Similar Datasets
Project description:Glioblastomas are universally fatal cancers that contain self-renewing glioblastoma stem cells (GSCs) that initiate tumors. Traditional anti-cancer drug discovery based on in vitro cultures tends to identify targets with poor therapeutic index and fails to accurately model the effects of the tumor microenvironment. Here, leveraging in vivo genetic screening, we identified the H3K4me3 regulator DPY30 as an in vivo-specific glioblastoma dependency. Based on the hypothesis that in vivo epigenetic regulation may define critical GSC dependencies, we interrogated active chromatin landscapes of GSCs derived from intracranial xenografts and cell culture through Histone H3 lysine 4 trimethylation (H3K4me3) chromatin immunoprecipitation and transcriptome analysis. Intracranial-specific genes marked by H3K4me3 included FOS, NFkB, and phosphodiesterase family members. In intracranial tumors, DPY30 regulated angiogenesis and hypoxia pathways in an H3K4me3-dependent manner, but was dispensable in cultured GSCs. PDE4B was a key downstream effector of DPY30; the PDE4 inhibitor, rolipram, preferentially targeted DPY30-expressing cells and impaired in vivo glioblastoma growth without affecting cultured tumor cells. Collectively, DPY30 selectively regulates H3K4me3 modification on genes critical to support angiogenesis and tumor growth in vivo, laying the foundation for the DPY30-PDE4B axis as a specific and novel therapeutic target in glioblastoma with a broad therapeutic index.
2021-10-17 | GSE185955 | GEO
Project description:Glioblastomas are universally fatal cancers that contain self-renewing glioblastoma stem cells (GSCs) that initiate tumors. Traditional anti-cancer drug discovery based on in vitro cultures tends to identify targets with poor therapeutic index and fails to accurately model the effects of the tumor microenvironment. Here, leveraging in vivo genetic screening, we identified the H3K4me3 regulator DPY30 as an in vivo-specific glioblastoma dependency. Based on the hypothesis that in vivo epigenetic regulation may define critical GSC dependencies, we interrogated active chromatin landscapes of GSCs derived from intracranial xenografts and cell culture through Histone H3 lysine 4 trimethylation (H3K4me3) chromatin immunoprecipitation and transcriptome analysis. Intracranial-specific genes marked by H3K4me3 included FOS, NFkB, and phosphodiesterase family members. In intracranial tumors, DPY30 regulated angiogenesis and hypoxia pathways in an H3K4me3-dependent manner, but was dispensable in cultured GSCs. PDE4B was a key downstream effector of DPY30; the PDE4 inhibitor, rolipram, preferentially targeted DPY30-expressing cells and impaired in vivo glioblastoma growth without affecting cultured tumor cells. Collectively, DPY30 selectively regulates H3K4me3 modification on genes critical to support angiogenesis and tumor growth in vivo, laying the foundation for the DPY30-PDE4B axis as a specific and novel therapeutic target in glioblastoma with a broad therapeutic index.
2021-10-17 | GSE185954 | GEO
Project description:Glioblastoma Stem Cells Reprogram Chromatin In Vivo To Generate Selective Therapeutic Dependencies
| PRJNA771531 | ENA
Project description:Glioblastoma Stem Cells Reprogram Chromatin In Vivo To Generate Selective Therapeutic Dependencies [ChIP-Seq]
| PRJNA771534 | ENA
Project description:Glioblastoma Stem Cells Reprogram Chromatin In Vivo To Generate Selective Therapeutic Dependencies [RNA-Seq]
| PRJNA771533 | ENA
Project description:Glioblastoma is a universally lethal cancer with a median survival time of approximately 15 months. Despite substantial efforts to define druggable targets, there are no therapeutic options that notably extend the lifespan of patients with glioblastoma. While previous work has largely focused on in vitro cellular models, here we demonstrate a more physiologically relevant approach to target discovery in glioblastoma. We adapted pooled RNA interference (RNAi) screening technology for use in orthotopic patient-derived xenograft models, creating a high-throughput negative-selection screening platform in a functional in vivo tumour microenvironment. Using this approach, we performed parallel in vivo and in vitro screens and discovered that the chromatin and transcriptional regulators needed for cell survival in vivo are non-overlapping with those required in vitro. We identified transcription pause-release and elongation factors as one set of in vivo-specific cancer dependencies, and determined that these factors are necessary for enhancer-mediated transcriptional adaptations that enable cells to survive the tumour microenvironment. Our lead hit, JMJD6, mediates the upregulation of in vivo stress and stimulus response pathways through enhancer-mediated transcriptional pause-release, promoting cell survival specifically in vivo. Targeting JMJD6 or other identified elongation factors extends survival in orthotopic xenograft mouse models, suggesting that targeting transcription elongation machinery may be an effective therapeutic strategy for glioblastoma. More broadly, this study demonstrates the power of in vivo phenotypic screening to identify new classes of 'cancer dependencies' not identified by previous in vitro approaches, and could supply new opportunities for therapeutic intervention.
| S-EPMC5896562 | biostudies-literature
Project description:Acute myeloid leukemia (AML) is fueled by leukemic stem cells (LSC) whose determinants are challenging to discern from hematopoietic stem cells (HSC) or uncover by approaches focused on general cell properties. We have identified a set of RNA-binding proteins (RBP) selectively enriched in human AML LSCs. Using an in vivo two-step CRISPR-Cas9 screen to assay stem cell functionality, we found 32 RBPs essential for LSCs in MLL-AF9;NrasG12D AML. Loss-of-function approaches targeting key hit RBP ELAVL1 compromised LSC-driven in vivo leukemic reconstitution, and selectively depleted primitive malignant versus healthy cells. Integrative multiomics revealed differentiation, splicing, and mitochondrial metabolism as key features defining the leukemic ELAVL1-mRNA interactome with mitochondrial import protein, TOMM34, being a direct ELAVL1-stabilized target whose repression impairs AML propagation. Altogether, using a stem cell-adapted in vivo CRISPR screen, this work demonstrates pervasive reliance on RBPs as regulators of LSCs and highlights their potential as therapeutic targets in AML.SignificanceLSC-targeted therapies remain a significant unmet need in AML. We developed a stem-cell-adapted in vivo CRISPR screen to identify key LSC drivers. We uncover widespread RNA-binding protein dependencies in LSCs, including ELAVL1, which we identify as a novel therapeutic vulnerability through its regulation of mitochondrial metabolism. This article is highlighted in the In This Issue feature, p. 171.
| S-EPMC10150294 | biostudies-literature
Project description:Glioblastoma (GBM) is the most aggressive primary malignant brain cancer and urgently requires effective treatments. Chimeric antigen receptor T (CAR-T) cell therapy offers a potential treatment method, but it is often hindered by poor infiltration of CAR-T cells in tumors and highly immunosuppressive tumor microenvironment (TME). Here, we armed an oncolytic adenovirus (oAds) with a chemokine CXCL11 to increase the infiltration of CAR-T cells and reprogram the immunosuppressive TME, thus improving its therapeutic efficacy. In both immunodeficient and immunocompetent orthotopic GBM mice models, we showed that B7H3-targeted CAR-T cells alone failed to inhibit GBM growth but, when combined with the intratumoral administration of CXCL11-armed oAd, it achieved a durable antitumor response. Besides, oAd-CXCL11 had a potent antitumor effect and reprogramed the immunosuppressive TME in GL261 GBM models, in which increased infiltration of CD8+ T lymphocytes, natural killer (NK) cells, and M1-polarized macrophages, while decreased proportions of myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) and M2-polarized macrophages were observed. Furthermore, the antitumor effect of the oAd-CXCL11 was CD8+ T cell dependent. Our findings thus revealed that CXCL11-armed oAd can improve immune-virotherapy and can be a promising adjuvant of CAR-T therapy for GBM.
| S-EPMC9840126 | biostudies-literature
Project description:Previous studies have suggested that PTEN loss is associated with p110β signaling dependency, leading to the clinical development of p110β-selective inhibitors. Here we use a panel pre-clinical models to reveal that PI3K isoform dependency is not governed by loss of PTEN and is impacted by feedback inhibition and concurrent PIK3CA/PIK3CB alterations. Furthermore, while pan-PI3K inhibition in PTEN-deficient tumors is efficacious, upregulation of Insulin Like Growth Factor 1 Receptor (IGF1R) promotes resistance. Importantly, we show that this resistance can be overcome through targeting AKT and we find that AKT inhibitors are superior to pan-PI3K inhibition in the context of PTEN loss. However, in the presence of wild-type PTEN and PIK3CA-activating mutations, p110α-dependent signaling is dominant and selectively inhibiting p110α is therapeutically superior to AKT inhibition. These discoveries reveal a more nuanced understanding of PI3K isoform dependency and unveil novel strategies to selectively target PI3K signaling nodes in a context-specific manner.
| S-EPMC8379232 | biostudies-literature
Project description:CIC-DUX4-rearranged sarcoma (CDS) is a rare and aggressive soft tissue tumor that occurs most frequently in young adults. The key oncogenic driver of this disease is the expression of the CIC-DUX4 fusion protein as a result of chromosomal rearrangements. CIC-DUX4 displays chromatin binding properties, and is therefore believed to function as an aberrant transcription factor. However, the chromatin remodeling events induced by CIC-DUX4 are not well understood, limiting our ability to identify new mechanism-based therapeutic strategies for these patients. Here, we generated a genome-wide profile of CIC-DUX4 DNA occupancy and associated chromatin states in human CDS cell models and primary tumors. Combining chromatin profiling, proximity ligation assays, as well as genetic and pharmacological perturbations, we show that CIC-DUX4 operates as a potent transcriptional activator at its binding sites. This property is in contrast with the repressive function of the wild-type CIC protein, and is mainly mediated through the direct interaction of CIC-DUX4 with the acetyltransferase p300. In keeping with this, we show p300 to be essential for CDS tumor cell proliferation; additionally, we find its pharmacological inhibition to significantly impact tumor growth in vitro and in vivo. Taken together, our study elucidates the mechanisms underpinning CIC-DUX4-mediated transcriptional regulation.
| S-EPMC10814785 | biostudies-literature