Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA226257 | ENA |
REPOSITORIES: ENA
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Project description:APOBEC Cytidine Deaminase Mutagenesis Pattern is Widespread in Human Cancers
| PRJNA226256 | ENA
Project description:<p><b>Reprinted from Roberts et al. "An APOBEC cytidine deaminase mutagenesis pattern is widespread in human cancers", Nature Genetics, 45:970-976, 2013, with permission of Nature Publishing Group:</b></p> <p>Recent studies indicate that a subclass of APOBEC cytidine deaminases, which convert cytosine to uracil during RNA editing and retrovirus or retrotransposon restriction, may induce mutation clusters in human tumors. We show here that throughout cancer genomes APOBEC-mediated mutagenesis is pervasive and correlates with APOBEC mRNA levels. Mutation clusters in whole-genome and exome data sets conformed to the stringent criteria indicative of an APOBEC mutation pattern. Applying these criteria to 954,247 mutations in 2,680 exomes from 14 cancer types, mostly from The Cancer Genome Atlas (TCGA), showed a significant presence of the APOBEC mutation pattern in bladder, cervical, breast, head and neck, and lung cancers, reaching 68% of all mutations in some samples. Within breast cancer, the HER2-enriched subtype was clearly enriched for tumors with the APOBEC mutation pattern, suggesting that this type of mutagenesis is functionally linked with cancer development. The APOBEC mutation pattern also extended to cancer-associated genes, implying that ubiquitous APOBEC-mediated mutagenesis is carcinogenic.</p>
| phs000677 | dbGaP
Project description:Intratumoral genetic heterogeneity and mutational burden have been suggested to be the fuel and the source of resistance for many molecularly targeted therapies throughout a multitude of cancers. Emerging evidence indicates that tumor cells could hijack the powerful mutagenesis machinery mediated by the DNA deaminase APOBEC family proteins to intensify mutagenesis, promote intratumoral heterogeneity, and foster therapy resistance through a cell-autonomous mechanism. However, this mechanism has yet to be characterized. Utilizing prostate cancer (PCa) as a relevant model, we have identified the Synaptotagmin Binding Cytoplasmic RNA Interacting Protein (SYNCRIP) as a molecular brake for APOBEC-driven mutagenesis, intratumoral heterogeneity, and resistance to Androgen Receptor (AR) targeted therapies. Through a multi-disciplinary approach integrating bulk and single cell RNA-Seq (scRNA-Seq), whole-genome exome-sequencing (WES), and CRISPR library screening, we identified eight mutated resistance driver genes and revealed unparalleled details of how these heterogeneously aberrant subclones fuel the evolution of AR therapy resistance. For the first time, these findings exposed a cell-autonomous mechanism activating APOBEC-driven mutagenesis, consequently fueling mutational burden, genetic heterogeneity, and therapy resistance, and suggested that APOBEC proteins could be the potential therapeutic targets for preventing or overcoming resistance in PCa.
2023-07-20 | GSE202321 | GEO
Project description:Retroviruses cause lifelong infections resulting from their ability to thwart innate immunity. The Apobec family of cytidine deaminases are part of the innate immune response that recognizes and mutates foreign nucleic acids, including those from multiple viruses. Multiple retroviral antagonists of Apobecs have been identified, including mouse mammary tumor virus (MMTV)-encoded Rem protein. Previous experiments have shown that Rem-null MMTV or closely related TBLV proviruses from BALB/c tumors accumulate G-to-A and C-to-T mutations typical of Apobecs compared to wild-type proviruses expressing Rem. The difference in mutations between Rem-expressing and non-expressing MMTV strains largely disappeared in mice lacking the Apobec family member, activation-induced cytidine deaminase (AID). These results suggested that Rem is an AID antagonist. In this study, we attempted to study AID-mediated mutations of TBLV proviruses lacking Rem expression obtained from tumors in C57BL/6 (B6) wild-type and AID-knockout backgrounds. Surprisingly, no differences in G-to-A mutations were observed in TBLV proviruses regardless of Rem expression, yet such mutations were significantly reduced in proviruses obtained from mA3/AID-double knockout mice relative to those from wild-type B6 or AID-knockout mice. Many cellular mRNAs involving the innate immune response, but not Apobecs, were elevated in the absence relative to the presence of Rem expression on the B6 AID-knockout background. These results revealed that Apobec-mediated mutagenesis is dependent on mouse strain and suggested a second means of Rem-dependent immune evasion.
2024-04-15 | GSE263655 | GEO
Project description:Retroviruses cause lifelong infections resulting from their ability to thwart innate immunity. The Apobec family of cytidine deaminases are part of the innate immune response that recognizes and mutates foreign nucleic acids, including those from multiple viruses. Multiple retroviral antagonists of Apobecs have been identified, including mouse mammary tumor virus (MMTV)-encoded Rem protein. Previous experiments have shown that Rem-null MMTV or closely related TBLV proviruses from BALB/c tumors accumulate G-to-A and C-to-T mutations typical of Apobecs compared to wild-type proviruses expressing Rem. The difference in mutations between Rem-expressing and non-expressing MMTV strains largely disappeared in mice lacking the Apobec family member, activation-induced cytidine deaminase (AID). These results suggested that Rem is an AID antagonist. In this study, we attempted to study AID-mediated mutations of TBLV proviruses lacking Rem expression obtained from tumors in C57BL/6 (B6) wild-type and AID-knockout backgrounds. Surprisingly, no differences in G-to-A mutations were observed in TBLV proviruses regardless of Rem expression, yet such mutations were significantly reduced in proviruses obtained from mA3/AID-double knockout mice relative to those from wild-type B6 or AID-knockout mice. Many cellular mRNAs involving the innate immune response, but not Apobecs, were elevated in the absence relative to the presence of Rem expression on the B6 AID-knockout background. These results revealed that Apobec-mediated mutagenesis is dependent on mouse strain and suggested a second means of Rem-dependent immune evasion.
2024-04-16 | GSE263741 | GEO
Project description:Interventions: Blood samples(10 points) are collected after the first administration of capecitabine for pharmacokinetic analysis and cytidine deaminase activity measurement.
Primary outcome(s): To evaluate the correlation AUC of 5-DFUR/AUC of 5-DFCR ratio and cytidine deaminase activity.
Study Design: Single arm Non-randomized
| 2634538 | ecrin-mdr-crc
Project description:APOBEC-AID family of cytidine deaminase prefers single-stranded nucleic acids for cytidine to uracil deamination. Single-stranded nucleic acids are commonly involved in the DNA repair system for breaks generated by CRISPR-Cas9. Here, we show in human cells that APOBEC3s can trigger the cytidine deamination of single-stranded oligodeoxynucleotides, which ultimately results in base substitution mutations in genomic DNA through the homology-directed repair (HDR) of Cas9-generated double-strand breaks . In addition, the APOBEC3-catalyzed deamination in genomic single-stranded DNA formed during the repair of Cas9 nickase-generated single-strand breaks can be further processed to yield mutations mainly involving insertions or deletions (indels). Mechanistically, both APOBEC3-mediated deamination and DNA repair proteins play important roles in the generation of these indels. Correspondingly, optimizing conditions for the repair of CRISPR-Cas9-generated DNA breaks, such as using double-stranded donors in HDR or temporarily suppressing endogenous APOBEC3s, can substantially repress these unwanted mutations in genomic DNA.
2017-11-10 | GSE105146 | GEO
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
2010-09-25 | GSE24338 | GEO
Project description:This study evaluates the similarity of adaptive immune mechanisms between jawless and jawed vertebrates using lamprey cytidine deaminase (CDA). We identified the ancestral gene Lr-CDAs of the AID/APOBEC deaminase family and evaluated its biological function in vivo. Lr-CDA1 deletion affected the assembly of three types of variable lymphocyte receptors (VLRs). We identified a switch-like region in lamprey gVLRs bound to Lr-CDAs, which upon repression, downregulated VLRB expression. Overall, we propose that lampreys have an early form of class switch recombination (CSR) that is mediated by Lr-CDAs and acts on gVLRs, affecting the assembly, maturation, and diversity regulation of VLR genes in Lethenteron reissneri. This CSR process in lampreys is linked to tumorigenesis and chromosomal translocation markers via Lr-CDAs.
2024-04-16 | GSE252201 | GEO
Project description:Oncogenic driver mutations are those that provide a proliferative or survival advantage to neoplastic cells resulting in clonal selection. Although most cancer causing mutations have been detected in the protein-coding regions of the cancer genome, driver mutations have recently also been discovered within noncoding genomic sequences. Thus, a current challenge is to gain precise understanding of how these unique genomic elements function in cancer pathogenesis, while clarifying mechanisms of gene regulation and identifying new targets for therapeutic intervention. Here we report a C-to-T single nucleotide transition that occurs as a somatic mutation in noncoding sequences 4 kb upstream of the transcriptional start site of the LMO1 oncogene in primary samples from patients with T-cell acute lymphoblastic leukaemia. This single nucleotide alteration conforms to an APOBEC-like cytidine deaminase mutational signature, and generates a new binding site for the MYB transcription factor, leading to the formation of an aberrant transcriptional enhancer complex that drives high levels of expression of the LMO1 oncogene. Since APOBEC-signature mutations are common in a broad spectrum of human cancers, we suggest that noncoding nucleotide transitions such as the one described here may activate potent oncogenic enhancers not only in T-lymphoid cells but in other cell lineages as well.
2017-03-08 | GSE94391 | GEO