Dataset Information

Comprehensive analyses of partially methylated domains and differentially methylated regions in esophageal cancer reveal both cell-type- and cancer-specific epigenetic regulation [WGBS]

ABSTRACT: As one of the most common malignancies, esophageal cancer has two subtypes, squamous cell carcinoma (ESCC) and adenocarcinoma (EAC), arising from distinct cells-of-origin. However, distinguishing cell-type-specific molecular features from cancer-specific characteristics has been challenging. Here, we analyze whole-genome bisulfite sequencing (WGBS) data on 45 esophageal tumor and nonmalignant samples from both subtypes. We develop a novel sequence-aware method to identify large partially methylated domains (PMDs), revealing profound heterogeneity at both the methylation level (depth) and genomic distribution (breadth) of PMDs across tumor samples. We identify subtype-specific PMDs, which are associated with repressive transcription, chromatin B compartments and high somatic mutation rate. While the genomic locations of these PMDs are pre-established in normal cells, the degree of loss is significantly higher in tumors. We find that cell-type-specific deposition of H3K36me2 may underlie the genomic distribution PMDs. At a smaller genomic scale, both cell-type- and cancer-specific differentially methylated regions (DMRs) are identified for each subtype. Using binding motif analysis within these DMRs, we show that a cell-type-specific transcription factor such as HNF4A can maintain the binding sites that it establishes in normal cells, while being recruited to new binding sites with novel partners such as FOSL1 in cancer. Finally, leveraging pan-tissue single-cell and pan-cancer epigenomic datasets, we demonstrate that a substantial fraction of the cell-type-specific PMDs and DMRs identified here in esophageal cancer, are actually markers that co-occur in other cancers originating from related cell types. These findings advance our understanding of the DNA methylation dynamics at various genomic scales in normal and malignant states, providing novel mechanistic insights into cell-type- and cancer-specific epigenetic regulations. Whole-genome bisulfite sequencing (WGBS) for EAC ESO26 cell line and ESCC TE5 cell line.

ORGANISM(S): Homo sapiens

PROVIDER: GSE210218 | GEO | 2023/08/04

REPOSITORIES: GEO

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Project description:As one of the most common malignancies, esophageal cancer has two subtypes, squamous cell carcinoma (ESCC) and adenocarcinoma (EAC), arising from distinct cells-of-origin. However, distinguishing cell-type-specific molecular features from cancer-specific characteristics has been challenging. Here, we analyze whole-genome bisulfite sequencing (WGBS) data on 45 esophageal tumor and nonmalignant samples from both subtypes. We develop a novel sequence-aware method to identify large partially methylated domains (PMDs), revealing profound heterogeneity at both the methylation level (depth) and genomic distribution (breadth) of PMDs across tumor samples. We identify subtype-specific PMDs, which are associated with repressive transcription, chromatin B compartments and high somatic mutation rate. While the genomic locations of these PMDs are pre-established in normal cells, the degree of loss is significantly higher in tumors. We find that cell-type-specific deposition of H3K36me2 may underlie the genomic distribution PMDs. At a smaller genomic scale, both cell-type- and cancer-specific differentially methylated regions (DMRs) are identified for each subtype. Using binding motif analysis within these DMRs, we show that a cell-type-specific transcription factor such as HNF4A can maintain the binding sites that it establishes in normal cells, while being recruited to new binding sites with novel partners such as FOSL1 in cancer. Finally, leveraging pan-tissue single-cell and pan-cancer epigenomic datasets, we demonstrate that a substantial fraction of the cell-type-specific PMDs and DMRs identified here in esophageal cancer, are actually markers that co-occur in other cancers originating from related cell types. These findings advance our understanding of the DNA methylation dynamics at various genomic scales in normal and malignant states, providing novel mechanistic insights into cell-type- and cancer-specific epigenetic regulations. Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for histone H3K36me2 in EAC OE19 cell line, ESCC KYSE70 and TE5 cell lines.

Project description:Esophageal cancers (ECs) are highly aggressive tumors with poor prognosis and few treatment options. This study investigated the possibility of treating esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) cells by inhibitors of broad and specific histone deacetylases (HDACi; SAHA, MS-275, FK228) and/or of DNMT (Azacytidine, AZA). Drug targets (HDAC1,2,3 and DNMT1) were present in non-neoplastic (HET-1A), ESCC (OE21) and EAC (OE33) cell lines. All cell lines responded to HDACi by reduced HDAC activity and increased histone acetylation as well as to AZA by up-regulation of p21. Expression of drug targets remained largely unaffected by HDACi and AZA treatment. Importantly, cell viability, apoptosis, cell cycle dynamics and DNA damage were only affected by HDACi and/or AZA in ESCC and EAC, but not the non-neoplastic cells. This was specifically seen for the combination of MS-275 and AZA, leading to enhanced cancer cell selectivity and drug efficiency. By transcriptome analyses of MS-275, AZA and MS-275/AZA treated cells, known (e.g. p21) as well as novel regulated genes significantly associated with the cellular effects post HDACi and/or AZA treatment in ESCC and EAC cells were identified. Finally, human EC tissue specimens frequently expressed the actionable drug targets HDAC1/2/3 and DNMT1. In summary, a combined HDACi (MS-275)/AZA treatment is cancer cell selective and efficient in vitro. Since the majority of ECs express the drug targets in situ, this paves the way for further investigations of HDACi/AZA treatment in esophageal cancer cells and their translation into a clinico-pathological setting. To elucidate the transcriptome response to HDAC inhibitors of normal esophageal cells and esophageal tumor cells, total RNA was isolated from non-neoplastic esophageal epithelial cells (Het1A cells) a well as from two esophageal tumor cell lines (OE21 and OE33), respectively. Cells were treated with either MS-275, Azacytidine (AZA) or in combination of both. DMSO treatment was used as control in each case. Total RNA was isolated from cells 24 h after treatment and experiments were performed in biological triplicates.

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Comprehensive analyses of partially methylated domains and differentially methylated regions in esophageal cancer reveal both cell-type- and cancer-specific epigenetic regulation [WGBS]

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