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  • 1
    In: Journal of Virology, American Society for Microbiology, Vol. 92, No. 16 ( 2018-08-15)
    Abstract: Kaposi's sarcoma-associated herpesvirus (KSHV, HHV-8) is a gammaherpesvirus associated with several human malignancies. DNA methylation at CpG dinucleotides is an epigenetic mark dysregulated in many cancer types and in KSHV-infected cells. Several previous studies have analyzed in detail the CpG methylation of the KSHV episomal genomes, but little is known about the impact of KSHV on the human genome. Our knowledge of cellular CpG methylation in the context of KSHV infection is currently limited to four hypermethylated human gene promoters. Therefore, we undertook a comprehensive CpG methylation analysis of the human methylome in KSHV-infected cells and KSHV-associated primary effusion lymphoma (PEL). We performed Infinium HumanMethylation450K and MethylationEpic BeadChip arrays and identified panels of hyper- and hypomethylated cellular promoters in KSHV-infected cells. We combined our genome-wide methylation analysis with high-throughput RNA sequencing (RNA-seq) to add functional outcomes to the virally induced methylation changes. We were able to correlate many downregulated genes with promoter hypermethylation and upregulated genes with hypomethylation. In addition, we show that treating the cells with a demethylating agent leads to reexpression of these downregulated genes, indicating that, indeed, DNA methylation plays a role in the repression of these human genes. Comparison between de novo infection and PEL suggests that the virus induces initial hypermethylation followed by a slow increase in genome-wide hypomethylation. This study extends our understanding of the relationship between epigenetic changes induced by KSHV infection and tumorigenesis. IMPORTANCE In cancer cells, certain promoters become aberrantly methylated, contributing to the phenotype of the tumor. KSHV infection seems to modify cellular CpG methylation, but only a few methylated promoters have been identified in KSHV-infected cells. Here, we investigated the CpG methylation of the human genome in KSHV-associated primary effusion lymphoma (PEL) and KSHV-infected cells. We have identified many hyper- and hypomethylated gene promoters and correlated their methylation with cellular gene expression. These differentially methylated cellular promoters can distinguish KSHV-positive cells from uninfected cells and may serve as the foundation for the use of these differentially methylated regions as potential biomarkers for KSHV-associated malignancies. Drugs that reverse these cancerous methylation patterns have the potential to inhibit tumor growth. Here, we show that treating PEL cells with a demethylating drug (5-aza-2′-deoxycytidine) led to inhibition of cell growth, raising the possibility of testing this drug for the treatment of PEL.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2018
    detail.hit.zdb_id: 1495529-5
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  • 2
    In: Molecular Oncology, Wiley, Vol. 16, No. 10 ( 2022-05), p. 2098-2114
    Abstract: Glioblastoma (GBM) is the most common type of glioma and is uniformly fatal. Currently, tumour heterogeneity and mutation acquisition are major impedances for tailoring personalized therapy. We collected blood and tumour tissue samples from 25 GBM patients and 25 blood samples from healthy controls. Cell‐free DNA (cfDNA) was extracted from the plasma of GBM patients and from healthy controls. Tumour DNA was extracted from fresh tumour samples. Extracted DNA was sequenced using a whole‐genome sequencing procedure. We also collected 180 tumour DNA datasets from GBM patients publicly available at the TCGA/PANCANCER project. These data were analysed for mutations and gene–gene fusions that could be potential druggable targets. We found that plasma cfDNA concentrations in GBM patients were significantly elevated (22.6 ± 5 ng·mL −1 ), as compared to healthy controls (1.4 ± 0.4 ng·mL −1 ) of the same average age. We identified unique mutations in the cfDNA and tumour DNA of each GBM patient, including some of the most frequently mutated genes in GBM according to the COSMIC database ( TP53 , 18.75%; EGFR , 37.5%; NF1 , 12.5%; LRP1B , 25%; IRS4 , 25%). Using our gene–gene fusion database, ChiTaRS 5.0, we identified gene–gene fusions in cfDNA and tumour DNA, such as KDR – PDGFRA and NCDN – PDGFRA , which correspond to previously reported alterations of PDGFRA in GBM (44% of all samples). Interestingly, the PDGFRA protein fusions can be targeted by tyrosine kinase inhibitors such as imatinib, sunitinib, and sorafenib. Moreover, we identified BCR – ABL1 (in 8% of patients), COL1A1 – PDGFB (8%), NIN – PDGFRB (8%), and FGFR1 – BCR (4%) in cfDNA of patients, which can be targeted by analogues of imatinib. ROS1 fusions ( CEP85L – ROS1 and GOPC – ROS1 ), identified in 8% of patient cfDNA, might be targeted by crizotinib, entrectinib, or larotrectinib. Thus, our study suggests that integrated analysis of cfDNA plasma concentration, gene mutations, and gene–gene fusions can serve as a diagnostic modality for distinguishing GBM patients who may benefit from targeted therapy. These results open new avenues for precision medicine in GBM, using noninvasive liquid biopsy diagnostics to assess personalized patient profiles. Moreover, repeated detection of druggable targets over the course of the disease may provide real‐time information on the evolving molecular landscape of the tumour.
    Type of Medium: Online Resource
    ISSN: 1574-7891 , 1878-0261
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2322586-5
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  • 3
    In: Journal of Cell Science, The Company of Biologists, Vol. 124, No. 11 ( 2011-06-01), p. 1891-1902
    Abstract: Despite the activity of cellular quality-control mechanisms, subsets of mature and newly synthesized polypeptides fail to fold properly and form insoluble aggregates. In some cases, protein aggregation leads to the development of human neurodegenerative maladies, including Alzheimer's and prion diseases. Aggregates of misfolded prion protein (PrP), which appear in cells after exposure to the drug cyclosporin A (CsA), and disease-linked PrP mutants have been found to accumulate in juxtanuclear deposition sites termed ‘aggresomes’. Recently, it was shown that cells can contain at least two types of deposition sites for misfolded proteins: a dynamic quality-control compartment, which was termed ‘JUNQ’, and a site for terminally aggregated proteins called ‘IPOD’. Here, we show that CsA-induced PrP aggresomes are dynamic structures that form despite intact proteasome activity, recruit chaperones and dynamically exchange PrP molecules with the cytosol. These findings define the CsA–PrP aggresome as a JUNQ-like dynamic quality-control compartment that mediates the refolding or degradation of misfolded proteins. Together, our data suggest that the formation of PrP aggresomes protects cells from proteotoxic stress.
    Type of Medium: Online Resource
    ISSN: 1477-9137 , 0021-9533
    Language: English
    Publisher: The Company of Biologists
    Publication Date: 2011
    detail.hit.zdb_id: 219171-4
    detail.hit.zdb_id: 1483099-1
    SSG: 12
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  • 4
    In: Journal of Biological Chemistry, Elsevier BV, Vol. 286, No. 9 ( 2011-03), p. 6911-6917
    Type of Medium: Online Resource
    ISSN: 0021-9258
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2011
    detail.hit.zdb_id: 2141744-1
    detail.hit.zdb_id: 1474604-9
    SSG: 12
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