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SRX5562448: GSM3684344: DIPGXIII-P15; Homo sapiens; ATAC-seq
1 ILLUMINA (Illumina HiSeq 2500) run: 49.9M spots, 12.5G bases, 3Gb downloads

Submitted by: NCBI (GEO)
Study: Pervasive H3K27 acetylation leads to ERV expression and a therapeutic vulnerability in H3K27M gliomas [ATAC-seq]
show Abstracthide Abstract
Epigenetic alterations are recurrently observed in cancer and are the subject of active therapeutic investigations. Midline high-grade gliomas (HGGs) are deadly brain tumors characterized by lysine-to-methionine substitutions at position 27 in histone 3 (H3) variants (denoted H3K27M), which are core components of the nucleosome. H3K27M, the first event in midline HGG development, results in a drastic loss of the repressive histone mark H3K27 tri-methylation (H3K27me3), and a notable increase in H3K27 acetylation (H3K27ac), a mark associated with active chromatin and cellular identity. H3K27ac gain was suggested to promote tumorigenesis in H3K27M-HGGs, but how these opposing marks shape oncogenesis remains controversial. We therefore characterized the active regulatory chromatin states in H3.3K27M and H3K27 wild-type HGGs and in H3.3K27M CRISPR/Cas9 knockout tumor-derived cell lines, as an isogenic tumor model of the mutation. We show that H3.3K27M-HGGs have distinct promoter, enhancer, super-enhancer, and core transcription factor circuitries from wild-type HGGs. However, while removal of H3.3K27M restores gross H3K27ac levels to those of wild-type HGGs, we observe minimal disruption of H3K27ac deposition at these active transcriptional elements, suggesting that they are a function of the cell of origin and independent of direct H3K27M mutagenesis and active regulation. Using quantitative ChIP-seq, we show that in H3.3K27M-HGGs, H3K27ac is pervasively deposited across the genome, including at normally silent repeat elements, leading to their increased baseline expression. H3.3K27M cells respond to DNA demethylating agents and histone deacetylase inhibitors, which further increase repeat element expression, including that of specific endogenous retroviral (ERVs) families. Our findings decouple cell lineage programs from H3K27M-dependent pervasive deposition of H3K27 acetylation. De-repression of ERVs may enhance the triggering of innate immune pathways, representing a therapeutic vulnerability in H3.3K27M HGGs. Overall design: We sequenced 2 H3.3K27WT (pcGBM2, G477; 2 replicates total) and 2 H3.3K27M (DIPGVI, DIPGXIII; 6 replicates total) patient-derived cell lines as well as Crispr/Cas9 H3.3K27M-KO clones for one of the cell lines (3 replicates total; DIPGXIII-KO) using ATAC-Seq. P-XX designates passages of replicates. Please note that the G477-LPG sample raw data is not provided due to patient privacy concerns and will be deposited at EGA under accession number EGAS00001003572.
Sample: DIPGXIII-P15
SAMN11239239 • SRS4526010 • All experiments • All runs
Organism: Homo sapiens
Library:
Instrument: Illumina HiSeq 2500
Strategy: ATAC-seq
Source: GENOMIC
Selection: other
Layout: PAIRED
Construction protocol: Adherent cell cultures were dissociated and 100 000 cells were washed twice in cold PBS at 4°C. Cells were resuspended in 100 uL Hypotonic Cell Lysis Buffer (0.1% Sodium Citrate Tribasic Dihydrate, 0.1% Triton X-100) and titurated until cells were dissolved. Samples were incubated on ice 30 minutes, centrifuged at 2000 g for 5 minutes at 4°C, and pellet resuspended in 100 uL Normal Cell Lysis Buffer (10 mM Tris-HCl, pH 7.4, 10 mM NaCl, 3 mM MgCl2, 0.1% IGEPAL CA-630), titurated, incubated on ice 30 minutes, centrifuged at 2000 g for 5 minutes at 4°C, and supernatant removed. The transposase reaction was carried out by titurating in 25 uL per sample in TD Buffer (10 mM Tris-HCl, pH 8.00, 5 mM Magnesium Chloride) with 5 uL Transposase (Illumina Nextera Kit), and incubated at 37°C for 30 minutes, and 8.5 uL of 100mM EDTA was added, samples transferred to ice, and DNA recovered using MinElute PCR Purification columns (Qiagen). Libraries were generated by PCR in 50 uL reaction (25 uL sample, 10 uL 5x Phusion HF buffer, 0.5 uL Phusion Polymerase, 1 uL 10mM dNTPs, 0.5 uL of each custom Illumina primers at 12.5 uM). The PCR reaction followed 98°C for 30 seconds, followed by 12 cycles of 98°C for 10s, 63°C for 30s, 72°C for 1 min, followed by 72°C for 5 min. DNA was recovered using GeneRead Purification columns (Qiagen). The libraries were sequenced to 50 million reads per sample on Illumina HiSeq 2500 using Nextera Sequencing Primers.
Experiment attributes:
GEO Accession: GSM3684344
Links:
Runs: 1 run, 49.9M spots, 12.5G bases, 3Gb
Run# of Spots# of BasesSizePublished
SRR877233749,874,52512.5G3Gb2019-05-31

ID:
7507904

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