Project description:The incidence of esophageal adenocarcinoma (EAC) has risen 600% over the last 30 years. With an extremely poor five-year survival rate of only 15%, identification of new therapeutic targets for EAC is of great importance. Here, we analyze the mutation spectra from the whole exome sequencing of 149 EAC tumors/normal pairs, 15 of which have also been subjected to whole genome sequencing. We identify a novel mutational signature in EACs defined by a high prevalence of A to C transversions at Ap*A dinucleotides. Statistical analysis of the exome data identified 26 genes that are mutated at a significant frequency. Of these 26 genes, only four (TP53, CDKN2A, SMAD4, and PIK3CA) have been previously implicated in EAC. The novel significantly mutated genes include several chromatin modifying factors and candidate contributors to EAC: SPG20, TLR4, ELMO1, and DOCK2. Notably, functional analyses of EAC-derived mutations in ELMO1 increase cellular invasion. Therefore, we suggest a new hypothesis about the potential activation of the RAC1 pathway to be a contributor to EAC tumorigenesis. The study aimed to analyze 150 primary, human esophageal adenocarcinoma samples by whole genome and whole exome sequencing (which will be deposited to dbGAP following the TCGA practice). RNA expression data was used to determine gene expression in 14 of the samples analyzed by whole genome sequencing. No normals were analyzed.
Project description:The incidence of esophageal adenocarcinoma (EAC) has risen 600% over the last 30 years. With an extremely poor five-year survival rate of only 15%, identification of new therapeutic targets for EAC is of great importance. Here, we analyze the mutation spectra from the whole exome sequencing of 149 EAC tumors/normal pairs, 15 of which have also been subjected to whole genome sequencing. We identify a novel mutational signature in EACs defined by a high prevalence of A to C transversions at Ap*A dinucleotides. Statistical analysis of the exome data identified 26 genes that are mutated at a significant frequency. Of these 26 genes, only four (TP53, CDKN2A, SMAD4, and PIK3CA) have been previously implicated in EAC. The novel significantly mutated genes include several chromatin modifying factors and candidate contributors to EAC: SPG20, TLR4, ELMO1, and DOCK2. Notably, functional analyses of EAC-derived mutations in ELMO1 increase cellular invasion. Therefore, we suggest a new hypothesis about the potential activation of the RAC1 pathway to be a contributor to EAC tumorigenesis.
Project description:Background and aims: The aim of this study was to analyze the molecular characteristics of adenocarcinoma of the gastroesophageal junction (AGEJ) compared to esophageal (EAC) and gastric adenocarcinomas (GCFB) from The Cancer Genome Atlas (TCGA) and Seoul National University (SNU) cohorts using next-generation sequencing. Methods: Based on mRNA expression of EAC (n=78) and GCFB (n=102) from the TCGA cohort, a molecular classification model using the Bayesian compound covariate predictor classified AGEJ/cardia (n=48) from the TCGA cohort and AGEJ/upper third gastric adenocarcinoma (n=46) from the SNU cohort into the EAC-like or GCFB-like groups. The molecular characteristics between the EAC-like and GCFB-like groups were compared.
Project description:Objectives: Long non-coding RNAs (lncRNAs) have been shown to play important roles in the development and progression of cancer. However, functional lncRNAs and their downstream mechanisms are largely unknown in the molecular pathogenesis of esophageal adenocarcinoma (EAC) and its progression. Design: lncRNAs that are abnormally upregulated in EACs were identified by RNA-seq analysis, followed by quantitative RT-PCR (qRTPCR) validation using tissues from 31 EAC patients. Cell biological assays in combination with siRNA-mediated knockdown were performed in order to probe the functional relevance of these lncRNAs. Results: We discovered that a lncRNA, HNF1A-AS1, is markedly upregulated in human primary EACs relative to their corresponding normal esophageal tissues (mean fold change 7.2, p<0.01). We further discovered that HNF1A-AS1 knockdown significantly inhibited cell proliferation and anchorage independent growth, suppressed S-phase entry, and inhibited cell migration and invasion in multiple in vitro EAC models (p<0.05). A gene ontological analysis revealed that HNF1A-AS1 knockdown preferentially affected genes that are linked to assembly of chromatin and the nucleosome, a mechanism essential to cell cycle progression. The well-known cancer-related lncRNA, H19, was the gene most markedly inhibited by HNF1A-AS1 knockdown. Consistent to this finding, there was a significant positive correlation between HNF1A-AS1 and H19 expression in primary EACs (p<0.01). In order to identify novel oncogenic lncRNAs in esophageal adenocarcinogenesis, we carried out RNA-seq of a matched NE-BE-EAC tissue pair
Project description:Efforts to address the poor prognosis associated with esophageal adenocarcinoma (EAC) have been hampered by a lack of biomarkers to identify early disease and therapeutic targets. Despite extensive efforts to understand the somatic mutations associated with EAC over the past decade, a gap remains in understanding how the atlas of genomic aberrations in this cancer impacts the proteome and which somatic variants are of importance for the disease phenotype. We performed a quantitative proteomic analysis of 23 EACs and matched adjacent normal esophageal and gastric tissues. We explored the correlation of transcript and protein abundance using tissue-matched RNAseq and proteomic data from 7 patients and further integrated these data with a cohort of EAC RNA-seq data (n=264 patients), EAC whole-genome sequencing (n=454 patients) and external published datasets.
Project description:<p>The incidence of esophageal adenocarcinoma (EAC) has risen 600% over the last 30 years. When coupled to the five-year survival rate of only 15% for this disease, identification of new therapeutic targets for EAC is of great importance. Here, we analyze the mutational spectra identified from the whole genome sequencing of 16 EACs and complete exome sequencing of 149 EAC tumors and matched germline samples. We identify a novel mutation signature marked by high prevalence of A to C transversions at AA*(N) trinucleotides. Notably, the development of EAC is preceded by pathologic intestinal metaplasia of the lower esophagus, Barrett's esophagus, itself a response to injury from gastric-esophageal reflux disease (GERD). Thus, we hypothesize to represent these AA*(N) mutations to a novel signature of GERD-induced mutagenesis. Analysis of the exome data identified 26 genes subject to statistically significant recurrent mutation. Of these 26 genes, only TP53, CDKN2A, SMAD4, and PIK3CA had been previously implicated in EAC. Novel mutations include those targeting chromatin modifying factors and novel candidate contributors to EAC: SPG20, TLR4, ELMO1 and DOCK2. Of these, ELMO1 and DOCK2 are notably direct dimerization partners that act to activate Rac1 to enhance cellular invasiveness, thus generating new hypotheses about the potential for the Rac1 pathway to be a novel target for therapy of EAC.</p> <p>"Reprinted from 'Unraveling the mutational complexity of esophageal adenocarcinoma', with permission from Nature Genetics."</p>
Project description:Samples were obtained from 8 patients with Barrett's associated adenocarcinomas after transhiatal esophagectomy. Samples representative of the normal esophageal epithelium (N), Barrett’s esophagus (B) and esophageal adenocarcinomas (ADC) were obtained from every patient by experienced GI pathologists. RNA were extracted and samples were profiled for detection of genes differentially expressed in B and ADC relative to N and in ADC relative to B. Keywords: other
Project description:Epigenetic modifications in the form of altered DNA or histone methylation can influence gene expression patterns critical for neoplastic initiation and progression. The fact that abnormal gene expression can be driven by epigenetic alterations led us to examine the correlation between DNA methylation, trimethylation of histone 3 lysine 9 (H3K9me3) and lysine 27 (H3K27me3), and gene expression in esophageal adenocarcinoma (EAC). Using genome-wide approaches (chromatin immunoprecipitation/sequencing (ChIP-Seq) and methylation arrays), we identified gene targets that were enriched with the chromatin-repressive marks H3K9me3, H3K27me3, and/or DNA hypermethylation across patients with EAC. Using RNA-Seq, we found genes involved in cellular morphology and movement, epithelial cell differentiation, epithelial junction signaling, as well as genes involved in epithelial-mesenchymal transition (EMT) were down-regulated in patients with poorly differentiated EAC. Additionally, comparative analyses of ChIP-Seq, DNA methylation, and RNA-Seq data allowed us to identify a group of genes downregulated in EAC is associated with aberrant H3K27me3 enrichment or a combination of H3K27me3 and DNA hypermethylation in the poorly differentiated EAC cases. Furthermore, by comparison to TCGA data sets, H3K27me3 enrichment is associated with aberrant DNA methylation across numerous EAC cases, suggesting that dysregulation of H3K27me3 and DNA methylation is crucial in the pathogenesis of EAC.
Project description:<p>The incidence of esophageal adenocarcinoma (EAC) has risen 600% over the last 30 years. When coupled to the five-year survival rate of only 15% for this disease, identification of new therapeutic targets for EAC is of great importance. Here, we analyze the mutational spectra identified from the whole genome sequencing of 16 EACs and complete exome sequencing of 149 EAC tumors and matched germline samples. We identify a novel mutation signature marked by high prevalence of A to C transversions at AA*(N) trinucleotides. Notably, the development of EAC is preceded by pathologic intestinal metaplasia of the lower esophagus, Barrett's esophagus, itself a response to injury from gastric-esophageal reflux disease (GERD). Thus, we hypothesize to represent these AA*(N) mutations to a novel signature of GERD-induced mutagenesis. Analysis of the exome data identified 26 genes subject to statistically significant recurrent mutation. Of these 26 genes, only TP53, CDKN2A, SMAD4, and PIK3CA had been previously implicated in EAC. Novel mutations include those targeting chromatin modifying factors and novel candidate contributors to EAC: SPG20, TLR4, ELMO1 and DOCK2. Of these, ELMO1 and DOCK2 are notably direct dimerization partners that act to activate Rac1 to enhance cellular invasiveness, thus generating new hypotheses about the potential for the Rac1 pathway to be a novel target for therapy of EAC.</p> <p>"Reprinted from 'Unraveling the mutational complexity of esophageal adenocarcinoma', with permission from Nature Genetics."</p>