Strong Activation of Retroviral LTRs in HCC
Ontology highlight
ABSTRACT: 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.
SECONDARY ACCESSION(S): PRJNA278792PRJNA278791
REPOSITORIES: dbGaP
Similar Datasets
Project description:An increasing number of non-coding RNAs (ncRNAs) are implicated in various human diseases including cancer; however ncRNA transcriptome of hepatocellular carcinoma (HCC) remains largely unexplored. We use CAGE (Cap Analysis of Gene Expression) to comprehensively map transcription start sites (TSSs) across different etiologies of human HCC as well as mouse HCC, with particular emphasis on ncRNAs distant from protein-coding genes. We find thousands of significantly up-regulated distal ncRNAs in HCC tumors compared to their matched non-tumors, which are as many as protein-coding genes. Moreover, we identify many LTR retroviral promoters activated in HCC tissues and expressed in a subfamily-specific manner, which account for approximately 20% of the up-regulated distal ncRNAs. The transcripts derived from LTRs, determined by 3' RACE, are multi-exon nuclear ncRNAs typically 0.5-2kb in length. This study sheds light on ncRNA transcriptome of human and mouse HCC. Expression profiles using CAGE for 37 mouse HCC. The human data are archived at dbGaP (phs000885.v1.p1). An umbrella BioProject has been created to associate the GEO and dbGaP BioProjects: PRJNA278792
2015-09-10 | E-GEOD-60982 | biostudies-arrayexpress
Project description:An increasing number of non-coding RNAs (ncRNAs) are implicated in various human diseases including cancer; however ncRNA transcriptome of hepatocellular carcinoma (HCC) remains largely unexplored. We use CAGE (Cap Analysis of Gene Expression) to comprehensively map transcription start sites (TSSs) across different etiologies of human HCC as well as mouse HCC, with particular emphasis on ncRNAs distant from protein-coding genes. We find thousands of significantly up-regulated distal ncRNAs in HCC tumors compared to their matched non-tumors, which are as many as protein-coding genes. Moreover, we identify many LTR retroviral promoters activated in HCC tissues and expressed in a subfamily-specific manner, which account for approximately 20% of the up-regulated distal ncRNAs. The transcripts derived from LTRs, determined by 3' RACE, are multi-exon nuclear ncRNAs typically 0.5-2kb in length. This study sheds light on ncRNA transcriptome of human and mouse HCC.
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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.
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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.
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