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- Agarwal, Prasoon, et al.
(författare)
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The epigenomic map of multiple myeloma reveals the importance of Polycomb gene silencing for the malignancy
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Multiple myeloma (MM) is characterized by accumulation of post-germinal center, isotype switched, long-living plasma cells with retained proliferation capacity within the bone marrow. MM is highly heterogeneous and remains fatal. This heterogeneity has hampered identification of a common underlying mechanism for disease establishment and the development of targeted therapy. We recently provided proof-of-principle that gene silencing associated with H3K27me3 contributes to the malignancy of MM. Here we present the first epigenomic map of MM for H3K27me3 and H3K4me3 derived by ChIP- and RNA sequencing from freshly-isolated bone marrow plasma cells from four patients. We compile lists of targets common among the patients as well as unique to MM when compared with PBMCs. Indicating the clinical relevance of our findings, we find increased silencing of H3K27me3 targets with disease progression and in patients presenting with a poor prognosis. Bivalent genes further significantly correlated to under-expressed genes in MM and were unique to MM when compared to PBMCs. Furthermore, bivalent genes, unlike H3K27me3 targets, significantly associated with transcriptional activation upon Polycomb inhibition indicating a potential for drug targeting. Thus, we suggest that gene silencing by Polycomb plays an important role in the development of the malignant phenotype of the MM cell during tumor progression.
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| 3. |
- Alzrigat, Mohammad
(författare)
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Targeted Inhibition of Polycomb Repressive Complexes in Multiple Myeloma : Implications for Biology and Therapy
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multiple myeloma (MM) is a hematological malignancy of antibody producing plasmablasts/plasma cells. MM is characterized by extensive genetic and clonal heterogeneity, which have hampered the attempts to identify a common underlying mechanism for disease establishment and development of appropriate treatment regimes. This thesis is focused on understanding the role of epigenetic regulation of gene expression mediated by the polycomb repressive complexes 1 and 2 (PRC1 and 2) in MM and their impact on disease biology and therapy.In paper I the genome-wide distribution of two histone methylation marks; H3K27me3 and H3K4me3 were studied in plasma cells isolated from newly diagnosed MM patients or age-matched normal donors. We were able to define targets of H3K27me3, H3K4me3 and bivalent (carry both marks) which are, when compared to normal individuals, unique to MM patients. The presence of H3K27me3 correlated with silencing of MM unique H3K27me3 targets in MM patients at advanced stages of the disease. Notably, the expression pattern of H3K27me3-marked genes correlated with poor patient survival. We also showed that inhibition of the PRC2 enzymatic subunit EZH2 using highly selective inhibitors (GSK343 and UNC1999) demonstrated anti-myeloma activity using relevant in vitro models of MM. These data suggest an important role for gene repression mediated by PRC2 in MM, and highlights the PRC2 component EZH2 as a potential therapeutic target in MM.In paper II we further explored the therapeutic potential of UNC1999, a highly selective inhibitor of EZH2 in MM. We showed that EZH2 inhibition by UNC1999 downregulated important MM oncogenes; IRF-4, XBP-1, BLIMP-1and c-MYC. These oncogenes have been previously shown to be crucial for disease establishment, growth and progression. We found that EZH2 inhibition reactivated the expression of microRNAs genes previously found to be underexpressed in MM and which possess potential tumor suppressor functions. Among the reactivated microRNAs we identified miR-125a-3p and miR-320c as predicted negative regulators of the MM-associated oncogenes. Notably, we defined miR-125a-3p and miR-320c as targets of EZH2 and H3K27me3 in MM cell lines and patients samples. These findings described for the first time PRC2/EZH2/H3K27me3 as regulators of microRNA with tumor suppressor functions in MM. This further strengthens the oncogenic features of EZH2 and its potential as a therapeutic target in MM.In paper III we evaluated the therapeutic potential of targeting PRC1 in MM using the recently developed chemical PTC-209; an inhibitor targeting the BMI-1 subunit of PRC1. Using MM cell lines and primary cells isolated from newly diagnosed or relapsed MM patients, we found that PTC-209 has a potent anti-MM activity. We showed, for the first time in MM, that PTC-209 anti-MM effects were mediated by on-target effects i.e. downregulation of BMI-1 protein and the associated repressive histone mark H2AK119ub, but that other subunits of the PRC1 complex were not affected. We showed that PTC-209 reduced MM cell viability via significant induction of apoptosis. More importantly, we demonstrated that PTC-209 shows synergistic anti-MM activity with other epigenetic inhibitors targeting EZH2 (UNC1999) and BET-bromodomains (JQ1). This work highlights the potential use of BMI-1 and PRC1 as potential therapeutic targets in MM alone or in combination with other anti-MM agents including epigenetic inhibitors.
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- Arvidsson, Anna K, et al.
(författare)
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Klimatanpassning av vägkonstruktion, drift och underhåll
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Klimatförändringarna är en realitet och påverkar vårt samhälle och därigenom även våra transporter. Genom att klimatanpassa transportsystemen blir systemen mer robusta och risken för transportstörningar blir mindre. För vägars konstruktion, drift och underhåll innebär klimatanpassningen i de flesta fall relativt stora förändringar men det saknas idag en övergripande bild av det totala klimatanpassningsbehovet nationellt sett samt vilka åtgärder som behöver tas och som är rimliga att tas. Eftersom klimatförändringarna generellt varierar mellan Sveriges klimatzoner är det förenat med stora svårigheter att förutsäga vilken påverkan klimatförändringarna får på vägarnas beteende och livslängd. Inom vinterväghållningen i Sverige kommer saltanvändandet totalt sett att minska på grund av det varmare klimatet. Plogningstillfällena kommer antagligen minska, men beredskapen bör inte minskas för mycket eftersom de mer extrema tillfällena kommer att öka. För att lyckas klimatanpassa vägtransportsystemen så att de blir robusta konstaterar vi att det finns ett stort behov för att ta fram mer kunskap om vägkonstruktionens påverkan av ett förändrat klimat, samt inom drift och underhåll hur man skall anpassa sig genom olika typer av varierande och flexibla klimatanpassningsåtgärder och till effekterna av extrema väderhändelser.
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| 7. |
- Atienza-Párraga, Alba, et al.
(författare)
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Epigenomic re-configuration of primary multiple myeloma underlies the synergistic effect of combined DNMT and EZH2 inhibition.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Multiple myeloma (MM) is characterized by an overexpression of EZH2 and a subsequent increase in H3K27me3-mediated silencing. However, the genome-wide redistribution of this mark in context with other epigenetic tags remains largely unexplored. Here, we show that EZH2 physically interacts with DNMT1 and that combined inhibition leads to a reduced G2/M arrest and increased apoptosis in MM. In addition, we present a catalogue of the genomic regulatory regions in normal plasma cells (NPC) as defined by their individual combination of histone marks. We used ChIP-seq and ATAC-seq data to generate whole-genome NPC chromatin annotations which we further analysed using DNA methylation arrays and RNA-seq. Comparison between NPC and MM demonstrated that, despite the global hypomethylation, enhancers show a tendency towards a higher DNA methylation levels in MM, whereas Polycomb and heterochromatic sites, highly methylated in NPC, show intermediate levels of the mark. Across all examined regulatory regions, 5-azacytidine treatment strongly reduced DNA methylation in MM. Furthermore, we find an extensive re-structuration of the global histone patterns in MM. We noticed a widespread increase in H3K27me3 except at active TSSs/promoters and enhancers, where we found a selective gain of the mark, suggestive of a directed silencing. In contrast, poised TSSs lose H3K27me3 and gain the activation mark H3K27ac, reflecting potential activation. Taken together, we present a comprehensive map of the epigenomic changes in MM as compared to NPC and provide insights into the interplay between EZH2 and DNMT1 in MM.
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