3838 results for "*geneti*"

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• A system-wide approach to monitor responses to synergistic BRAF and EGFR inhibition in colorectal cancer cells

  Molecular heterogeneity of tumors, epigenetic changes and a diverse range of molecular mechanisms are main contributors to drug resistance, which represents one of the great challenges in cancer treatment. A deeper understanding of the molecular biology of cancer has resulted in better targeted therapies, where one or multiple drugs are adopted in novel therapies to tackle resistance. This beneficial effect of using combination treatments has to some extent also been observed in colorectal cancer (CRC) patients harboring the BRAF(V600E) mutation, whereby dual inhibition of BRAF(V600E) and EGFR increases antitumor activity. Notwithstanding this success, it is not clear whether this combination treatment is the only or most effective treatment to block resistance. Here, we investigate molecular responses upon single and multi-target treatments, over time, using BRAF(V600E) mutant CRC cells as a well-define model system. Through integration of transcriptomic, proteomic and phosphoproteomics data we obtain a comprehensive overview, revealing both well-known and novel responses. We primarily observe widespread upregulation of tyrosine kinases (RTKs) and and metabolic pathways. This points to by which the treated cells switch energy sources as a defensive response entering a quiescent like state, while activating signalling to re-activate the MAPK pathway.

  Study EGAS00001002654

• Liver biopsy derived induced pluripotent stem cells provide an unlimited supply for the generation of patient-specific hepatocyte-like cells

  Background: Hepatocyte-like cells (HLCs) differentiated from induced pluripotent stem cells (iPSCs) have emerged as a promising cell culture model to study metabolism, biotransformation, viral infections and genetic liver diseases. However the derivation of iPSCs is restricted by ethical and procedural constraints. Furthermore, incomplete HLC differentiation remains a major challenge. iPSC may carry-on a tissue of origin dependent expression memory influencing iPSC differentiation into different cell types. If liver derived iPSCs (Li-iPSCs) maintain a liver specific gene expression profile is not known. It is also not known, if Li-iPSCs would allow the generation of more fully differentiated HLCs.Methods: Primary liver cells (PLCs) were expanded from liver needle biopsies and reprogrammed into Li-iPSCs using a non-integrative Sendai virus-based system. Li-iPSCs were differentiated into HLCs using established differentiation protocols. The HLC phenotype was characterized at the protein, functional and transcriptional level. RNA sequencing data were generated from the originating liver biopsies, the Li-iPSCs, fibroblast derived iPSCs, and differentiated HLCs, and used to characterize and compare their transcriptome profiles.Results: PLCs were obtained from small pieces of liver biopsies and could be reprogrammed into Li-iPSCs. Li-iPSCs indeed retain a liver specific transcriptional footprint. Li-iPSCs can be propagated to provide an unlimited supply of cells for differentiation into Li-HLCs. Similar to HLCs derived from fibroblasts, Li-HLCs could not be fully differentiated into hepatocytes. Relative to the originating liver, Li-HLCs showed lower expression of liver specific transcription factors and increased expression of genes involved in the differentiation of other tissues.Conclusions: PLCs and Li-iPSCs obtained from small pieces of human needle liver biopsies constitute a novel unlimited source for the production of HLCs. Despite the preservation of a liver specific gene expression footprint in Li-iPSCs, the generation of fully differentiated hepatocytes cannot be achieved with the current differentiation protocols.

  Study EGAS00001002676

• A targeted gene panel that covers coding, noncoding, and short tandem repeat regions improves the diagnosis of patients with neurodegenerative diseases

  Genetic testing for diagnosis of neurodegenerative diseases (NDs) is highly challenging because of genotype heterogeneity and overlapping clinical manifestations. Targeted-gene panels (TGPs), coupled with next-generation sequencing (NGS), can facilitate the profiling of a large repertoire of ND-related genes and help with differential diagnosis. Due to the technical limitations inherent in NGS and TGPs, short tandem repeat (STR) variations are often ignored. However, STR expansions are known to cause such NDs as Huntington’s disease and several types of spinocerebellar ataxias, such as SCA type 3 (SCA3).Here, we studied the clinical utility of a custom-made TGP that targets 199 NDs and 311 ND-associated genes on 118 undiagnosed patients. At least one known pathogenic or likely pathogenic variation was found in 54 (45.8%) patients; 27 (22.9%) of the 118 patients demonstrated clinical profiles that matched the variants. Based on the findings from the TGP, we refined the original diagnosis of 16 patients. A high concordance of single-nucleotide polymorphisms (99.9%) and small insertions and deletions (93.2%) were observed when comparing the results from TGP and whole-exome sequencing of four patients. We tested an in-house STR detection algorithm, and it reached a specificity of 0.88 and a sensitivity of 0.82 in our SCA3 cohort. This study also uncovered a trove of novel and recurrent variants that may enrich the repertoire of ND-related genetic markers. We propose that a combination of comprehensive TGPs and the bioinformatics analysis pipeline can improve the clinical diagnosis and accelerate the diagnosis of NDs.

  Study EGAS00001003737

• FinHer_Breast_Cancer_Study

  The purpose of this study is to sequence 500 known cancer genes in 960 newly diagnosed high risk breast cancer patients treated with current standard of care therapies and trastuzumab, for somatic alteration and copy number changes. We will be using next gen sequencing technology to determine the prognostic relevance of these somatic genetic alterations and of teh low frequency events to determine if they are associated with trastuzumab benefit or HER2 positive breast cancer, i.e. treatment interaction. The samples will be analysed adn correlated with clinical variables including outcome.

  Study EGAS00001000648

• Combination_therapies_for_personalized_cancer_medicine

  It is the ambition of the team formed by members of the Netherlands Cancer Institute (NKI) and the Cancer Genome Project at the Wellcome Trust Sanger Institute (WTSI) to unravel the genomic and phenotypic complexity of human cancers in order to identify optimal drug combinations for personalized cancer therapy. Our integrated approach will entail (i) deep sequencing of human tumours and cognate mouse tumours; (ii) drug screens in a 1000+ fully characterized tumour cell line panel; (iii) high-throughput in vitro and in vivo shRNA and cDNA drug resistance and enhancement screens; (iv) computational analysis of the acquired data, leading to significant response predictions; (v) rigorous validation of these predictions in genetically engineered mouse models and patient-derived xenografts. This integrated effort is expected to yield a number of combination therapies and companion-diagnostics biomarkers that will be further explored in our existing clinical trial networks.

  Study EGAS00001000655

• Small variants in mtDNA Canary Islands - WES Illumina (ITER)

  The mitochondrial genome (mtDNA) is of interest for a range of fields including evolutionary, forensic, and medical genetics. Human mitogenomes can be classified into evolutionary related haplogroups that provide ancestral information and pedigree relationships. Because of this and the advent of high-throughput sequencing (HTS) technology, there is a diversity of bioinformatic tools for haplogroup classification. We present a benchmarking of the 11 most salient tools for human mtDNA classification using empirical whole-genome (WGS) and whole-exome (WES) short-read sequencing data from 36 unrelated donors. Besides, because of its relevance, we also assess the best performing tool in third-generation long noisy read WGS data obtained with nanopore technology for a subset of the donors. We found that, for short-read WGS, most of the tools exhibit high accuracy for haplogroup classification irrespective of the input file used for the analysis. However, for short- read WES, Haplocheck and MixEmt were the most accurate tools. Based on the performance shown for WGS and WES, and the accompanying qualitative assessment, Haplocheck stands out as the most complete tool. For third-generation HTS data, we also showed that Haplocheck was able to accurately retrieve mtDNA haplogroups for all samples assessed, although only after following assembly-based approaches (either based on a referenced-based assembly or a hybrid de novo assembly). Taken together, our results provide guidance for researchers to select the most suitable tool to conduct the mtDNA analyses from HTS data.

  Study EGAS00001005678

• Clonal expansion and epigenetic reprogramming following deletion or amplification of mutant IDH1

  IDH1 mutation is the earliest genetic alteration in low-grade gliomas (LGGs), but its role in tumor recurrence is unclear. Mutant IDH1 drives overproduction of the oncometabolite D-2-hydroxyglutarate (2HG) and a CpG island (CGI) hypermethylation phenotype (G-CIMP). To investigate the role of mutant IDH1 at recurrence, we performed a longitudinal analysis of 50 IDH1 mutant LGGs. We discovered six cases with copy number alterations (CNAs) at the IDH1 locus at recurrence. Deletion or amplification of IDH1 was followed by clonal expansion and recurrence at a higher grade. Successful cultures derived from IDH1 mutant, but not IDH1 wild-type, gliomas systematically deleted IDH1 in vitro and in vivo, further suggestive of selection against the heterozygous mutant state as tumors progress. Tumors and cultures with IDH1 CNA had decreased 2HG, maintenance of G-CIMP, and DNA methylation reprogramming outside CGI. Thus, while IDH1 mutation initiates gliomagenesis, in some patients, mutant IDH1 and 2HG are not required for later clonal expansions.

  Study EGAS00001001854

• Genetic subclone heterogeneity of tumor-initiating cells in human colorectal cancer

  A subset of tumor-initiating cells (TIC) drives colorectal cancer (CRC) progression in serial mouse xenografts. The TIC compartment itself is heterogeneous and comprises hierarchically organized long-term TIC, tumor transient amplifying cells, and delayed contributing TIC. To address the genomic heterogeneity of the CRC TIC compartment, genome-wide high-coverage whole genome sequencing was performed on patient tumors (n=3), corresponding serially passaged TIC-enriched spheres, and serial xenografts.HIPO P002

  Study EGAS00001001857

• Whole transcriptome and exome sequencing of childhood ALL

  Gene fusion is a major class of genomic abnormalities in childhood acute lymphoblastic leukemia (ALL) and sentinel chromosomal rearrangements involving EP300 and CREBBP may cause global epigenetic deregulation during leukemogenesis with potentials for therapeutic targeting. This dataset includes whole transcriptome sequencing of 231 children with acute lymphoblastic leukemia from a Singapore-Malaysia frontline clinical treatment protocol.

  Study EGAS00001001858

• Next-Generation Sequencing of AV Nodal Reentry Tachycardia patients

  Atrioventricular nodal reentry tachycardia (AVNRT) is the most common form of regular paroxysmal supraventricular tachycardia. This arrhythmia affects women twice as frequently as men, and is often diagnosed in patients below 40 years of age. Familial clustering, early onset of symptoms, and lack of structural anomaly indicate involvement of genetic factors in AVNRT pathophysiology. We hypothesized that AVNRT patients have a high prevalence of variants in genes that are highly expressed in the atrioventricular conduction axis of the heart and potentially involved in arrhythmic diseases. Next-generation sequencing of 67 genes was applied to the DNA profile of 298 AVNRT patients and 10 AVNRT family members using HaloPlex Target Enrichment System.In total, we identified 229 variants in 60 genes; 215 missenses, four frame shifts, four codon deletions, three missense and splice sites, two stop-gain variants, and one start-lost variant. Sixty-five of these were not present in the Exome Aggregation Consortium (ExAC) database. Furthermore, we report two AVNRT families with co-segregating variants. Seventy-five of 284 AVNRT patients (26.4%) and three family members to different AVNRT probands had one or more variants in genes affecting the sodium handling. Fifty-four out of 284 AVNRT patients (19.0%) had variants in genes affecting the calcium handling of the heart. We furthermore find a large proportion of variants in the HCN1-4 genes. We did not detect a significant enrichment of rare variants in the tested genes.This could be an indication that AVNRT might be an electrical arrhythmic disease with abnormal sodium and calcium handling.

  Study EGAS00001002745