9296 results for "cancer rna-seq"

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• Accurate mapping of mitochondrial DNA deletions and duplications using deep sequencing

  Deletions and duplications in mitochondrial DNA (mtDNA) cause mitochondrial disease and accumulate in conditions such as cancer and age-related disorders, but validated high-throughput methodology that can readily detect and discriminate between these two types of events is lacking. Here we present MitoSAlt, a computational method for accurate identification, quantification and visualization of mtDNA deletions and duplications from whole genome, whole exome or transcriptome sequencing data. MitoSAlt was tested on simulated sequencing reads and human patient samples with single deletions and duplications to verify its accuracy. Application to mouse models of mtDNA maintenance disease further demonstrated the ability to detect deletions and duplications even at low levels of heteroplasmy. MitoSAlt paves the way for simple and reliable determination of mtDNA deletions and duplications across a wide range of relevant conditions and available sequencing datasets.  

  Study EGAS00001004380

• Oncogenic chimeric transcription factors drive tumor-specific transcription, processing, and translation of silent genomic regions

  Many cancers are characterized by gene fusions encoding oncogenic chimeric transcription factors (TFs) such as EWS::FLI1 in Ewing sarcoma (EwS). Here, we find that EWS::FLI1 induces the robust expression of a specific set of novel spliced and polyadenylated transcripts within otherwise transcriptionally silent regions of the genome. These neogenes (NGs) are virtually undetectable in large collections of normal tissues or non-EwS tumors and can be silenced by CRISPR interference at regulatory EWS::FLI1-bound microsatellites. Ribosome profiling and proteomics further show that some NGs are translated into highly EwS-specific peptides. More generally, we show that hundreds of NGs can be detected in diverse cancers characterized by chimeric TFs. Altogether, this study identifies the transcription, processing, and translation of novel, specific, highly expressed multi-exonic transcripts from otherwise silent regions of the genome as a new activity of aberrant TFs in cancer.

  Study EGAS00001006293

• RNAseq_of_healthy_mesothelial_cells_and_primary_mesothelioma_cell_lines

  Mesothelioma is a rare and aggressive cancer associated with previous exposure to asbestos. Currently there are no effective treatments for mesothelioma and majority of patients will die within a year after diagnosis. Although a large number of preclinical and clinical trials assessed the efficacy of various therapuetic modes, including anti-angiogenic therapies, immunotherapy, antibody-drug conjugates and oncolytic viruses, none of the tested molecules entered the clinic. Thus, to better understand what drives mesothelioma carcinogenesis and to identify novel targets for therapy, in this project we aim at performing a comprehensive transcriptomic analysis of heathy mesothelial cells and a panel of mesothelioma cells lines. Primary mesothelial cell lines were established in prof. Marciniak lab from human pleural specimens, while primary mesothelioma cell lines were obtained from MesobanK. Both models constitute low passage cell lines and therefore should closely represent genetics of the original tissue.

  Study EGAS00001005728

• How mitochondrial DNA research can benefit from data reuse through EGA?

  Mitochondria are the only cellular organelles harbouring their own DNA, which encodes for proteins essentials in its respiration process. Despite its discovery in 1960, Mitochondrial DNA is often overlooked compared to nuclear DNA. Indeed, not all sequencing technologies capture a good representation of mtDNA (mitochondrial DNA). Recently, Ed Reznik's team (The Ed Reznik Lab | Memorial Sloan Kettering Cancer Center) carried out a massive analysis and reanalysis of single cells WGS (whole genome sequencing) produced with an amplification-free protocol (Direct library prep, DLP). As they demonstrated in the paper Single-cell mtDNA dynamics in tumors is driven by coregulation of nuclear and mitochondrial genomes - PMC, DLP is more effective in catching mtDNA compared to classical single-cell sequencing. These data allowed the team to unravel mtDNA dynamics in tumoral and normal samples, highlighting how mtDNA and nuclear DNA are co-regulated and their ratio is critical for phenotype. Data reuse to achieve the greatest results For this project, Reznik's team re-used data from 3 studies stored at the European Genome-phenome Archive (EGAS00001006343, EGAS00001004448 and EGAS00001003190) that comprised a total of 602 datasets. All of them were initially produced by the teams of Sam Aparicio and Sohrab P. Shah at the Memorial Sloan Kettering Cancer Centre, where Ed Reznik is a promising group leader. This demonstrates, once again, that networking, collaboration and data sharing can achieve the greatest results when coupled with innovative and smart ideas. At the EGA we are proud to provide the scientific community with an infrastructure to enable all those very smart ideas out there to find the right data to be tested.

  Blog mitochondrial-dna-research

• Frequent mutations in chromatin-remodelling genes in pulmonary carcinoids

  Pulmonary carcinoids are rare neuroendocrine tumours of the lung. The molecular alterations underlying the pathogenesis of these tumours have not been systematically studied so far. Here we perform gene copy number analysis (n¼54), genome/exome (n¼44) and transcriptome (n¼69) sequencing of pulmonary carcinoids and observe frequent mutations in chromatin-remodelling genes. Covalent histone modifiers and subunits of the SWI/SNF complex are mutated in 40 and 22.2% of the cases, respectively, with MEN1, PSIP1 and ARID1A being recurrently affected. In contrast to small-cell lung cancer and large-cell neuroendocrine tumours, TP53 and RB1 mutations are rare events, suggesting that pulmonary carcinoids are not early progenitor lesions of the highly aggressive lung neuroendocrine tumors but arise through independent cellular mechanisms. These data also suggest that inactivation of chromatinremodelling genes is sufficient to drive transformation in pulmonary carcinoids.

  Study EGAS00001000650

• Therapeutic Targeting of Ependymoma as Informed by Oncogenic Enhancer Profiling

  Genomic sequencing has driven precision-based oncology therapy; however, genetic drivers remain unknown or non-targetable for many malignancies, demanding alternative approaches to identify therapeutic leads. Ependymomas are chemotherapy-resistant brain tumours, which, despite genomic sequencing, lack effective molecular targets. Here, we mapped active chromatin landscapes in 42 primary ependymomas in two non-overlapping primary ependymoma cohorts. Enhancer regions revealed novel oncogenes, molecular targets, and pathways, which when subjected to small molecule inhibitor or shRNA treatment, increased survival and slowed proliferation in mouse and neurosphere patient-derived models of ependymomas. This study represents one of the largest enhancer mapping study of any cancer type to date, and provides a framework for target and drug discovery for other cancers recalcitrant to therapeutic development because of their lack of known genetic drivers.

  Study EGAS00001002696

• Melanoma Genome Sequencing Project

  Melanoma is the most prevalent cause of skin cancer morbidity and mortality. In order to characterize the full range of somatic mutations that may drive the growth of melanoma, we are sequencing tumor and normal DNA from a set of roughly 150 melanomas. For the majority of samples (approximately 90% of the cases) mutations in protein coding genes will be assessed in the exonic DNA of tumor-normal pairs using hybrid capture and paired-end DNA sequencing. Additionally, in a few DNA samples (approximately 10% of the cases) the entire genomes will be analyzed to assess the possible contribution of complex structural rearrangements contributing to oncogenesis. The sequencing data are supplemented by copy number profiling on the same tumors using high-density SNP arrays. Integration of these approaches will enable the unbiased and comprehensive characterization of both known and novel recurrent DNA alterations that arise in melanoma.

  Study phs000452

• Genomic Sequencing of Ewing Sarcoma

  Pediatric Ewing sarcoma is a pediatric cancer that primarily arises from the bone. It is characterized by chimeric fusions of the EWS gene and an ETS family transcription factor. In this study, we performed massively parallel sequencing of a larger collection of Ewing sarcoma tumors to define the genomic landscape of this disease. We found that these tumors are among of the most genetically normal cancers currently characterized. There was also a marked absence of recurrent mutations in immediately targetable signaling transduction pathway genes. In this study we answer outstanding questions about ETS transcription factor expression, effects of treatment on mutational burden in Ewing sarcoma tumors, and describe patterns of tumor evolution. We also found that loss-of-function mutations in STAG2 were present in approximately 15% of Ewing sarcoma tumors and loss of STAG2 expression was associated with disease metastasis in this patient cohort.

  Study phs000804

• Xeroderma Pigmentosum, Complementation Group C, (XPC) and Non-XPC Cutaneous Squamous Cell Carcinoma (cSCC) Mutation Rate Study

  Base mutations occur at higher frequencies within heterochromatin and late-replicating DNA. In this study, we show that regional differences in mutation frequency are absent in portions of the genome that are not transcribed within cutaneous squamous cell carcinomas (cSCCs) with an XPC-\- genetic background. The XPC-\- genetic background predicates a loss of global genome nucleotide excision repair (GG-NER), thus our data shows that regional differences in mutation frequency are a result of differential access of DNA repair protein. Unexpectedly, we also note that greater transcription reduces mutations on both strands of genes in heterochromatin, and only to those levels observed in euchromatin, in a XPC-dependent fashion. Therefore, transcription likely reduces mutation prevalence by increasing access to DNA repair proteins. This tripartite relationship between DNA repair, transcription, and chromatin state shows a new cancer risk factor in human populations.

  Study phs000830

• Functionally-defined Therapeutic Targets in Diffuse Intrinsic Pontine Glioma (DIPG)

  Diffuse Intrinsic Pontine Glioma (DIPG) is a universally fatal childhood cancer. Here, we performed a chemical screen in patient-derived DIPG cell cultures along with RNAseq expression analysis and integrated computational modeling to identify potentially effective therapeutic strategies. Panobinostat, among the more promising agents identified, demonstrated efficacy in pontine orthotopic xenograft models of both H3K27M and histone WT DIPG. These data suggest the potential utility of specific drug combinations and provides evidence of in vivo treatment efficacy of the multi-histone deacetylase inhibitor panobinostat. We are depositing to dbGaP deep sequencing whole exome data for 22 patient tumor samples and 13 matched normals, along with RNAseq data for 12 patient tumor samples and 6 normal pediatric brain tissue samples. In addition, we are depositing 22 RNAseq samples from DIPG cell lines before and after panobinostat treatment.

  Study phs000900