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Oncogenic lncRNAs alter epigenetic memory at a fragile chromosomal site in human cancer cells [ChIP-seq]

ABSTRACT: Chromosome instability is a key event in cancer progression. The essential histone H3 variant CENP-A plays a fundamental role in defining centromere identity, structure, and function, but is innately overexpressed in several types of solid cancers. In the cancer background, excess CENP-A is deposited ectopically on chromosome arms, including at the 8q24/cMYC locus, by invading transcription-coupled H3.3 chaperone pathways. Intriguingly, in many cancers, transcription of lncRNAs is upregulated and correlates with poor prognosis, therapeutic resistance, and cancer recurrence in patients. Here, we report that the transcription of chromosome 8q24-derived oncogenic lncRNAs plays an unanticipated role in altering the chromatin landscape of the 8q24 locus. We report that transcription of oncogenic ncRNAs and associated R-loop formation at the 8q24 genomic locus results in the recruitment of H3.3 chaperone-CENP-A histone variant complexes to 8q24. Finally, we demonstrate that a transgene cassette which encodes a specific oncogenic lncRNA from the 8q24 region integrated into a naïve chromosome locus, recruits CENP-A to the new location specifically in a cis-acting manner. These data provide a plausible mechanistic link between locus-specific oncogenic lncRNAs, aberrant local chromatin structure, and the generation of new epigenetic memory in human cancer cells.

ORGANISM(S): Homo sapiens

PROVIDER: GSE180938 | GEO | 2022/03/09

REPOSITORIES: GEO

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Oncogenic lncRNAs alter epigenetic memory at a fragile chromosomal site in human cancer cells [RNA-seq]

Project description:Chromosome instability is a key event in cancer progression. The essential histone H3 variant CENP-A plays a fundamental role in defining centromere identity, structure, and function, but is innately overexpressed in several types of solid cancers. In the cancer background, excess CENP-A is deposited ectopically on chromosome arms, including at the 8q24/cMYC locus, by invading transcription-coupled H3.3 chaperone pathways. Intriguingly, in many cancers, transcription of lncRNAs is upregulated and correlates with poor prognosis, therapeutic resistance, and cancer recurrence in patients. Here, we report that the transcription of chromosome 8q24-derived oncogenic lncRNAs plays an unanticipated role in altering the chromatin landscape of the 8q24 locus. We report that transcription of oncogenic ncRNAs and associated R-loop formation at the 8q24 genomic locus results in the recruitment of H3.3 chaperone-CENP-A histone variant complexes to 8q24. Finally, we demonstrate that a transgene cassette which encodes a specific oncogenic lncRNA from the 8q24 region integrated into a naïve chromosome locus, recruits CENP-A to the new location specifically in a cis-acting manner. These data provide a plausible mechanistic link between locus-specific oncogenic lncRNAs, aberrant local chromatin structure, and the generation of new epigenetic memory in human cancer cells.

2022-03-09 | GSE180923 | GEO

Oncogenic lncRNAs alter epigenetic memory at a fragile chromosomal site in human cancer cells [WGS]

2022-03-09 | GSE180957 | GEO

HJURP antagonizes CENP-A mislocalization driven by the H3.3 chaperones HIRA and DAXX

Project description:The centromere specific histone H3 variant CENP-A/CENH3 specifies where the kinetochore is formed in most eukaryotes. Despite tight regulation of CENP-A levels in normal cells, overexpression of CENP-A is a feature shared by various types of solid tumors and results in its mislocalization to non-centromeric DNA. How CENP-A is assembled ectopically and the consequences of this mislocalization remain topics of high interest. Here, we report that in human colon cancer cells, the H3.3 chaperones HIRA and DAXX promote ectopic CENP-A deposition. Moreover, the correct balance between levels of the centromeric chaperone HJURP and CENP-A is essential to preclude ectopic assembly by H3.3 chaperones. In addition, we find that ectopic localization can recruit kinetochore components, and correlates with mitotic defects and DNA damage in G1 phase. Finally, CENP-A occupancy at the 8q24 locus is also correlated with amplification and overexpression of the MYC gene within that locus. Overall, these data provide insights into the causes and consequences of histone variant mislocalization in human cancer cells.

2018-10-10 | GSE120230 | GEO

Genome-wide maps of WT and over-expressing CenH3/CENP-A in Human HeLa S3 cells

Project description:Centromeres are essential to ensure proper chromosome segregation in eukaryotes. Their definition relies on the presence of a centromere-specific H3 histone variant CenH3, known as CENP-A in mammals. Its overexpression in aggressive cancers raises questions concerning its effect on chromatin dynamics and contribution to tumorigenesis. We find that CenH3 overexpression in human cells leads to ectopic enrichment at sites of active histone turnover. Furthermore, in over-expressing conditions, we see the formation of a novel heterotypic particle (CenH3-H4/H3.3-H4) that occludes CTCF binding, but this occlusion has only a minor effect on gene expression. Ectopic localization and CTCF occlusion depends on the H3.3 chaperone DAXX, rather than its dedicated chaperone HJURP. This DAXX-dependent occlusion also occurs in naturally overexpressing cancer cells. Furthermore, our cellular model reveals a DAXX-dependent survival advantage when challenged by DNA damage. Our findings illustrate how changes in histone variant levels can disrupt chromatin dynamics in disease and provides a possible mechanism for cell resistance to anti-cancer treatments. Examination of CenH3 ChIP-seq and RNA-seq transcriptional programs in two conditions - WT and CenH3 over-expressing.

2014-02-12 | E-GEOD-42951 | biostudies-arrayexpress

DNAJC9 prevents CENP-A mislocalization and chromosomal instability by maintaining the fidelity of histone supply chains

Project description:The centromeric histone H3 variant CENP-A is overexpressed in many cancers. The mislocalization of CENP-A to noncentromeric regions contributes to chromosomal instability (CIN), a hallmark of cancer. However, pathways that promote or prevent CENP-A mislocalization remain poorly defined. Here, we performed a genome-wide RNAi screen for regulators of CENP-A localization which identified DNAJC9, a J-domain protein implicated in histone H3–H4 protein folding, as a factor restricting CENP-A mislocalization. Cells lacking DNAJC9 exhibit mislocalization of CENP-A throughout the genome, and CIN phenotypes. Global interactome analysis showed that DNAJC9 depletion promotes the interaction of CENP-A with the DNA-replication-associated histone chaperone MCM2. CENP-A mislocalization upon DNAJC9 depletion was dependent on MCM2, defining MCM2 as a driver of CENP-A deposition at ectopic sites when H3–H4 supply chains are disrupted. Cells depleted for histone H3.3, also exhibit CENP-A mislocalization. In summary, we have defined novel factors that prevent mislocalization of CENP-A, and demonstrated that the integrity of H3–H4 supply chains regulated by histone chaperones such as DNAJC9 restrict CENP-A mislocalization and CIN.

2024-04-11 | PXD043961 | Pride

Genome-wide maps of WT and over-expressing CenH3/CENP-A in Human HeLa S3 cells

2014-02-12 | GSE42951 | GEO

DAXX Suppression of ALT

Project description:<p>Many tumors maintain chromosome ends through a telomerase-independent, homologous recombination based mechanism called alternative lengthening of telomeres (ALT). While ALT occurs in only a subset of tumors, it is strongly associated with mutations in the genes encoding components of the histone H3.3 chaperone complex, ATRX and DAXX. To date the mechanistic role of ATRX and particularly DAXX mutations in potentiating ALT remains poorly understood. We identify an osteosarcoma cell line, G292, with a unique chromosomal translocation resulting in loss of DAXX function, while retaining functional ATRX. Using this distinctive resource, we demonstrate that introduction of wild type DAXX suppresses the ALT phenotype and restores localization of the ATRX/DAXX complex to PML bodies. This provides the first direct molecular evidence that ongoing DAXX deficiency is essential for maintenance of the ALT phenotype and highlights the potential for therapeutic targeting of this oncogenic pathway.</p>

| phs001495 | dbGaP

Endogenous mammalian histone H3.3 exhibits chromatin-related functions during development

Project description:Background. The histone variant H3.3 plays key roles in regulating chromatin states and transcription. However, the role of endogenous H3.3 in mammalian cells and during development has been less thoroughly investigated. To address this gap, we report the production and phenotypic analysis of mice and cells with targeted disruption of the H3.3-encoding gene, H3f3b. Results. H3f3b KO mice exhibit a semi-lethal phenotype traceable at least in part to defective cell division and chromosome segregation. H3f3b KO cells have widespread ectopic CENP-A protein localization suggesting one possible mechanism for defective chromosome segregation. KO cells have abnormal karyotypes and cell cycle profiles as well. The transcriptome and euchromatin-related epigenome were moderately affected by loss of H3f3b in MEFs with ontology most notably pointing to changes in chromatin regulatory and histone coding genes. Reduced numbers of H3f3b KO mice survive to maturity and almost all survivors from both sexes are infertile. Conclusions. Taken together, our studies suggest that endogenous mammalian histone H3.3 has important roles in regulating chromatin and chromosome functions that in turn are important for cell division, genome integrity, and development. Examination of H3K9Ac and H3K4me3 in wild-type and H3.3 null MEFs

2013-04-24 | E-GEOD-34546 | biostudies-arrayexpress

The 8q24 Enhancer Region including rs6983267 Directly Interacts with Promoter of Oncogenic LncRNA CARLo-5

Project description:The mechanism by which rs6983267 at 8q24.21 increases cancer risk is unclear for the lack of protein?coding genes in the region although the variant is strongly associated with cancer pathogenesis. Here we identify long non-coding RNAs (lncRNAs) near the 8q24 region and show that expression of lncRNA CARLo-5 is significantly correlated with the risk allele of the cancer-associated variant rs6883267. We further report that the 8q24 enhancer region including the variant directly interacts with active regulatory region of the lncRNA CARLo-5 promtoer. Finally, we demonstrate that CARLo-5 has an oncogenic function by regulating cell proliferation and cell-cycle. Our data provide new insight of disease-related variants in a gene desert. Comparison and identification of cell cycle-related genes differentially expressed by CARLo-5 knockdown using Nanostring analysis in HCT116 cells.

2014-03-05 | E-GEOD-48877 | biostudies-arrayexpress

The CENP-T/-W complex is a binding partner of the histone chaperone FACT

Project description:The CENP-T/-W histone fold complex, as an integral part of the inner kinetochore, is essential for building a proper kinetochore at the centromere in order to direct chromosome segregation during mitosis. Notably, CENP-T/-W is not inherited at centromeres and new deposition is absolutely required at each cell cycle for kinetochore function. However, the mechanisms underlying this new deposition of CENP-T/-W at centromeres are unclear. Here, we find that CENP-T deposition at centromeres is uncoupled from DNA synthesis. We identify Spt16 and SSRP1, subunits of the H2A-H2B histone chaperone FACT, as CENP-W binding partners through a proteomic screen. We find that the C-terminal region of Spt16 binds specifically to the histone fold region of CENP-T/-W. Furthermore, depletion of Spt16 impairs CENP-T and CENP-W deposition at endogenous centromeres and site directed targeting of Spt16 alone is sufficient to ensure local de novo CENP-T accumulation. We propose a model in which the FACT chaperone stabilizes the soluble CENP-T/-W complex in the cell and promotes dynamics of exchange, enabling CENP-T/-W deposition at centromeres.

2016-06-14 | PXD004099 | Pride

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