Altered chromosomal topology drives oncogenic programs in SDH-deficient GISTs
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ABSTRACT:
PROVIDER: PRJNA420090 | ENA |
REPOSITORIES: ENA
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Project description:Epigenetic aberrations are widespread in cancer, yet the underlying mechanisms and causality remain poorly understood. A subset of gastrointestinal stromal tumors (GISTs) lack canonical kinase mutations but instead have succinate dehydrogenase (SDH)-deficiency and global DNA hyper-methylation. Here we associate this hyper-methylation with changes in genome topology that activate oncogenic programs. To investigate epigenetic alterations systematically, we mapped DNA methylation, CTCF insulators, enhancers, and chromosome topology in KIT-mutant, PDGFRA-mutant, and SDH-deficient GISTs. Although these respective subtypes shared similar enhancer landscapes, we identified hundreds of putative insulators where DNA methylation replaced CTCF binding in SDH-deficient GISTs. We focused on a disrupted insulator that normally partitions a core GIST super-enhancer from the FGF4 oncogene. Recurrent loss of this insulator alters locus topology in SDH-deficient GISTs, allowing aberrant physical interaction between enhancer and oncogene. CRISPR-mediated excision of the corresponding CTCF motifs in an SDH-intact GIST model disrupted the boundary and strongly up-regulated FGF4 expression. We also identified a second recurrent insulator loss event near the KIT oncogene, which is also highly expressed across SDH-deficient GISTs. Finally, we established a patient-derived xenograft (PDX) from an SDH-deficient GIST that faithfully maintains the epigenetic state of the parental tumor, including hyper-methylation and insulator defects. This PDX model is highly sensitive to FGF receptor (FGFR) inhibitor, and more so to combined FGFR and KIT inhibition, validating the functional significance of the underlying epigenetic lesions. Our study reveals how epigenetic alterations can drive oncogenic programs in the absence of canonical kinase mutations, with implications for mechanistic targeting of aberrant pathways in cancers.
2019-10-16 | GSE107447 | GEO
Project description:<p>Metabolic lesions with pleiotropic effects on epigenetic regulation and other cellular processes are widely implicated in cancer, yet their oncogenic mechanisms remain poorly understood. Succinate dehydrogenase (SDH) deficiency causes a subset of gastrointestinal stromal tumors (GISTs) with DNA hyper-methylation. Here we associate this hyper-methylation with changes in chromosome topology that activate oncogenic programs. To investigate epigenetic alterations in this disease, we systematically mapped DNA methylation, CTCF insulators, enhancers and chromosome topology in KIT-mutant, PDGFRA-mutant and SDH-deficient GISTs. Although these respective subtypes share similar enhancer landscapes, we identified hundreds of putative insulators where DNA methylation replaced CTCF binding in SDH-deficient GISTs. We focused on disrupted insulators that partitions super-enhancers from FGF3, FGF4 and the KIT oncogene. Recurrent loss of this insulator alters locus topology in SDH-deficient GISTs, allowing aberrant physical interaction between enhancers and oncogenes. CRISPR-mediated excision of the corresponding CTCF motif in an SDH-intact model disrupted the boundary and up-regulated FGFs and KIT expression. Our findings reveal how a metabolic lesion destabilizes chromatin structure to facilitate the initiation and selection of epigenetic alterations that drive oncogenic programs in the absence of canonical mutations.</p>
| phs001906 | dbGaP
Project description:Epigenetic aberrations are widespread in cancer, yet the underlying mechanisms and causality remain poorly understood1-3. A subset of gastrointestinal stromal tumours (GISTs) lack canonical kinase mutations but instead have succinate dehydrogenase (SDH) deficiency and global DNA hyper-methylation4,5. Here, we associate this hyper-methylation with changes in genome topology that activate oncogenic programs. To investigate epigenetic alterations systematically, we mapped DNA methylation, CTCF insulators, enhancers, and chromosome topology in KIT-mutant, PDGFRA-mutant and SDH-deficient GISTs. Although these respective subtypes shared similar enhancer landscapes, we identified hundreds of putative insulators where DNA methylation replaced CTCF binding in SDH-deficient GISTs. We focused on a disrupted insulator that normally partitions a core GIST super-enhancer from the FGF4 oncogene. Recurrent loss of this insulator alters locus topology in SDH-deficient GISTs, allowing aberrant physical interaction between enhancer and oncogene. CRISPR-mediated excision of the corresponding CTCF motifs in an SDH-intact GIST model disrupted the boundary between enhancer and oncogene, and strongly upregulated FGF4 expression. We also identified a second recurrent insulator loss event near the KIT oncogene, which is also highly expressed across SDH-deficient GISTs. Finally, we established a patient-derived xenograft (PDX) from an SDH-deficient GIST that faithfully maintains the epigenetics of the parental tumour, including hypermethylation and insulator defects. This PDX model is highly sensitive to FGF receptor (FGFR) inhibition, and more so to combined FGFR and KIT inhibition, validating the functional significance of the underlying epigenetic lesions. Our study reveals how epigenetic alterations can drive oncogenic programs in the absence of canonical kinase mutations, with implications for mechanistic targeting of aberrant pathways in cancers.
| S-EPMC6913936 | biostudies-literature
Project description:Inter-chromosomal contacts demarcate genome topology along a spatial gradient
| PRJNA1013014 | ENA
Project description:Pediatric GIST commonly harbors a disabled succinate dehydrogenase complex (SDH), which yields tumors with highly conserved genomes but characteristic epigenomic signatures. Mysteriously, nearly half of such SDH-deficient GIST, including tumors from Carney Triad patients, lack identifiable mutations in SDH component genes and genes required for complex assembly (SDHA, SDHB, SDHC, SDHD, SDHAF, termed SDHx). Genomic sequencing coupled with DNA methylation and transcriptional profiling have exposed SDHC promoter-specific CpG island epimutation and concomitant gene silencing in the majority of SDHx-WT GIST.
2015-01-02 | GSE56670 | GEO
Project description:We have discovered a striking connection between mitochondrial dysfunction and epigenomic instability, manifested by global biallelic DNA cytosine 5-methylation and loss of 5-hydroxymethycytosine within succinate dehydrogenase (SDH)-null gastrointestinal stromal tumors (GIST) relative to those bearing KIT or PDGFRA tyrosine kinase driver mutations. The duality of Krebs versus kinase molecular and epigenomic profiles in GIST provides compelling evidence linking mitochondrial process to nuclear structure and function and underscores an essential role for succinate metabolism in the maintenance of epigenomic programming and tumor suppression. Bisulfite-converted DNA from 144 samples were analyzed with the Illumina GoldenGate Methylation Cancer Panel I array.
2013-05-22 | E-GEOD-34387 | biostudies-arrayexpress
Project description:Pediatric GIST commonly harbors a disabled succinate dehydrogenase complex (SDH), which yields tumors with highly conserved genomes but characteristic epigenomic signatures. Mysteriously, nearly half of such SDH-deficient GIST, including tumors from Carney Triad patients, lack identifiable mutations in SDH component genes and genes required for complex assembly (SDHA, SDHB, SDHC, SDHD, SDHAF, termed SDHx). Genomic sequencing coupled with DNA methylation and transcriptional profiling have exposed SDHC promoter-specific CpG island epimutation and concomitant gene silencing in the majority of SDHx-WT GIST. We performed whole genome expression profiling on 20 FFPE dSDH GIST tumors using Affymetrix U133P2 arrays which contain >54K gene target probesets. Included here were data from 7 SDHx-w.t. and 13 SDHx mutants that passed array QC.
2015-01-02 | E-GEOD-56670 | biostudies-arrayexpress
Project description:We have discovered a striking connection between mitochondrial dysfunction and epigenomic instability, manifested by global biallelic DNA cytosine 5-methylation and loss of 5-hydroxymethycytosine within succinate dehydrogenase (SDH)-null gastrointestinal stromal tumors (GIST) relative to those bearing KIT or PDGFRA tyrosine kinase driver mutations. The duality of Krebs versus kinase molecular and epigenomic profiles in GIST provides compelling evidence linking mitochondrial process to nuclear structure and function and underscores an essential role for succinate metabolism in the maintenance of epigenomic programming and tumor suppression.
2013-05-22 | GSE34387 | GEO
Project description:Succinate dehydrogenase (SDH) is a mitochondrial protein complex responsible for the oxidation of succinate to fumarate in the tricarboxylic acid cycle. Loss-of-function mutations in any of the SDH genes are associated with susceptibility to develop neu-roendrocrine neoplasms and renal cell carcinoma. However, the impact of SDH loss on cell metabolism and the mechanisms enabling growth of SDH-defective cells are largely unexplored. To address this issue we generated Sdhb-ablated kidney mouse cells and compared their transcriptomic profile with that of Sdhb-proficient cells. Results of this gene analysis are provided in the here deposited gene array.
2016-01-22 | E-MTAB-4349 | biostudies-arrayexpress
Project description:Non-homologous chromosomal contacts (NHCCs) between different chromosomes participate considerably in gene and genome regulation. However, due to analytical challenges, NHCCs are currently considered as singular, stochastic events, and their extent and fundamental principles across cell types and sexes remain controversial. To determine the fundamental properties of NHCCs, we developed a supervised and unsupervised learning algorithm, termed Signature. Signature revealed 40,282 NHCCs and their properties across 62 Hi-C datasets of 53 diploid human cell types. Genomic regions of NHCCs are gene-dense, highly expressed, and harbor genes for cell-specific and sex-specific functions. Extensive inter-telomeric and inter-centromeric clustering occurs across cell types and 61 NHCCs are consistently found at the nuclear speckles. These constitutive ‘anchor loci’ facilitate an axis of genome activity whilst cell-type-specific NHCCs act in discrete hubs. Our results suggest that non-random chromosome positioning is supported by constitutive NHCCs that shape genome topology along an off-centered spatial gradient of genome activity.
2024-10-02 | GSE242273 | GEO