Project description:Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers worldwide and has a poor prognosis. Promoters represent an essential regulatory element of gene transcription in the human genome. In order to understand the promoter methylation in relation with gene transcription in HCCs, we applied a liquid hybridization capture-based bisulfite sequencing (LHC-BS) approach to examine the promoter methylome of HCCs, for which we customized 150,407 capture probes and enabled coverage of 91.8% of the RefSeq gene promoters within the human genome. We found the differential promoter DNA methylation between HCCs and peripheral normal tissues. Then we integrated promoter methylomic and transcriptomic profiling and described gene expression and regulation in HCCs. Lastly, we validated the key genes in a larger number of samples and screened candidate genes aberrantly regulated by DNA methylation in human HCCs. Capture-based whole genome promoter bisulfite-seq for 8 pairs of HCC tumor and non-tumor liver (NTL) samples.
Project description:Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers worldwide and has a poor prognosis. Promoters represent an essential regulatory element of gene transcription in human genome. In order to understand the promoter methylation in relation with gene transcription in HCCs, We applied a liquid hybridization capture-based bisulfite sequencing (LHC-BS) approach to examine the promoter methylome of HCCs, for which we customized 150,407 capture probes and enabled coverage of 91.8% of the RefSeq gene promoters within human genome. We found the differential promoter DNA methylation between HCCs and peripheral normal tissues. Then we integrated promoter methylomic and transcriptomic profiling and described gene expression and regulation in HCCs. Lastly, We validated the key genes in larger number of samples and screened candidate genes aberrantly regulated by DNA methylation in human HCCs.
Project description:Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers worldwide and has a poor prognosis. Promoters represent an essential regulatory element of gene transcription in the human genome. In order to understand the promoter methylation in relation with gene transcription in HCCs, we applied a liquid hybridization capture-based bisulfite sequencing (LHC-BS) approach to examine the promoter methylome of HCCs, for which we customized 150,407 capture probes and enabled coverage of 91.8% of the RefSeq gene promoters within the human genome. We found the differential promoter DNA methylation between HCCs and peripheral normal tissues. Then we integrated promoter methylomic and transcriptomic profiling and described gene expression and regulation in HCCs. Lastly, we validated the key genes in a larger number of samples and screened candidate genes aberrantly regulated by DNA methylation in human HCCs.
Project description:Renal cell carcinoma (RCC) is among the ten most common malignancies. By far, the most common histology is clear cell (ccRCC). The Cancer Genome Atlas and other large scale sequencing studies of ccRCC have been integral to the current understanding of molecular events underlying RCC and its biology. However, these data sets have focused on primary RCC which often demonstrates indolent behavior. In contrast, metastatic disease is the major cause of mortality associated with ccRCC. However, data sets examining metastatic tumor are sparse. We therefore undertook an integrative analysis of gene expression and DNA methylome profiling of metastatic ccRCC in addition to primary RCC and normal kidney. Integrative analysis of the methylome and transcriptome identified over 30 RCC specific genes whose mRNA expression inversely correlated with promoter methylation including several known targets of hypoxia inducible factors (HIFs). Notably, genes encoding several metabolism-related proteins were identified as differentially regulated via methylation. Collectively, our data provide novel insight into biology of aggressive RCC. Furthermore, they demonstrate a clear role for epigenetics in the promotion of HIF signaling and invasive phenotypes in renal cancer.
Project description:Chronic infections by hepatitis B virus (HBV) and hepatitis C virus (HCV) appear to be the most significant causes of hepatocellular carcinoma (HCC). Aberrant promoter methylation is known to be deeply involved in cancer, including HCC. In this study, we analyzed aberrant promoter methylation on genome-wide scale in 6 HCCs including 3 HBV-related and 3 HCV-related HCCs, 6 matched noncancerous liver tissues and 3 normal liver tissues by methylated DNA immunoprecipitation-on-chip analysis. Candidate genes with promoter methylation were detected more frequently in HCV-related HCC. Candidate genes methylated preferentially to HBV-related or HCV-related HCCs were detected and selected, and methylation levels of the selected genes were validated using 125 liver tissue samples, including 61 HCCs (28 HBV-related HCCs and 33 HCV-related HCCs) and matched 59 matched noncancerous livers, and 5 normal livers, by quantitative methylation analysis using MALDI-TOF mass spectrometry. Among analyzed genes, preferential methylation in HBV-related HCC was validated in 1 gene only. However, 15 genes were found methylated preferentially in HCV-related HCC, which was independent from age. Hierarchical clustering of HCC using these 15 genes stratified HCV-related HCC as a cluster of frequently methylated samples. The 15 genes included genes inhibitory to cancer-related signaling such as RAS/RAF/ERK and Wnt/b-catenin pathways. It was indicated that genes methylated preferentially in HCV-related HCC exist, and it was suggested that DNA methylation might play an important role in HCV-related HCC by silencing cancer-related pathway inhibitors. we analyzed aberrant promoter methylation in 6 HCC clinical samples (including 3 HBV-related HCCs and 3 HCV-related HCCs) and their matched noncancerous tissues on genome-wide scale by the method. Candidate regions of promoter methylation preferentially to HBV-related HCC and HCV-related HCC were selected, and the methylation levels of these genes were measured quantitatively using MALDI-TOF mass spectrometry. Expression levels of these 6 pairs of HCC and 4 more pairs of HCCs and surrounding noncancerous tissues were analyzed by expression array and are reported in this Series. <br><br>This experiment was reloaded in November 2010 after additional curation. this dataset is part of the TransQST collection.
Project description:Chronic infections by hepatitis B virus (HBV) and hepatitis C virus (HCV) appear to be the most significant causes of hepatocellular carcinoma (HCC). Aberrant promoter methylation is known to be deeply involved in cancer, including HCC. In this study, we analyzed aberrant promoter methylation on genome-wide scale in 6 HCCs including 3 HBV-related and 3 HCV-related HCCs, 6 matched noncancerous liver tissues and 3 normal liver tissues by methylated DNA immunoprecipitation-on-chip analysis. Candidate genes with promoter methylation were detected more frequently in HCV-related HCC. Candidate genes methylated preferentially to HBV-related or HCV-related HCCs were detected and selected, and methylation levels of the selected genes were validated using 125 liver tissue samples, including 61 HCCs (28 HBV-related HCCs and 33 HCV-related HCCs) and matched 59 matched noncancerous livers, and 5 normal livers, by quantitative methylation analysis using MALDI-TOF mass spectrometry. Among analyzed genes, preferential methylation in HBV-related HCC was validated in 1 gene only. However, 15 genes were found methylated preferentially in HCV-related HCC, which was independent from age. Hierarchical clustering of HCC using these 15 genes stratified HCV-related HCC as a cluster of frequently methylated samples. The 15 genes included genes inhibitory to cancer-related signaling such as RAS/RAF/ERK and Wnt/b-catenin pathways. It was indicated that genes methylated preferentially in HCV-related HCC exist, and it was suggested that DNA methylation might play an important role in HCV-related HCC by silencing cancer-related pathway inhibitors.
Project description:<p>The ncRNA transcriptome of human hepatocellular carcinoma (HCC) is largely unexplored. We used CAGE to characterize transcription start sites across different etiologies of human HCCs with emphasis on ncRNAs. Here we report that retroviral LTR promoters, expressed in healthy tissues such as testis and placenta but not liver, are widely activated in HCC. Despite HCC heterogeneity, a subset of LTR-derived ncRNAs were more than 10-fold up-regulated in the vast majority of samples. HCCs with a high LTR activity mostly had a viral etiology, were less differentiated and showed higher risk of recurrence. CAGE enabled us to build a promoter map for HCC, which uncovers a new layer of complexity in HCC genomics.</p>
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.