Identification of TSGs Frequently Methylated in Renal Cell carcinoma (expression profiles of Renal cell lines following de-methylation)
Ontology highlight
ABSTRACT: Promoter region hypermethylation and transcriptional silencing is a frequent cause of tumour suppressor gene (TSG) inactivation in many types of human cancers. Functional epigenetic studies, in which gene expression is induced by treatment with demethylating agents, may identify novel genes with tumour-specific methylation. We used high-density gene expression microarrays in a functional epigenetic study of 11 renal cell carcinoma (RCC) cell lines. Twenty eight genes were then selected for analysis of promoter methylation status in cell lines and primary RCC. Eight genes (BNC1, PDLIM4/RIL, REPRIMORPRM, CST6, SFRP1, GREM1, COL14A1 and COL15A1) demonstrated frequent (>30% of RCC tested) tumour-specific promoter region methylation. Hypermethylation was associated with transcriptional silencing. Re-expression of BNC1, CST6, RPRM, and SFRP1 suppressed the growth of RCC cell lines. Whereas, RNAi-knock-down of BNC1, SFRP1 and COL14A1 increased the growth potential of RCC cell lines. Methylation of BNC1 or COL14A1 was associated with a poorer prognosis independent of tumour size, stage or grade. The identification of these epigenetically inactivated candidate RCC tumour suppressor genes can provide insights into renal tumourigenesis and a basis for developing novel therapies and biomarkers for prognosis and detection.
Project description:Promoter region hypermethylation and transcriptional silencing is a frequent cause of tumour suppressor gene (TSG) inactivation in many types of human cancers. Functional epigenetic studies, in which gene expression is induced by treatment with demethylating agents, may identify novel genes with tumour-specific methylation. We used high-density gene expression microarrays in a functional epigenetic study of 11 renal cell carcinoma (RCC) cell lines. Twenty eight genes were then selected for analysis of promoter methylation status in cell lines and primary RCC. Eight genes (BNC1, PDLIM4/RIL, REPRIMORPRM, CST6, SFRP1, GREM1, COL14A1 and COL15A1) demonstrated frequent (>30% of RCC tested) tumour-specific promoter region methylation. Hypermethylation was associated with transcriptional silencing. Re-expression of BNC1, CST6, RPRM, and SFRP1 suppressed the growth of RCC cell lines. Whereas, RNAi-knock-down of BNC1, SFRP1 and COL14A1 increased the growth potential of RCC cell lines. Methylation of BNC1 or COL14A1 was associated with a poorer prognosis independent of tumour size, stage or grade. The identification of these epigenetically inactivated candidate RCC tumour suppressor genes can provide insights into renal tumourigenesis and a basis for developing novel therapies and biomarkers for prognosis and detection. We used expression microarrays to identified genes that were frequently methylated and silenced in RCC by determining the globlal expression patterns of RCC-derived cell lines following de-methylation by treatment with 5-Aza-2'-deoxycytidine.
Project description:In summary, our study demonstrated the methylation sites of SFRP1 gene promoter in patients with colorectal cancer and adenoma and found SFRP1_16_17_18 CpG site was good performance as a diagnostic marker of colorectal cancer.
Project description:Abstract The interplay between histone modifications and promoter hypermethylation provides a causative explanation for epigenetic gene silencing in cancer. Less is known about the upstream initiators that direct this process. Here, we report that the Cystatin M (CST6) tumor suppressor gene is concurrently down-regulated with other loci in breast epithelial cells co-cultured with cancer-associated fibroblasts (CAFs). Promoter hypermethylation of CST6 is associated with aberrant AKT1 activation in epithelial cells, as well as the disabled INNP4B regulator resulted from the suppression by CAFs. Repressive chromatin, marked by trimethyl-H3K27 and dimethyl-H3K9, and de novo DNA methylation is established at the promoter. The findings suggest that microenvironmental stimuli are triggers in this epigenetic cascade, leading to the long-term silencing of CST6 in breast tumors. Our present findings implicate a causal mechanism defining how tumor stromal fibroblasts support neoplastic progression by manipulating the epigenome of mammary epithelial cells. The result also highlights the importance of direct cell-cell contract between epithelial cells and the surrounding fibroblasts that confer this epigenetic perturbation. Since this two-way interaction is anticipated, the described co-culture system can be used to determine the effect of epithelial factors on fibroblasts in future studies.
Project description:To test the hypothesis that the propensity for silencing of tumor suppressor genes in the respiratory epithelium of chronic smokers by promoter hypermethylation is influenced by sequence variations that modify the activity of genes and microRNAÕs that directly or indirectly influence de novo methylation and chromatin remodeling.
Project description:Promoter methylation was assayed in a number of breast cancer and control normal samples along with the effects of 5'-aza-2'-deoxycytidine on breast cancer cell line transcriptomes. Aberrant promoter hypermethylation is frequently observed in cancer. The potential for this to contribute to tumour development depends on whether the genes affected are repressed because of their methylation. Many aberrantly methylated genes play important roles in development and are bivalently marked in ES cells suggesting that their aberrant methylation may reflect developmental processes. We investigated this possibility by analysing promoter methylation in 19 breast cancer cell lines, 10 normal tissues and 47 primary breast tumours. In order to determine the role of DNA methylation in silencing genes in breast cancer, we also examined the effects of the demethylating agent 5-aza-2?-deoxycytidine on gene expression in 3 breast cancer cell lines and HCT116 cells. Gene expression changes were also assayed in the DNA methyltransferase deficient HCT116 DKO cell line. Our findings implicate aberrant DNA methylation as a marker of cell lineage rather than tumour progression and suggest that, in most cases, it does not cause the repression with which it is associated. A number of human breast cancer cell lines, breast tumours and normal tissues were analysed on Illumina Infinium Methylation27 Beadchips to assay promoter methylation. Selected cell lines were analysed on expression arrays before and after treatment with 5-aza-2'-deoxycytidine.
Project description:Promoter methylation was assayed in a number of breast cancer and control normal samples along with the effects of 5'-aza-2'-deoxycytidine on breast cancer cell line transcriptomes. Aberrant promoter hypermethylation is frequently observed in cancer. The potential for this to contribute to tumour development depends on whether the genes affected are repressed because of their methylation. Many aberrantly methylated genes play important roles in development and are bivalently marked in ES cells suggesting that their aberrant methylation may reflect developmental processes. We investigated this possibility by analysing promoter methylation in 19 breast cancer cell lines, 10 normal tissues and 47 primary breast tumours. In order to determine the role of DNA methylation in silencing genes in breast cancer, we also examined the effects of the demethylating agent 5-aza-2?-deoxycytidine on gene expression in 3 breast cancer cell lines and HCT116 cells. Gene expression changes were also assayed in the DNA methyltransferase deficient HCT116 DKO cell line. Our findings implicate aberrant DNA methylation as a marker of cell lineage rather than tumour progression and suggest that, in most cases, it does not cause the repression with which it is associated.
Project description:Although renal cell carcinoma (RCC) is the sixth-leading cause of cancer death, the molecular events leading to disease onset and progression are not well understood. Genomic profiling of clear cell RCC (cRCC) patients indicated that loss of a negative regulator of the Wnt pathway, secreted frizzled-related protein 1 (sFRP1), occurred in the majority of more than 100 patients tested. To our knowledge, this is the first report of loss of sFRP1 expression in patients diagnosed with cRCC; this loss occurs in early stage cRCC, suggesting that it may be an important early event in renal carcinogenesis. Genomic profiling of patient matched normal and cRCC tissues identified Wnt regulated genes to be aberrantly increased in cRCC tissues suggesting sFRP1 suppresses Wnt signaling in cRCC. In order to test the hypothesis that sFRP1 acts as a tumor suppressor in cRCC, we have stably expressed sFRP1 in cRCC cells. sFRP1 expression in cRCC cells resulted in decreased growth in cell culture, inhibition of anchorage-independent growth, and decreased tumor volume in a nude mouse model. Together these data suggest an important role for sFRP1 as a tumor suppressor in cRCC. Keywords: Disease state analysis
Project description:Recent advancement in cancer research has shown that tumours are highly heterogeneous and multiple phenotypically different cell populations are found in single nodule. Cancer development and tumour growth is driven by specific type of cells - cancer stem cells or tumour initiating cells (CSCs/TICs), which are to be responsible for tumour growth, metastatic spread and drug resistance. This research was designed to verify the presence of tumour initiating cells in renal cancer cell lines. Subsequently, we aimed to characterize phenotype and cell biology of CD105+ cells, defined previously as renal cell carcinoma tumour initiating cells. Main goal of the project was to describe gene expression profile of tumour initiating cells originating from primary tumour and of metastatic origin. Metastatic RCC cell lines (ACHN and Caki-1) demonstrated higher colony forming ability comparing to primary RCC cell lines. We investigated presence of CD105+ cells in RCC cell lines. Furthermore, metastatic RCC cell lines have higher CD105+ cell population and higher expression for stemness genes (Oct-4 and Nanog). CD105+ cells adopt 3D grapes like structure under handing drop condition. Sorted CD105+ cells were found positive for human MSC makers such as CD90, CD73, CD44, CD146 and alkaline phosphatase activity. In addition, CD105+ cells were unable to expressed maker for CD24, CD34, CD11b, CD19, CD45 and HLA-DR. 1411 genes were commonly differentially expressed in CD105+ cells (both from primary (Caki-2) and metastatic RCC (ACHN)) cells in comparison to healthy kidney epithelial cell line (ASE-5063). TGF-β, Wnt/β-catenine, Epithelial-Mesenchymal Transition (EMT), Rap1 signaling, PI3K-Akt signaling and Hippo signaling pathway were altered in CD105+ cells after IPA and KEGG pathway analysis. TGFB1, ERBB2, and TNF are most significant transcriptional regulators activated in these cells. Altogether, our results indicate that RCC-CD105+ cells may represents a novel target for CSCs/TICs phenotype and their gene expression profile could be used as initial data for new functional studies and drug design.
Project description:Background: Neuroblastoma is a childhood cancer in which many children still have poor outcomes, emphasising the need to better understand its pathogenesis. Despite recent genome-wide mutation analyses, most neuroblastomas do not contain recognisable driver mutations, suggesting that epigenetic changes could underlie many cases. Methods: To discover genes that become epigenetically deregulated during neuroblastoma tumorigenesis, we compared neuroblastomas to their neural crest precursor cells, using genome-wide DNA methylation analysis; probing CpG island promoter microarrays with methyl CpG-immunoprecipitated DNA. Results: We identified 93 genes that were significantly differently methylated between neuroblastoma cell lines and neural crest cells, of which 26 (28%) were hypermethylated and 67 (72%) were hypomethylated. Concentrating on hypermethylated genes to identify candidate tumour suppressor loci, we found the cell engulfment and adhesion factor gene MEGF10 to be epigenetically repressed by DNA hypermethylation or by H3K27/K9 methylation in neuroblastoma cell lines. MEGF10 showed significantly down-regulated expression in neuroblastoma tumour samples; furthermore patients with the lowest-expressing tumours had reduced relapse-free survival. Knock-down of MEGF10 expression in neuroblastoma cell lines promoted cell growth. Conclusion: Our results suggest that MEGF10 is a clinically relevant, epigenetically-deregulated neuroblastoma tumour suppressor.
Project description:Promoter hypermethylation and transcriptional silencing is a common epigenetic mechanism of tumour suppressor inactivation in cancer, including malignant brain tumours. To identify targets of epigenetic silencing mediated by CpG island methylation in paediatric ependymoma, we used a pharmacological unmasking approach through treatment with the demethylating agent 5-Aza-2’-deoxycytidine followed by global expression microarray analysis.