Project description:Tumor suppressor genes (TSGs) are sometimes inactivated by transcriptional silencing through promoter hypermethylation. To identify novel methylated TSGs in melanoma, we carried out global mRNA expression profiling on a panel of 12 melanoma cell lines treated with a combination of 5-Aza-2-deoxycytidine (5AzadC) and an inhibitor of histone deacetylase, Trichostatin A. Reactivation of gene expression after drug treatment was assessed using Illumina whole-genome microarrays. After qRT-PCR confirmation, we followed up 8 genes (AKAP12, ARHGEF16, ARHGAP27, ENC1, PPP1R3C, PPP1R14C, RARRES1, and TP53INP1) by quantitative DNA methylation analysis using mass spectrometry of base-specific cleaved amplification products in panels of melanoma cell lines and fresh tumors. PPP1R3C, ENC1, RARRES1, and TP53INP1, showed reduced mRNA expression in 35–59% of the melanoma cell lines compared to melanocytes and which was correlated with a high proportion of promoter methylation (>40–60%). The same genes also showed extensive promoter methylation in 6–25% of the tumor samples, thus confirming them as novel candidate TSGs in melanoma.
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:Tumor suppressor genes (TSGs) are sometimes inactivated by transcriptional silencing through promoter hypermethylation. To identify novel methylated TSGs in melanoma, we carried out global mRNA expression profiling on a panel of 12 melanoma cell lines treated with a combination of 5-Aza-2-deoxycytidine (5AzadC) and an inhibitor of histone deacetylase, Trichostatin A. Reactivation of gene expression after drug treatment was assessed using Illumina whole-genome microarrays. After qRT-PCR confirmation, we followed up 8 genes (AKAP12, ARHGEF16, ARHGAP27, ENC1, PPP1R3C, PPP1R14C, RARRES1, and TP53INP1) by quantitative DNA methylation analysis using mass spectrometry of base-specific cleaved amplification products in panels of melanoma cell lines and fresh tumors. PPP1R3C, ENC1, RARRES1, and TP53INP1, showed reduced mRNA expression in 35–59% of the melanoma cell lines compared to melanocytes and which was correlated with a high proportion of promoter methylation (>40–60%). The same genes also showed extensive promoter methylation in 6–25% of the tumor samples, thus confirming them as novel candidate TSGs in melanoma. We sought to identify melanoma TSGs silenced by promoter methylation by carrying out an array-based analysis in a well-annotated panel of 12 cell lines after combined treatment with 5AzadC and an inhibitor of histone deacetylase, Trichostatin A (TSA). Expression profiles were generated for each cell line before and after drug treatment using Illumina Sentrix Human-6 Expression version 2 BeadChips. Genes reactivated in all 12 cell lines were removed from further analysis since they are likely responding to drug treatment as part of the ‘‘cellular stress response,’’ or due to promoter demethylation of genes normally silenced in the melanocytic lineage. Genes were further filtered to identify those with an average of >4-fold increased expression in at least four samples in the panel of 12 lines and >10-fold increase in at least one of the cell lines.
Project description:Epigenetic regulation of tumor suppressor genes (TSGs) has been shown to play a central role in melanomagenesis. Integrating gene expression and methylation array analysis we identified novel candidate TSGs frequently methylated in melanoma. We validated the methylation status of the most promising TSGs using the highly sensitive, specific and comprehensive Sequenom Epityper assay in a large panel of melanoma cell lines and resected melanomas, and compared the findings with that from cultured melanocytes. We found transcript levels of UCHL1, COL1A2, THBS1 and TNFRSF10D were inversely correlated with promoter methylation. The effect of this methylation on expression was confirmed at the protein level. Identification of these candidate TSGs and how their silencing is related to melanoma development will increase our understanding of the etiology of this cancer and may provide tools for its early diagnosis.
Project description:Epigenetic regulation of tumor suppressor genes (TSGs) has been shown to play a central role in melanomagenesis. Integrating gene expression and methylation array analysis we identified novel candidate TSGs frequently methylated in melanoma. We validated the methylation status of the most promising TSGs using the highly sensitive, specific and comprehensive Sequenom Epityper assay in a large panel of melanoma cell lines and resected melanomas, and compared the findings with that from cultured melanocytes. We found transcript levels of UCHL1, COL1A2, THBS1 and TNFRSF10D were inversely correlated with promoter methylation. The effect of this methylation on expression was confirmed at the protein level. Identification of these candidate TSGs and how their silencing is related to melanoma development will increase our understanding of the etiology of this cancer and may provide tools for its early diagnosis. Analysed samples consisted of 11 melanoma cell lines and 1 neonatal foreskin melanocyte pool as a reference. Melanoma cell lines overlap with members of the DNA copy number analysis series GSE9003 and expression profiling series GSE7127 . The matching copy number data GEO samples IDs are noted in characteristics: Matching CN Sample ID and characteristics: Matching expn Sample ID columns respectively.
Project description:The implication of epigenetic alterations in the pathogenesis of melanoma is increasingly recognized. Here we performed genome-wide DNA methylation analysis of primary cutaneous melanoma and benign melanocytic naevus interrogating 14,495 genes using beadchip technology. This first genome-wide view of promoter methylation in primary cutaneous melanoma revealed an array of recurrent DNA methylation alterations with potential diagnostic applications. Among 106 frequently hypermethylated genes there were many novel methylation targets and tumor suppressor genes. Highly recurrent methylation of the HOXA9, MAPK13, CDH11, PLEKHG6, PPP1R3C and CLDN11genes was established. Promoter methylation of MAPK13, encoding p38?, was present in 67% of primary and 85% of metastatic melanomas. Restoration of MAPK13 expression in melanoma cells exhibiting epigenetic silencing of this gene reduced proliferation, indicative of tumor suppressive functions. This study demonstrates that DNA methylation alterations are widespread in melanoma and suggests that epigenetic silencing of MAPK13 contributes to melanoma progression. Bisulphite converted genomic DNA from 5 fresh-frozen benign naevus and 24 fresh-frozen primary melanoma biopsy samples were hybridised to Illumina's Infinium HumanMethylation27 Beadchips
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:The implication of epigenetic alterations in the pathogenesis of melanoma is increasingly recognized. Here we performed genome-wide DNA methylation analysis of primary cutaneous melanoma and benign melanocytic naevus interrogating 14,495 genes using beadchip technology. This first genome-wide view of promoter methylation in primary cutaneous melanoma revealed an array of recurrent DNA methylation alterations with potential diagnostic applications. Among 106 frequently hypermethylated genes there were many novel methylation targets and tumor suppressor genes. Highly recurrent methylation of the HOXA9, MAPK13, CDH11, PLEKHG6, PPP1R3C and CLDN11genes was established. Promoter methylation of MAPK13, encoding p38?, was present in 67% of primary and 85% of metastatic melanomas. Restoration of MAPK13 expression in melanoma cells exhibiting epigenetic silencing of this gene reduced proliferation, indicative of tumor suppressive functions. This study demonstrates that DNA methylation alterations are widespread in melanoma and suggests that epigenetic silencing of MAPK13 contributes to melanoma progression.