Publications by authors named "Aurelie Ernst"

Single-cell DNA sequencing (scDNA-seq) enables decoding somatic cancer variation. Existing methods are hampered by low throughput or cannot be combined with transcriptome sequencing in the same cell. We propose HIPSD&R-seq (HIgh-throughPut Single-cell Dna and Rna-seq), a scalable yet simple and accessible assay to profile low-coverage DNA and RNA in thousands of cells in parallel.

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Paediatric medulloblastomas with chromothripsis are characterised by high genomic instability and are among the tumours with the worst prognosis. However, the molecular makeup and the determinants of the aggressiveness of chromothriptic medulloblastoma are not well understood. Here, we apply spatial transcriptomics to profile a cohort of 13 chromothriptic and non-chromothriptic medulloblastomas from the same molecular subgroup.

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Article Synopsis
  • - Chromothripsis is a process where a single catastrophic event causes significant genomic rearrangements, but its variability across different tumor clones and response to treatments is not well understood.
  • - This study investigates chromothripsis in p53-deficient medulloblastoma and neural stem cells, focusing on the genomic and transcriptomic changes involved.
  • - The researchers analyze the order of genetic events, explore subclonal variation, and identify how chromothripsis influences cancer development, targeted therapies, and the fitness of neural progenitor cells.
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Chromothripsis is a mutational phenomenon in which a single catastrophic event generates extensive rearrangements of one or a few chromosomes. This extreme form of genome instability has been detected in 30-50% of cancers. Studies conducted in the past few years have uncovered insights into how chromothripsis arises and deciphered some of the cellular and molecular consequences of chromosome shattering.

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Cancer genomes harbor a broad spectrum of structural variants (SVs) driving tumorigenesis, a relevant subset of which escape discovery using short-read sequencing. We employed Oxford Nanopore Technologies (ONT) long-read sequencing in a paired diagnostic and post-therapy medulloblastoma to unravel the haplotype-resolved somatic genetic and epigenetic landscape. We assembled complex rearrangements, including a 1.

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Following fertilization, it is only at the 32-64-cell stage when a clear segregation between cells of the inner cell mass and trophectoderm is observed, suggesting a 'T'-shaped model of specification. Here, we examine whether the acquisition of these two states in vitro, by nuclear reprogramming, share similar dynamics/trajectories. Using a comparative parallel multi-omics analysis (i.

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Chromothripsis is a form of genomic instability characterized by the occurrence of tens to hundreds of clustered DNA double-strand breaks in a one-off catastrophic event. Rearrangements associated with chromothripsis are detectable in numerous tumor entities and linked with poor prognosis in some of these, such as Sonic Hedgehog medulloblastoma, neuroblastoma and osteosarcoma. Hence, there is a need for therapeutic strategies eliminating tumor cells with chromothripsis.

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Fibrotic scar tissue limits central nervous system regeneration in adult mammals. The extent of fibrotic tissue generation and distribution of stromal cells across different lesions in the brain and spinal cord has not been systematically investigated in mice and humans. Furthermore, it is unknown whether scar-forming stromal cells have the same origin throughout the central nervous system and in different types of lesions.

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Background: Medulloblastomas with chromothripsis developing in children with Li-Fraumeni Syndrome (germline TP53 mutations) are highly aggressive brain tumors with dismal prognosis. Conventional photon radiotherapy and DNA-damaging chemotherapy are not successful for these patients and raise the risk of secondary malignancies. We hypothesized that the pronounced homologous recombination deficiency in these tumors might offer vulnerabilities that can be therapeutically utilized in combination with high linear energy transfer carbon ion radiotherapy.

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Chromothripsis is a form of genomic instability that was shown to play a major role in cancer. Beyond cancer, this type of catastrophic event is also involved in germline structural variation, genome mosaicism in somatic tissues, infertility, mental retardation, congenital malformations and reproductive development in plants. Several assays have been developed to model chromothripsis in vitro and to dissect the mechanistic basis of this phenomenon.

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Adult pilocytic astrocytomas (PAs) have been regarded as indistinguishable from pediatric PAs in terms of genome-wide expression and methylation patterns. It has been unclear whether adult PAs arise early in life and remain asymptomatic until adulthood, or whether they develop during adulthood. We sought to determine the age and origin of adult human PAs using two types of "marks" in the genomic DNA.

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Chromothripsis is a unique form of genome instability characterized by tens to hundreds of DNA double-strand breaks on one or very few chromosomes, followed by error-prone repair. The derivative chromosome(s) display massive rearrangements, which lead to the loss of tumor suppressor function and to the activation of oncogenes. Chromothripsis plays a major role in cancer as well as in other conditions, such as congenital diseases.

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Chromothripsis is a form of genome instability by which a presumably single catastrophic event generates extensive genomic rearrangements of one or a few chromosomes. Widely assumed to be an early event in tumor development, this phenomenon plays a prominent role in tumor onset. In this study, an analysis of chromothripsis in 252 human breast cancers from two patient cohorts (149 metastatic breast cancers, 63 untreated primary tumors, 29 local relapses, and 11 longitudinal pairs) using whole-genome and whole-exome sequencing reveals that chromothripsis affects a substantial proportion of human breast cancers, with a prevalence over 60% in a cohort of metastatic cases and 25% in a cohort comprising predominantly luminal breast cancers.

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In vitro assays for clustered DNA lesions will facilitate the analysis of the mechanisms underlying complex genome rearrangements such as chromothripsis, including the recruitment of repair factors to sites of DNA double-strand breaks (DSBs). We present a novel method generating localized DNA DSBs using UV irradiation with photomasks. The size of the damage foci and the spacing between lesions are fully adjustable, making the assay suitable for different cell types and targeted areas.

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Chromothripsis is a recently identified mutational phenomenon, by which a presumably single catastrophic event generates extensive genomic rearrangements of one or a few chromosome(s). Considered as an early event in tumour development, this form of genome instability plays a prominent role in tumour onset. Chromothripsis prevalence might have been underestimated when using low-resolution methods, and pan-cancer studies based on sequencing are rare.

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Background: Pilocytic astrocytoma (PA) is the most common pediatric brain tumor. While genome and transcriptome landscapes are well studied, data of the complete methylome, tumor cell composition, and immune infiltration are scarce.

Methods: We generated whole genome bisulfite sequence (WGBS) data of 9 PAs and 16 control samples and integrated available 154 PA and 57 control methylation array data.

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Chromothripsis and chromoanasynthesis are catastrophic events leading to clustered genomic rearrangements. Whole-genome sequencing revealed frequent complex genomic rearrangements (n = 16/26) in brain tumors developing in mice deficient for factors involved in homologous-recombination-repair or non-homologous-end-joining. Catastrophic events were tightly linked to Myc/Mycn amplification, with increased DNA damage and inefficient apoptotic response already observable at early postnatal stages.

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Micronuclei are extra-nuclear bodies containing whole chromosomes that were not incorporated into the nucleus after cell division or damaged chromosome fragments. Even though the link between micronuclei and DNA damage is described for a long time, little is known about the functional organization of micronuclei and their contribution to tumorigenesis. We showed fusions between micronuclear membranes and lysosomes by electron microscopy and linked lysosome function to DNA damage levels in micronuclei.

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Background: Medulloblastoma is associated with rare hereditary cancer predisposition syndromes; however, consensus medulloblastoma predisposition genes have not been defined and screening guidelines for genetic counselling and testing for paediatric patients are not available. We aimed to assess and define these genes to provide evidence for future screening guidelines.

Methods: In this international, multicentre study, we analysed patients with medulloblastoma from retrospective cohorts (International Cancer Genome Consortium [ICGC] PedBrain, Medulloblastoma Advanced Genomics International Consortium [MAGIC], and the CEFALO series) and from prospective cohorts from four clinical studies (SJMB03, SJMB12, SJYC07, and I-HIT-MED).

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Background: Nijmegen breakage syndrome is an autosomal recessive disorder characterized by microcephaly, immunodeficiency, hypersensitivity to X-irradiation, and a high predisposition to cancer. Nibrin, the product of the gene, is part of the MRE11/RAD50 (MRN) complex that is involved in the repair of DNA double strand breaks (DSBs), and plays a critical role in the processing of DSBs in immune gene rearrangements, telomere maintenance, and meiotic recombination. NBS skin fibroblasts grow slowly in culture and enter early into senescence.

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Leiomyosarcoma (LMS) is an aggressive mesenchymal malignancy with few therapeutic options. The mechanisms underlying LMS development, including clinically actionable genetic vulnerabilities, are largely unknown. Here we show, using whole-exome and transcriptome sequencing, that LMS tumors are characterized by substantial mutational heterogeneity, near-universal inactivation of TP53 and RB1, widespread DNA copy number alterations including chromothripsis, and frequent whole-genome duplication.

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Chromothripsis is a recently discovered form of genomic instability, characterized by tens to hundreds of clustered DNA rearrangements resulting from a single dramatic event. Telomere dysfunction has been suggested to play a role in the initiation of this phenomenon, which occurs in a large number of tumor entities. Here, we show that telomere attrition can indeed lead to catastrophic genomic events, and that telomere patterns differ between cells analyzed before and after such genomic catastrophes.

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In 2011, a novel form of genome instability was reported by Stephens et al., characterized by tens to hundreds of locally clustered rearrangements affecting one or a few chromosome(s) in cancer cells. This phenomenon, termed chromothripsis, is likely due to a single catastrophic event leading to the simultaneous formation of multiple double-strand breaks, which are repaired by error-prone mechanisms.

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