AVATAR_TS - samples
Ontology highlight
ABSTRACT:
PROVIDER: EGAD00001009695 | EGA |
REPOSITORIES: EGA
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Project description:We previously identified somatic activating KRAS mutations in a majority of human arteriovenous malformations (AVMs), using whole exome sequencing. We have now performed targeted sequencing on AVMS, investigating genes in the RAS-MAPK pathway, angiogenesis and brain vascular disorders among others.
| EGAS00001006729 | EGA
Project description:<p>Although multi-agent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die due to chemo-refractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape and pattern of clonal evolution at relapse in pediatric ALL cases. These analyses showed that ALL relapses originate from a common ancestral precursor clone of the diagnosis and relapsed populations and frequently harbor mutations implicated in chemotherapy resistance. RAS-MAPK pathway activating mutations in NRAS, KRAS and PTPN11 were present in 24/55 (44%) cases in our series. Notably, while some cases showed emergence of RAS mutant clones at relapse, in others, RAS mutant clones present at diagnosis were replaced by RAS wild type populations. Mechanistically, functional dissection of mouse and human wild type Kras and mutant Kras (Kras G12D) isogenic leukemia cells demonstrated induction of methotrexate resistance, but also improved response to vincristine, in mutant Kras- expressing lymphoblasts. These results identify chemotherapy driven selection as a central mechanism of leukemia clonal evolution and pave the road for the development of tailored personalized therapies for the treatment of relapsed ALL. </p>
| phs001072 | dbGaP
Project description:Mutations affecting the RAS-MAPK pathway frequently occur in relapse neuroblastoma tumors, which suggests that activation of this pathway is associated with a more aggressive phenotype. To explore this hypothesis we generated several model systems to define a neuroblastoma RAS-MAPK pathway signature. We could show that activation of this pathway in primary tumors indeed correlates with poor survival and is associated with known activating mutations in ALK and other RAS-MAPK pathway genes. From integrative analysis we could show that mutations in PHOX2B, CIC and DMD are also associated with an activated RAS-MAPK pathway. Mutation of PHOX2B and deletion of CIC in neuroblastoma cell lines induces activation of the RAS-MAPK pathway. This activation was independent of phosphorylated ERK in the CIC knock out systems. Furthermore, deletion of CIC causes a significant increase in tumor growth in vivo. These results show that the RAS-MAPK pathway is involved in tumor progression, and establish CIC as a powerful tumor suppressor that functions downstream of this pathway in neuroblastoma.
2018-08-22 | GSE115406 | GEO
Project description:Basal cell carcinomas (BCCs) rely on Hedgehog (HH) pathway growth signal amplification by the microtubule-based organelle, the primary cilium. Despite naïve tumors responsiveness to Smoothened inhibitors (Smoi), resistance in advanced tumors remains frequent. While the resistant BCCs usually maintain HH pathway activation, squamous cell carcinomas with Ras/MAPK pathway activation also arise, with the molecular basis of tumor type and pathway selection still obscure. Here we identify the primary cilium as a critical determinant controlling tumor pathway switching. Strikingly, Smoi-resistant BCCs possess an increased mutational load in ciliome genes, resulting in reduced primary cilia and HH pathway activation compared to naive or Gorlin patient BCCs. Gene set enrichment analysis of resistant BCCs with a low HH pathway signature reveals increased Ras/MAPK pathway activation. Tissue analysis confirms an inverse relationship between primary cilia presence and Ras/MAPK activation, and primary cilia removal in BCCs potentiates Ras/MAPK pathway activation. Moreover, activating Ras in HH-responsive cell lines confers resistance to both canonical (vismodegib) and non-canonical (aPKC and MRTF inhibitors) HH pathway inhibitors, while conferring sensitivity to MAPK inhibitors. Our results provide new insights into BCC treatment and identify the primary cilium as an important lineage gatekeeper, preventing HH to Ras/MAPK pathway switching.
2018-10-10 | GSE120954 | GEO
Project description:This is a Phase 1b/2, multi-center, open label umbrella study of patients ≥12 years of age with recurrent, progressive, or refractory melanoma or other solid tumors with alterations in the key proteins of the RAS/RAF/MEK/ERK pathway, referred to as the MAPK pathway.
| 2385126 | ecrin-mdr-crc
Project description:The majority of neuroblastoma patients have tumors that initially respond to chemotherapy, but a large proportion of patients will experience therapy-resistant relapses. The molecular basis of this aggressive phenotype is unknown. Whole genome sequencing of 23 paired diagnostic and relapsed neuroblastomas showed clonal evolution from the diagnostic tumor with a median of 29 somatic mutations unique to the relapse sample. Eighteen of the 23 relapse tumors (78%) showed RAS-MAPK pathway mutations. Seven events were detected only in the relapse tumor while the others showed clonal enrichment. In neuroblastoma cell lines we also detected a high frequency of activating mutations in the RAS-MAPK pathway (11/18, 61%) and these lesions predicted for sensitivity to MEK inhibition in vitro and in vivo. Our findings provide a rationale for genetic characterization of relapse neuroblastoma and show that RAS-MAPK pathway mutations may function as a biomarker for new therapeutic approaches to refractory disease.
| EGAS00001001183 | EGA
Project description:The majority of neuroblastoma patients have tumors that initially respond to chemotherapy, but a large proportion of patients will experience therapy-resistant relapses. The molecular basis of this aggressive phenotype is unknown. Whole genome sequencing of 23 paired diagnostic and relapsed neuroblastomas showed clonal evolution from the diagnostic tumor with a median of 29 somatic mutations unique to the relapse sample. Eighteen of the 23 relapse tumors (78%) showed RAS-MAPK pathway mutations. Seven events were detected only in the relapse tumor while the others showed clonal enrichment. In neuroblastoma cell lines we also detected a high frequency of activating mutations in the RAS-MAPK pathway (11/18, 61%) and these lesions predicted for sensitivity to MEK inhibition in vitro and in vivo. Our findings provide a rationale for genetic characterization of relapse neuroblastoma and show that RAS-MAPK pathway mutations may function as a biomarker for new therapeutic approaches to refractory disease.
| EGAD00001001360 | EGA
Project description:Mitochondrial dysfunction causes biophysical, metabolic and signalling changes that alter homeostasis and reprogram cells. We used a Drosophila model in which TFAM is overexpressed in the nervous system with or without Ras/MAPK pathway inhibition, by knock-down of the ETS transcription factor pointed, to investigate the how mitochondrial dysfunction and Ras/MAPK signalling affect the transcriptome. We used microarray analysis to investigate gene expression in cases of mitochondrial dysfunction in the CNS with or without Ras/MAPK pathway inhibition by knock-down of pointed (Pnt) and anterior open (Aop).
2018-05-05 | GSE114054 | GEO
Project description:Craniosynostosis (CS) is the premature fusion of the cranial sutures,occurring either in isolated or syndromic form. CS was described in over 180 genetic syndromes that comprise 15-30% of all CS cases. Syndromic CS usually has a monogenic inheritance and originates in most of the patients from mutations within the FGFR1, FGFR2, FGFR3, and TWIST1 genes. Causative alterations in other genes, or rarely copy number variations (CNVs) were also reported. In this paper, we describe a patient with Noonan-like facial dysmorphism accompanied by intellectual disability, and compound CS, involving coronal, sagittal, and squamous sutures. We have shown that the index carried a large and rare heterozygous deletion, which encompassed 12.782 Mb and mapped to a chromosomal region of 7q32.3-q35 (HG38 – chr7:131837067-144607071). The aberration comprised 109 protein-coding genes, including BRAF, that encodes serine/threonine-protein kinase B-Raf, being a part of the RAS/MAPK signaling pathway. The RAS/MAPK pathway plays an essential role in human development, hence its dysregulation not surprisingly results in severe congenital anomalies, such as phenotypically overlapping syndromes termed RASopathies. To our best knowledge, we report here the first CNV causing haploinsufficiency of BRAF, resulting in dysregulation of the RAS/MAPK cascade, and consequently, in the phenotype observed in our patient. To conclude, with this report, we have pointed to the involvement of the RAS/MAPK signaling pathway in CS development. Moreover, we have shown that the molecular analysis based on both DNA and RNA profiling, undoubtedly constitutes a comprehensive diagnostic and research strategy for elucidating a cause of genetic diseases.
2020-06-01 | GSE150754 | GEO
Project description:sychological stress and affective disorders are clinically associated with hypertension and vascular disease, but the biological links between the conditions have not been fully explored. To examine this relationship, we used chronic social defeat (CSD) stress, which produces anxiety-like and depressive-like behavioral declines in susceptible mice. In such mice, CSD also produces cerebrovascular microbleeds in scattered locations. Here, we showed further evidence of vascular pathology and blood–brain barrier breakdown by visualizing plasma immunoglobulins and erythrocytes within the parenchyma and perivascular spaces of CSD brains. To further characterize the impact of stress on the cerebrovasculature, brain endothelial cells (bECs) were isolated, and global gene expression profiles were generated. Bioinformatic analysis of CSD-induced transcriptional changes in bECs showed enrichment in pathways that delineate the vascular response to injury. These pathways followed a temporal sequence of inflammation, oxidative stress, growth factor signaling, and wound healing (i.e., platelet aggregation, hemostasis, fibrinogen deposition, and angiogenesis). Immunohistochemical staining for markers of fibrinogen deposition and angiogenesis confirmed the existence of the markers at the sites of vascular disruptions. Recovery after CSD cessation was marked by recruitment of leukocytes perhaps participating in vascular repair. The data suggest that co-morbidity of affective disorders and vascular diseases may be attributed in part to a common link in altered endothelial cell function
2020-08-13 | GSE156123 | GEO