run time. An AB Sciex 5500 triple quadrupole mass spectrometer operated in positive electrospray ionization mode was used for the detection of 5-aza-2'-deoxycytidine, 2'-deoxycytidine, and 5-methyl-2'-deoxycytidine. The assay range was 2-400ng/mL for 5-aza-2'-deoxycytidine, 50-10,000ng/mL for 2'-deoxycytidine, and was 5-1000ng/mL for 5-methyl-2'-deoxycytidine. The assay proved to be accurate (93.0-102.2%) and precise (CV≤6.3%) across all analytes. All analytes exhibited long-term frozen digest matrix stability at -70°C for at least 117 days. The method was applied for the measurement of genomic 5-aza-2'-deoxycytidine and 5-methyl-2'-deoxycytidine content following exposure of in vitro cell culture and in vivo animal models to decitabine.

5-Aza-2''-deoxycytidine inhibits retinoblastoma cell by reactivating epigenetically silenced RASSF1A gene

AIM

To investigate the effect of 5-Aza-2'-deoxycytidine (5-Aza-CdR), a DNA methyltransferase (DNMT) inhibitor, on the growth and survival of the Chinese retinoblastoma (RB) cell line HXO-RB44.

METHODS

The DNA methylation status of the Ras association domain family (RASSF1A) promoter in the presence of 5-Aza-CdR at different concentrations was analyzed by methylation-specific polymerase chain reaction (MSP). RASSF1A mRNA and protein levels were measured by semiquantitative RT-PCR and immunohistochemistry staining, respectively, when cells were treated with 5.0µmol/L of 5-Aza-CdR. The effect of 5.0µmol/L 5-Aza-CdR on the proliferation and viability of HXO-RB44 cells was examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry.

RESULTS

5-Aza-CdR efficiently induced cell cycle arrest at G0/G1 and apoptotic death in HXO-RB44 cells. MSP analysis showed that unmethylated RASSF1A DNA increased and methylated RASSF1A decreased in a dose-dependent manner in a range of 0.5-5.0µmol/L 5-Aza-CdR. Accordingly, RASSF1A expression was reactivated at both mRNA and protein levels. Incubation time of 5-Aza-CdR treatment also functioned as a factor for the demethylation status of RASSF1A promoter DNA, with a plateau on day four. 5-Aza-CdR at 5.0µmol/L completely demethylated the RASSF1A promoter in HXO-RB44 cells on day four, and as a result, RASSF1A expression increased significantly from day 4 to day 7.

CONCLUSION

5-Aza-CdR inhibits the growth of the HXO-RB44 RB cell line and induces apoptosis by demethylating the RASSF1A gene.

Identification of a meiosis-specific protein, MEIOB, as a novel cancer/testis antigen and its augmented expression in demethylated cancer cells

Cancer/testis (CT) antigens, which are expressed in various cancer cells but not in normal cells except germline cells of the testis, have been used as targets for cancer vaccine therapy. 5-Aza-2'-deoxycytidine (DAC), a potent inhibitor of genomic and promoter-specific DNA methylation, inhibits DNA methyltransferase activity and is reported to induce the expression of certain CT antigens by the demethylation of promoter CpG islands of the treated cells. Here, using DAC-treated cancer cells, we searched for novel attractive target molecules that would be useful for cancer immunotherapy and found a meiosis-specific protein, meiosis specific with OB domains (MEIOB), to be a novel CT antigen. Indeed, the MEIOB gene is expressed only in the testis and not in other normal tissues. The mRNA expression of MEIOB was greatly enhanced in several lung cancer cell lines after the treatment with DAC. Furthermore, we identified a variety of helper epitopes of the MEIOB antigen, which were recognized by MEIOB antigen-specific T cells in a HLA-restriction manner. Finally, we demonstrated that IFN-γ production of MEIOB peptide-specific helper T cells in response to HLA-matched cancer cells was greatly augmented by treatment with DAC and IFN-γ. Taken together, these findings show DAC to be a promising tool for finding novel CT antigens and for developing a future novel combination cancer vaccine chemotherapy.

The interplay between epigenetic silencing, oncogenic KRas and HIF-1 regulatory pathways in control of BNIP3 expression in human colorectal cancer cells

Bcl-2/adenovirus E1B-19kDa-interacting protein 3 (BNIP3) is an important mediator of cell survival and a member of the Bcl-2 family of proteins that regulate programmed cell death and autophagy. We have previously established a link between the expression of oncogenic HRas and up-regulation of BNIP3 and the control of autophagy in cancer cells. However, in view of varied expression of BNIP3 in different tumor types and emerging uncertainties as to the role of epigenetic silencing, oncogenic regulation and the role of BNIP3 in cancer are still poorly understood. In the present study we describe profound effect of KRas on the expression of methylated BNIP3 in colorectal cancer cells and explore the interplay between HIF-1, hypoxia pathway and oncogenic KRas in this context. We observed that BNIP3 mRNA remains undetectable in aggressive DLD-1 cells harboring G13D mutant KRAS and HT-29 colorectal cancer cells unless the cells are exposed to demethylating agents such as 5-aza-2'-deoxycytidine. Following this treatment BNIP3 expression remains uniquely dependent on the Ras activity. We found that hypoxia or pharmacological activation of HIF-1 alone contributes to, but is not sufficient for efficient induction of BNIP3 mRNA transcription in cells lacking mutant KRas activity. The up-regulation of BNIP3 by KRas in this setting is mediated by the MAPK pathway, and is attenuated by the respective inhibitors (PD98059, U0126). Thus, we demonstrate the novel mechanism where activity of Ras is essential for 5-aza-2'-deoxycytidine-mediated BNIP3 expression. Moreover, we found that 5-aza-2'-deoxycytidine-mediated or enforced up-regulation of BNIP3 in DLD-1 cells results in KRas-dependent resistance to 5-Fluorouracil.

Effects of 5-Aza-2'-deoxycytidine on the methylation state and function of the WWOX gene in the HO-8910 ovarian cancer cell line

The aim of this study was to explore the effects of 5-Aza-2′-deoxycytidine (5-Aza-CdR), a DNA methylation inhibitor, on the methylation state and function of the WWOX gene in the HO-8910 ovarian cancer cell line. The HO-8910 cells were divided into two groups, a control group and a 5-Aza-CdR-treated group. The methylation state of the WWOX gene was evaluated using a methylation-specific PCR assay. The effect of 5-Aza-CdR on the HO-8910 cells was analyzed using MTT and cell invasion assays, as well as flow cytometry. The animal models were established by intraperitoneal transplantation of the cells into nude mice. Following treatment with 5-Aza-CdR, a demethylation state was detected in the HO-8910 cells. WWOX protein expression was significantly higher in the 5-Aza-CdR-treated group compared with that in the control group. The cell growth rate at each tested time point and the number of invasive cells were lower in the 5-Aza-CdR-treated group compared with that in the control group. Flow cytometry revealed that 67.13% of the cells were arrested at the G₀/G₁ stage in the 5-Aza-CdR-treated group. The tumorigenic ability of the 5-Aza-CdR-treated group was lower compared with that of the control group. In conclusion, the methylation state of the WWOX gene in HO-8910 cells may be reversed using 5-Aza-CdR, which may also inhibit the growth of these cells.

Cocaine represses protein phosphatase-1Cβ through DNA methylation and Methyl-CpG Binding Protein-2 recruitment in adult rat brain

Repeated cocaine exposure induces epigenetic factors such as DNA methyl-binding proteins, indicating that resulting changes in gene expression are mediated by alterations in brain DNA methylation. While the activity of protein phosphatase type-1 (PP1) is involved in cocaine effects and in brain plasticity, the expression of the PP1Cβ catalytic subunit gene was identified here as modulated by cocaine. Its expression was induced together with that of PP1Cγ in the brain of Methyl-CpG Binding Protein-2 (Mecp2) mutant mice, whereas PP1Cα expression was not affected, illustrating a different regulation of PP1C isoforms. Repeated cocaine administration was found to increase DNA methylation at the PP1Cβ gene together with its binding to Mecp2 in rat caudate putamen, establishing a link between two genes involved in cocaine-related effects and in learning and memory processes. Cocaine also increased DNMT3 expression, resulting in PP1Cβ repression that did not occur in the presence of DNMT inhibitor. Cocaine-induced PP1Cβ repression was observed in several brain structures, as evaluated by RT-qPCR, immunohistochemistry and Western blot, but did not occur after a single cocaine injection. Our data demonstrate that PP1Cβ is a direct MeCP2-target gene in vivo. They suggest that its repression may participate to behavioral adaptations triggered by the drug.

5-Aza-2'-deoxycytidine enhances maspin expression and inhibits proliferation, migration, and invasion of the bladder cancer T24 cell line

BACKGROUND

Downregulation of maspin expression has been linked to bladder cancer development, and that DNA methylation may be important for regulating maspin gene activation in bladder cancer cells. Thus, we attempted to explore the effects of the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-Aza-CdR), on the maspin expression and the biological behaviors in bladder cancer T24 cells.

METHOD

The methylation status of maspin in T24 cells was investigated by methylation-specific polymerase chain reaction (PCR). After treated with different concentrations of 5-Aza-CdR (0, 0.25, 0.5, 1, and 2 μM), the maspin gene mRNA expression and protein expression were examined by real-time PCR and western blotting analysis. Cell proliferations were evaluated by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Flow cytometry was used to identify the apoptosis rates. Migration and invasive ability were determined by the transwell assay. Using the western blotting analysis, the changes of Cyclin D1, VEGF-C, VEGFR-3, MMP-2, MMP-9, caspase-3 p17, Bax, and Bcl-2 expression were measured.

RESULTS

Promoter DNA methylation of maspin was observed in T24 cells. The expression levels of maspin mRNA and protein in T24 cells were increased in a dose manner after treatment with increasing 5-Aza-CdR (p<0.05). The proliferation, migration, and invasion of cells were significantly inhibited with increasing 5-Aza-CdR, whereas the apoptosis was greatly increased (p<0.05). These were associated with the decreased ratio of Bcl-2/Bax, activation of caspase-3, and decreased expression of Cyclin D1, VEGF-C, VEGFR-3, MMP-2 and MMP-9.

CONCLUSIONS

The present study demonstrates that maspin is silenced by DNA methylation in bladder T24 cells, and its expression can be reactivated by treatment with 5-Aza-CdR. 5-Aza-CdR could result in obvious inhibitions of the proliferation, migration, and invasion of T24 cells, which may serve as a potential strategy for the treatment of bladder cancer.

Inhibition of shoot induction by 5-azacytidine and 5-aza-2'-deoxycytidine in Petunia involves DNA hypomethylation

Shoot bud regeneration from Petunia leaf disks was inhibited when they were cultured with the demethylating agents, 5-azacytidine (AzaC) and 5-aza-2'-deoxycytidine (AzadC), in shoot induction (SI) medium. Explants induced shoot primordia if they were transferred after 1 week from the medium containing the drugs to medium without drugs. The fresh weight of leaf disks cultured on SI medium for 2 weeks in the presence of the drugs was 60-80% lower when compared to control shoot-forming cultures. Internode length was reduced when shoots were transferred to phytohormone-free Murashige and Skoog medium containing the drugs. However, no other morphological abnormalities were seen in these shoots, even at 20 µM AzaC or 5 µM AzadC. Coupled restriction enzyme digestion (with HpaII and MspI) and random amplification of genomic DNA was performed to detect the level of methylation of CCGG sites in the DNA of the explants exposed to AzaC and AzadC. Over 15 amplified bands were detectable in the control. Five of these bands were absent in the amplified products when digested DNA from the drug-treated explants was used as the template, showing that hypomethylation of DNA had occurred. This suggests that inhibition of shoot bud formation in the presence of the drugs AzaC and AzadC may be due to the altered methylation status.