3906 results for "*geneti*"

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• DNA Methylation loss coupled with mitotic cell division promotes immune evasion of tumours with high mutation load

  Mitotic cell division increases tumour mutation burden and copy number load with a positive and inverse correlation, respectively, with the clinical benefit of immunotherapy. Markers of cell division correlate also with genomic demethylation involving methylation loss in late-replicating partial methylation domains. Here we find that immunomodulatory pathway genes are concentrated in these domains and transcriptionally repressed in demethylated tumours with CpG island promoter hypermethylation. Global methylation loss correlated with immune evasion signatures independently of mutation burden and aneuploidy. Methylome data of our cohort (n = 60) and a published cohort (n = 81) in lung cancer and a melanoma cohort (n = 40) consistently demonstrated that genomic methylation alterations counteract the contribution of high mutation burden and increase immunotherapeutic resistance. Higher predictive power was observed for methylation loss than mutation burden. We also found that genomic hypomethylation correlates with the immune escape signatures of aneuploid tumours. Hence, DNA methylation alterations implicate epigenetic modulation as a combination regimens for precision immunotherapy.

  Study EGAS00001003731

• 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

• 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

• Glioblastoma initiating cells are sensitive to histone demethylase inhibition due to epigenetic deregulation

  Tumor-initiating cells are a subpopulation of cells that have self-renewal capacity to regenerate a tumor. Here, we identify stem cell-like chromatin features in human glioblastoma initiating cells (GICs) and link them to a loss of the repressive histone H3 lysine 9 trimethylation (H3K9me3) mark. Increasing H3K9me3 levels by histone demethylase inhibition led to cell death in GICs but not in their differentiated counterparts. The induction of apoptosis was accompanied by a loss of the activating H3 lysine 9 acetylation (H3K9ac) modification and accumulation of DNA damage and downregulation of DDR genes. Upon knockdown of histone demethylases KDM4C and KDM7A both differentiation and DNA damage was induced. Thus, the H3K9me3-H3K9ac equilibrium is crucial for GIC viability and represents a chromatin feature that can be exploited to specifically target this tumor subpopulation.

  Study EGAS00001003750

• 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

• DIPG RNA and exome sequencing

  DIPG is a paediatric high-grade glioma that diffusely infiltrates the brainstem and is the leading cause of paediatric brain tumour death. Here we performed RNA and whole exome sequencing on DIPG and control samples to analyse transcriptomic and genetic alterations associated with this devastating disease, and to understand the relationship between them.

  Study EGAS00001004749

• 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

• Variation in the Glucose Transporter gene SLC2A2 is associated with glycaemic response to metformin

  Metformin is the first-line antidiabetic drug with over 100 million users worldwide, yet its mechanism of action remains unclear1. Here the Metformin Genetics (MetGen) Consortium reports a three-stage genome wide association study (GWAS), consisting of 13,123 participants of different ancestries. The C-allele of rs8192675 in the intron of SLC2A2, which encodes the facilitated glucose transporter GLUT2, was associated with a 0.17% (p=6.6x10-14) greater metformin induced HbA1c reduction in 10,577 participants of European ancestry. rs8192675 is the top cis-eQTL for SLC2A2 in 1,226 human liver samples, suggesting a key role for hepatic GLUT2 in regulation of metformin action. In obese individuals C-allele homozygotes at rs8192675 had a 0.33% (3.6mmol/mol) greater absolute HbA1c reduction than T-allele homozygotes.This is about half the effect seen with the addition of a DPP-4 inhibitor, and equates to a dose difference of 550mg of metformin, suggesting rs8192675 as a potential biomarker for stratified medicine.

  Study EGAS00001001875