14976 results for "cancer studies using rna-seq"

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• Detection of rare mutations, copy number variation, and DNA methylation in the same template DNA molecules

  The analysis of cell-free DNA (cfDNA) from plasma offers great promise for the earlier detection of cancer. At present, changes in DNA sequence, methylation, or copy number are the most sensitive ways to detect the presence of cancer. To further increase the sensitivity of such assays with limited amounts of sample, it would be useful to be able to evaluate the same template molecules for all these changes. Here we report an approach, called MethylSaferSeqS, that achieves this goal, and can be applied to any standard library preparation method suitable for massively parallel sequencing. The innovative step was to copy both strands of each DNA-barcoded molecule with a primer that allows the subsequent separation of the original strands (retaining their 5-methylcytosine residues) from the copied strands (in which the 5-methylcytosine residues are replaced with unmodified cytosine residues). The epigenetic and genetic alterations present in the DNA molecules can then be obtained from the original and copied strands, respectively. We applied this approach to plasma from 265 individuals, including 198 with cancers of the pancreas, ovary, lung and colon, and found the expected patterns of mutations, copy number alterations, and methylation. Furthermore, we could determine which original template DNA molecules were methylated and/or mutated. MethylSaferSeqS should be useful for addressing a variety of questions relating genetics and epigenetics in the future.

  Study EGAS00001006839

• Genomics of Hepatocellular Carcinoma

  Despite the growing incidence of hepatocellular carcinoma (HCC) due to increased hepatitis C virus infection and non-alcoholic steatohepatitis in Western populations, the genetic determinants of this cancer have yet to be established. A minority (15-20%) of HCC occurs in livers without cirrhosis or other chronic disease. Because the liver is functionally preserved in these patients and surgical resection of the tumor may be performed safely, and because of the scarcity of livers available for transplantation, non-cirrhotic patients undergo surgical resection for HCC treatment. These resected tumors present investigatory opportunities in two ways: First, they provide tumor specimen which have not been treated with chemotherapy and embolization. Second, the absence of cirrhosis may provide an unconfounded background from which to investigate the genetic tumorigenesis of HCC. In livers with cirrhosis, genetic instability is prevalent as assessed by assays for microsatellite instability, loss of heterozygosity and aberrant DNA methylation. In contrast, in livers without cirrhosis, the non-tumor tissue surrounding HCC have been found to have fewer genetic aberrations. It has been postulated that the pathologic process of cirrhosis may result in the accumulation of many "passenger"; as well as "driver" mutations, and that the examination of the HCC cancer genome may be facilitated in non-cirrhotic livers because of the absence of an accumulated background noise of mutations.

  Study phs001106

• Mutational signatures of aflatoxin

  Aflatoxin B1 (AFB1) is a mutagen and IARC (International Agency for Research on Cancer) Group 1 carcinogen that causes hepatocellular carcinoma (HCC). Here we present the first whole genome data on the mutational signatures of AFB1 exposure from a total of > 40,000 mutations in four experimental systems: two different human cell lines, and in liver tumors in wild-type mice and in mice that carried a hepatitis B surface antigen transgene – this to model the multiplicative effects of aflatoxin exposure and hepatitis B in causing HCC. AFB1 mutational signatures from all four experimental systems were remarkably similar. We integrated the experimental mutational signatures with data from newly-sequenced HCCs from Qidong County, China, a region of well-studied aflatoxin exposure. This indicated that COSMIC mutational signature 24, previously hypothesized to stem from aflatoxin exposure, indeed likely represents AFB1 exposure, possibly combined with other exposures. Among published somatic mutation data, we found evidence of AFB1 exposure in 0.7% of HCCs treated in North America, 1% of HCCs from Japan, but 16% of HCCs from Hong Kong. Thus, aflatoxin exposure apparently remains a substantial public health issue in some areas. This aspect of our study exemplifies the promise of future widespread resequencing of tumor genomes in providing new insights into the contribution of mutagenic exposures to cancer incidence.

  Study EGAS00001002490

• Sequence Data from the phase 2 PrE0505 trial of Durvalumab with First Line Platinum-Pemetrexed for Unresectable Pleural Mesothelioma

  Mesothelioma is a rare and fatal cancer with limited therapeutic options until the recent approval of combination immune checkpoint blockade. We report the results of the phase 2 PrE0505 trial (NCT02899195) of the anti-PD-L1 antibody, durvalumab, plus platinum-based and pemetrexed chemotherapy for patients with previously untreated unresectable pleural mesothelioma. The primary endpoint was overall survival compared to historic control with cisplatin and pemetrexed chemotherapy. The combination of durvalumab with chemotherapy met the pre-specified primary endpoint reaching a median survival of 20.4 months vs. 12.1 months with historic control. Treatment emergent adverse events were consistent with known side effects of chemotherapy and all adverse events due to immunotherapy were grade ≤2. Integrated genomic and immune cell repertoire analyses revealed that a higher immunogenic mutation burden coupled with a more diverse T cell repertoire were linked with favorable clinical outcome. Structural genome-wide analyses demonstrated a higher degree of genomic instability in responding tumors of epithelioid histology. Patients with germline alterations in cancer predisposing genes, especially those involved in DNA repair, were more likely to attain long term survival. Our findings indicate that concurrent durvalumab with platinum-based chemotherapy has promising clinical activity and that responses are driven by the complex genomic background of malignant pleural mesothelioma.

  Study EGAS00001005426

• 5- FU treated organoids

  5-Fluorouracil (5-FU) is a chemotherapeutic drug component that is commonly used for the treatment of solid cancers. The anticancer properties of 5-FU have been attributed to interference with nucleotide synthesis and through direct incorporation into the DNA as being a pyrimidine analog. As both mechanisms of action may have a mutational impact on surviving tumor cells, we performed three independent analyses to characterize the genomic consequences of 5-FU treatment: i) in vitro treatment of intestinal organoids with 5-FU followed by whole genome sequencing, ii) genome-wide mutation analyses in tumor samples from 5-FU treated patients with breast or colorectal cancer, and iii) analysis of paired biopsies from patients treated with 5-FU between biopsies. Our results demonstrate that both in vitro and in vivo 5-FU causes a mutational pattern that is dominated by T>G substitutions in a CTT context and with strong resemblance to COSMIC signature 17. Interestingly, this signature is also found in non 5-FU treated patients, most prominently in esophageal tumors, indicating that distinct endogenous and exogenous triggers can converge into highly similar mutational signatures. Furthermore, our results suggest that 5-FU may have adverse mutagenic effects on healthy cells and contributes to genetic variability in surviving cancer cells thereby contributing to tumor evolution.

  Study EGAS00001003592

• Ischemia Reperfusion Responses in Human Lung Transplants at the Single Cell Resolution

  Ischemia reperfusion is an unavoidable step of organ transplantation. Development of therapeutics for lung injury during transplantation has proved challenging; understanding lung injury from human data at the single cell resolution is required to accelerate the development of therapeutics. Donor lung biopsies from six human lung transplant cases were collected at the end of cold preservation and 2-hour reperfusion and underwent single cell RNA sequencing. Donor and recipient origin of cells from the reperfusion timepoint were deconvolved. Gene expression profiles were (1) compared between each donor cell type between timepoints and (2) compared between donor and recipient cells. Inflammatory responses from donor lung macrophages were found after reperfusion with upregulation of multiple cytokines and chemokines, especially IL-1 and IL-1. Significant inflammatory responses were found in alveolar epithelial cells (featured by CXCL8) and lung endothelial cells (featured by IL-6 upregulation). Different inflammatory responses were noted between donor and recipient monocytes and CD8+ T cells. The inflammatory signals and differences between donor and recipient cells observed provide insight into the cellular and molecular mechanisms of ischemia reperfusion induced lung injury. Further investigations may lead to the development of novel targeted therapeutics.

  Study EGAS50000000490

• Harnessing Epigenetic Regulators to improve HSC-based lentiviral gene therapy

  Curative benefits of autologous and allogeneic transplantation of hematopoietic stem cells (HSCs) have been proven for various diseases. However, the low number of true HSCs that can be collected from patients and subsequently in vitro maintenance and expansion of true HSCs for genetic correction remain challenging. Addressing this issue, we here focused on optimizing culture conditions to improve the ex vivo expansion of true HSCs for gene therapy purposes. In particular, we explore the use of epigenetic regulators to enhance the effectiveness of HSC-based lentiviral (LV) gene therapy. The HDAC inhibitor Quisinostat and the bromodomain inhibitor CPI203 each promote ex vivo expansion of functional HSCs, as validated by xenotransplantation assays and single cell RNA-sequencing analysis. We confirmed the stealth effect of LV transduction on the loss of HSC numbers in commonly used culture protocols, while addition of Quisinostat or CPI203 improved expansion of HSCs in transduction protocols. Of note, we demonstrated that addition of Quisinostat improved LV transduction efficiency of HSCs and early progenitors. Our suggested culture conditions highlight the potential therapeutic effect of epigenetic regulators in hematopoietic stem cell biology and their clinical applications to advance HSC-based gene correction.

  Study EGAS50000000175

• Biallelic loss of function PAX4 variants are a Novel Cause of Transient Neonatal Diabetes

  The identification of genes in which loss of function (LoF) variants cause neonatal diabetes mellitus (NDM) can provide unique insights into the development and function of human pancreatic beta cells. We describe the identification of biallelic PAX4 LoF variants in 2 unrelated individuals with transient NDM: one due to a homozygous p.(Arg126*) PAX4 stop gain variant and a second due to a homozygous c.-352_104del 2.65kb deletion affecting the first 4 exons and promoter of the PAX4 Matched Annotation from NCBI and EMBL-EBI select transcript. We confirmed reduced transcript expression due to nonsense mediated decay for the e p.(Arg126*) variant in CRISPR-edited iPSC-derived pancreatic endoderm cells. Analysis of PAX4 binding through integration of CUT&RUN and RNA-sequencing in PAX4 depleted endocrine cells identified genes directly regulated by PAX4 involved in both pancreatic islet development and glucose-sensitive insulin secretion. The remitting and relapsing diabetes in both probands demonstrates that in contrast to mice PAX4 is not essential for the development of pancreatic beta-cells and supports differences in the requirements of functional beta-cell mass across the life-course.

  Study EGAS50000000857

• Non-neuronal TGF-β–mediated extracellular matrix remodeling drives neurodegeneration in a PSP-Richardson syndrome model

  Progressive supranuclear palsy-Richardson syndrome (PSP-RS) is a devastating neurodegenerative disorder marked by rapid motor decline, cognitive impairment, and widespread accumulation of pathological tau. Yet, the molecular triggers of sporadic PSP-RS remain elusive. In this study, we combined patient-derived midbrain organoids with integrative multi-omics to uncover a previously unrecognized pathological cascade. At the core lies an early and aberrant activation of TGF-β signaling, which initiates profound extracellular matrix (ECM) remodeling and aberrant integrin-mediated focal adhesion. This cascade leads to persistent hyperactivation of PI3K/AKT and MAPK/ERK pathways, disrupting cytoskeletal integrity, impairing autophagy, promoting pathological tau phosphorylation and mislocalization, and ultimately driving synaptic degeneration. Single-cell RNA sequencing revealed an ectopic expansion of vascular leptomeningeal-like cells (VLMCs), a collagen-producing population, accompanied by a broad ECM gene dysregulation unique to PSP-RS. Remarkably, pharmacological blockade of TGF-β, AKT, ERK, or mTOR signaling reversed tau pathology and restored synaptic integrity. These findings position TGF-β-driven ECM remodeling as a master regulator of neurodegeneration in sporadic PSP-RS and unveil multiple actionable therapeutic targets for this currently untreatable disease.

  Study EGAS50000001236

• Whole-genome methylation profiling of menstrual stem cells identifies novel biomarkers for endometriosis

  Endometriosis is a highly prevalent condition that remains underdiagnosed and poorly managed due to the lack of clinically validated biomarkers and limited understanding of its underlying pathophysiology. Although menstrual blood–derived stem cells (MenSCs) have been implicated in disease pathogenesis, their potential as a diagnostic source has not been systematically explored. We conducted a clinical study including 42 women (19 with endometriosis and 23 controls) to evaluate whether DNA methylation profiles from freshly isolated MenSCs could identify disease-specific biomarkers. Whole-genome DNA methylation sequencing identified differentially methylated regions (DMRs) enriched in genes associated with key features of endometriosis, including inflammation, tissue remodelling, and developmental processes. These DMRs robustly discriminated cases from controls, independently of technical and clinical confounders. Machine learning models trained and validated on these regions demonstrated strong diagnostic performance (specificity 83%, sensitivity 79%). Integration with an independent single-cell RNA sequencing dataset suggested that the identified DMRs may influence gene expression, supporting their biological relevance. Collectively, these findings highlight MenSC DNA methylation profiling as a promising, non-invasive strategy for early diagnosis and personalised management of endometriosis. (PubMed IDs will be provided once the manuscript is published.)

  Study EGAS50000001640