Polycomb-mediated repression of EphrinA5 promotes growth and invasion of glioblastoma
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ABSTRACT:
PROVIDER: PRJNA595392 | ENA |
REPOSITORIES: ENA
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Project description:Glioblastoma (GBM) is the most common and most aggressive intrinsic brain tumour in adults. Integrated transcriptomic and epigenomic analyses of glioblastoma initiating cells (GIC) in a mouse model uncovered a novel epigenetic regulation of EfnA5. In this model, Bmi1 enhances H3K27me3 at the EfnA5 locus and reinforces repression of selected target genes in a cellular context dependent fashion. EfnA5 mediate Bmi1-dependent proliferation and invasion in vitro and tumour formation in an allograft model. Importantly, we show that this novel Polycomb feed-forward loop is also active in human GIC and we provide preclinical evidence of druggability of EFNA5 in GBM xenografts overexpressing BMI1.
2020-02-01 | GSE141961 | GEO
Project description:Glioblastoma (GBM) is the most common and most aggressive intrinsic brain tumour in adults. Integrated transcriptomic and epigenomic analyses of glioblastoma initiating cells (GIC) in a mouse model uncovered a novel epigenetic regulation of EfnA5. In this model, Bmi1 enhances H3K27me3 at the EfnA5 locus and reinforces repression of selected target genes in a cellular context-dependent fashion. EfnA5 mediates Bmi1-dependent proliferation and invasion in vitro and tumour formation in an allograft model. Importantly, we show that this novel Polycomb feed-forward loop is also active in human GIC and we provide pre-clinical evidence of druggability of the EFNA5 signalling pathway in GBM xenografts overexpressing Bmi1.
| S-EPMC7082224 | biostudies-literature
Project description:The mammalian SWI/SNF, or BAF complex, has a conserved and direct role in antagonizing polycomb-mediated repression. Yet, BAF also promotes repression by polycomb in stem cells and cancer. How BAF both antagonizes and promotes polycomb-mediated repression remains unknown. Here, we utilize targeted protein degradation to dissect the BAF-polycomb axis in embryonic stem cells on short timescales. We report that rapid BAF depletion redistributes PRC1 and PRC2 complexes from highly occupied domains, like Hox clusters, to weakly occupied sites normally opposed by BAF. Polycomb redistribution from highly repressed domains results in their decompaction, gain of active epigenomic features, and transcriptional derepression. Surprisingly, through dose-dependent degradation of PRC1 & PRC2 we identify a conventional role for BAF in polycomb-mediated repression, in addition to global polycomb redistribution. These findings provide new mechanistic insight into the highly dynamic state of the Polycomb-Trithorax axis.
2021-06-11 | GSE173550 | GEO
Project description:The mammalian SWI/SNF, or BAF complex, has a conserved and direct role in antagonizing polycomb-mediated repression. Yet, BAF also promotes repression by polycomb in stem cells and cancer. How BAF both antagonizes and promotes polycomb-mediated repression remains unknown. Here, we utilize targeted protein degradation to dissect the BAF-polycomb axis in embryonic stem cells on short timescales. We report that rapid BAF depletion redistributes PRC1 and PRC2 complexes from highly occupied domains, like Hox clusters, to weakly occupied sites normally opposed by BAF. Polycomb redistribution from highly repressed domains results in their decompaction, gain of active epigenomic features, and transcriptional derepression. Surprisingly, through dose-dependent degradation of PRC1 & PRC2 we identify a conventional role for BAF in polycomb-mediated repression, in addition to global polycomb redistribution. These findings provide new mechanistic insight into the highly dynamic state of the Polycomb-Trithorax axis.
2021-06-11 | GSE173499 | GEO
Project description:mSWI/SNF promotes distal repression by titrating polycomb dosage
| PRJNA605717 | ENA
Project description:Glioblastoma cells are characterized by a highly invasive behavior whose mechanisms are not yet understood. Using the wound healing and Boyden chamber assays we compared in the present study the migration and invasion abilities of 5 glioblastoma cell lines (DK-MG, GaMG, U87-MG, U373-MG, SNB19) differing in p53 and PTEN status. We also analyzed by Western blotting the expression of PTEN, p53, mTOR and several other marker proteins involved in cell adhesion, migration and invasion. Among 5 cell lines, GaMG cells exhibited the fastest rate of wound closure, whereas U87-MG cells showed the most rapid chemotactic migration in the Boyden chamber assay. In DK-MG and GaMG cells, F-actin mainly occurred in the numerous stress fibers spanning the cytoplasm, whereas U87-MG, U373-MG and SNB19 cells preferentially expressed F-actin in filopodia and lamellipodia. Moreover, the two glioblastoma lines mutated in both p53 and PTEN genes (U373-MG and SNB19) were found to exhibit the fastest invasion rates through the Matrigel matrix. Here, we performed a gene expression profiling of the five glioblastoma cell lines to examine the molecular framework of differences in invasive behavior to find possible targets for chemo- and radiation therapy.
2014-09-05 | E-GEOD-53124 | biostudies-arrayexpress
Project description:Ubiquitination plays an important role in proliferating and invasive characteristic of glioblastoma (GBM), similar to many other cancers. Tripartite motif 25 (TRIM25) is a member of the TRIM family of proteins, which are involved in tumorigenesis through substrate ubiquitination. Here, we found TRIM25 is upregulated in GBM and promotes glioblastoma cell growth and invasion, both in vitro and in vivo. Subsequently, we screened a panel of proteins that interact with TRIM25; mass spectrometry and co-immunoprecipitation showed that NONO was a potential substrate of TRIM25. TRIM25 knockdown reduced the K63-linked ubiquitination of NONO, which suppressed the splicing function of NONO. The dysfunctional NONO further leads to the retention of the second intron in the pre-mRNA of PRMT1 and inhibit the activation of the PRMT1/c-MYC pathway. In summary, we demonstrated that TRIM25 promotes glioblastoma cell growth and invasion by regulating the PRMT1/c-MYC pathway through mediation of the splicing factor NONO. Efforts to target the E3 ligase activity of TRIM25 or the complex interactions between TRIM25 and NONO may be useful in the treatment of GBM.
2023-07-11 | GSE236661 | GEO
Project description:Glioblastoma cells are characterized by a highly invasive behavior whose mechanisms are not yet understood. Using the wound healing and Boyden chamber assays we compared in the present study the migration and invasion abilities of 5 glioblastoma cell lines (DK-MG, GaMG, U87-MG, U373-MG, SNB19) differing in p53 and PTEN status. We also analyzed by Western blotting the expression of PTEN, p53, mTOR and several other marker proteins involved in cell adhesion, migration and invasion. Among 5 cell lines, GaMG cells exhibited the fastest rate of wound closure, whereas U87-MG cells showed the most rapid chemotactic migration in the Boyden chamber assay. In DK-MG and GaMG cells, F-actin mainly occurred in the numerous stress fibers spanning the cytoplasm, whereas U87-MG, U373-MG and SNB19 cells preferentially expressed F-actin in filopodia and lamellipodia. Moreover, the two glioblastoma lines mutated in both p53 and PTEN genes (U373-MG and SNB19) were found to exhibit the fastest invasion rates through the Matrigel matrix.
2014-09-05 | GSE53124 | GEO
Project description:The Polycomb system modifies chromatin and plays an essential role in repressing gene expression to control normal mammalian development. However, the components and mechanisms that define how Polycomb protein complexes achieve this remain enigmatic. Here we use combinatorial genetic perturbation coupled with quantitative genomics to discover the central determinants of Polycomb-mediated gene repression in mouse embryonic stem cells. We demonstrate that canonical Polycomb repressive complex 1 (PRC1), which mediates higher order chromatin structures, contributes little to gene repression. Instead, we uncover an unexpectedly high degree of synergy between variant PRC1 complexes which is fundamental to gene repression. We further demonstrate that variant PRC1 complexes are responsible for distinct pools of H2A monoubiquitylation that are associated with repression of Polycomb target genes and silencing during X-chromosome inactivation. Together, these discoveries reveal a new variant PRC1-dependent logic for Polycomb-mediated gene repression.
2019-04-26 | GSE119618 | GEO
Project description:The Polycomb system modifies chromatin and plays an essential role in repressing gene expression to control normal mammalian development. However, the components and mechanisms that define how Polycomb protein complexes achieve this remain enigmatic. Here we use combinatorial genetic perturbation coupled with quantitative genomics to discover the central determinants of Polycomb-mediated gene repression in mouse embryonic stem cells. In contrast to prevailing views, we demonstrate that canonical Polycomb repressive complex 1 (PRC1), which mediates higher order chromatin structures, contributes little to gene repression. Instead, we uncover an unexpectedly high degree of synergy between variant PRC1 complexes which is fundamental to gene repression. We further demonstrate that variant PRC1 complexes are responsible for distinct pools of H2A monoubiquitylation that are associated with repression of Polycomb target genes and silencing during X-chromosome inactivation. Together, these discoveries reveal a new variant PRC1-dependent logic for Polycomb-mediated gene repression.
2019-04-26 | GSE119619 | GEO