The histone variant H2A.X is a regulator of Epithelial–Mesenchymal Transition
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE75444 | GEO | 2016/02/10
SECONDARY ACCESSION(S): PRJNA304305
REPOSITORIES: GEO
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Project description:The epithelial-mesenchymal transition (EMT), considered essential for metastatic cancer, has been a focus of much research, but important questions remain. Here, we show that silencing or removing H2A.X, a histone H2A variant involved in cellular DNA repair and robust growth, induced mesenchymal-like characteristics including activation of EMT transcription factors, Slug and ZEB1, in HCT116 human colon cancer cells. Ectopic H2A.X re-expression partially reversed these changes; as did silencing Slug and ZEB1. In an experimental metastasis model, the HCT116 parental and H2A.X-null cells exhibited similar metastases levels, but the cells with re-expressed H2A.X exhibited substantially elevated levels. We surmise that H2A.X re-expression led to partial EMT reversal and increased robustness in the HCT116 cells, permitting them to both form tumors and to metastasize. In a human adenocarcinoma panel, H2A.X levels correlated inversely with Slug and ZEB1 levels. Together, these results point to H2A.X as a novel regulator of EMT. 9 samples in total including 4 replicates of control shRNA and 5 replicates of shH2A.X.
2016-02-10 | E-GEOD-75444 | biostudies-arrayexpress
Project description:The epithelial-mesenchymal transition (EMT) is thought to be essential for cancer metastasis. While chromatin remodeling is involved in EMT, histone variants contribution in EMT remains poorly investigated. Recently, we showed that silencing or removal of the histone variant H2A.X induced mesenchymal-like characteristics, including activation of the EMT transcription factors, Slug and ZEB1, in human colon cancer cells. Here, we provide the evidence that H2A.X loss in human non-tumorigenic breast cell line MCF10A results in a robust EMT activation, as substantiated by a genome-wide expression analysis. Cells deficient for H2A.X exhibit enhanced migration and invasion, along with an activation of a set of mesenchymal genes and a concomitant repression of epithelial genes. In the breast model, the EMT-related transcription factor Twist1 cooperates with Slug to regulate EMT upon H2A.X loss. Of interest, H2A.X expression level tightly correlates with Twist1, and to a lesser extent with Slug in the panel of human breast cancer cell lines of the NCI-60 datasets. These new findings indicate that H2A.X is involved in the EMT processes in cells of different origins but pairing with transcription factors for EMT may be tissue specific.
2016-06-21 | GSE80180 | GEO
Project description:Epithelial-to-mesenchymal transition (EMT) is a fundamental process in development and disease. If aberrantly activated it is a trigger for tumour progression and metastasis (Thiery et al 2009 Cell). It is now known that EMT activation is also associated with the maintenance of stem-cell properties (Mani et al. 2008 Cell). Since Zinc-finger enhancer binding transcription factor 1 (ZEB1) is a crucial EMT activator, we analyzed the changes in the gene expression profile that accompany shRNA mediated loss of ZEB1 in HCT116 colorectal cancer cells. HCT116 is a cell line that exhibits mesenchymal characteristics, but reverts to an epithelial phenotype upon ZEB1 knock down (Spaderna et al. 2008 Cancer Research). HCT116 cells were stably transfected with control (GFP) or ZEB1 shRNA. Upon puromycin selection, single cell clones were picked and characterized. Cells from two control versus two ZEB1 knockdown clones were harvested, total RNA was isolated and processed to hybridization.
2016-06-15 | E-MTAB-3480 | biostudies-arrayexpress
Project description:TGF-beta is a known driver of epithelial-mesenchymal transition (EMT) which is associated with tumor aggressiveness and metastasis. However, EMT has not been fully explored in clinical specimens of castration-resistant prostate cancer (CRPC) metastases. To assess EMT in CRPC, gene expression analysis was performed on 149 visceral and bone metastases from 62 CRPC patients and immunohistochemical analysis was performed on 185 CRPC bone and visceral metastases from 42 CRPC patients. In addition, to assess the potential of metastases to seed further metastases the mitochondrial genome was sequenced at different metastatic sites in one patient. TGF-beta was increased in bone versus visceral metastases. While primarily cytoplasmic; nuclear and cytoplasmic Twist were significantly higher in bone than in visceral metastases. Slug and Zeb1 were unchanged, with the exception of nuclear Zeb1 being significantly higher in visceral metastases. Importantly, nuclear Twist, Slug, and Zeb1 were only present in a subset of epithelial cells that had an EMT-like phenotype. Underscoring the relevance of EMT-like cells, mitochondrial sequencing revealed that metastases could seed additional metastases in the same patient. In conclusion, while TGF-beta expression and EMT-associated protein expression is present in a considerable number of CRPC visceral and bone metastases, nuclear Twist, Slug, and Zeb1 localization and an EMT-like phenotype (elongated nuclei and cytoplasmic compartment) was only present in a small subset of CRPC bone metastases. Mitochondrial sequencing from different metastases in a CRPC patient provided evidence for the seeding of metastases from previously established metastases, highlighting the biological relevance of EMT-like behavior in CRPC metastases.
2015-12-18 | GSE74685 | GEO
Project description:H2A.X is an H2A variant histone in eukaryotes, unique for its ability to respond to DNA damage, initiating the DNA repair pathway. H2A.X replacement within the histone octamer is mediated by the FAcilitates Chromatin Transactions (FACT) complex, a key chromatin remodeler. FACT is required for DEMETER (DME)-mediated DNA demethylation at certain loci in Arabidopsis thaliana female gametophytes during reproduction. Here, we sought to investigate whether H2A.X is involved in DME- and FACT-mediated DNA demethylation during reproduction. H2A.X is encoded by two genes in Arabidopsis genome, HTA3 and HTA5. We generated h2a.x double mutants, which displayed a normal growth profile, whereby flowering time, seed development, and root tip organization, S-phase progression and proliferation were all normal. However, h2a.x mutants were more sensitive to genotoxic stress, consistent with previous reports. H2A.X fused to Green Fluorescent Protein (GFP) under the H2A.X promoter was highly expressed especially in newly developing Arabidopsis tissues, including in male and female gametophytes, where DME is also expressed. We examined DNA methylation in h2a.x developing seeds and seedlings using whole genome bisulfite sequencing, and found that CG DNA methylation is decreased genome-wide in h2a.x mutant seeds. Hypomethylation was most striking in transposon bodies, and occurred on both parental alleles in the developing endosperm, but not the embryo or seedling. h2a.x-mediated hypomethylated sites overlapped DME targets, but also included other loci, predominately located in heterochromatic transposons and intergenic DNA. Our genome-wide methylation analyses suggest that H2A.X could function in preventing access of the DME demethylase to non-canonical sites. Alternatively, H2A.X may be involved in recruiting methyltransferases to those sites. Overall, our data show that H2A.X is required to maintain DNA methylation homeostasis in the unique chromatin environment of the Arabidopsis endosperm.
2023-08-07 | GSE233920 | GEO
Project description:It has widely accepted that 5-methylcytosine is the only form of DNA methylation in mammalian genomes, whereas the other forms, such as N6-methyladenine, primarily exist in prokaryotes and only a few eukaryotes. Herein, we demonstrated the surprising presence of N6-methyladenine in mammalian genomes, especially, mouse embryonic stem cells. This modification is enriched at histone variant H2A.X-deposited genomic regions in wild type embryonic stem cells. Our work also showed that a previously unknown DNA demethylase, Alkbh1, is the major demethylase for N6-methyladenine in embryonic stem cells. Increase of N6-methyladenine levels in Alkbh1 deficient cells leads to silencing of genes that regulate embryonic development. Surprisingly, genes located on the X-chromosome, but not the Y-chromosome or autosomes are preferentially silenced by N6-methyladenine. Strikingly, N6-methyladenine in Alkbh1 deficient cells are specifically deposition at young, full-length subfamilies of LINE1 transposons that are strongly enriched on the X chromosome. Furthermore, N6-methyladenine deposition on LINE1s pattern is inversely correlated with their evolutionary age. The deposition of N6-methyladenine results in epigenetic silencing of such L1s, which are otherwise actively transcribed in wild type embryonic stem cells, and the neighboring enhancers and genes. Furthermore, N6-methyladenine induced-silencing resists gene activation signals during embryonic stem cell differentiation. Thus, N6-methyladenine adopts a new function in epigenetic silencing in evolution, distinct from its role in gene activation in other organisms. In summary, our results demonstrate that N6-methyladenine unexpectedly constitutes a crucial component of the epigenetic regulation repertoire in mammalian genomes. First, we used a native-ChIP approach to enrich for DNA molecules residing in H2A.X-deposition regions in mouse ESCs as previously described. Then, co-purified DNA molecules from WT or KO ESCs were subject to SMRT sequencing and data analysis for DNA modifications (Pacific Biosciences). H2A.X Native ChIP coupling with SMRT sequencing (separate the short "S" and long "L" part to sequencing)
2016-03-30 | E-GEOD-71940 | biostudies-arrayexpress
Project description:With the advent of the induced pluripotent stem cell (iPSC) technology, how to distinguish the developmental potentials of the iPSC clones with molecular approaches becomes an imperative issue. Herein, we demonstrated that histone variant H2A.X plays an unexpected role in distinguishing the developmental potentials of iPSC. We showed that H2A.X is specifically targeted to and negatively regulates extra-embryonic lineage gene expression in embryonic stem cell (ESCs) and therefore, it prevents trophectoderm (TE) lineage differentiation under inductive conditions. ESC-specific H2A.X deposition and functions are faithfully recapitulated in the iPSC lines that support the development of “all-iPS” animals. In iPSC lines that fail to support embryonic development, aberrant H2A.X depositions result in upregulation of extra-embryonic lineage genes and predisposition to extra-embryonic tissue differentiation. In summary, our work has revealed novel epigenetic mechanisms for maintaining cell lineage commitment, which can be used to distinguish the quality of the iPSC lines. Detect and compare different H2A.X deposition patterns in ES cells [GSE42306] and TS cells, with Illumina HiSeq 2000
2014-09-07 | E-GEOD-57216 | biostudies-arrayexpress
Project description:It is well-known that embryonic stem cells (ESC) are much more sensitive to replication-induced stress than differentiated cells but the underpinning mechanisms are largely unknown. H2A.X, a minor variant of H2A, constitutes only 1-10% of the mammalian genome. H2A.X plays a well-known for role in the DNA damage response and maintaining stability in the genome, including the regions frequently experiencing replication stress, such as the fragile sites. Intriguingly, several recent studies have reported that H2A.X function is elevated in ESC; and others reported that H2A.X function is provoked during cellular reprogramming (in induced pluripotent stem cells, iPSC), indicating that increased proliferation during iPS may trigger replication stress and the H2A.X DNA damage response. However, several studies of genomic instability in iPSC led to different conclusions on this important issue. For example, frequent copy number variants (CNV) were reported at the genomic regions sensitive to replication stress, such as the fragile sites. On the other hand, another study reported the lack of genomic instability in mouse iPS clones that are able to generate “all-iPS” animals in tetraploid complementation assays (4N+ iPSC), indicative of a potential link between pluripotency and genome integrity. However, whether if high level genomic instability occurs in the 4N- iPSC iPSC clones at replication stress sensitive regions is unknown. Moreover, due to the lack of mechanistic insights on genome integrity maintenance, how pluripotency and genome integrity are connected remains elusive. Here we show that H2A.X plays unexpected roles in maintaining pluripotency and genome integrity in ESC and iPSC. In ESC, it is specially enriched at genomic regions sensitive to replication stress so that it protects genome integrity thereat. Faithful H2A.X deposition is critical for genome integrity and pluripotency in iPSC. H2A.X depositions in 4N+ iPSC clones faithfully recapitulate the ESC pattern and therefore, prevent genome instability. On the other hand, insufficient H2A.X depositions in 4N- iPSC clones at such regions lead to genome instability and defects in replication stress response and DNA repair, reminiscent of the H2A.X deficient ESC. In this study, male 129sv/C57 ES cell genomic DNA was used as reference control, to identify CNV sites in iPS cell lines. And also detect H2A.X (-/-) ES cell (129/Sv) CNVs, with the H2A.X(f/f) ES cell DNA (129/Sv) as control. DNA samples were compared on NimbleGen Mouse CGH 3x720K Whole-Genome Tiling Array (Build MM9).
2014-09-07 | E-GEOD-42266 | biostudies-arrayexpress
Project description:It is well-known that embryonic stem cells (ESC) are much more sensitive to replication-induced stress than differentiated cells but the underpinning mechanisms are largely unknown. H2A.X, a minor variant of H2A, constitutes only 1-10% of the mammalian genome. H2A.X plays a well-known for role in the DNA damage response and maintaining stability in the genome, including the regions frequently experiencing replication stress, such as the fragile sites. Intriguingly, several recent studies have reported that H2A.X function is elevated in ESC; and others reported that H2A.X function is provoked during cellular reprogramming (in induced pluripotent stem cells, iPSC), indicating that increased proliferation during iPS may trigger replication stress and the H2A.X DNA damage response. However, several studies of genomic instability in iPSC led to different conclusions on this important issue. For example, frequent copy number variants (CNV) were reported at the genomic regions sensitive to replication stress, such as the fragile sites. On the other hand, another study reported the lack of genomic instability in mouse iPS clones that are able to generate “all-iPS” animals in tetraploid complementation assays (4N+ iPSC), indicative of a potential link between pluripotency and genome integrity. However, whether if high level genomic instability occurs in the 4N- iPSC iPSC clones at replication stress sensitive regions is unknown. Moreover, due to the lack of mechanistic insights on genome integrity maintenance, how pluripotency and genome integrity are connected remains elusive. Here we show that H2A.X plays unexpected roles in maintaining pluripotency and genome integrity in ESC and iPSC. In ESC, it is specially enriched at genomic regions sensitive to replication stress so that it protects genome integrity thereat. Faithful H2A.X deposition is critical for genome integrity and pluripotency in iPSC. H2A.X depositions in 4N+ iPSC clones faithfully recapitulate the ESC pattern and therefore, prevent genome instability. On the other hand, insufficient H2A.X depositions in 4N- iPSC clones at such regions lead to genome instability and defects in replication stress response and DNA repair, reminiscent of the H2A.X deficient ESC. Detect and compare different H2A.X deposition patterns in ES cells and iPS cells, with Illumina HiSeq 2000 and Illumina Genome Analyzer IIx
2014-09-07 | E-GEOD-42306 | biostudies-arrayexpress
Project description:It is well-known that embryonic stem cells (ESC) are much more sensitive to replication-induced stress than differentiated cells but the underpinning mechanisms are largely unknown. H2A.X, a minor variant of H2A, constitutes only 1-10% of the mammalian genome. H2A.X plays a well-known for role in the DNA damage response and maintaining stability in the genome, including the regions frequently experiencing replication stress, such as the fragile sites. Intriguingly, several recent studies have reported that H2A.X function is elevated in ESC; and others reported that H2A.X function is provoked during cellular reprogramming (in induced pluripotent stem cells, iPSC), indicating that increased proliferation during iPS may trigger replication stress and the H2A.X DNA damage response. However, several studies of genomic instability in iPSC led to different conclusions on this important issue. For example, frequent copy number variants (CNV) were reported at the genomic regions sensitive to replication stress, such as the fragile sites. On the other hand, another study reported the lack of genomic instability in mouse iPS clones that are able to generate “all-iPS” animals in tetraploid complementation assays (4N+ iPSC), indicative of a potential link between pluripotency and genome integrity. However, whether if high level genomic instability occurs in the 4N- iPSC iPSC clones at replication stress sensitive regions is unknown. Moreover, due to the lack of mechanistic insights on genome integrity maintenance, how pluripotency and genome integrity are connected remains elusive. Here we show that H2A.X plays unexpected roles in maintaining pluripotency and genome integrity in ESC and iPSC. In ESC, it is specially enriched at genomic regions sensitive to replication stress so that it protects genome integrity thereat. Faithful H2A.X deposition is critical for genome integrity and pluripotency in iPSC. H2A.X depositions in 4N+ iPSC clones faithfully recapitulate the ESC pattern and therefore, prevent genome instability. On the other hand, insufficient H2A.X depositions in 4N- iPSC clones at such regions lead to genome instability and defects in replication stress response and DNA repair, reminiscent of the H2A.X deficient ESC.
2014-09-07 | GSE42266 | GEO