Promoter and enhancer RNAs regulate chromatin reorganization and activation of miR-10b/HOXD locus and neoplastic transformation in glioma
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PROVIDER: PRJNA676045 | ENA |
REPOSITORIES: ENA
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Project description:Using a combination of chromatin capture techniques, ChIP-Seq, single-molecule in situ RNA analysis, and computational analysis of large-scale TCGA datasets, we identified an epigenetic mechanism underlying common activation of HOXD/miR-10b locus in otherwise highly heterogenous glioma brain tumors. We demonstrate for the first time that two remote lncRNAs, one associated with a genomic promoter and another with a newly identified enhancer, cooperatively shape the 3D chromatin structure and looping, leading to the activation of a large gene cluster (12 genes, 110 KB) that includes the regulatory miRNA essential for glioma survival. This work describes a new mechanism contributing to neoplastic transformation in gliomagenesis, and identifies new avenues for therapeutic interventions based on the promoter and enhancer associated regulatory transcripts. Overall design: We used 4C-Seq technique with HOXD3/HOXD4/miR10b_gene_body as a viewpoint (NlaIII) to characterize the differences in 3D chromatin architecture between tumorigenic adherent glioma cell line (LN229, U251), low-passage glioma-initiating stem-like cells grown as spheroids (GBM8, GBM6, GBM4) and fetal human astrocytes, neuroprogenitors (NPC) in 500 kb HOXD/miR10b TAD domain. Moreover we examined changes in HOXD/miR10b TAD architecture after HOXD-AS2 (promoter) OR LINC01116 (enhancer) KD in glioma and 'transformed' astrocytes with active LINC01116 (enhancer). Additionally, HOXD/miR10b chromatin architecture was analyzed after the activation of LINC01116 (enhancer RNA) in fetal human astrocytes.
2021-11-11 | GSE161256 | GEO
Project description:Using a combination of chromatin capture techniques, ChIP-Seq, single-molecule in situ RNA analysis, and computational analysis of large-scale TCGA datasets, we identified an epigenetic mechanism underlying common activation of HOXD/miR-10b locus in otherwise highly heterogenous glioma brain tumors. We demonstrate for the first time that two remote lncRNAs, one associated with a genomic promoter and another with a newly identified enhancer, cooperatively shape the 3D chromatin structure and looping, leading to the activation of a large gene cluster (12 genes, 110 KB) that includes the regulatory miRNA essential for glioma survival. This work describes a new mechanism contributing to neoplastic transformation in gliomagenesis, and identifies new avenues for therapeutic interventions based on the promoter and enhancer associated regulatory transcripts. Overall design: In order to characterize epigenetic status of HOXD/miR10b genomic we performed ChIP-Seq with H3K27Ac (#4353, Cell Signaling) and H3K27Me3 (#4353, Cell Signaling) in low-passage glioma-initiating stem-like cells grown as spheroids (GBM8) and fetal human astrocytes. To analyse whether CTCF/Rad21 binding changes after HOXD-AS2 or LINC01116 KD in GBM8 and LINC01116 activation in fetal human astrocytes we performed ChIP-Seq CTCF (#3418, Cell Signaling), Rad21 (ab992, Abcam) .
2021-11-11 | GSE161257 | GEO
Project description:Promoter and enhancer RNAs regulate chromatin reorganization and activation of miR-10b/HOXD locus and neoplastic transformation in glioma [4C-seq]
| PRJNA676096 | ENA
Project description:Promoter and enhancer RNAs regulate chromatin reorganization and activation of miR-10b/HOXD locus and neoplastic transformation in glioma [ChIP-seq]
| PRJNA676095 | ENA
Project description:The transcriptional activation of HoxD genes during mammalian limb development involves dynamic interactions with two topologically associating domains (TADs) flanking the HoxD cluster. In particular, the activation of the most posterior HoxD genes in developing digits is controlled by regulatory elements located in the centromeric TAD (C-DOM) through long-range contacts.To assess the structure-function relationships underlying such interactions, we measured compaction levels and TAD discreteness using a combination of chromosome conformation capture (4C-seq) and DNA FISH. We assessed the robustness of the TAD architecture by using a series of genomic deletions and inversions that impact the integrity of this chromatin domain and that remodel long-range contacts. We report multi-partite associations between HoxD genes and up to three enhancers. We find that the loss of native chromatin topology leads to the remodeling of TAD structure following distinct parameters.Our results reveal that the recomposition of TAD architectures after large genomic re-arrangements is dependent on a boundary-selection mechanism in which CTCF mediates the gating of long-range contacts in combination with genomic distance and sequence specificity. Accordingly, the building of a recomposed TAD at this locus depends on distinct functional and constitutive parameters.
2017-01-01 | S-EPMC5547506 | BioStudies
Project description:This SuperSeries is composed of the SubSeries listed below. Overall design: Refer to individual Series
2021-11-11 | GSE161258 | GEO
Project description:MicroRNA (miRNA) expression profiling studies revealed a number of miRNAs dysregulated in the malignant brain tumor glioblastoma. Molecular functions of these miRNAs in gliomagenesis are mainly unknown. We show that inhibition of miR-10b, a miRNA not expressed in human brain and strongly upregulated in both low-grade and high-grade gliomas, reduces glioma cell growth by cell-cycle arrest and apoptosis. These cellular responses are mediated by augmented expression of the direct targets of miR-10b, including BCL2L11/Bim, TFAP2C/AP-2?, CDKN1A/p21, and CDKN2A/p16, which normally protect cells from uncontrolled growth. Analysis of The Cancer Genome Atlas expression data set reveals a strong positive correlation between numerous genes sustaining cellular growth and miR-10b levels in human glioblastomas, while proapoptotic genes anticorrelate with the expression of miR-10b. Furthermore, survival of glioblastoma patients expressing high levels of miR-10 family members is significantly reduced in comparison to patients with low miR-10 levels, indicating that miR-10 may contribute to glioma growth in vivo. Finally, inhibition of miR-10b in a mouse model of human glioma results in significant reduction of tumor growth. Altogether, our experiments validate an important role of miR-10b in gliomagenesis, reveal a novel mechanism of miR-10b-mediated regulation, and suggest the possibility of its future use as a therapeutic target in gliomas.
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Project description:Chromatin condensation plays an important role in the regulation of gene expression. Recently, it was shown that the transcriptional activation of Hoxd genes during vertebrate digit development involves modifications in 3D interactions within and around the HoxD gene cluster. This reorganization follows a global transition from one set of regulatory contacts to another, between two topologically associating domains (TADs) located on either side of the HoxD locus. Here, we use 3D DNA FISH to assess the spatial organization of chromatin at and around the HoxD gene cluster and report that although the two TADs are tightly associated, they appear as spatially distinct units. We measured the relative position of genes within the cluster and found that they segregate over long distances, suggesting that a physical elongation of the HoxD cluster can occur. We analyzed this possibility by super-resolution imaging (STORM) and found that tissues with distinct transcriptional activity exhibit differing degrees of elongation. We also observed that the morphological change of the HoxD cluster in developing digits is associated with its position at the boundary between the two TADs. Such variations in the fine-scale architecture of the gene cluster suggest causal links among its spatial configuration, transcriptional activation, and the flanking chromatin context.
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Project description:Glioblastoma (GBM) brain tumor remains among the most lethal and incurable human diseases. Oncogenic microRNA-10b (miR-10b) is strongly and universally upregulated in GBM, and its inhibition by antisense oligonucleotides (ASOs) reduces the growth of heterogeneous glioma cells; therefore, miR-10b represents a unique therapeutic target for GBM. Here we explored the effects of miR-10b gene editing on GBM. Using the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system, we investigated effects of miR-10b gene editing on the growth of cultured human glioma cells, tumor-initiating stem-like cells, and mouse GBM xenografts, as well as the oncogene-induced transformation of normal astrocytes. We show that GBM is strictly "addicted" to miR-10b and that miR-10b gene ablation is lethal for glioma cell cultures and established intracranial tumors. miR-10b loss-of-function mutations lead to the death of glioma, but not other cancer cell lines. We have not detected escaped proliferative clones of GBM cells edited in the miR-10b locus. Finally, neoplastic transformation of normal astrocytes was abolished by the miR-10b-editing vectors. This study demonstrates the feasibility of gene editing for brain tumors in vivo and suggests virus-mediated miR-10b gene ablation as a promising therapeutic approach that permanently eliminates the key regulator essential for tumor growth and survival.
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Project description:MicroRNA-10b may target numerous genes in gliomagenesis. The target genes of miR-10b may differ according to the cellular context. We used microarray analyses to determine the phenotypic effects and gene targets of miR-10b by silencing miR-10b in invasive U87-2M1 glioma cells. Early passage U87-2M1 cells treated with the baculoviral control decoy vector or miR-10b decoy vector were selected for RNA extraction and hybridization on microarray
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