Analysis of normal lung cells treated with 5-aza-dC to induce DNA demethylation
Ontology highlight
ABSTRACT: 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: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: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: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:Salivary gland adenoid cystic carcinoma (ACC) is a rare malignancy amongst head and neck tumors that is poorly understood on a molecular level. We sought to perform a comprehensive approach for novel oncogene candidate screening under the control of promoter methylation in order to learn more about the molecular basis of this unusual disease. We performed global demethylation of normal salivary gland cell strains using 5-aza-deoxycytidine (5-Aza dC) and trichostatin (TSA). Expression arrays were performed, and the profiles of treated and untreated cells compared. We then used expression microarray analysis of primary ACC and normal salivary gland samples to generate ACC-specific expression profiling. Next, we integrated the two profiles to identify a subset of genes for further validation of decreased methylation in the promoter region in ACC vs normals. Finally, only genes that showed decreased methylation in ACC compared to normal were further validated for mRNA, protein, and promoter methylation levels in a larger ACC cohort.
Project description:To investigate the biochemical and genetic alterations that occur in response to cigarette smoke exposure among airway epithelial cells from different sites in the lungs, we performed microarray-based analysis using small airway epithelial cells (SAEC) and normal human bronchial epithelial cells (NHBE) following 24 h of cigarette smoke extract (CSE). In microarray-based analysis, the small airway showed higher susceptibility to CS compared to the large airway, such as enhanced expression of inflammatory-related pathways including the TNF signaling pathway. Among the TNF-related genes, PTGS2, also known as COX-2, showed the greatest difference in expression levels, with higher CSE-induced increments of both mRNA and protein expression in SAEC compared to NHBE.
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).
Project description:Treatment-related DNA hypermethylation may play a role in creating drug resistant phenotypes by inactivating genes that are required for cytotoxicity, but there have been no genome-wide studies to systematically investigate methylation of individual genes following exposure to chemotherapy. We used microarrays and a pharmacologic unmasking protocol in isogenic cisplatin-sensitive and -resistant cell lines to identify genes that were down-regulated in cisplatin-resistant cells and could be re-activated by the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-Aza-dC). We identified several hundred genes that were down-regulated in each resistant cell line. Of these, 30 genes were common to > 2 cell lines, and/or reported to be down-regulated in previous studies. siRNA knockdown of two candidate genes increased cell viability with cisplatin treatment in sensitive parental cell lines Cisplatin-sensitive and -resistant SCC cells and KB and KB cisplatin-resistant clones (n=2) were split to low density and treated with freshly prepared 5 microM 5-Aza-dC dissolved in 50% acetic acid/50% PBS or were mock treated with the same volume of vehicle in the media for 5 days. Subsequently, RNA was extracted and hybridized on Affymetrix U133A microarrays. Signal intensity and statistical significance was established for each transcript, and a 2-fold decrease in signal in each paired sensitive/resistant cell line in combination with 1.5-fold increase after 5Aza-dC treatment was used to identify candidate genes.
Project description:Expression data from pancreatic cancer cell lines and non-neoplastic pancreatic cell line HPDE To identify genes epigenetically silenced and regulated in pancreatic cancer We compared the gene expression profiles of 6 pancreatic cancer cell lines (panc215, A32-1, A38-5, panc2.5, panc2.8, and panc3.014), to the non-neoplastic pancreas cell line, HPDE. We also compared the baseline gene expression of the pancreatic cancer cell lines to expression patterns after treatment with 5-aza-dC alone, TSA alone, and to a combination of 5-aza-dC/TSA.
Project description:To understand the roles of DNA methylation and histone deacetylation in plant gene network that controls plant tolerance to freezing treatment, we used Affymetrix GeneChips ATH-121501 to analysis. For microarray analysis, Arabidopsis (ecotype Columbia) seedlings grew in four types of sterile growth medium: no any other modifying agents, added 7g/ml 0.5 M aza-dC in water (DNA methylation inhibitor), added TSA in methanol (histone deacetylation inhibitor), both aza-dC and TSA, all for 16 day in growth chamber (16-h day length at 70% relative humidity, 23 M-BM-0C) , then all seedlings were cold treated at 0 M-BM-0C for 24 h in growth chamber (16-h day length at 70% relative humidity). A total of 3305 genes expression were statistically analysized. Our study provides some clues that the transcript levels of some cold-responsive genes regulated by DNA methylation and histone deacetylation. This will be valuable for understanding gene regulation by epigenetic modifications under freezing stress. Keywords: Cold Stress response, DNA methylation, histone deacetylation Three replicates for aza-dc and TSA treatment, and two replicates for Mock and both aza-dc and TSA treatment. All samples were treated 0M-BM-0C 24h.