BRCA2 abrogation triggers innate immune responses potentiated by treatment with PARP inhibitors
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA509430 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR8311450_1.fastq.gz | Fastqsanger.gz | |||
| SRR8311450_2.fastq.gz | Fastqsanger.gz | |||
| SRR8311460_1.fastq.gz | Fastqsanger.gz | |||
| SRR8311460_2.fastq.gz | Fastqsanger.gz | |||
| SRR8311470_1.fastq.gz | Fastqsanger.gz |
Items per page: 5 1 - 5 of 96 |
Similar Datasets
Project description:Heterozygous germline mutations in BRCA2 predispose to breast and ovarian cancer. Contrary to non-cancerous cells, where BRCA2 deletion causes cell cycle arrest or cell death, BRCA2 inactivation in tumors is associated with uncontrolled cell proliferation. We set out to investigate this conundrum by exploring modalities of cell adaptation to loss of BRCA2 and focused on genome-wide transcriptome alterations. Human cells in which BRCA2 expression was inhibited using a doxycycline (DOX)-inducible shRNA for 4 or 28 days were subjected to RNA-seq analyses. Gene sets differentially expressed in BRCA2-deficient versus -proficient cells revealed a biphasic response to BRCA2 abrogation. The early, acute response consisted of downregulation of genes involved in cell cycle progression, DNA replication and repair and was associated with cell cycle arrest in G1. Surprisingly, the late, chronic response consisted exclusively of upregulation of innate immune response genes controlled by interferon. Activation of the cGAS-STING pathway detected in these cells further substantiated the concept that long-term BRCA2 abrogation triggers cell-intrinsic immune signaling. Importantly, we found that treatment with PARP inhibitors stimulated the interferon response in cells and tumors lacking BRCA2. We propose that PARP inhibitors suppress growth of BRCA2-deficient cells and tumors, in part, by activating interferon signaling.
2018-12-11 | GSE123631 | GEO
Project description:Breast cancer gene 2 (BRCA2) deleterious mutations confer sensitivity to poly(ADP-ribose) polymerase (PARP) inhibition due to its critical role in DNA repair. PARP inhibitor Olaparib is now approved and several other PARP inhibitors are now in different stages of clinical trials. Development of resistance to PARP inhibitors limits their clinical utility. The mechanism of resistance remains not fully understood. Here we show that amplification of mutant BRCA2 confers PARP inhibitor resistance. The amplification of mutant BRCA2 gene copies correlates with an increase in mutant BRCA2 expression and an increase in the levels of its interacting proteins PALB2 and RAD51. In addition, homologous recombination mediated DNA repair is rescued in these cells as evidenced by the formation of RAD51 focus formation. The overexpressed mutant BRCA2 is essential for the observed PARP inhibitor resistance because knockdown of its expression is sufficient to re-sensitize these cells to PARP inhibition. Collectively, our results indicate a new mechanism of resistance to PARP inhibitor in BRCA2 mutant cancer cells
2017-09-02 | GSE86394 | GEO
Project description:Heterozygous germline mutations in BRCA2 predispose to breast and ovarian cancer. Contrary to non-cancerous cells, where BRCA2 deletion causes cell cycle arrest or cell death, tumors carrying BRCA2 inactivation continue to proliferate. Here we set out to investigate adaptation to loss of BRCA2 focusing on genome-wide transcriptome alterations. Human cells in which BRCA2 expression is inhibited for 4 or 28 days are subjected to RNA-seq analyses revealing a biphasic response to BRCA2 abrogation. The early, acute response consists of downregulation of genes involved in cell cycle progression, DNA replication and repair and is associated with cell cycle arrest in G1. Surprisingly, the late, chronic response consists predominantly of upregulation of interferon-stimulated genes (ISGs). Activation of the cGAS-STING-STAT pathway detected in these cells further substantiates the concept that BRCA2 abrogation triggers cell-intrinsic immune signaling. Importantly, we find that treatment with PARP inhibitors stimulates the interferon response in cells and tumors lacking BRCA2.
| S-EPMC6637138 | biostudies-literature
Project description:Transcription-Replication Conflicts drive the Synthetic Lethality of PARP Inhibitors with BRCA2-Deficiency
| PRJNA909256 | ENA
Project description:Mutations in the tumour suppressor BRCA2 are associated with predisposition to breast and ovarian cancers. BRCA2 has a central role in genome integrity by facilitating the repair of toxic DNA double-strand breaks (DSBs) by homologous recombination. BRCA2 acts by promoting RAD51 nucleofilament formation on resected single-stranded DNA, but how BRCA2 activity is regulated during HR is not fully understood. Here, we delineate a pathway where ATM and ATR kinases phosphorylate a highly conserved region in BRCA2 in response to DNA DSBs. These phosphorylations stimulate the binding of the protein phosphatase PP2A-B56 to BRCA2 through a conserved binding motif. We show that the phosphorylation-dependent formation of the BRCA2-PP2A-B56 complex is required for efficient RAD51 loading to sites of DNA damage and HR-mediated DNA repair. Moreover, we find that several cancer-associated mutations in BRCA2 deregulate the BRCA2-PP2A-B56 interaction and sensitize cells to PARP inhibition. Collectively, our work uncovers PP2A-B56 as a positive regulator of BRCA2 function in HR with clinical implications for BRCA2 and PP2A-B56 mutated cancers.
2021-07-26 | MSV000087884 | MassIVE
Project description:Inactivating germline monoallelic mutations in the tumor suppressor BRCA2 predispose to breast and ovarian cancer. BRCA2 is essential in DNA repair via homologous recombination (HR). Tumorigenesis in this setting is thought to require the inactivation of the second allele; however, this event is not always observed suggesting haploinsufficiency. We investigated this question recreating two BRCA2 pathogenic truncating variants in heterozygosis in breast epithelial cells. One prompted sensitivity to PARP inhibitors (PARPi) and reduced HR capacity unlike the other. The other resulted in transcriptomic and epigenetic changes including histone H4 acetylation levels and NF-kB activation that we link to PCAF acetyl transferase. These changes impacted on cell migration and proliferation in 2D and 3D, processes that were also deregulated in tumors. Our work demonstrates that distinct truncating variants of BRCA2 are not phenotypically equivalent. It also identifies PCAF as shaping BRCA2-related gene expression. These findings may have implications in cancer prevention.
2024-11-21 | GSE272335 | GEO
Project description:Abnormalities provoked in human cells heterozygous for clinically relevant truncating mutations in BRCA2 by their exposure to naturally occurring aldehydes define a mechanism promoting carcinogenesis in mutation carriers. The ubiquitous metabolite and environmental toxin, formaldehyde, triggers replication fork instability and structural chromosomal aberrations in BRCA2 heterozygous cells. These abnormalities arise from a previously unrecognized effect of formaldehyde to selectively induce the proteasomal degradation of BRCA2, inducing functional haploinsufficiency only in cells where BRCA2 expression is already compromised by a heterozygous mutation. Similar effects are observed with acetaldehyde, a toxic product of alcohol catabolism. Replication fork instability and chromosomal aberrations in aldehyde-exposed cells arise from the unscheduled accumulation of RNA-DNA hybrids, revealing a mechanism driving genomic instability in BRCA2 heterozygous cells. We propose a model for cancer pathogenesis in which aldehyde exposure unmasks the carcinogenic potential of heterozygous BRCA2 mutations, with public health implications in mutation carriers.
2017-06-02 | PXD006106 | Pride
Project description:Deleterious alterations of the gene encoding BRCA2, a protein involved in homologous recombination (HR), contribute to the pathogenesis of a subset of ovarian, breast, prostate and pancreatic cancers as well as their increased sensitivity to platinating agents and poly(ADP-ribose) polymerase inhibitors (PARPis). While secondary mutations that restore a functional BRCA2 protein are detected in a fraction of cases that become drug resistant, the causes of resistance in other cases are poorly understood. Here we characterized clones derived from the BRCA2-mutant ovarian cancer line PEO1 by PARPi selection. Colony forming assays demonstrated cross-resistance of these clones to multiple PARPis, cisplatin and doxorubicin. Despite persistence of the signature 4965C>G (p.Y1655X) BRCA2 nonsense mutation, HR was restored in the resistant cells. Immunoprecipitation followed by immunoblotting or mass spectrometry demonstrated expression of low levels of BRCA2 protein, including peptides distal to the premature termination codon. Reporter assays demonstrated readthrough selective for the UAG stop codon in the resistant clones but not parental PEO1 cells. Mass spectrometry and immunoblotting provided evidence for readthrough of stop codons, particularly UAGs, in additional proteins in the resistant clones. BRCA2 gene interruption either 5’ or 3’ to the stop codon restored sensitivity of the resistant clones to PARPis and cisplatin, implicating the low level BRCA2 expression in resistance. Accordingly, the present results identify low level readthrough of nonsense codons as a potential mechanism of drug resistance that might need to be considered when assessing the impact of BRCA2 nonsense mutations.
2024-09-01 | GSE243142 | GEO
Project description:Multiple replication abnormalities cause cells lacking BRCA2 to enter mitosis with under-replicated DNA and to activate mitotic DNA synthesis (MiDAS). However, the precise position of these MiDAS sites, as well as their origin, remains unknown. Here we labelled mitotic nascent DNA and performed high-throughput sequencing to identify at high-resolution the sites where MiDAS occurs in the absence of BRCA2. This approach revealed 150 genomic loci affected by MiDAS, which map within regions replicating during early S-phase and are therefore distinct from the aphidicolin-induced common fragile sites. Moreover, these sites largely localise near early firing origins and within genes transcribed in early S, suggesting that they stem from transcription-replication conflicts (TCRs). Inhibiting transcription with 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB) during early S-phase abrogates MiDAS. Strikingly, MiDAS sites co-localise with genomic loci where R-loops form in unchallenged conditions, suggesting that R-loop accumulation caused by BRCA2 inactivation leads to DNA lesion which are repaired by MiDAS. RAD52 is required in this process, as its abrogation in BRCA2-deficient cells reduces the rate of MiDAS and causes DNA damage accumulation in G1. Furthermore, MiDAS sites triggered by BRCA2 inactivation are hotspots for genomic rearrangement in BRCA2-mutated breast tumours. These results indicate that BRCA2 acts in early S-phase to protect TRC- and R-loop-induced DNA lesions, thereby preventing them from becoming a source of genomic instability and tumorigenesis.
2022-08-01 | GSE196163 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE32124: Effects of BRCA2 cis-regulation in normal breast and cancer risk amongst BRCA2 mutation carriers [expression data] GSE32258: Effects of BRCA2 cis-regulation in normal breast and cancer risk amongst BRCA2 mutation carriers [SNP data] Refer to individual Series
2012-02-01 | E-GEOD-32259 | biostudies-arrayexpress