14659 results for "PLOS+ONE+Pennsylvania+German+ACS+language+code+pdc+open+access+study"

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• Complex genotype-phenotype relationships shape the response to treatment of Down Syndrome Childhood Acute Lymphoblastic Leukaemia

  Extensive genetic and epigenetic variegation has been demonstrated in many malignancies. Importantly, their interplay has the potential to contribute to disease progression and treatment resistance. To shed light on the complex relationships between these different sources of intra-tumour heterogeneity, we explored their relative contributions to the evolutionary dynamics of Acute Lymphoblastic Leukaemia (ALL) in children with Down syndrome, which has particularly poor prognosis. We quantified the tumour propagating potential of genetically distinct sub-clones using serial transplantation assays and SNP-arrays. While most leukaemias were characterized by a single dominant subclone, others were highly heterogeneous. Importantly, we provide clear and direct evidence that genotypes and phenotypes with functional relevance to leukemic progression and treatment resistance can co-segregate within the disease. Hence, individual genetic lesions can be restricted to well-defined cell immunophenotypes, corresponding to different stages of the leukemic differentiation hierarchy and varied proliferation potentials. As a result of this difference in fitness, which can be accurately quantified via competitive transplantation assays, matching diagnostic, post-treatment, and relapse leukaemias can be dominated by different genotypes, including pre-leukemic clones persisting throughout the disease progression and treatment. Intriguingly, plasticity also appears to be a temporally defined property that can segregate with genotype. These results suggest that Down Syndrome ALL should be viewed as a complex matrix of cells exhibiting genetic and epigenetic heterogeneity that foster extensive clonal evolution and competition. Therapeutic intervention reshapes this ‘eco-system’ and may provide the right conditions for the preferential expansion of selected compartments and subsequently relapse.

  Study EGAS50000001287

• Comprehensive genomic analysis of colorectal cancer with microsatellite instability

  Microsatellite instability-high (MSI-H) colorectal cancers (CRCs) account for 10?15% of all CRCs. MSI-H CRC is characterized by a large number of somatic insertions/deletions (indels) resulting from either mutations within or the silencing of genes involved in the DNA mismatch repair (MMR) system. A subset of MSI-H CRCs is associated with Lynch syndrome (LS), which is caused by germline MMR gene mutations, leading to hereditary cancer predisposition. Other than frequent somatic mutations in BRAF, the transformation mechanisms underlying MSI-H CRC are largely unknown. Here, genomic DNA from 149 MSI-H CRC specimens was analyzed using whole-exome sequencing, and 93 of these samples were subjected to genome-wide DNA methylation analysis. Furthermore, transcriptome sequencing was conducted on 111 samples. Genomic/epigenomic analyses identified three subgroups within our cohort: (1) MSI-H CRCs with silenced MLH1 that share frequent indels, a specific mutation/copy number alteration profile and promoter DNA methylation; (2) LS-associated MSI-H CRCs with MMR genes containing germline mutations; and (3) the remaining MSI-H CRCs with frequent somatic disruptive mutations of MLH1 or MSH2. Unexpectedly, only the first group was found to frequently carry fusion-type protein kinases (15% of this group and 9.9% of all MSI-H CRCs) that are promising therapeutic targets. Thus, MSI-H CRCs can be classified into three subgroups with distinctive genomic as well as epigenomic statuses, probably reflecting the oncogenic processes of these cancers. Fusion-type kinases are enriched in MSI-H CRCs, shedding new light on potential treatment strategies.

  Study JGAS000113

• Durable clinical impacts and mechanisms of action and resistance in histone K27 methylation-targeting epigenetic therapy

  Epigenomes allow the rectification of disordered cancer gene expressions, thereby providing new targets for pharmacological interventions in cancer therapy. The clinical utility of targeting histone H3 lysine tri-methylation (H3K27me3) as an epigenetic hallmark has been demonstrated. However, in actual therapeutic settings, the mechanism by which H3K27me3-targeting therapies exert their effects and the response of tumor cells remain unclear. Here we show the potency and mechanisms of action and resistance of a newly developed EZH1/2 dual inhibitor, valemetostat, in the clinical trials of patients with adult T-cell leukemia/lymphoma (ATL). Valemetostat administration reduced the tumor size and demonstrated durable clinical benefits. Integrative single-cell analyses of patients before and after the administration of valemetostat showed that valemetostat abolishes the highly condensed chromatin structure formed by the plastic H3K27me3 and neutralizes multiple gene loci, such as tumor suppressor genes. Nevertheless, subsequent long-term treatment encounters the emergence of resistant clones with reconstructed aggregate chromatin that closely resemble the pre-dose state. The acquired mutations at the EZH2???compound interface result in the propagation of the clones with re-increased H3K27me3. In patients free of this mutation, TET2 mutation or elevated DNMT3A expression causes similar chromatin recondensation through de novo DNA methylation at the H3K27me3-associated regions. We identified subpopulations with distinct metabolic and gene translation characteristics implicated in primary susceptibility until the acquisition of the heritable (epi)mutations. Targeting chromatin homeostasis might provide opportunities for further sustained epigenetic cancer therapies.

  Study JGAS000553

• CAGE-seq analysis of osteoblast derived from cleidocranial dysplasia human induced pluripotent stem cells

  Non-coding RNAs (ncRNAs) comprise a major portion of transcripts and serve an essential role in biological processes. Although the importance of major transcriptomes in osteogenesis has been extensively studied, the function of ncRNAs in human osteogenesis remains unclear. Previously, we developed hiPSCs from patients with cleidocranial dysplasia (CCD) caused by runt-related transcription factor 2 (RUNX2) haploinsufficiency. To gain insight into ncRNAs in osteogenesis, we surveyed differential ncRNA expression profiling and promoter differences of RUNX2 using patient-specific iPSCs and cap analysis gene expression (CAGE) technology to define the promoter landscape. Revertant iPSCs (Rev1 iPSCs) edited by CRISPR/Cas9 system to harbor mutation-corrected RUNX2 exhibited increased proximal promoter expression of RUNX2, while CCD iPSCs did not. We identified 2271 ncRNA genes with altered expression levels before and after differentiation, 31 of which showed at least 20-fold higher expression in Rev1 iPSCs. Bioinformatic analysis also categorized AC007392.3, LINC00379, RP11-122D10.1, and RP11-90J7.2 as enhancer regulatory regions, and HOXA-AS2, MIR219-2, and RP11-834C11.3 as dyadic regulatory regions of these ncRNAs. In addition, two miRNAs, termed MIR199A2 and MIR152, were found to have high enrichment of osteogenic-related terms. Upon further examination of the role of MIR152 on osteoblast differentiation, we found that MIR152 knockdown induced upregulation of ALP and COL1A1 in Saos-2 cells. Thus, ncRNAs were found to regulate the osteogenic differentiation potentials of hiPSCs that are used for bone regeneration and repair owing to their differentiation potentials. These data allow understanding ncRNA profiles of hiPSCs during osteogenesis.

  Study JGAS000248

• Sequence analysis of colorectal serrated lesions

  Recent studies have shown that colorectal serrated lesions, which include sessile serrated adenomas (SSAs) and traditional serrated adenomas (TSAs), are precursors of colorectal cancer. However, the molecular mechanisms underlying the carcinogenesis, particularly in TSAs, remain largely uncharacterized. To clarify their molecular and clinicopathological characteristics, we performed mutation and methylation analyses of cancer-associated genes in 78 serrated lesions, including TSAs, SSAs and microvesicular hyperplastic polyps. Target exon sequence analysis was performed with 39 genes, including genes known to be frequently mutated in colorectal cancers and/or serrated lesions. We also used bisulfite pyrosequencing to assess the methylation status of various cancer-associated genes and marker genes of the CpG island methylator phenotype (CIMP). The prevalence of mutations in genes associated with Wnt signaling was significantly higher in TSAs than SSAs (65% vs. 28%, p < 0.01). Among those, RNF43 mutations were observed in 38% of TSAs and 17% of SSAs. In immunohistochemical studies of 39 serrated lesions, the prevalence of abnormal nuclear ?-catenin accumulation was significantly higher in TSAs (57%) than SSAs (8%) (P = 0.01). SMOC1 methylation was detected in 54% of TSAs but in no SSAs (p < 0.01). Additionally, SMOC1 methylation was more prevalent among TSAs with KRAS mutation (82%) than with BRAF mutation (38%, p = 0.03). Lesions with CIMP-high or RNF43 mutations were detected only in TSAs with BRAF mutation, suggesting two distinct carcinogenic pathways in TSAs. Mutations in genes associated with Wnt signaling play a greater role in the carcinogenesis of TSAs than SSAs.

  Study JGAS000217

• Innate myeloid cell sbuset-specific gene expression patterns in the human colon are altered in Crohn's disease patients

  Background: There is a heterogeneous subset innate myeloid cells, such as macrophages and dendritic cells, in the human intestinal lamina propria. Several studies have demonstrated that these cells contribute to the maintenance of gut homeostasis through induction of inflammatory responses and tolerance via cell type-specific mechanisms; whereas, disrupted innate immune responses are implicated in the pathogenesis of Crohn?s disease. However, the detailed mechanisms by which each innate myeloid subset regulates gut homeostasis and inflammation largely remains unknown. Aim: We aimed to clarify the comprehensive gene expression profiles of innate myeloid cell subsets in the lamina propria from normal human colons (NC) and the inflamed colon sites from patients with Crohn?s disease (CDi). Methods: We performed RNA-sequencing analysis and precise bioinformatics analysis on three innate myeloid cell subsets, CD14-CD11c-, CD14-CD11c+, and CD14+CD11c+CD163low cells from NC and CDi. Results: Transcriptional analysis of the three subsets from the NC showed distinct gene expression patterns and gene ontology (GO) enrichment analysis revealed the associated innate myeloid subset-specific biological process (BP) terms. In addition, changes in gene expression patterns were observed in innate myeloid subsets from CDi. Furthermore, the core GO-BP terms for the genes upregulated in the innate myeloid cells from CDi were distinct from those found in NC. Conclusion: Our data identified the innate myeloid cell subset-specific transcriptomes and the associated enriched GO-BP terms in the NC and found these patterns were altered in CDi.

  Study JGAS000127

• DNA demethylation is associated with malignant progression of low-grade gliomas

  To elucidate the mechanisms of tumor progression is key to discovering strategies for treating patients with lower-grade glioma. Thus to characterize the changes in the molecular profile during malignant progression, we performed methylation array analysis (122 tumors), whole-exome sequencing (36 tumors and matched normal samples), and RNA sequencing (31 tumors). This cohort included 24 matched pairs of initial lower-grade gliomas and recurrent tumors, most of which showed malignant progression when they recurred. Nearly half of IDH-mutant glioblastomas that had progressed from lower-grade gliomas exhibited characteristic partial DNA demethylation in previously methylated genomic regions of their corresponding initial tumors, which had the glioma CpG island methylator phenotype (G-CIMP). In these glioblastomas, cell cycle-related genes were upregulated, RB and PI3K-AKT pathway genes were frequently altered. Notably, bioinformatics analysis revealed that late-replicating domain was significantly enriched in the demethylated regions that were mostly located in non-regulatory regions, suggesting that the loss of DNA methylation during malignant transformation may involve mainly passive demethylation due to a delay in maintenance of methylation during accelerated cell division. Nonetheless, a limited number of genes including IGF2BP3, which potentially drives cell proliferation, were presumed to be upregulated due to demethylation of their promoter. Thus, cell proliferation was further promoted by passive demethylation in the promoter region of these oncogenic genes. Our data indicated that demethylation of the G-CIMP profile found in a subset of recurrent gliomas reflects accelerated cell divisions accompanied by malignant transformation. Oncogenic genes activated by such epigenetic change represent potential therapeutic targets.

  Study JGAS000146

• Heterogeneity of IKZF1 genomic alterations and risk of relapse in childhood B-cell precursor acute lymphoblastic leukemia

  Purpose Genomic alterations of IKZF1 are common and associated with adverse clinical features in B-ALL, but the relationship between the type of IKZF1 alteration, disease subtype and outcome are incompletely understood. Patients and Methods We used transcriptome and genomic sequencing, and SNP microarray data to determine leukemia subtype and genomic alterations for 688 pediatric patients with B-ALL enrolled into St. Jude Total Therapy 15 and 16 studies. Results IKZF1 alterations were identified in 115 (16.7%) patients, commonly in BCR::ABL1 (78%) and CRLF2-rearranged, BCR::ABL1-like B-ALL (70%), and were associated with five-year cumulative incidence of relapse (CIR) of 14.8 ± 3.3% compared to 5.0 ± 0.9% for patients without any IKZF1 alteration (P < 0.0001). IKZF1 deletions of exon 4-7 (P = 0.0002), genomic IKZF1plus with any IKZF1 deletion (P = 0.006) or with focal IKZF1 deletion (P = 0.0007), and unfavorable genomic subtypes (P < 0.005) were independently adversely prognostic. Patients with both IKZF1 exon 4-7 deletion and unfavorable genomic subtype had a significantly increased risk of relapse (HR = 58.3; 95% CI, 11.9 – 285.4, P < 0.0001) whereas IKZF1 sequence mutations were not independently predictive of outcome. Conclusions Genomic IKZF1plus with any IKZF1 deletion, IKZF1 deletion of exon 4-7, and unfavorable subtype confer increased risk of relapse. The combination of unfavorable genomic subtype and IKZF1 deletion of exon 4-7 identified patients at greatest risk of relapse despite MRD-directed therapy. The type of IKZF1 alteration together with subtype are informative for risk stratification and predict response in patients with B-ALL.

  Study EGAS50000000106

• DNA methylation and the adverse metabolic outcomes of adiposity

  Overweight and obesity affect ~1.5 billion people worldwide, and are major risk factors for type-2 diabetes (T2D), cardiovascular disease and related metabolic and inflammatory disturbances.1,2 Although the mechanisms linking adiposity to its clinical sequelae are poorly understood, recent studies suggest that adiposity may influence DNA methylation,3-6 a key regulator of gene expression and molecular phenotype.7 Here we use epigenome-wide association to show that body mass index (BMI, a key measure of adiposity) is associated with widespread changes in DNA methylation (187 genetic loci at P&lt;1x10-7, range P=9.2x10-8 to 6.0x10-46; N=10,261 samples). Genetic association analyses demonstrate that the alterations in DNA methylation are predominantly the consequence of adiposity, rather than the cause. We find the methylation loci are enriched for functional genomic features in multiple tissues (P&lt;0.05), and show that sentinel methylation markers identify gene expression signatures at 38 loci (P&lt;9.0x10-6, range P=5.5x10-6 to 6.1x10-35, N=1,785 samples). The methylation loci identified highlight genes involved in lipid and lipoprotein metabolism, substrate transport, and inflammatory pathways. Finally, we show that the disturbances in DNA methylation predict future type-2 diabetes (relative risk per 1SD increase in Methylation Risk Score: 2.3 [2.07-2.56]; P=1.1x10-54). Our results provide new insights into the biologic pathways influenced by adiposity, and may enable development of new strategies for prediction and prevention of type-2 diabetes and other adverse clinical consequences of obesity.

  Study EGAS00001001922

• High-throughput Detection of Clinically Relevant Mutations in Archived Tumor Samples By Multiplexed PCR and Next Generation Sequencing

  PURPOSE: Tailoring cancer treatment to tumor molecular characteristics promises to make personalized medicine a reality. However, reliable genetic profiling of archived clinical specimens has been hindered by limited sensitivity and high false positive rates. Here, we describe a novel methodology, MMP-seq, which enables sensitive and specific high-throughput, high content genetic profiling in archived clinical samples. EXPERIMENTAL DESIGN: We first validated MMP-seq’s technical performance in 66 cancer cell lines and a Latin square cross-dilution of known somatic mutations. We next characterized the performance of MMP-seq in 17 formalin-fixed paraffin embedded (FFPE) clinical samples using matched fresh frozen (FF) tissue from the same tumors as benchmarks. To demonstrate the potential clinical utility of our methodology, we profiled FFPE tumor samples from 73 endometrial cancer patients. RESULTS: We demonstrated that MMP-seq enabled rapid and simultaneous profiling of a panel of 88 cancer genes in 48 samples, and detected variants at frequencies as low as 0.4%. We identified DNA degradation and deamination as the main error sources and developed practical and robust strategies for mitigating these issues, and dramatically reduced the false positive rate. Applying MMP-seq to a cohort of endometrial tumor samples identified extensive, potentially actionable alterations in the PI3K and RAS pathways, including novel PIK3R1 hotspot mutations that may disrupt negative regulation of PIK3CA. CONCLUSIONS: MMP-seq provides a robust solution for comprehensive, reliable and high- throughput genetic profiling of clinical tumor samples, paving the way for the incorporation of genomic-based testing into clinical investigation and practice.

  Study EGAS00001000674