Ontology highlight
ABSTRACT:
REPOSITORIES: ENA
Similar Datasets
Project description:The aim of this study is to determine the clinical relevance of telomerase activation versus ALT as biomarkers in pre-treatment neuroblastoma, and to assess the potential value of telomerase as a therapeutic target. Therefore, the genomic status of TERT and MYCN was assessed in 457 pretreatment neuroblastomas by fluorescence-in-situ-hybridization. ALT was examined in 273/457 tumors by detection of ALT-associated promyelocytic leukemia nuclear bodies, and TERT expression was determined by 4x44k microarrays in 223 of these. The presence of activated telomerase, i.e., TERT rearrangements, MYCN amplification, or high TERT expression without these alterations, was associated with poorest overall survival, and was an independent prognostic marker in multivariable analyses.
2019-09-16 | E-MTAB-8248 | biostudies-arrayexpress
Project description:Telomere maintenance mechanisms (TMM) are a hallmark of high-risk neuroblastoma, and are conferred by activation of telomerase or alternative lengthening of telomeres (ALT). However, detection of TMM is not yet part of the clinical routine, and consensus on TMM detection, especially on ALT assessment, remains to be achieved. Based on our results we here propose a workflow to reliably detect TMM in neuroblastoma. We show that unambiguous classification is feasible following a stepwise approach that determines both, activation of telomerase and ALT. The workflow proposed in this study can be used in clinical routine and provides a framework to systematically evaluate telomere maintenance mechanisms in risk stratification and treatment allocation of neuroblastoma patients.
2022-09-19 | GSE211653 | GEO
Project description:Neuroblastoma is a malignant pediatric tumor of the sympathetic nervous system1. Roughly half of these tumors regress spontaneously or are cured by limited therapy. By contrast, high-risk neuroblastomas have an unfavorable clinical course despite intensive multimodal treatment, and their molecular basis has remained largely elusive2-4. We have performed whole-genome sequencing of 56 neuroblastomas (high-risk, n=39; low-risk, n=17) and discovered recurrent genomic rearrangements affecting a chromosomal region (5p15.22) proximal of the telomerase reverse transcriptase gene (TERT). These rearrangements occurred only in high-risk neuroblastomas (12/39, 31%) in mutually exclusive fashion with MYCN amplifications and ATRX mutations, which are known genetic events in this tumor type1,2,5. In an extended case series (n=217), TERT rearrangements defined a subgroup of high-risk tumors with particularly poor outcome. Despite the large diversity of these rearrangements, they all induced massive transcriptional upregulation of TERT. In the remaining high-risk tumors, TERT expression was also elevated in MYCN-amplified tumors, whereas alternative lengthening of telomeres was present in neuroblastomas without TERT or MYCN alterations, suggesting that telomere lengthening represents a central mechanism defining this subtype. The 5p15.22 rearrangements juxtapose the TERT coding sequence to strong enhancer elements, resulting in massive chromatin remodeling and DNA methylation of the affected region. Supporting a functional role of TERT, neuroblastoma cells bearing rearrangements or amplified MYCN exhibited both upregulated TERT expression and enzymatic telomerase activity. In summary, our findings show that remodeling of the genomic context abrogates transcriptional silencing of TERT in high-risk neuroblastoma and places telomerase activation in the center of transformation in a large fraction of these tumors.
| EGAS00001001308 | EGA
Project description:Telomere maintenance mechanisms (TMM) are a hallmark of high-risk neuroblastoma, and are conferred by activation of telomerase or alternative lengthening of telomeres (ALT). However, detection of TMM is not yet part of the clinical routine, and consensus on TMM detection, especially on ALT assessment, remains to be achieved.
We here propose a workflow to reliably detect TMM in neuroblastoma. We show that unambiguous classification is feasible following a stepwise approach that determines both, activation of telomerase and ALT. The workflow proposed in this study can be used in clinical routine and provides a framework to systematically and reliably determine telomere maintenance mechanisms for risk stratification and treatment allocation of neuroblastoma patients.
| EGAS00001006510 | EGA
Project description:The MYCN locus is amplified in about half of high-risk neuroblastoma tumors. To identify genomic loci occupied by MYCN protein in the MYCN-amplified neuroblastoma cell lines NGP, Kelly and NB-1643, we performed chromatin immunoprecipitation coupled with Next-Generation Sequencing (ChIP-seq) using an anti-MYCN antibody.
2017-08-02 | GSE94782 | GEO
Project description:Purpose: Neuroblastoma is characterized by substantial clinical heterogeneity. Despite intensive treatment, the survival rates of high-risk neuroblastoma patients are still disappointingly low. Somatic chromosomal copy number aberrations have been shown to be associated with patient outcome, particularly in low- and intermediate-risk neuroblastoma patients. To improve outcome prediction in high-risk neuroblastoma, we aimed to design a prognostic classification method based on copy number aberrations. Methods: In an international collaboration, normalized high-resolution DNA copy number data (arrayCGH and SNP arrays) from 556 high-risk neuroblastomas obtained at diagnosis were collected from nine collaborative groups and segmented using the same method. We applied logistic and Cox proportional hazard regression to identify genomic aberrations associated with poor outcome. Results: In this study, we identified two types of copy number aberrations that are associated with extremely poor outcome. (i) Distal 6q losses were detected in 5.9% of patients and were associated with a ten-year survival probability of only 3.4%. (ii) Amplifications of regions not encompassing the MYCN locus were detected in 18% of patients and were associated with a ten-year survival probability of only 5.8%. Conclusion: Using a unique large copy number dataset of high-risk neuroblastoma cases, we identified a small subset of high-risk neuroblastoma patients with extremely low survival probability that might be eligible for inclusion in clinical trials of new therapeutics. The amplicons may also nominate alternative treatments that target the amplified genes.
2018-03-13 | GSE103123 | GEO
Project description:Whole genome sequencing detected structural rearrangements of TERT in 17/75 high stage neuroblastoma with 5 cases resulting from chromothripsis. Rearrangements were associated with increased TERT expression and targeted immediate up- and down-stream regions of TERT, placing in 7 cases a super-enhancer close to the breakpoints. TERT rearrangements (23%), ATRX deletions (11%) and MYCN amplifications (37%) identify three almost non-overlapping groups of high stage neuroblastoma, each associated with very poor prognosis
2015-10-21 | GSE73537 | GEO
Project description:RNA-seq for four neuroblastoma samples (Paired-end protocol). Neuroblastoma is a pediatric cancer of the peripheral nervous system in which structural chromosome aberrations are emblematic of aggressive tumors. In this study, we investigated somatic rearrangements in two neuroblastoma cell lines and two primary tumors using paired-end sequencing of mate-pair libraries (SRA accession number ERP001414) and RNA-seq. In one cell line and in the two primary tumors, this approach confirmed the localization of the majority of rearrangements within one or two chromosomes, consistent with the phenomenon of chromothripsis. RNA-seq experiments confirmed expression of several predicted chimeric genes and genes with disrupted exon structure including ALK, NBAS, FHIT, PTPRD and ODZ4. RNA-seq analysis allowed the identification of abnormal transcripts expressed from genomic rearrangements that may be involved in neuroblastoma oncogenesis.
2013-03-03 | E-MTAB-1367 | biostudies-arrayexpress
Project description:High-risk neuroblastoma is a devastating malignancy with few therapeutic options. We identify withaferin A (WA) as a natural ferroptosis inducing agent in neuroblastoma, which acts through a novel double-edged mechanism. WA targets and inactivates glutathione peroxidase 4, as well as increases intracellular labile Fe(II) upon excessive activation of heme oxygenase-1, which both independently result in ferroptosis. This double-edged mechanism results in a high efficacy of WA compared to etoposide in killing a heterogeneous panel of high-risk neuroblastoma cells, and in suppressing neuroblastoma xenografts growth and relapse rate. Nano-targeting of WA allows systemic application and suppressed tumor growth due to an enhanced targeting to the tumor site. Collectively, our data propose a novel therapeutic strategy to kill cancer cells by ferroptosis. High-risk neuroblastoma is a devastating malignancy with few therapeutic options. We identify withaferin A (WA) as a natural ferroptosis inducing agent in neuroblastoma, which acts through a novel double-edged mechanism. WA targets and inactivates glutathione peroxidase 4, as well as increases intracellular labile Fe(II) upon excessive activation of heme oxygenase-1, which both independently result in ferroptosis. This double-edged mechanism results in a high efficacy of WA compared to etoposide in killing a heterogeneous panel of high-risk neuroblastoma cells, and in suppressing neuroblastoma xenografts growth and relapse rate. Nano-targeting of WA allows systemic application and suppressed tumor growth due to an enhanced targeting to the tumor site. Collectively, our data propose a novel therapeutic strategy to kill cancer cells by ferroptosis.
2018-05-01 | GSE112384 | GEO
Project description:Chromosome segregation errors have been linked to DNA damage and genomic rearrangements. Accumulating evidence has shown that catastrophic genomic rearrangements, like chromothripsis, can result from lagging chromosomes undergoing aberrant DNA replication and DNA damage in micronuclei. Detailed characterization of genomic rearrangements resulting from DNA damage in micronuclei has been hampered because of difficulties in culturing daughter cells with DNA damage. Here, we employ a method by which a specific single chromosome is trapped in a micronucleus, followed by transfer to an acceptor cell. Next, stably propagating clonal cell lines with an extra chromosome were established and analyzed by copy number profiling and whole genome sequencing. While non-transformed, p53 proficient and telomerase-immortalized RPE1 cells showed a stable genome following addition of the transferred chromosome, we observed frequent de novo genomic rearrangements in cells derived from the HCT116 colorectal cancer cell line after chromosome transfer. The de novo rearrangements varied from simple deletions and duplications to complex rearrangements. Phase-informative SNPs revealed that the rearrangements specifically occurred on the transferred chromosome. We found that the complex rearrangements recapitulated all features of chromothripsis, including massive oscillation between two copy number states, localization to a single chromosome, random joining of chromosome fragments and non-homologous or micro-homologous repair. We describe an approach that enables the isolation of clonal cell lines with genomic rearrangements and chromothripsis on a specific chromosome in p53 proficient cells. The procedure enables further investigation of the exact mechanism leading to chromothripsis and the analysis of its consequences for cell survival (viability) and cancer development.
2015-08-13 | GSE71978 | GEO