4772 results for "*oma"

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• Ultra-Fast Patient-Derived Xenografts Identify Functional and Spatial Tumour Heterogeneities that Drive Therapeutic Resistance

  Treatment of patients with advanced cancers increasingly relies on agents targeting specific molecular or cellular aberrations. These expensive therapies often fail because of pre-existing drug resistance. Intra-tumoural molecular and micro-environmental heterogeneity resistance can create resistance in one or more subclones of a tumour, leading to spatio-functional heterogeneity. We created a rapid approach for quantifying tumour functional phenotypes based on tumour-implantation into the chorioallantoic membrane of chick embryos. We apply this technique to 43 separate biopsies from 6 patients with renal cell carcinoma (RCC) with 36 replicates per biopsy, achieving a 93.6% engraftment rate (1449/1548). Challenging these models with sunitinib, an anti-angiogenic therapy frequently used in RCC allowed us to quantify spatio-functional heterogeneity in individual patients. Prediction of de novo drug resistance in advanced cancer patients would facilitate precision medicine by tailoring systemic therapies and improve clinical trial design outcome measures. We describe a patient-derived xenograft platform where fresh patient tumour samples are implanted into the chorioallantoic membrane (CAM) of chick embryos at high engraftment efficiencies, permitting large scale “tumour avatar” studies to guide the selection of drugs and to predict clinical drug resistance outcomes in renal cell carcinoma (RCC) patients. Applying this “tumour avatar” model in a co-clinical trial on RCC patients, we observe intra-tumoural functional heterogeneity with sunitinib treatment, revealing the presence of drug-resistant clones prior to the initiation of therapy. Multi-regional exome Matched DNA sequencing of the primary tumour and metastases revealed DNA mutational signatures associated with sunitinib resistance at baseline and after treatment. These These studies demonstrate a rapid and affordable method of findings confirm the existence of genetic and surveying functional tumour heterogeneities heterogeneity.

  Study EGAS00001002627

• We performed whole-exome sequencing of 20 samples (10 actinic keratosis and 10 cutaneous squamous cell carcinoma) to investigate a potential relationship between DNA methylation-based subtypes and genetic mutation patterns (Rodriguez-Paredes et al., Nat Commun 2017)

  Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer type and arises from keratinocytes. Most cSCC progress from a UV-induced precancerous lesion termed actinic keratosis (AK). Despite various efforts to characterize these lesions molecularly, the etiology of AK and its progression to cSCC remain only partially understood. Here we have used Infinium MethylationEPIC BeadChips to interrogate the DNA methylation status of about 850.000 CpGs in epidermal preparations from healthy skin, AK and cSCC. Importantly, we found that the premalignant AK samples displayed classical features of cancer methylomes and were highly similar to cSCC methylomes. Further analysis identified typical features of stem cell methylomes, such as a reduced DNA methylation age, non-CpG methylation and stem cell-related keratin and enhancer methylation patterns. Interestingly, this signature was detected only in one half of the AK and cSCC samples, while the other half showed keratin and enhancer methylation patterns that were more closely related to the control epidermis. These findings suggest the existence of two distinct subclasses of AK and cSCC that originate from distinct keratinocyte differentiation stages.

  Study EGAS00001002670

• The identification of genetic vulnerabilities in head and neck cancers for the development of novel treatments.

  The global cancer burden is expected to double by the year 2030 and this will disproportionately affect the Asian continent. Head and neck squamous cell carcinoma (HNSCC) is endemic in Asia. It is the sixth most common cancer worldwide and the second most common in Malaysia, with approximately 600,000 new cases per year globally. Longterm survival remains less than 50%, underscoring the need for better therapeutic strategies. In this proposal we aim to bring new technological advancements in the identification of critical genes in HNSCC and the identification of compounds for the development of new therapies in HNSCC. We propose to genomically characterise 16 unique Asian H&N cancer cell lines, to classify sub groups where identification of essential genes that can be targeted for tumor control can be applied in a more rational way. Further, we propose to use zebrafish, an established drug discovery platform to identify promising pathway-specific compounds that could be further studied using CRISPR/Cas9 lethality screens and biological models to better identify novel therapeutic strategies to combat this major health problem in Asia.

  Study EGAS00001002682

• Alternative splicing isoforms in patient-derived hepatocellular carcinoma cells

  The aim of this study was to obtain a landscape of alternative splicing (AS) in human hepatocellular carcinoma (HCC). We applied hybrid sequencing by integrating Pacbio long-read and Illumina short-read RNA sequencing data from 8 patient-derived HCC cell lines, and used an immortalized hepatocyte cell line as reference. This study revealed features of annotated and novel splice variants in HCC cells, including transcript length, AS type and protein changes. We also identified novel isoforms and tumor specific isoforms, which may represent potential biomarkers and targets for therapeutic development.

  Study EGAS00001002697

• Extensive three-dimensional intratumor proteomic heterogeneity revealed by multiregion sampling in high-grade serous ovarian tumor specimens

  Enriched tumor epithelium, tumor-associated stroma, and whole tissue were collected by laser microdissection from thin sections across spatially separated levels of ten high-grade serous ovarian carcinomas (HGSOCs) and analyzed by mass spectrometry, reverse phase protein arrays, and RNA sequencing. Unsupervised analyses of protein abundance data revealed independent clustering of an enriched stroma and enriched tumor epithelium, with whole tumor tissue clustering driven by overall tumor “purity.” Comparing these data to previously defined prognostic HGSOC molecular subtypes revealed protein and transcript expression from tumor epithelium correlated with the differentiated subtype, whereas stromal proteins (and transcripts) correlated with the mesenchymal subtype. Protein and transcript abundance in the tumor epithelium and stroma exhibited decreased correlation in samples collected just hundreds of microns apart. These data reveal substantial tumor microenvironment protein heterogeneity that directly bears on prognostic signatures, biomarker discovery, and cancer pathophysiology and underscore the need to enrich cellular subpopulations for expression profiling. (Companion proteomic data is available in the ProteomeXchange Consortium, PRIDE: PXD026570).

  Study EGAS00001005786

• Brain_Disease_Wellcome_Leap_Delta_Tissue_DNA

  Investigating how the tumour microenvironment regulates glioblastoma cell states using genomic analysis.

  Study EGAS00001005799

• Defective Homologous Recombination DNA Repair as Therapeutic Target in Advanced-Stage Chordoma (HIPO_021)

  HIPO project: HIPO_021 Importance: Chordomas are rare tumors of the axial skeleton and skull base with few therapeutic options and no clinically validated molecular drug targets. The value of comprehensive genomic analyses for guiding medical therapy of patients with advanced-stage chordoma is unknown.Objective: To identify therapeutically tractable genetic lesions in a cohort of chordoma patients within a genomics-guided precision oncology program and to document the outcome of individualized, molecularly targeted chordoma therapy.Design, Setting, and Participants: We performed whole-exome sequencing of tumor and matched germline control samples from seven patients with locally advanced or metastatic chordoma who were enrolled in a cross-institutional molecular stratification registry trial for younger adults with advanced-stage cancer across all histologies and patients with rare tumors. All patients were heavily pretreated and had progressive disease prior to molecular analysis.Interventions: Individualized medical therapy was administered according to the patients’ molecular profiles.Main Outcomes and Measures: Candidate therapeutic targets identified by whole-exome sequencing and response to genotype-directed therapy.Results: All patients harbored alterations of two or more genes known to be involved in DNA repair via homologous recombination (HR), including heterozygous deletions of ERCC6, FANC family members, RAD51L (n = 6), BRCA2 (n = 5), ATR, CHEK2, RAD18, RAD51B, and XRCC3 (n = 4); inactivating PTEN mutations coupled with loss of heterozygosity (n = 2); and pathogenic germline variants in BRCA2 (n = 1), NBN (n = 1), and CHEK2 (n = 1) that were accompanied by somatic deletion of the corresponding wild-type alleles. Consistently, a mutational signature associated with defective HR was enriched in all samples and co-occurred with extensive genomic instability, as evidenced by HR deficiency scores and high numbers of large-scale state transitions. These results prompted off-label treatment with the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib in a patient whose tumor was refractory to irradiation and systemic treatment with imatinib, which led to a prolonged response and substantial clinical improvement.Conclusions and Relevance: Advanced-stage chordomas are frequently characterized by genomic imprints of defective HR DNA repair. HR deficiency represents a new therapeutic opportunity in this intractable disease through repositioning of PARP inhibitors that warrants further exploration in clinical trials.

  Study EGAS00001002720

• Single-cell RNA sequencing of 22 Hodgkin lymphoma tumors and 5 reactive lymph nodes

  Hodgkin lymphoma (HL) is characterized by an extensively dominant tumor microenvironment (TME) composed of different types of non-cancerous immune cells with rare malignant cells. Characterization of the cellular components and their spatial relationship is crucial to understanding crosstalk and therapeutic targeting in the TME. We performed single-cell RNA sequencing of more than 127,000 cells from 22 HL tissue specimens and 5 reactive lymph nodes, profiling for the first time the phenotype of the HL-specific immune microenvironment at single-cell resolution. Library preparation was performed using the 10x Genomics Chromium system, and Illumina sequencing was used to generate 3' gene expression data for every cell. Downstream analysis was performed in R to identify HL-specific microenvironment patterns and identify novel cell populations.

  Study EGAS00001004085

• Exon4-mutations in KRAS Affect MEK-ERK and Pi3K-AKT Signaling in Multiple Myeloma

  Approximately 40% of MM cases harbor a point mutation in either KRAS or NRAS. However, it is still unclear whether RAS-mutations are associated with disease outcome. Specifically, no information exists whether KRAS-mutations have an impact on survival in MM patients at diagnosis that were treated with novel agents (e.g. bortezomib, lenalidomide). Targeting KRAS directly for therapeutic purposes is still impossible, but recently the first covalent mutant-specific inhibitor targeting KRASG12C made it into clinical trials. However, other KRAS-hotspot-mutations exist in MM patients, including the less common exon4-mutations. Within the current study, the coding regions of KRAS in 80 MM patients at diagnosis, uniformly treated with bortezomib and high-dose chemotherapy, were deep-sequenced. Moreover, the functional impact of KRASG12A as well as the two exon4-mutations A146T (AMO1) and A146V (MM patient) on different survival pathways was investigated. Specifically, an siRNA-mediated knockdown in AMO1 was performed and KRASWT, KRASG12A, KRAS146T and KRAS146V were overexpressed in the KRASWT cell lines JJN3 and OPM2 using lentiviral transduction and the transposase based Sleeping Beauty system. KRAS-mutations were not associated with survival. Yet, the expression of all KRAS-mutants had an impact on MEK/ERK-signaling in two independent MM cell lines and on AKT/PI3K-signaling in one MM cell line.

  Study EGAS00001004110

• Gene expression-based prediction of pazopanib efficacy in sarcoma (HIPO, H021)

  The multi-receptor tyrosine kinase (RTK) inhibitor pazopanib is approved for the treatment of advanced non-adipocytic soft-tissue sarcoma and has also shown activity in other sarcoma subtypes. However, its clinical efficacy is highly variable, and no reliable predictors exist to date to select patients who are most likely to benefit from this drug. We analyzed the molecular profiles and clinical outcomes of pazopanib-treated sarcoma patients enrolled in a prospective observational study by the German Cancer Consortium, DKTK MASTER, that employs whole-genome/exome sequencing (WGS/WES) and transcriptome sequencing to inform the care of adults with advanced cancer across histologies who are younger than 51 and patients with rare tumors, including rare subtypes of more common entities, regardless of age.​ Among a total of 109 patients with available WGS/WES data, there was no correlation between clinical parameters, specific genetic alterations, or mutational signatures and clinical outcome. In contrast, analysis of a subcohort of 62 patients who underwent molecular analysis before pazopanib treatment and had transcriptome sequencing data available showed that mRNA levels of NTRK3 (hazard ratio [HR]=0.53, p=0.021), IGF1R (HR=1.82, p=0.027), and KDR (HR=0.50, p=0.011) were independently associated with progression-free survival (PFS). Based on the expression of these RTK genes, i.e., the features NTRK3-high, IGF1R-low, and KDR-high, we developed a pazopanib efficacy predictor (PEP) that stratified patients into three groups with significantly different PFS (p<0.0001). Application of the PEP to an independent cohort of pazopanib-treated sarcoma patients from DKTK MASTER (n=43) confirmed its potential to separate patient groups with significantly different PFS (p=0.02), whereas no such association was observed in sarcoma patients from DKTK MASTER (n=77) or The Cancer Genome Atlas sarcoma cohort (n=256) who were not treated with pazopanib. A score based on the combined expression of NTRK3, IGF1R, and KDR allows identification of sarcoma patients with good, intermediate, and poor outcome following pazopanib therapy and warrants investigation as a predictive tool in prospective studies to optimize the use of this drug in the clinic.

  Study EGAS00001005836