Project description:Analysis of 2 cultured normal lung cell lines, Normal Human Bronchial Epithelial (NHBE) and Human Small Airway Epithelial (SAEC) cells (Lonza, Walkersville, MD), following treatment with 5-aza-dC to induce DNA demethylation. These results provide insight into the role of epigenetic alterations, specifically demethylation, in differential gene expression in various lung neoplasms.
Project description:Analysis of 2 cultured normal lung cell lines, Normal Human Bronchial Epithelial (NHBE) and Human Small Airway Epithelial (SAEC) cells (Lonza, Walkersville, MD), following treatment with 5-aza-dC to induce DNA demethylation. These results provide insight into the role of epigenetic alterations, specifically demethylation, in differential gene expression in various lung neoplasms. Two normal lung cell lines, NHBE and SAEC, were treated with 5uM 5-aza deoxycytidine for 72 hours and Trichostatin A for 24 hours prior to harvesting total RNA for expression array analysis using the Affymetrix Human Genome U133 Plus 2.0 expression platform. Signal intensity and statistical significance was established for each transcript using dChip version 2005. Two-fold increase based on the 90% confidence interval of the result and expression minus baseline >50 was used as the statistical cutoff value after 5Aza-dC and/or TSA treatment to identify upregulated candidate genes.
Project description:To assess transcriptional regulation by DNA demethylation in SAEC, we carried out a microarray analysis of SAEC treated with a demethylating agent (5-aza-dC) and a HDAC inhibitor (TSA). We used the Agilent SurePrint G3 Human Gene Expression 8x60K v3 microarray which contains probes for 26,083 Entrez genes and 30,606 lncRNAs.
Project description:Background: DNA methylation is important for maintenance of the silent state of genes on the inactive X chromosome (Xi). Here, we screened for siRNAs and chemicals that reactivate an Xi-linked reporter in the presence of 5-aza-2’-deoxycytidine (5-aza-2’-dC), an inhibitor of DNA methyltransferase 1, at a concentration that, on its own, is not sufficient for Xi-reactivation. Results: We found that inhibition of ribonucleotide reductase (RNR) induced expression of the reporter. RNR inhibition potentiated the effect of 5-aza-2’-dC by enhancing its DNA incorporation, thereby decreasing genome-wide DNA methylation levels. Since both 5-aza-2’-dC and RNR-inhibitors are used in the treatment of hematological malignancies, we treated myeloid leukemia cell lines with 5-aza-2’-dC and the RNR inhibitor hydroxyurea, and observed synergistic inhibition of cell growth and decreases in genome-wide DNA methylation. Conclusions: Taken together, our study identifies a drug combination that enhances DNA demethylation by altering nucleotide metabolism. We demonstrate that XCR assays can be used to optimize epigenetic activity of drug combinations.
Project description:Background: DNA methylation is important for maintenance of the silent state of genes on the inactive X chromosome (Xi). Here, we screened for siRNAs and chemicals that reactivate an Xi-linked reporter in the presence of 5-aza-2’-deoxycytidine (5-aza-2’-dC), an inhibitor of DNA methyltransferase 1, at a concentration that, on its own, is not sufficient for Xi-reactivation. Results: We found that inhibition of ribonucleotide reductase (RNR) induced expression of the reporter. RNR inhibition potentiated the effect of 5-aza-2’-dC by enhancing its DNA incorporation, thereby decreasing genome-wide DNA methylation levels. Since both 5-aza-2’-dC and RNR-inhibitors are used in the treatment of hematological malignancies, we treated myeloid leukemia cell lines with 5-aza-2’-dC and the RNR inhibitor hydroxyurea, and observed synergistic inhibition of cell growth and decreases in genome-wide DNA methylation. Conclusions: Taken together, our study identifies a drug combination that enhances DNA demethylation by altering nucleotide metabolism. We demonstrate that XCR assays can be used to optimize epigenetic activity of drug combinations. Reduced representation bisulfite sequencing (MspI,~40-220bp size fraction) of murine and human cells.
Project description:Promoter methylation is able to induce downregulation of gene expression. 5-Aza-2'-deoxycytidine(Aza), methytransferase inhibitor, induce CpG demethylation. Here, 5-Aza-2'-deoxycytidine(Aza) is treated in a human breast cancer cell, MCF7, for detection of gene expression change.
Project description:Expression profiling the response to inhibition of DNA methylation and histone deacetylation. Comparison of expression in HepG2 cells treated with 5-aza-dC, Trichostatin A, both, or none (control) to change methylation and acetylation status. Background:DNA methylation and histone deacetylation are epigenetic mechanisms that play major roles in eukaryotic gene regulation. We hypothesize that many genes in the human hepatoma cell line HepG2 are regulated by DNA methylation and histone deacetylation. Treatment with 5-aza-2'-deoxycytidine (5-aza-dC) to inhibit DNA methylation with and/or Trichostatin A (TSA) to inhibit histone deacetylation should allow us to identify genes that are regulated epigenetically in hepatoma cells. Results:5-aza-dC had a much larger effect on gene expression in HepG2 cells than did TSA, as measured using Affymetrix® HG-U133A Plus 2.0 microarrays. The expression of 1504 probe sets was affected by 5-aza-dC (at p < 0.01), 535 probe sets by TSA, and 1929 probe sets by the combination of 5-aza-dC and TSA. 5-aza-dC treatment turned on the expression of 211 probe sets that were not detectably expressed in its absence. Expression of imprinted genes regulated by DNA methylation, such as H19 and NNAT, was turned on or greatly increased in response to 5-aza-dC. Genes involved in liver processes such as xenobiotic metabolism (CYP3A4, CYP3A5, and CYP3A7) and steroid biosynthesis (CYP17A1 and CYP19A1), and CCAAT element-binding proteins (CEBPA, CEBPB, and CEBPG) were affected by 5-aza-dC or the combination. Many of the genes that fall within these groups are also expressed in the developing fetal liver. Quantitative real-time RT-PCR assays confirmed selected gene expression changes seen in microarray analyses. Conclusions:Epigenetics play a role in regulating the expression of several genes involved in essential liver processes such as xenobiotic metabolism and steroid biosynthesis in HepG2 cells. Many genes whose expression is normally silenced in these hepatoma cells were re-expressed by 5-aza-dC treatment. Many genes that are expressed in the fetal liver are up-regulated by demethylation, indicating that DNA methylation is a major factor in restricting the expression of fetal genes during liver development. Keywords: comparison of treatments
Project description:A neuroblastoma cell line, NB-1, was treated with mock, a DNA demethylating agent (5-aza-2'-deoxycytidine: 5-aza-dC), a synthetic retinoic acid (tamibarotene: TBT), and the combination of 5-aza-dC and TBT. A genome-wide gene expression analysis was performed using SurePrint G3 Human Gene Expression 8 x 60K v2 Microarray.
Project description:Purpose: The major aim of this study was to investigate the role of DNA methylation (referred to as methylation) on microRNA (miRNA) silencing in non-small cell lung cancers (NSCLC). Experimental Design: We performed microarray expression analyses of 856 miRNAs in NSCLC A549 cells before and after treatment with the DNA methyltransferase inhibitor 5-aza-2´-deoxycytidine (Aza-dC) and with a combination of Aza-dC and the histone deacetylase inhibitor trichostatin A. MiRNA methylation was determined in 11 NSCLC cell lines and in primary tumors and corresponding non-malignant lung tissue samples of 101 stage I-III NSCLC patients. Results: By comparing microarray data of untreated and drug treated A549 cells, we identified 33 miRNAs whose expression was upregulated after drug treatment and which are associated with a CpG island. Thirty (91%) of these miRNAs were found to be methylated in at least 1 of 11 NSCLC cell lines analysed. Moreover, miR-9-3 and miR-193a were found to be tumor-specifically methylated in NSCLC patients. We observed a shorter disease-free survival of miR-9-3 methylated lung squamous cell carcinoma (LSCC) patients compared to miR-9-3 unmethylated LSCC patients by multivariate analysis (HR = 3.8, 95% CI = 1.3 to 11.2, p = 0.017) and a shorter overall survival of miR-9-3 methylated LSCC patients compared to miR-9-3 unmethylated LSCC patients by univariate analysis (p = 0.013). Conclusions: Overall, our results suggest that methylation is an important mechanism for inactivation of certain miRNAs in NSCLCs and that miR-9-3 methylation may serve as a prognostic parameter in LSCC patients. MiRNA expression (LC Sciences, mirBASE12) was analyzed before and after treatment of A549 cells with 5-aza-2´-deoxycytidine (Aza-dC) and a combination of Aza-dC and trichostatin A (TSA). Experiments were performed in duplicates.
Project description:Epigenetic changes largely contribute to the regulation of gene expression in cancer cells. DNA methylation is part of the epigenetic gene regulation complex which is relevant for the pathogenesis of cancer. We performed a genome-wide search for methylated CpG islands in tumors and corresponding non-malignant lung tissue samples of 101 stage I-III non-small cell lung cancer (NSCLC) patients by combining methylated DNA immunoprecipitation and microarray analysis using NimbleGenM-BM-4s 385K Human CpG Island plus Promoter arrays. By testing for differences in methylation between tumors and corresponding non-malignant lung tissues, we identified 298 tumor-specifically methylated genes. From many of these genes epigenetic regulation was unknown so far. Gene Ontology analysis revealed an over-representation of genes involved in regulation of gene expression and cell adhesion. Expression of 182 of 298 genes was found to be upregulated after 5-aza-2M-BM-4-deoxycytidine (Aza-dC) and/or trichostatin A (TSA) treatment of 3 NSCLC cell lines by Affymetrix microarray analysis. In addition, methylation of selected genes in primary NSCLCs and corresponding non-malignant lung tissue samples were analyzed by methylation-sensitive high resolution melting analysis (MS-HRM). Our results obtained by MS-HRM analysis confirmed our data obtained by MeDIP-chip analysis. Moreover, by comparing methylation results from MeDIP-chip analysis with clinico-pathological parameters of the patients we observed methylation of HOXA2 as potential parameter for shorter disease-free survival of NSCLC patients. In conclusion, using a genome-wide approach we identified a large number of tumor-specifically methylated genes in NSCLC patients. Our results stress the importance of DNA methylation for the pathogenesis of NSCLCs. Overall, samples of 3 untreated, with Aza-dC treated and with Aza-dC/TSA treated NSCLC cell lines were hybridized to Affymetrix HG-U133_plus_2.0 microarrays (18 in total).