E61c48e6-93e0-4f2d-ae00-cc8f04c486ca - samples
Ontology highlight
ABSTRACT:
PROVIDER: EGAD00001005124 | EGA |
REPOSITORIES: EGA
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Project description:Cancer stem cells are characterized by their self-renewal properties and their ability to regenerate a tumor. They have chromatin features that are reminiscent of embryonic stem cells. Here, we link these stem cell-like characteristics of human glioblastoma initiating cells (GICs) to a loss of heterochromatin features. Increased histone H3 lysine 9 trimethylation (H3K9me3) levels due to histone demethylase inhibition led to cell death in GICs but not in their differentiated counterparts. The induction of apoptosis was accompanied by the accumulation of DNA double-strand breaks. By ChIP-seq and RNA-seq analysis we found that DNA repair genes of the ATM and ATR pathway lost the active H3 lysine 9 acetylation (H3K9ac) and were downregulated upon knockdown of the histone demethylases KDM4C and KDM7A, while regulators of neuron differentiation were up-regulated. Thus, the H3K9me3-H3K9ac equilibrium is a crucial feature for maintaining the stemness in GICs and represents a chromatin feature that can be exploited to specifically target this tumor subpopulation.
2020-03-02 | GSE122832 | GEO
Project description:Tumor-initiating cells are a subpopulation of cells that have self-renewal capacity to regenerate a tumor. Here, we identify stem cell-like chromatin features in human glioblastoma initiating cells (GICs) and link them to a loss of the repressive histone H3 lysine 9 trimethylation (H3K9me3) mark. Increasing H3K9me3 levels by histone demethylase inhibition led to cell death in GICs but not in their differentiated counterparts. The induction of apoptosis was accompanied by a loss of the activating H3 lysine 9 acetylation (H3K9ac) modification and accumulation of DNA damage and downregulation of DDR genes. Upon knockdown of histone demethylases KDM4C and KDM7A both differentiation and DNA damage was induced. Thus, the H3K9me3-H3K9ac equilibrium is crucial for GIC viability and represents a chromatin feature that can be exploited to specifically target this tumor subpopulation.
| EGAS00001003750 | EGA
Project description:Glioblastoma multiforme is the most common and most aggressive type of primary brain tumor. The brain-infiltrative character of glioblastoma makes complete surgical removal of the tumor impossible and neither radiation nor current chemotherapy provide cure. Recent evidence shows that glioblastoma multiforme consists of heterogeneous cell populations which differ in tumor-forming potential. Enriched tumor-initiating capacity has been linked to poorly differentiated glioblastoma cells sharing features with neural stem cells. Thus, these cells are important targets for new therapeutic strategies. We aim to identify novel targets controlling maintenance and differentiation in glioblastoma-initiating cells through high throughput screening. To this end, we utilized libraries of small chemical compounds and small interference RNAs in combination with automated imaging and data analysis. Patient-derived glioblastoma cells were expanded and characterized using neural stem cell conditions. In culture, the cells showed low differentiation but expression of neural stem cell markers such as Nestin and Sox2. Upon intracranial injection into SCID mice these cells gave rise to tumors displaying the hallmarks of the human disease. Differentiation of glioblastoma-initiating cells (for example elicited through bone morphogenetic protein, BMP) was associated with strong morphological changes. Hence, cellular morphology, as well as markers specific for differentiation or death were used as screen readout. Lentiviral RNA interference-based screening yielded several gene knockdowns leading to ‘forced’ differentiation of glioblastoma-initiating cells. For example, knockdown of TRRAP (transformation/transcription domain associated protein) led to strongly increased differentiation and loss of proliferative and self-renewing capacity in these cells. TRRAP is an adapter protein implicated in oncogenic transformation through c-MYC transcription activation, also participating in chromatin remodeling and DNA repair. Glioblastoma-initiating cells with reduced TRRAP displayed increased apoptosis upon treatment with the genotoxic agent temozolomide. In vivo, Trapp knockdown cells were not able to give rise to glioblastoma upon transplantation into the brain of SCID mice. Together, these findings support a crucial role for TRRAP in maintenance and tumorigenicity of glioblastoma-initiating cells and might offer future therapeutic options. Two treatments compared to control: two different shRNA sequences for TRRAP were compared to a control shRNA sequence in their effects on global transcription in brain tumor initiating cells
2011-03-14 | E-GEOD-27931 | biostudies-arrayexpress
Project description:Anaplastic lymphoma kinase (ALK) is expressed in around 60% of glioblastomas and conveys tumorigenic function. Therefore, ALK inhibitory strategies with alectinib were investigated in glioblastoma cells. We demonstrated that alectinib inhibited proliferation and clonogenicity of ALK expressing glioblastoma initiating cells, whereas cells without ALK expression or after ALK depletion via knockdown showed primary resistance against alectinib. The aim of this analysis was to investigate molecular mechanisms of alectinib mediated treatment effects in the ALK expressing S24 cells, which represent a primary glioblastoma cell culture, and after knockdown of ALK.
2019-11-09 | GSE140145 | GEO
Project description:Glioblastoma multiforme is the most common and most aggressive type of primary brain tumor. The brain-infiltrative character of glioblastoma makes complete surgical removal of the tumor impossible and neither radiation nor current chemotherapy provide cure. Recent evidence shows that glioblastoma multiforme consists of heterogeneous cell populations which differ in tumor-forming potential. Enriched tumor-initiating capacity has been linked to poorly differentiated glioblastoma cells sharing features with neural stem cells. Thus, these cells are important targets for new therapeutic strategies. We aim to identify novel targets controlling maintenance and differentiation in glioblastoma-initiating cells through high throughput screening. To this end, we utilized libraries of small chemical compounds and small interference RNAs in combination with automated imaging and data analysis. Patient-derived glioblastoma cells were expanded and characterized using neural stem cell conditions. In culture, the cells showed low differentiation but expression of neural stem cell markers such as Nestin and Sox2. Upon intracranial injection into SCID mice these cells gave rise to tumors displaying the hallmarks of the human disease. Differentiation of glioblastoma-initiating cells (for example elicited through bone morphogenetic protein, BMP) was associated with strong morphological changes. Hence, cellular morphology, as well as markers specific for differentiation or death were used as screen readout. Lentiviral RNA interference-based screening yielded several gene knockdowns leading to ‘forced’ differentiation of glioblastoma-initiating cells. For example, knockdown of TRRAP (transformation/transcription domain associated protein) led to strongly increased differentiation and loss of proliferative and self-renewing capacity in these cells. TRRAP is an adapter protein implicated in oncogenic transformation through c-MYC transcription activation, also participating in chromatin remodeling and DNA repair. Glioblastoma-initiating cells with reduced TRRAP displayed increased apoptosis upon treatment with the genotoxic agent temozolomide. In vivo, Trapp knockdown cells were not able to give rise to glioblastoma upon transplantation into the brain of SCID mice. Together, these findings support a crucial role for TRRAP in maintenance and tumorigenicity of glioblastoma-initiating cells and might offer future therapeutic options.
2011-03-14 | GSE27931 | GEO
Project description:Epigenetic profiling of colorectal cancer initiating cells (CC-ICs) to identify bivalently marked genes (H3K4me3 and H3K27me3 ChIP-seq), and investigation of changes in transcriptome following EZH2 inhibition using RNA-seq.
| EGAD00001004133 | EGA
Project description:We used ChIP-Seq to profile AR binding and H3K27 acetylation genome-wide in LNCaP cells with and without PRMT inhibition and knockdown.
2022-01-28 | GSE153661 | GEO
Project description:ZFHX4 and CHD4 ChIP sequencing in glioblastoma tumor initiating cells
| PRJNA228347 | ENA
Project description:Ewing sarcoma (EWS) is a malignant pediatric bone cancer. Most Ewing sarcomas are driven by EWS-FLI1 oncogenic transcription factor that plays roles in transcriptional regulation, DNA damage response, cell cycle checkpoint control, and alternative splicing. USP1, a deubiquitylase which regulates DNA damage and replication stress responses, is overexpressed at both the mRNA and protein levels in EWS cell lines compared to human mesenchymal stem cells, the EWS cell of origin. The functional significance of high USP1 expression in Ewing sarcoma is not known. Here, we identify USP1 as a transcriptional target of EWS-FLI1 and a key regulator of EWS cell survival. We show that EWS-FLI1 knockdown decreases USP1 mRNA and protein levels. ChIP and ChIP-seq analyses show EWS-FLI1 occupancy on the USP1 promoter. Importantly, USP1 knockdown or inhibition arrests EWS cell growth and induces cell death by apoptosis. We observe destabilization of Survivin (also known as BIRC5 or IAP4) and activation of caspases-3 and -7 following USP1 knockdown or inhibition in the absence of external DNA damage stimuli. Notably, EWS cells display hypersensitivity to combinatorial treatment of doxorubicin or etoposide, EWS standard of care drugs, and USP1 inhibitor compared to single agents alone. Together, our study demonstrates that USP1 is regulated by EWS-FLI1, the USP1-Survivin axis promotes EWS cell survival, and USP1 inhibition sensitizes EWS cells to standard of care chemotherapy.
2024-01-26 | PXD041033 | Pride
Project description:Tumorpsheres and mammospheres were used to propagate mouse breast tumor-initiating cells and their normal stem/progenitor counterparts, respectively. Mammospheres induced to differentiate were used to model the more differentiated cells of the mouse mammary gland. We used microarrays to find differentrially expressed genes between tumorspheres, mammospheres, and mammospheres induced to differentiate
2012-01-30 | GSE32463 | GEO