| 1. |
- Berg, Tracy J., et al.
(författare)
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The Irradiated Brain Microenvironment Supports Glioma Stemness and Survival via Astrocyte-Derived Transglutaminase 2
- 2021
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Ingår i: Cancer Research. - : American Association For Cancer Research (AACR). - 0008-5472 .- 1538-7445. ; 81:8, s. 2101-2115
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Tidskriftsartikel (refereegranskat)abstract
- The tumor microenvironment plays an essential role in supporting glioma stemness and radioresistance. Following radiotherapy, recurrent gliomas form in an irradiated microenvironment. Here we report that astrocytes, when pre-irradiated, increase stemness and survival of cocultured glioma cells. Tumor-naive brains increased reactive astrocytes in response to radiation, and mice subjected to radiation prior to implantation of glioma cells developed more aggressive tumors. Extracellular matrix derived from irradiated astrocytes were found to be a major driver of this phenotype and astrocyte-derived transglutaminase 2 (TGM2) was identified as a promoter of glioma stemness and radioresistance. TGM2 levels increased after radiation in vivo and in recurrent human glioma, and TGM2 inhibitors abrogated glioma stemness and survival. These data suggest that irradiation of the brain results in the formation of a tumor-supportive microenvironment. Therapeutic targeting of radiation-induced, astrocyte-derived extracellular matrix proteins may enhance the efficacy of standard-of-care radiotherapy by reducing stemness in glioma. Significance: These findings presented here indicate that radiotherapy can result in a tumor-supportive microenvironment, the targeting of which may be necessary to overcome tumor cell therapeutic resistance and recurrence.
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| 2. |
- Marques, Carolina, et al.
(författare)
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NF1 regulates mesenchymal gliblastoma plasticity and aggressiveness through the AP-1 transcription factor FOSL1
- 2021
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The molecular basis underlying glioblastoma (GBM) heterogeneity and plasticity is not fully understood. Using transcriptomic data of human patient-derived brain tumor stem cell lines (BTSCs), classified based on GBM-intrinsic signatures, we identify the AP-1 transcription factor FOSL1 as a key regulator of the mesenchymal (MES) subtype. We provide a mechanistic basis to the role of the neurofibromatosis type 1 gene (NF1), a negative regulator of the RAS/MAPK pathway, in GBM mesenchymal transformation through the modulation of FOSL1 expression. Depletion of FOSL1 in NF1-mutant human BTSCs and Kras-mutant mouse neural stem cells results in loss of the mesenchymal gene signature and reduction in stem cell properties and in vivo tumorigenic potential. Our data demonstrate that FOSL1 controls GBM plasticity and aggressiveness in response to NF1 alterations.
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| 3. |
- Pudelko, Linda, et al.
(författare)
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Glioblastoma and glioblastoma stem cells are dependent on functional MTH1
- 2017
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Ingår i: Oncotarget. - : Impact Journals LLC. - 1949-2553. ; 8:49, s. 84671-84684
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Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma multiforme (GBM) is an aggressive form of brain cancer with poor prognosis. Cancer cells are characterized by a specific redox environment that adjusts metabolism to its specific needs and allows the tumor to grow and metastasize. As a consequence, cancer cells and especially GBM cells suffer from elevated oxidative pressure which requires antioxidant-defense and other sanitation enzymes to be upregulated. MTH1, which degrades oxidized nucleotides, is one of these defense enzymes and represents a promising cancer target. We found MTH1 expression levels elevated and correlated with GBM aggressiveness and discovered that siRNA knock-down or inhibition of MTH1 with small molecules efficiently reduced viability of patient-derived GBM cultures. The effect of MTH1 loss on GBM viability was likely mediated through incorporation of oxidized nucleotides and subsequent DNA damage. We revealed that MTH1 inhibition targets GBM independent of aggressiveness as well as potently kills putative GBM stem cells in vitro. We used an orthotopic zebrafish model to confirm our results in vivo and light-sheet microscopy to follow the effect of MTH1 inhibition in GBM in real time. In conclusion, MTH1 represents a promising target for GBM therapy and MTH1 inhibitors may also be effective in patients that suffer from recurring disease.
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| 4. |
- Xie, Yuan
(författare)
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Modeling glioblastoma heterogeneity to decipher its biology
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Glioblastoma multiforme (GBM) is the most common and lethal form of primary brain tumor that mainly affects adults. GBM displays remarkable intra- and inter-tumoral heterogeneity and contains a subpopulation of cells named glioma stem cells that is believed to be responsible for tumor maintenance, progression and recurrence.We have established and characterized a biobank of 48 cell lines derived from GBM patients. The cells were explanted and maintained as adherent cultures in serum-free, defined neural stem cell medium. These GBM cells (GCs) displayed NSC marker expression in vitro, had orthotopic tumor initiating capability in vivo, harboured genomic alterations characteristic of GBM and represented all four TCGA molecular subtypes. Our newly established biobank is also connected with a database (www.hgcc.se) that provides all molecular and clinical data. This resource provides a valuable platform of valid in vitro and in vivo models for basic GBM research and drug discovery.By using RCAS/tv-a mouse models for glioma, we found that GBMs originating from a putative NSC origin caused more tumorigenic GCs that had higher self-renewal abilities than those originating from putative glial precursor cell origin. By transcriptome analysis a mouse cell origin (MCO) gene signature was generated to cluster human GCs and GBM tissue samples and a functional relationship between the differentiation state of the initially transformed cell and the phenotype of GCs was discovered, which provides the basis for a new predictive MCO-based patient classification.LGR5 was found to be highly expressed in the most malignant mouse GC lines of putative NSC origin and also enriched in proneural GBMs characterized by PDGFRA alterations and OLIG2 up-regulation. By overexpressing or depleting LGR5 we discovered that high LGR5 expression in proneural GC lines increased the tumorigenicity, self-renewal and invasive capacities of the cells and could potentiate WNT signalling through its ligand RSPO1. Through transcriptome analysis we identified the candidate genes CCND2, PDGFRA, OLIG2, DKK1 that were found to be regulated by LGR5.In the last study, we found that mouse OPCs could initiate both astrocytic and oligdendroglial gliomas, which indicated that oncogenic signalling is dominant to cell of origin in affecting the histology of gliomas.
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