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Abstract
AbstractIn B cells, IgD is expressed together with IgM through alternative splicing of primary VHDJH-Cμ-s-m-Cδ-s-m RNAs, and also through IgD class switch DNA recombination (CSR) via double-strand DNA breaks (DSB) and synapse of Sμ with σδ. How such DSBs are resolved is still unknown, despite our previous report showing that Rad52 effects the ‘short-range’ microhomology-mediated synapsis of intra-Sμ region DSBs. Here we find that induction of IgD CSR downregulates Zfp318, and promotes Rad52 phosphorylation and recruitment to Sμ and σδ, thereby leading to alternative end-joining (A-EJ)-mediated Sμ-σδ recombination with extensive microhomologies, VHDJH-Cδs transcription and sustained IgD secretion. Rad52 ablation in mouse Rad52−/− B cells aborts IgD CSR in vitro and in vivo and dampens the specific IgD antibody response to OVA. Rad52 knockdown in human B cells also abrogates IgD CSR. Finally, Rad52 phosphorylation is associated with high levels of IgD CSR and anti-nuclear IgD autoantibodies in patients with systemic lupus erythematosus and in lupus-prone mice. Our findings thus show that Rad52 mediates IgD CSR through microhomology-mediated A-EJ in concert with Zfp318 downregulation.
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van de Kooij B, van Attikum H. Genomic Reporter Constructs to Monitor Pathway-Specific Repair of DNA Double-Strand Breaks. Front Genet 2022; 12:809832. [PMID: 35237296 PMCID: PMC8884240 DOI: 10.3389/fgene.2021.809832] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/23/2021] [Indexed: 11/29/2022] Open
Abstract
Repair of DNA Double-Strand Breaks (DSBs) can be error-free or highly mutagenic, depending on which of multiple mechanistically distinct pathways repairs the break. Hence, DSB-repair pathway choice directly affects genome integrity, and it is therefore of interest to understand the parameters that direct repair towards a specific pathway. This has been intensively studied using genomic reporter constructs, in which repair of a site-specific DSB by the pathway of interest generates a quantifiable phenotype, generally the expression of a fluorescent protein. The current developments in genome editing with targetable nucleases like Cas9 have increased reporter usage and accelerated the generation of novel reporter constructs. Considering these recent advances, this review will discuss and compare the available DSB-repair pathway reporters, provide essential considerations to guide reporter choice, and give an outlook on potential future developments.
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Niewolik D, Schwarz K. Physical ARTEMIS:DNA-PKcs interaction is necessary for V(D)J recombination. Nucleic Acids Res 2022; 50:2096-2110. [PMID: 35150269 PMCID: PMC8887466 DOI: 10.1093/nar/gkac071] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/12/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023] Open
Abstract
The nuclease ARTEMIS and the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are involved in the repair of physiological and pathogenic DNA double strand breaks. Both proteins are indispensable for the hairpin-opening activity in V(D)J recombination and therefore essential for the adaptive immune response. ARTEMIS and DNA-PKcs interact, however experimental evidence for in vivo significance is missing. We demonstrate that mutations abolishing this protein-protein interaction affect nuclease function. In DNA-PKcs, mutation L3062R impairs the physical interaction with ARTEMIS and was previously identified as pathogenic variant, resulting in radiosensitive severe combined immunodeficiency. In ARTEMIS, specific mutations in two conserved regions affect interaction with DNA-PKcs. In combination they impair V(D)J recombination activity, independent of ARTEMIS autoinhibitory self-interaction between the ARTEMIS C-terminus and the N-terminal nuclease domain. We describe small fragments from both proteins, capable of interaction with the corresponding full-length partner proteins: In DNA-PKcs 42 amino acids out of FAT region 2 (PKcs3041-3082) can mediate interaction with ARTEMIS. In the nuclease we have defined 26 amino acids (ARM378-403) as minimal DNA-PKcs interacting fragment. The exact mapping of the ARTEMIS:DNA-PKcs interaction may pave the way for the design of specific inhibitors targeting the repair of DNA double strand breaks.
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Affiliation(s)
- Doris Niewolik
- Institute for Transfusion Medicine, University of Ulm, Ulm 89081, Germany
| | - Klaus Schwarz
- Institute for Transfusion Medicine, University of Ulm, Ulm 89081, Germany.,Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service Baden-Wuerttemberg-Hessen, Ulm 89081, Germany
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104
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Choi W, Lee ES. Therapeutic Targeting of DNA Damage Response in Cancer. Int J Mol Sci 2022; 23:ijms23031701. [PMID: 35163621 PMCID: PMC8836062 DOI: 10.3390/ijms23031701] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/25/2022] [Accepted: 01/29/2022] [Indexed: 02/07/2023] Open
Abstract
DNA damage response (DDR) is critical to ensure genome stability, and defects in this signaling pathway are highly associated with carcinogenesis and tumor progression. Nevertheless, this also provides therapeutic opportunities, as cells with defective DDR signaling are directed to rely on compensatory survival pathways, and these vulnerabilities have been exploited for anticancer treatments. Following the impressive success of PARP inhibitors in the treatment of BRCA-mutated breast and ovarian cancers, extensive research has been conducted toward the development of pharmacologic inhibitors of the key components of the DDR signaling pathway. In this review, we discuss the key elements of the DDR pathway and how these molecular components may serve as anticancer treatment targets. We also summarize the recent promising developments in the field of DDR pathway inhibitors, focusing on novel agents beyond PARP inhibitors. Furthermore, we discuss biomarker studies to identify target patients expected to derive maximal clinical benefits as well as combination strategies with other classes of anticancer agents to synergize and optimize the clinical benefits.
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Affiliation(s)
- Wonyoung Choi
- Research Institute, National Cancer Center, Goyang 10408, Korea;
- Center for Clinical Trials, National Cancer Center, Goyang 10408, Korea
| | - Eun Sook Lee
- Research Institute, National Cancer Center, Goyang 10408, Korea;
- Center for Breast Cancer, National Cancer Center, Goyang 10408, Korea
- Correspondence: ; Tel.: +82-31-920-1633
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105
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Rawsthorne-Manning H, Calahorro F, G. Izquierdo P, Tardy P, Boulin T, Holden-Dye L, O’Connor V, Dillon J. Confounds of using the unc-58 selection marker highlights the importance of genotyping co-CRISPR genes. PLoS One 2022; 17:e0253351. [PMID: 35041685 PMCID: PMC8765651 DOI: 10.1371/journal.pone.0253351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/29/2021] [Indexed: 11/19/2022] Open
Abstract
Multiple advances have been made to increase the efficiency of CRISPR/Cas9 editing using the model genetic organism Caenorhabditis elegans (C. elegans). Here we report on the use of co-CRISPR ‘marker’ genes: worms in which co-CRISPR events have occurred have overt, visible phenotypes which facilitates the selection of worms that harbour CRISPR events in the target gene. Mutation in the co-CRISPR gene is then removed by outcrossing to wild type but this can be challenging if the CRISPR and co-CRISPR gene are hard to segregate. However, segregating away the co-CRISPR modified gene can be less challenging if the worms selected appear wild type and are selected from a jackpot brood. These are broods in which a high proportion of the progeny of a single injected worm display the co-CRISPR phenotype suggesting high CRISPR efficiency. This can deliver worms that harbour the desired mutation in the target gene locus without the co-CRISPR mutation. We have successfully generated a discrete mutation in the C. elegans nlg-1 gene using this method. However, in the process of sequencing to authenticate editing in the nlg-1 gene we discovered genomic rearrangements that arise at the co-CRISPR gene unc-58 that by visual observation were phenotypically silent but nonetheless resulted in a significant reduction in motility scored by thrashing behaviour. This highlights that careful consideration of the hidden consequences of co-CRISPR mediated genetic changes should be taken before downstream analysis of gene function. Given this, we suggest sequencing of co-CRISPR genes following CRISPR procedures that utilise phenotypic selection as part of the pipeline.
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Affiliation(s)
| | - Fernando Calahorro
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Patricia G. Izquierdo
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Philippe Tardy
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, France
| | - Thomas Boulin
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, France
| | - Lindy Holden-Dye
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Vincent O’Connor
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - James Dillon
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
- * E-mail:
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106
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Lan B, Zeng S, Zhang S, Ren X, Xing Y, Kutschick I, Pfeffer S, Frey B, Britzen-Laurent N, Grützmann R, Cordes N, Pilarsky C. CRISPR-Cas9 Screen Identifies DYRK1A as a Target for Radiotherapy Sensitization in Pancreatic Cancer. Cancers (Basel) 2022; 14:cancers14020326. [PMID: 35053488 PMCID: PMC8773906 DOI: 10.3390/cancers14020326] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 12/17/2022] Open
Abstract
Simple Summary Pancreatic cancer is the fourth leading cause of cancer-related death in Western countries. Although several therapeutic strategies have been developed for pancreatic cancer, radiation therapy has not yet yielded satisfactory results. Unraveling the mechanism of radioresistance in pancreatic cancer and developing new therapeutic targets has become a major challenge. Therefore, we applied kinome-wide CRISPR-Cas9 loss-of-function screening combined with the 3D cell culture method and identified DYRK1A as a sensitive target for radiotherapy. Additionally, we confirmed that DYRK1A-targeted inhibitors could enhance the efficacy of radiotherapy. Our results further support the use of CRISPR-Cas9 screening to identify novel therapeutic targets and develop new strategies to enhance radiotherapy efficacy in pancreatic cancer. Abstract Although radiation therapy has recently made great advances in cancer treatment, the majority of patients diagnosed with pancreatic cancer (PC) cannot achieve satisfactory outcomes due to intrinsic and acquired radioresistance. Identifying the molecular mechanisms that impair the efficacy of radiotherapy and targeting these pathways are essential to improve the radiation response of PC patients. Our goal is to identify sensitive targets for pancreatic cancer radiotherapy (RT) using the kinome-wide CRISPR-Cas9 loss-of-function screen and enhance the therapeutic effect through the development and application of targeted inhibitors combined with radiotherapy. We transduced pancreatic cancer cells with a protein kinase library; 2D and 3D library cells were irradiated daily with a single dose of up to 2 Gy for 4 weeks for a total of 40 Gy using an X-ray generator. Sufficient DNA was collected for next-generation deep sequencing to identify candidate genes. In this study, we identified several cell cycle checkpoint kinases and DNA damage related kinases in 2D- and 3D-cultivated cells, including DYRK1A, whose loss of function sensitizes cells to radiotherapy. Additionally, we demonstrated that the harmine-targeted suppression of DYRK1A used in conjunction with radiotherapy increases DNA double-strand breaks (DSBs) and impairs homologous repair (HR), resulting in more cancer cell death. Our results support the use of CRISPR-Cas9 screening to identify new therapeutic targets, develop radiosensitizers, and provide novel strategies for overcoming the tolerance of pancreatic cancer to radiotherapy.
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Affiliation(s)
- Bin Lan
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Siyuan Zeng
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Shuman Zhang
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Xiaofan Ren
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Yuming Xing
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Isabella Kutschick
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Susanne Pfeffer
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Benjamin Frey
- Translational Radiobiology, Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany;
| | - Nathalie Britzen-Laurent
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Robert Grützmann
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
| | - Nils Cordes
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine Carl Gustav Carus Technische Universität Dresden, 01307 Dresden, Germany;
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, 01328 Dresden, Germany
- German Cancer Consortium, Partner Site Dresden: German Cancer Research Center, 69120 Heidelberg, Germany
- Department of Radiotherapy and Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Christian Pilarsky
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (B.L.); (S.Z.); (S.Z.); (X.R.); (Y.X.); (I.K.); (S.P.); (N.B.-L.); (R.G.)
- Correspondence:
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107
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Frequency and Spectrum of Mutations Induced by Gamma Rays Revealed by Phenotype Screening and Whole-Genome Re-Sequencing in Arabidopsis thaliana. Int J Mol Sci 2022; 23:ijms23020654. [PMID: 35054839 PMCID: PMC8775868 DOI: 10.3390/ijms23020654] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/26/2021] [Accepted: 01/04/2022] [Indexed: 12/29/2022] Open
Abstract
Genetic variations are an important source of germplasm diversity, as it provides an allele resource that contributes to the development of new traits for plant breeding. Gamma rays have been widely used as a physical agent for mutation creation in plants, and their mutagenic effect has attracted extensive attention. However, few studies are available on the comprehensive mutation profile at both the large-scale phenotype mutation screening and whole-genome mutation scanning. In this study, biological effects on M1 generation, large-scale phenotype screening in M2 generation, as well as whole-genome re-sequencing of seven M3 phenotype-visible lines were carried out to comprehensively evaluate the mutagenic effects of gamma rays on Arabidopsis thaliana. A total of 417 plants with visible mutated phenotypes were isolated from 20,502 M2 plants, and the phenotypic mutation frequency of gamma rays was 2.03% in Arabidopsis thaliana. On average, there were 21.57 single-base substitutions (SBSs) and 11.57 small insertions and deletions (InDels) in each line. Single-base InDels accounts for 66.7% of the small InDels. The genomic mutation frequency was 2.78 × 10−10/bp/Gy. The ratio of transition/transversion was 1.60, and 64.28% of the C > T events exhibited the pyrimidine dinucleotide sequence; 69.14% of the small InDels were located in the sequence with 1 to 4 bp terminal microhomology that was used for DNA end rejoining, while SBSs were less dependent on terminal microhomology. Nine genes, on average, were predicted to suffer from functional alteration in each re-sequenced line. This indicated that a suitable mutation gene density was an advantage of gamma rays when trying to improve elite materials for one certain or a few traits. These results will aid the full understanding of the mutagenic effects and mechanisms of gamma rays and provide a basis for suitable mutagen selection and parameter design, which can further facilitate the development of more controlled mutagenesis methods for plant mutation breeding.
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108
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Kuang C, Xiao Y, Hondmann D. Cleavage-free human genome editing. Mol Ther 2022; 30:268-282. [PMID: 34864205 PMCID: PMC8753458 DOI: 10.1016/j.ymthe.2021.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/17/2021] [Accepted: 11/30/2021] [Indexed: 01/07/2023] Open
Abstract
Most gene editing technologies introduce breaks or nicks into DNA, leading to the generation of mutagenic insertions and deletions by non-homologous end-joining repair. Here, we report a new, cleavage-free gene editing approach based on replication interrupted template-driven DNA modification (RITDM). The RITDM system makes use of sequence-specific DLR fusion molecules that are specifically designed to enable localized, temporary blockage of DNA replication fork progression, thereby exposing single-stranded DNA that can be bound by DNA sequence modification templates for precise editing. We evaluate the use of zinc-finger arrays for sequence recognition. We demonstrate that RITDM can be used for gene editing at endogenous genomic loci in human cells and highlight its safety profile of low indel frequencies and undetectable off-target side effects in RITDM-edited clones and pools of cells.
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Affiliation(s)
- Chenzhong Kuang
- Peter Biotherapeutics, Inc, 75 Kneeland Street, Boston, MA 02111, USA
| | - Yan Xiao
- Peter Biotherapeutics, Inc, 75 Kneeland Street, Boston, MA 02111, USA
| | - Dirk Hondmann
- Peter Biotherapeutics, Inc, 75 Kneeland Street, Boston, MA 02111, USA,Corresponding author: Dirk Hondmann, Peter Biotherapeutics, Inc, 75 Kneeland Street, Boston, MA 02111, USA.
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109
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Phosphorylation of TRIP13 at Y56 induces radiation resistance but sensitizes head and neck cancer to cetuximab. Mol Ther 2022; 30:468-484. [PMID: 34111559 PMCID: PMC8753291 DOI: 10.1016/j.ymthe.2021.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/10/2021] [Accepted: 06/01/2021] [Indexed: 01/07/2023] Open
Abstract
Radiation therapy, a mainstay of treatment for head and neck cancer, is not always curative due to the development of treatment resistance; additionally, multi-institutional trials have questioned the efficacy of concurrent radiation with cetuximab, the epidermal growth factor receptor (EGFR) inhibitor. We unraveled a mechanism for radiation resistance; that is, radiation induces EGFR, which phosphorylates TRIP13 (thyroid hormone receptor interactor 13) on tyrosine 56. Phosphorylated (phospho-)TRIP13 promotes non-homologous end joining (NHEJ) repair to induce radiation resistance. NHEJ is the main repair pathway for radiation-induced DNA damage. Tumors expressing high TRIP13 do not respond to radiation but are sensitive to cetuximab or cetuximab combined with radiation. Suppression of phosphorylation of TRIP13 at Y56 abrogates these effects. These findings show that EGFR-mediated phosphorylation of TRIP13 at Y56 is a vital mechanism of radiation resistance. Notably, TRIP13-pY56 could be used to predict the response to radiation or cetuximab and could be explored as an actionable target.
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110
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Shamshirgaran Y, Liu J, Sumer H, Verma PJ, Taheri-Ghahfarokhi A. Tools for Efficient Genome Editing; ZFN, TALEN, and CRISPR. Methods Mol Biol 2022; 2495:29-46. [PMID: 35696026 DOI: 10.1007/978-1-0716-2301-5_2] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The last two decades have marked significant advancement in the genome editing field. Three generations of programmable nucleases (ZFNs, TALENs, and CRISPR-Cas system) have been adopted to introduce targeted DNA double-strand breaks (DSBs) in eukaryotic cells. DNA repair machinery of the cells has been exploited to introduce insertion and deletions (indels) at the targeted DSBs to study function of any gene-of-interest. The resulting indels were generally assumed to be "random" events produced by "error-prone" DNA repair pathways. However, recent advances in computational tools developed to study the Cas9-induced mutations have changed the consensus and implied the "non-randomness" nature of these mutations. Furthermore, CRISPR-centric tools are evolving at an unprecedented pace, for example, base- and prime-editors are the newest developments that have been added to the genome editing toolbox. Altogether, genome editing tools have revolutionized our way of conducting research in life sciences. Here, we present a concise overview of genome editing tools and describe the DNA repair pathways underlying the generation of genome editing outcome.
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Affiliation(s)
- Yasaman Shamshirgaran
- Laboratory of Clinical Chemistry, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Jun Liu
- Stem Cells and Genome Editing, Genomics and Cellular Sciences, Agriculture Victoria Research, Bundoora, VIC, Australia
| | - Huseyin Sumer
- Department of Chemistry and Biotechnology, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Paul J Verma
- Aquatics & Livestock Sciences, South Australian Research and Development Institute, Roseworthy, SA, Australia
| | - Amir Taheri-Ghahfarokhi
- Quantitative Biology, Discovery Sciences, Biopharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
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111
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Deshpande RA, Paull TT. Characterization of DNA-PK-Bound End Fragments Using GLASS-ChIP. Methods Mol Biol 2022; 2444:171-182. [PMID: 35290638 DOI: 10.1007/978-1-0716-2063-2_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Endonucleolytic cleavage of DNA ends by the human Mre11-Rad50-Nbs1 (MRN) complex occurs in a manner that is promoted by DNA-dependent protein kinase (DNA-PK). A method is described to isolate DNA-PK-bound fragments released from chromatin in human cells using a modified Gentle Lysis and Size Selection chromatin immunoprecipitation (GLASS-ChIP) protocol. This method, combined with real-time PCR or next-generation sequencing, can identify sites of MRN endonucleolytic cutting adjacent to DNA-PK binding sites in human cells.
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Affiliation(s)
- Rajashree A Deshpande
- The Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Tanya T Paull
- The Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
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112
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Wang X, Zhao J. Targeted Cancer Therapy Based on Acetylation and Deacetylation of Key Proteins Involved in Double-Strand Break Repair. Cancer Manag Res 2022; 14:259-271. [PMID: 35115826 PMCID: PMC8800007 DOI: 10.2147/cmar.s346052] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 01/13/2022] [Indexed: 12/22/2022] Open
Abstract
DNA double-strand breaks (DSBs) play an important role in promoting genomic instability and cell death. The precise repair of DSBs is essential for maintaining genome integrity during cancer progression, and inducing genomic instability or blocking DNA repair is an important mechanism through which chemo/radiotherapies exert killing effects on cancer cells. The two main pathways that facilitate the repair of DSBs in cancer cells are homologous recombination (HR) and non-homologous end-joining (NHEJ). Accumulating data suggest that the acetylation and deacetylation of DSB repair proteins regulate the initiation and progression of the cellular response to DNA DSBs, which may further affect the chemosensitivity or radiosensitivity of cancer cells. Here, we focus on the role of acetylation/deacetylation in the regulation of ataxia-telangiectasia mutated, Rad51, and 53BP1 in the HR pathway, as well as the relevant roles of PARP1 and Ku70 in NHEJ. Notably, several histone deacetylase (HDAC) inhibitors targeting HR or NHEJ have been demonstrated to enhance chemo/radiosensitivity in preclinical studies. This review highlights the essential role of acetylation/deacetylation in the regulation of DSB repair proteins, suggesting that HDAC inhibitors targeting the HR or NHEJ pathways that downregulate DNA DSB repair genes may be worthwhile cancer therapeutic agents.
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Affiliation(s)
- Xiwen Wang
- Department of Thoracic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, People’s Republic of China
| | - Jungang Zhao
- Department of Thoracic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, People’s Republic of China
- Correspondence: Jungang Zhao, Department of Thoracic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, People’s Republic of China, Tel/Fax +86 13889311066, Email
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113
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Mirman Z, Sasi NK, King A, Chapman JR, de Lange T. 53BP1-shieldin-dependent DSB processing in BRCA1-deficient cells requires CST-Polα-primase fill-in synthesis. Nat Cell Biol 2022; 24:51-61. [PMID: 35027730 PMCID: PMC8849574 DOI: 10.1038/s41556-021-00812-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 11/09/2021] [Indexed: 12/19/2022]
Abstract
The efficacy of poly(ADP)-ribose polymerase 1 inhibition (PARPi) in BRCA1-deficient cells depends on 53BP1 and shieldin, which have been proposed to limit single-stranded DNA at double-strand breaks (DSBs) by blocking resection and/or through CST-Polα-primase-mediated fill-in. We show that primase (like 53BP1-shieldin and CST-Polα) promotes radial chromosome formation in PARPi-treated BRCA1-deficient cells and demonstrate shieldin-CST-Polα-primase-dependent incorporation of BrdU at DSBs. In the absence of 53BP1 or shieldin, radial formation in BRCA1-deficient cells was restored by the tethering of CST near DSBs, arguing that in this context, shieldin acts primarily by recruiting CST. Furthermore, a SHLD1 mutant defective in CST binding (SHLD1Δ) was non-functional in BRCA1-deficient cells and its function was restored after reconnecting SHLD1Δ to CST. Interestingly, at dysfunctional telomeres and at DNA breaks in class switch recombination where CST has been implicated, SHLD1Δ was fully functional, perhaps because these DNA ends carry CST recognition sites that afford SHLD1-independent binding of CST. These data establish that in BRCA1-deficient cells, CST-Polα-primase is the major effector of shieldin-dependent DSB processing.
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Affiliation(s)
- Zachary Mirman
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY, USA
| | - Nanda Kumar Sasi
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY, USA
| | - Ashleigh King
- Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - J Ross Chapman
- Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY, USA.
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114
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Zirin J, Bosch J, Viswanatha R, Mohr SE, Perrimon N. State-of-the-art CRISPR for in vivo and cell-based studies in Drosophila. Trends Genet 2021; 38:437-453. [PMID: 34933779 PMCID: PMC9007876 DOI: 10.1016/j.tig.2021.11.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/31/2022]
Abstract
For more than 100 years, the fruit fly, Drosophila melanogaster, has served as a powerful model organism for biological and biomedical research due to its many genetic and physiological similarities to humans and the availability of sophisticated technologies used to manipulate its genome and genes. The Drosophila research community quickly adopted CRISPR technologies and, in the 8 years since the first clustered regularly interspaced short palindromic repeats (CRISPR) publications in flies, has explored and innovated methods for mutagenesis, precise genome engineering, and beyond. Moreover, the short lifespan and ease of genetics have made Drosophila an ideal testing ground for in vivo applications and refinements of the rapidly evolving set of CRISPR-associated (CRISPR-Cas) tools. Here, we review innovations in delivery of CRISPR reagents, increased efficiency of cutting and homology-directed repair (HDR), and alternatives to standard Cas9-based approaches. While the focus is primarily on in vivo systems, we also describe the role of Drosophila cultured cells as both an indispensable first step in the process of assessing new CRISPR technologies and a platform for genome-wide CRISPR pooled screens.
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Affiliation(s)
- Jonathan Zirin
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
| | - Justin Bosch
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Raghuvir Viswanatha
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Stephanie E Mohr
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
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115
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Abegg D, Tomanik M, Qiu N, Pechalrieu D, Shuster A, Commare B, Togni A, Herzon SB, Adibekian A. Chemoproteomic Profiling by Cysteine Fluoroalkylation Reveals Myrocin G as an Inhibitor of the Nonhomologous End Joining DNA Repair Pathway. J Am Chem Soc 2021; 143:20332-20342. [PMID: 34817176 DOI: 10.1021/jacs.1c09724] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Chemoproteomic profiling of cysteines has emerged as a powerful method for screening the proteome-wide targets of cysteine-reactive fragments, drugs, and natural products. Herein, we report the development and an in-depth evaluation of a tetrafluoroalkyl benziodoxole (TFBX) as a cysteine-selective chemoproteomic probe. We show that this probe features numerous key improvements compared to the traditionally used cysteine-reactive probes, including a superior target occupancy, faster labeling kinetics, and broader proteomic coverage, thus enabling profiling of cysteines directly in live cells. In addition, the fluorine "signature" of probe 7 constitutes an additional advantage resulting in a more confident adduct-amino acid site assignment in mass-spectrometry-based identification workflows. We demonstrate the utility of our new probe for proteome-wide target profiling by identifying the cellular targets of (-)-myrocin G, an antiproliferative fungal natural product with a to-date unknown mechanism of action. We show that this natural product and a simplified analogue target the X-ray repair cross-complementing protein 5 (XRCC5), an ATP-dependent DNA helicase that primes DNA repair machinery for nonhomologous end joining (NHEJ) upon DNA double-strand breaks, making them the first reported inhibitors of this biomedically highly important protein. We further demonstrate that myrocins disrupt the interaction of XRCC5 with DNA leading to sensitization of cancer cells to the chemotherapeutic agent etoposide as well as UV-light-induced DNA damage. Altogether, our next-generation cysteine-reactive probe enables broader and deeper profiling of the cysteinome, rendering it a highly attractive tool for elucidation of targets of electrophilic small molecules.
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Affiliation(s)
- Daniel Abegg
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Martin Tomanik
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Nan Qiu
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Dany Pechalrieu
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Anton Shuster
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Bruno Commare
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Antonio Togni
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.,Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, United States
| | - Alexander Adibekian
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
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116
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Liu D, Lieber MR. The mechanisms of human lymphoid chromosomal translocations and their medical relevance. Crit Rev Biochem Mol Biol 2021; 57:227-243. [PMID: 34875186 DOI: 10.1080/10409238.2021.2004576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The most common human lymphoid chromosomal translocations involve concurrent failures of the recombination activating gene (RAG) complex and Activation-Induced Deaminase (AID). These are two enzymes that are normally expressed for purposes of the two site-specific DNA recombination processes: V(D)J recombination and class switch recombination (CSR). First, though it is rare, a low level of expression of AID can introduce long-lived T:G mismatch lesions at 20-600 bp fragile zones. Second, the V(D)J recombination process can occasionally fail to rejoin coding ends, and this failure may permit an opportunity for Artemis:DNA-dependent kinase catalytic subunit (DNA-PKcs) to convert the T:G mismatch sites at the fragile zones into double-strand breaks. The 20-600 bp fragile zones must be, at least transiently, in a single-stranded DNA (ssDNA) state for the first step to occur, because AID only acts on ssDNA. Here we discuss the key DNA sequence features that lead to AID action at a fragile zone, which are (a) the proximity and density of strings of cytosine nucleotides (C-strings) that cause a B/A-intermediate DNA conformation; (b) overlapping AID hotspots that contain a methyl CpG (WRCG), which AID converts to a long-lived T:G mismatch; and (c) transcription, which, though not essential, favors increased ssDNA in the fragile zone. We also summarize chromosomal features of the focal fragile zones in lymphoid malignancies and discuss the clinical relevance of understanding the translocation mechanisms. Many of the key principles covered here are also relevant to chromosomal translocations in non-lymphoid somatic cells as well.
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Affiliation(s)
- Di Liu
- Department of Pathology & Laboratory Medicine, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology and Immunology, and Section of Computational Biology in the Department of Biological Sciences, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Michael R Lieber
- Department of Pathology & Laboratory Medicine, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology and Immunology, and Section of Computational Biology in the Department of Biological Sciences, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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117
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Feng W, Smith CM, Simpson DA, Gupta GP. Targeting Non-homologous and Alternative End Joining Repair to Enhance Cancer Radiosensitivity. Semin Radiat Oncol 2021; 32:29-41. [PMID: 34861993 DOI: 10.1016/j.semradonc.2021.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Many cancer therapies, including radiotherapy, induce DSBs as the major driving mechanism for inducing cancer cell death. Thus, modulating DSB repair has immense potential for radiosensitization, although such interventions must be carefully designed to be tumor selective to ensure that normal tissue toxicities are not also increased. Here, we review mechanisms of error-prone DSB repair through a highly efficient process called end joining. There are two major pathways of end-joining repair: non-homologous end joining (NHEJ) and alternative end joining (a-EJ), both of which can be selectively upregulated in cancer and thus represent attractive therapeutic targets for radiosensitization. These EJ pathways each have therapeutically targetable pioneer factors - DNA-dependent protein kinase catalytic subunit (DNA-PKcs) for NHEJ and DNA Polymerase Theta (Pol θ) for a-EJ. We summarize the current status of therapeutic targeting of NHEJ and a-EJ to enhance the effects of radiotherapy - focusing on challenges that must be overcome and opportunities that require further exploration. By leveraging preclinical insights into mechanisms of altered DSB repair programs in cancer, selective radiosensitization through NHEJ and/or a-EJ targeting remains a highly attractive avenue for ongoing and future clinical investigation.
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Affiliation(s)
| | - Chelsea M Smith
- Lineberger Comprehensive Cancer Center; Pathobiology and Translational Science Graduate Program
| | | | - Gaorav P Gupta
- Lineberger Comprehensive Cancer Center; Pathobiology and Translational Science Graduate Program; Department of Radiation Oncology; Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC.
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118
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Doss RM, Xhunga S, Klimczak D, Cameron M, Verlare J, Wolkow TD. Fission yeast Ase1 PRC1 is required for the G 2-microtubule damage response. MOLECULAR BIOLOGY RESEARCH COMMUNICATIONS 2021; 10:179-188. [PMID: 35097140 PMCID: PMC8798275 DOI: 10.22099/mbrc.2021.41001.1650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Schizosaccharomyces pombe delays entry into mitosis following G2 microtubule damage. This pathway is dependent on Rad26ATRIP, the regulatory subunit of the Rad26ATRIP/Rad3ATR DNA damage response (DDR) complex. However, this G2 microtubule damage response pathway acts independently of the G2 DNA damage checkpoint pathway. To identify other proteins in this G2 microtubule damage pathway, we previously screened a cDNA overexpression library for genes that rescued the sensitivity of rad26Δ cells to the microtubule poison thiabendazole. A partial cDNA fragment encoding only the C-terminal regulatory region of the microtubule bundling protein Ase1 PRC1 was isolated. This fragment lacks the Ase1PRC1 dimerization and microtubule binding domains and retains the conserved C-terminal unstructured regulatory region. Here, we report that ase1Δ cells fail to delay entry into mitosis following G2 microtubule damage. Microscopy revealed that Rad26ATRIP foci localized alongside Ase1PRC1 filaments, although we suggest that this is related to microtubule-dependent double strand break mobility that facilitates homologous recombination events. Indeed, we report that the DNA repair protein Rad52 co-localizes with Rad26ATRIP at these foci, and that localization of Rad26ATRIP to these foci depends on a Rad26ATRIP N-terminal region containing a checkpoint recruitment domain. To our knowledge, this is the first report implicating Ase1PRC1 in regulation of the G2/M transition.
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Affiliation(s)
| | | | | | | | | | - Tom D. Wolkow
- Corresponding Author: Department of Biology, 1420 Austin Bluffs Parkway, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, Tel:+719 255 3663; Fax: +719 255-3047, E. mail:
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119
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Radiosensitisation of SCCVII tumours and normal tissues in mice by the DNA-dependent protein kinase inhibitor AZD7648. Radiother Oncol 2021; 166:162-170. [PMID: 34861268 DOI: 10.1016/j.radonc.2021.11.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/18/2021] [Accepted: 11/22/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND PURPOSE Inhibitors of DNA-dependent protein kinase (DNA-PK) are effective radiation sensitisers in preclinical tumours, but little is known about risks of normal tissue radiosensitisation. Here, we evaluate radiosensitisation of head and neck squamous cell carcinoma (HNSCC) cells by DNA-PK inhibitor AZD7648 under oxia and anoxia in vitro, and tumour (SCCVII), oral mucosa and small intestine in mice. MATERIALS AND METHODS Radiosensitisation of human (UT-SCC-54C) and murine (SCCVII) HNSCC cells by AZD7648 under oxia and anoxia was evaluated by clonogenic assay. Radiosensitisation of SCCVII tumours in C3H mice by oral AZD7648 (75 mg/kg) was determined by ex vivo clonogenic assay 3.5 days post-irradiation, with evaluation of normal tissue surrogate endpoints using 5-ethynyl-2'-deoxyuridine to facilitate detection of regenerating crypts in the ileum and repopulating S-phase cells in the ileum and oral mucosa of the same animals. RESULTS AZD7648 potently radiosensitised both cell lines, with similar sensitiser enhancement ratios for 10% survival (SER10) under oxia and anoxia. AZD7648 diffused rapidly through multicellular layers, suggesting rapid equilibration between plasma and hypoxic zones in tumours. SCCVII tumours were radiosensitised by AZD7648 (SER10 2.5). AZD7648 also enhanced radiation-induced body weight loss and suppressed regenerating intestinal crypts and repopulating S-phase cells in the ileum and tongue epithelium with SER values similar to SCCVII tumours. CONCLUSION AZD7648 is a potent radiation sensitiser of both oxic and anoxic tumour cells, but also markedly radiosensitises stem cells in the small intestine and oral mucosa.
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120
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Zhou S, Wu Y, Xie ZX, Jia B, Yuan YJ. Directed genome evolution driven by structural rearrangement techniques. Chem Soc Rev 2021; 50:12788-12807. [PMID: 34651628 DOI: 10.1039/d1cs00722j] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Directed genome evolution simulates the process of natural evolution at the genomic level in the laboratory to generate desired phenotypes. Here we review the applications of recent technological advances in genome writing and editing to directed genome evolution, with a focus on structural rearrangement techniques. We highlight how these techniques can be used to generate diverse genotypes, and to accelerate the evolution of phenotypic traits. We also discuss the perspectives of directed genome evolution.
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Affiliation(s)
- Sijie Zhou
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China. .,Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yi Wu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China. .,Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Ze-Xiong Xie
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China. .,Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Bin Jia
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China. .,Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Ying-Jin Yuan
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China. .,Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
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121
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Conversion of viridicatic acid to crustosic acid by cytochrome P450 enzyme-catalysed hydroxylation and spontaneous cyclisation. Appl Microbiol Biotechnol 2021; 105:9181-9189. [PMID: 34761275 PMCID: PMC8648635 DOI: 10.1007/s00253-021-11674-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/26/2021] [Accepted: 10/28/2021] [Indexed: 02/03/2023]
Abstract
Cytochrome P450 monooxygenases (P450s) are considered nature's most versatile catalysts and play a crucial role in regio- and stereoselective oxidation reactions on a broad range of organic molecules. The oxyfunctionalisation of unactivated carbon-hydrogen (C-H) bonds, in particular, represents a key step in the biosynthesis of many natural products as it provides substrates with increased reactivity for tailoring reactions. In this study, we investigated the function of the P450 enzyme TraB in the terrestric acid biosynthetic pathway. We firstly deleted the gene coding for the DNA repair subunit protein Ku70 by using split marker-based deletion plasmids for convenient recycling of the selection marker to improve gene targeting in Penicillium crustosum. Hereby, we reduced ectopic DNA integration and facilitated genetic manipulation in P. crustosum. Afterward, gene deletion in the Δku70 mutant of the native producer P. crustosum and heterologous expression in Aspergillus nidulans with precursor feeding proved the involvement of TraB in the formation of crustosic acid by catalysing the essential hydroxylation reaction of viridicatic acid. KEY POINTS: •Deletion of Ku70 by using split marker approach for selection marker recycling. •Functional identification of the cytochrome P450 enzyme TraB. •Fulfilling the reaction steps in the terrestric acid biosynthesis.
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122
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Impact of Chromatin Dynamics and DNA Repair on Genomic Stability and Treatment Resistance in Pediatric High-Grade Gliomas. Cancers (Basel) 2021; 13:cancers13225678. [PMID: 34830833 PMCID: PMC8616465 DOI: 10.3390/cancers13225678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/08/2021] [Accepted: 11/11/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Pediatric high-grade gliomas (pHGGs) are the leading cause of mortality in pediatric neuro-oncology, due in great part to treatment resistance driven by complex DNA repair mechanisms. pHGGs have recently been divided into molecular subtypes based on mutations affecting the N-terminal tail of the histone variant H3.3 and the ATRX/DAXX histone chaperone that deposits H3.3 at repetitive heterochromatin loci that are of paramount importance to the stability of our genome. This review addresses the functions of H3.3 and ATRX/DAXX in chromatin dynamics and DNA repair, as well as the impact of mutations affecting H3.3/ATRX/DAXX on treatment resistance and how the vulnerabilities they expose could foster novel therapeutic strategies. Abstract Despite their low incidence, pediatric high-grade gliomas (pHGGs), including diffuse intrinsic pontine gliomas (DIPGs), are the leading cause of mortality in pediatric neuro-oncology. Recurrent, mutually exclusive mutations affecting K27 (K27M) and G34 (G34R/V) in the N-terminal tail of histones H3.3 and H3.1 act as key biological drivers of pHGGs. Notably, mutations in H3.3 are frequently associated with mutations affecting ATRX and DAXX, which encode a chaperone complex that deposits H3.3 into heterochromatic regions, including telomeres. The K27M and G34R/V mutations lead to distinct epigenetic reprogramming, telomere maintenance mechanisms, and oncogenesis scenarios, resulting in distinct subgroups of patients characterized by differences in tumor localization, clinical outcome, as well as concurrent epigenetic and genetic alterations. Contrasting with our understanding of the molecular biology of pHGGs, there has been little improvement in the treatment of pHGGs, with the current mainstays of therapy—genotoxic chemotherapy and ionizing radiation (IR)—facing the development of tumor resistance driven by complex DNA repair pathways. Chromatin and nucleosome dynamics constitute important modulators of the DNA damage response (DDR). Here, we summarize the major DNA repair pathways that contribute to resistance to current DNA damaging agent-based therapeutic strategies and describe the telomere maintenance mechanisms encountered in pHGGs. We then review the functions of H3.3 and its chaperones in chromatin dynamics and DNA repair, as well as examining the impact of their mutation/alteration on these processes. Finally, we discuss potential strategies targeting DNA repair and epigenetic mechanisms as well as telomere maintenance mechanisms, to improve the treatment of pHGGs.
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Wong OGW, Li J, Cheung ANY. Targeting DNA Damage Response Pathway in Ovarian Clear Cell Carcinoma. Front Oncol 2021; 11:666815. [PMID: 34737943 PMCID: PMC8560708 DOI: 10.3389/fonc.2021.666815] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 09/08/2021] [Indexed: 12/24/2022] Open
Abstract
Ovarian clear cell carcinoma (OCCC) is one of the major types of ovarian cancer and is of higher relative prevalence in Asians. It also shows higher possibility of resistance to cisplatin-based chemotherapy leading to poor prognosis. This may be attributed to the relative lack of mutations and aberrations in homologous recombination-associated genes, which are crucial in DNA damage response (DDR), such as BRCA1, BRCA2, p53, RAD51, and genes in the Fanconi anemia pathway. On the other hand, OCCC is characterized by a number of genetic defects rendering it vulnerable to DDR-targeting therapy, which is emerging as a potent treatment strategy for various cancer types. Mutations of ARID1A, PIK3CA, PTEN, and catenin beta 1 (CTNNB1), as well as overexpression of transcription factor hepatocyte nuclear factor-1β (HNF-1β), and microsatellite instability are common in OCCC. Of particular note is the loss-of-function mutations in ARID1A, which is found in approximately 50% of OCCC. ARID1A is crucial for processing of DNA double-strand break (DSB) and for sustaining DNA damage signaling, rendering ARID1A-deficient cells prone to impaired DNA damage checkpoint regulation and hence sensitive to poly ADP ribose polymerase (PARP) inhibitors. However, while preclinical studies have demonstrated the possibility to exploit DDR deficiency in OCCC for therapeutic purpose, progress in clinical application is lagging. In this review, we will recapitulate the preclinical studies supporting the potential of DDR targeting in OCCC treatment, with emphasis on the role of ARID1A in DDR. Companion diagnostic tests (CDx) for predicting susceptibility to PARP inhibitors are rapidly being developed for solid tumors including ovarian cancers and may readily be applicable on OCCC. The potential of various available DDR-targeting drugs for treating OCCC by drawing analogies with other solid tumors sharing similar genetic characteristics with OCCC will also be discussed.
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124
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van de Kamp G, Heemskerk T, Kanaar R, Essers J. DNA Double Strand Break Repair Pathways in Response to Different Types of Ionizing Radiation. Front Genet 2021; 12:738230. [PMID: 34659358 PMCID: PMC8514742 DOI: 10.3389/fgene.2021.738230] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/30/2021] [Indexed: 01/12/2023] Open
Abstract
The superior dose distribution of particle radiation compared to photon radiation makes it a promising therapy for the treatment of tumors. However, the cellular responses to particle therapy and especially the DNA damage response (DDR) is not well characterized. Compared to photons, particles are thought to induce more closely spaced DNA lesions instead of isolated lesions. How this different spatial configuration of the DNA damage directs DNA repair pathway usage, is subject of current investigations. In this review, we describe recent insights into induction of DNA damage by particle radiation and how this shapes DNA end processing and subsequent DNA repair mechanisms. Additionally, we give an overview of promising DDR targets to improve particle therapy.
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Affiliation(s)
- Gerarda van de Kamp
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands.,Oncode Institute, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Tim Heemskerk
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands.,Oncode Institute, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands.,Oncode Institute, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Jeroen Essers
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands.,Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, Netherlands.,Department of Radiation Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands
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125
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Waldrip ZJ, Burdine L, Harrison DK, Azevedo-Pouly AC, Storey AJ, Moffett OG, Mackintosh SG, Burdine MS. DNA-PKcs kinase activity stabilizes the transcription factor Egr1 in activated immune cells. J Biol Chem 2021; 297:101209. [PMID: 34562454 PMCID: PMC8551498 DOI: 10.1016/j.jbc.2021.101209] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 11/25/2022] Open
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is known primarily for its function in DNA double-stranded break repair and nonhomologous end joining (NHEJ). However, DNA-PKcs also has a critical yet undefined role in immunity impacting both myeloid and lymphoid cell lineages spurring interest in targeting DNA-PKcs for therapeutic strategies in immune-related diseases. To gain insight into the function of DNA-PKcs within immune cells, we performed a quantitative phosphoproteomic screen in T cells to identify phosphorylation targets of DNA-PKcs. Our results indicate that DNA-PKcs phosphorylates the transcription factor Egr1 (early growth response protein 1) at serine 301. Expression of Egr1 is induced early upon T cell activation and dictates T cell response by modulating expression of cytokines and key costimulatory molecules such as IL (interleukin) 2, IL6, IFNγ, and NFκB. Inhibition of DNA-PKcs by treatment with a DNA-PKcs specific inhibitor NU7441 or shRNA knockdown increased proteasomal degradation of Egr1. Mutation of serine 301 to alanine via CRISPR-Cas9 reduced EGR1 protein expression and decreased Egr1-dependent transcription of IL2 in activated T cells. Our findings identify DNA-PKcs as a critical intermediary link between T cell activation and T cell fate and a novel phosphosite involved in regulating Egr1 activity.
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Affiliation(s)
- Zachary J Waldrip
- Division of Surgical Research, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA; Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, Arkansas, USA
| | - Lyle Burdine
- Division of Surgical Research, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA; Department of Transplant Surgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - David K Harrison
- Division of Surgical Research, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA; Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, Arkansas, USA
| | - Ana Clara Azevedo-Pouly
- Division of Surgical Research, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA; Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, Arkansas, USA
| | - Aaron J Storey
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Olivia G Moffett
- College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Samuel G Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Marie Schluterman Burdine
- Division of Surgical Research, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA; Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, Arkansas, USA.
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126
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Deshpande RA, Paull TT. Characterization of DNA-PK-bound end fragments using GLASS-ChIP. Methods Enzymol 2021; 661:205-217. [PMID: 34776213 DOI: 10.1016/bs.mie.2021.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Endonucleolytic cleavage of DNA ends by the human Mre11-Rad50-Nbs1 (MRN) complex occurs in a manner that is promoted by DNA-dependent Protein Kinase (DNA-PK). A method is described to isolate DNA-PK-bound fragments released from chromatin in human cells using a modified Gentle Lysis and Size Selection chromatin immunoprecipitation (GLASS-ChIP) protocol. This method, combined with real-time PCR or next-generation sequencing, can identify sites of MRN endonucleolytic cutting adjacent to DNA-PK binding sites in human cells.
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Affiliation(s)
- Rajashree A Deshpande
- The Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - Tanya T Paull
- The Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States.
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127
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Yosaatmadja Y, Baddock H, Newman J, Bielinski M, Gavard A, Mukhopadhyay SMM, Dannerfjord A, Schofield C, McHugh P, Gileadi O. Structural and mechanistic insights into the Artemis endonuclease and strategies for its inhibition. Nucleic Acids Res 2021; 49:9310-9326. [PMID: 34387696 PMCID: PMC8450076 DOI: 10.1093/nar/gkab693] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 07/20/2021] [Accepted: 08/11/2021] [Indexed: 12/23/2022] Open
Abstract
Artemis (SNM1C/DCLRE1C) is an endonuclease that plays a key role in development of B- and T-lymphocytes and in dsDNA break repair by non-homologous end-joining (NHEJ). Artemis is phosphorylated by DNA-PKcs and acts to open DNA hairpin intermediates generated during V(D)J and class-switch recombination. Artemis deficiency leads to congenital radiosensitive severe acquired immune deficiency (RS-SCID). Artemis belongs to a superfamily of nucleases containing metallo-β-lactamase (MBL) and β-CASP (CPSF-Artemis-SNM1-Pso2) domains. We present crystal structures of the catalytic domain of wildtype and variant forms of Artemis, including one causing RS-SCID Omenn syndrome. The catalytic domain of the Artemis has similar endonuclease activity to the phosphorylated full-length protein. Our structures help explain the predominantly endonucleolytic activity of Artemis, which contrasts with the predominantly exonuclease activity of the closely related SNM1A and SNM1B MBL fold nucleases. The structures reveal a second metal binding site in its β-CASP domain unique to Artemis, which is amenable to inhibition by compounds including ebselen. By combining our structural data with that from a recently reported Artemis structure, we were able model the interaction of Artemis with DNA substrates. The structures, including one of Artemis with the cephalosporin ceftriaxone, will help enable the rational development of selective SNM1 nuclease inhibitors.
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Affiliation(s)
- Yuliana Yosaatmadja
- Centre for Medicines Discovery, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Hannah T Baddock
- Department of Oncology, MRC-Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Joseph A Newman
- Centre for Medicines Discovery, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Marcin Bielinski
- The Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Angeline E Gavard
- Centre for Medicines Discovery, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | | | - Adam A Dannerfjord
- Centre for Medicines Discovery, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Christopher J Schofield
- The Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Peter J McHugh
- Department of Oncology, MRC-Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Opher Gileadi
- Centre for Medicines Discovery, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
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128
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Zhang DM, Szymanski J, Bergom C, Cuculich PS, Robinson CG, Schwarz JK, Rentschler SL. Leveraging Radiobiology for Arrhythmia Management: A New Treatment Paradigm? Clin Oncol (R Coll Radiol) 2021; 33:723-734. [PMID: 34535357 DOI: 10.1016/j.clon.2021.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 08/04/2021] [Accepted: 09/01/2021] [Indexed: 01/01/2023]
Abstract
Radiation therapy is a well-established approach for safely and non-invasively treating solid tumours and benign diseases with high precision and accuracy. Cardiac radiation therapy has recently emerged as a non-invasive treatment option for the management of refractory ventricular tachycardia. Here we summarise existing clinical and preclinical literature surrounding cardiac radiobiology and discuss how these studies may inform basic and translational research, as well as clinical treatment paradigms in the management of arrhythmias.
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Affiliation(s)
- D M Zhang
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - J Szymanski
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - C Bergom
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - P S Cuculich
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - C G Robinson
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - J K Schwarz
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - S L Rentschler
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Biomedical Engineering, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Developmental Biology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA.
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129
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VAV2 is required for DNA repair and implicated in cancer radiotherapy resistance. Signal Transduct Target Ther 2021; 6:322. [PMID: 34462423 PMCID: PMC8405816 DOI: 10.1038/s41392-021-00735-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/19/2021] [Accepted: 08/10/2021] [Indexed: 02/07/2023] Open
Abstract
Radiotherapy remains the mainstay for treatment of various types of human cancer; however, the clinical efficacy is often limited by radioresistance, in which the underlying mechanism is largely unknown. Here, using esophageal squamous cell carcinoma (ESCC) as a model, we demonstrate that guanine nucleotide exchange factor 2 (VAV2), which is overexpressed in most human cancers, plays an important role in primary and secondary radioresistance. We have discovered for the first time that VAV2 is required for the Ku70/Ku80 complex formation and participates in non-homologous end joining repair of DNA damages caused by ionizing radiation. We show that VAV2 overexpression substantially upregulates signal transducer and activator of transcription 1 (STAT1) and the STAT1 inhibitor Fludarabine can significantly promote the sensitivity of radioresistant patient-derived ESCC xenografts in vivo in mice to radiotherapy. These results shed new light on the mechanism of cancer radioresistance, which may be important for improving clinical radiotherapy.
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130
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Internally Symmetrical Stwintrons and Related Canonical Introns in Hypoxylaceae Species. J Fungi (Basel) 2021; 7:jof7090710. [PMID: 34575748 PMCID: PMC8469720 DOI: 10.3390/jof7090710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 01/01/2023] Open
Abstract
Spliceosomal introns are pervasive in eukaryotes. Intron gains and losses have occurred throughout evolution, but the origin of new introns is unclear. Stwintrons are complex intervening sequences where one of the sequence elements (5′-donor, lariat branch point element or 3′-acceptor) necessary for excision of a U2 intron (external intron) is itself interrupted by a second (internal) U2 intron. In Hypoxylaceae, a family of endophytic fungi, we uncovered scores of donor-disrupted stwintrons with striking sequence similarity among themselves and also with canonical introns. Intron–exon structure comparisons suggest that these stwintrons have proliferated within diverging taxa but also give rise to proliferating canonical introns in some genomes. The proliferated (stw)introns have integrated seamlessly at novel gene positions. The recently proliferated (stw)introns appear to originate from a conserved ancestral stwintron characterised by terminal inverted repeats (45–55 nucleotides), a highly symmetrical structure that may allow the formation of a double-stranded intron RNA molecule. No short tandem duplications flank the putatively inserted intervening sequences, which excludes a DNA transposition-based mechanism of proliferation. It is tempting to suggest that this highly symmetrical structure may have a role in intron proliferation by (an)other mechanism(s).
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131
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Hu H, Chen W, Zhang S, Xue Y, He Y, Gu Y. NEAT1/miR-101-dependent Up-regulation of DNA-PKcs Enhances Malignant Behaviors of Pancreatic Ductal Adenocarcinoma Cells. J Cancer 2021; 12:5622-5632. [PMID: 34405022 PMCID: PMC8364653 DOI: 10.7150/jca.58824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 07/09/2021] [Indexed: 12/25/2022] Open
Abstract
Background: Although we previously revealed that DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and important for gemcitabine resistance, the role of DNA-PKcs in the progression and metastasis of PDAC remain unclear. To date, the upstream signaling events stimulating DNA-PKcs overexpression in PDAC are still not well characterized. Methods: Expression of DNA-PKcs was measured by western blot. The levels of miRNA-101 and lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) were detected by real-time PCR. Cell viability was determined by CCK-8. Cell migration and cell invasion were measured by transwell assay. The regulatory relationship between NEAT1 and miR-101 was determined by a luciferase assay. Results: DNA-PKcs expression was significantly elevated in human PDAC tissues and cells. DNA-PKcs overexpression was correlated with TNM stage and lymph node metastasis. Higher expression of DNA-PKcs was closely correlated with patients of worse overall survival (OS). DNA-PKcs knockdown suppresses malignant behaviors of PDAC cells. Further study showed that miRNA-101 level was decreased in PDAC tissues and cells, which could be responsible for DNA-PKcs overexpression and DNA-PKcs mediated oncogenic actions in PDAC cells. Moreover, NEAT1 functions as an oncogene influencing cell proliferation, migration and invasion in part by serving as a competing endogenous RNA (ceRNAs) modulating miR-101 expression, leading to up-regulation of DNA-PKcs. Conclusion: These findings suggest that NEAT1/miR-101-dependent up-regulation of DNA-PKcs promotes the malignant behaviors of PDAC cells. The NEAT1/miR-101/DNA-PKcs axis may serve as a viable prognostic marker and therapeutic target for PDAC.
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Affiliation(s)
- Hao Hu
- Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Jiangnan University, 585 Xingyuan Rd, Liangxi District, Wuxi, 214041, China.,School of Medicine, Jiangnan University, Wuxi 214122, China.,Hepatobiliary and Pancreatic Surgery, The Third Hospital Affiliated to Nantong University, Wuxi 214041, China.,Medical School, Nantong University, Nantong 226001, China.,Wuxi Institute of Hepatobiliary Surgery, Wuxi 214041, China
| | - Wuqiang Chen
- Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Jiangnan University, 585 Xingyuan Rd, Liangxi District, Wuxi, 214041, China.,Wuxi Institute of Hepatobiliary Surgery, Wuxi 214041, China
| | - Shuo Zhang
- Hepatobiliary and Pancreatic Surgery, The Third Hospital Affiliated to Nantong University, Wuxi 214041, China.,Medical School, Nantong University, Nantong 226001, China
| | - Yuzheng Xue
- School of Medicine, Jiangnan University, Wuxi 214122, China.,Department of Gastroenterology, Affiliated Hospital of Jiangnan University, Wuxi 214041, China
| | - Youzhao He
- Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Jiangnan University, 585 Xingyuan Rd, Liangxi District, Wuxi, 214041, China.,Wuxi Institute of Hepatobiliary Surgery, Wuxi 214041, China
| | - Yuanlong Gu
- Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Jiangnan University, 585 Xingyuan Rd, Liangxi District, Wuxi, 214041, China.,School of Medicine, Jiangnan University, Wuxi 214122, China.,Wuxi Institute of Hepatobiliary Surgery, Wuxi 214041, China
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132
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Tang M, Pei G, Su D, Wang C, Feng X, Srivastava M, Chen Z, Zhao Z, Chen J. Genome-wide CRISPR screens reveal cyclin C as synthetic survival target of BRCA2. Nucleic Acids Res 2021; 49:7476-7491. [PMID: 34197614 PMCID: PMC8287926 DOI: 10.1093/nar/gkab540] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/04/2021] [Accepted: 06/23/2021] [Indexed: 01/15/2023] Open
Abstract
Poly (ADP-ribose) polymerase inhibitor (PARPi)-based therapies initially reduce tumor burden but eventually lead to acquired resistance in cancer patients with BRCA1 or BRCA2 mutation. To understand the potential PARPi resistance mechanisms, we performed whole-genome CRISPR screens to discover genetic alterations that change the gene essentiality in cells with inducible depletion of BRCA2. We identified that several RNA Polymerase II transcription Mediator complex components, especially Cyclin C (CCNC) as synthetic survival targets upon BRCA2 loss. Total mRNA sequencing demonstrated that loss of CCNC could activate the transforming growth factor (TGF)-beta signaling pathway and extracellular matrix (ECM)-receptor interaction pathway, however the inhibition of these pathways could not reverse cell survival in BRCA2 depleted CCNC-knockout cells, indicating that the activation of these pathways is not required for the resistance. Moreover, we showed that the improved survival is not due to restoration of homologous recombination repair although decreased DNA damage signaling was observed. Interestingly, loss of CCNC could restore replication fork stability in BRCA2 deficient cells, which may contribute to PARPi resistance. Taken together, our data reveal CCNC as a critical genetic determinant upon BRCA2 loss of function, which may help the development of novel therapeutic strategies that overcome PARPi resistance.
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Affiliation(s)
- Mengfan Tang
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Guangsheng Pei
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Dan Su
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chao Wang
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xu Feng
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mrinal Srivastava
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Zhen Chen
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,Human Genetics Center, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Junjie Chen
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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133
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Dysfunctional activity of classical DNA end-joining renders acquired resistance to carboplatin in human ovarian cancer cells. Cancer Lett 2021; 520:267-280. [PMID: 34375710 DOI: 10.1016/j.canlet.2021.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/13/2021] [Accepted: 08/02/2021] [Indexed: 12/13/2022]
Abstract
Ovarian cancer is the deadliest gynecological malignancy worldwide. Although chemotherapy is required as the most standard treatment strategy for ovarian cancer, the survival rates are very low, largely because of high incidence of recurrence due to resistance to conventional surgery and genotoxic chemotherapies. Carboplatin-resistant ovarian cancer cells were generated by continuous treatment over six months. Carboplatin-resistance induced morphological alterations and promoted the rates of proliferation and migration of SKOV3 compared to the parental cells. Interestingly, carboplatin-resistant SKOV3 showed the high levels of γH2AX foci formed at the basal level, and the levels of γH2AX foci remained even after the recovery time, suggesting that the DNA damage response and repair machinery were severely attenuated by carboplatin-resistance. Surprisingly, the expression levels of XRCC4, a critical factor in non-homologous end joining (NHEJ) DNA repair, were significantly decreased in carboplatin-resistant SKOV3 compared with those in non-resistant controls. Furthermore, restoration of NHEJ in carboplatin-resistant SKOV3 by suppression of ABCB1 and/or AR re-sensitized carboplatin-resistant cells to genotoxic stress and reduced their proliferation ability. Our findings suggest that attenuation of the NHEJ DNA repair machinery mediated by resistance to genotoxic stress might be a critical cause of chemoresistance in patients with ovarian cancer.
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134
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Schibeci Natoli Scialli N, Colitti B, Bertolotti L, Pezzoni G, Martignani E, Melega M, Brocchi E, Rosati S. Genome editing of a hybridoma cell line via the CRISPR/Cas9 system: A new approach for constitutive high-level expression of heterologous proteins in eukaryotic system. Vet Immunol Immunopathol 2021; 238:110286. [PMID: 34171554 DOI: 10.1016/j.vetimm.2021.110286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/22/2021] [Accepted: 06/14/2021] [Indexed: 11/20/2022]
Abstract
The power of the CRISPR/Cas9 system has revolutionized genome editing in many fields of biology. These applications have expanded exponentially over recent years, including those regarding protein expression technologies. The CRISPR/Cas9 system avoids random integration of the gene of interest and due to this characteristic can be exploited to obtain a stable cell line for the high-yield expression of recombinant proteins. Here we propose a method to edit a hybridoma cell line for the constitutive expression of proteins of interest using the CRISPR/Cas9 system. First, with the scope of optimizing the method, we replaced part of the light chain of immunoglobulin with the Green Fluorescent Protein (GFP) gene, obtaining a precise knock-in in the hybridoma genome. We confirmed the expression and secretion of GFP into the culture medium via fluorimetric analysis, as well as correct genome editing by RNA sequencing. Then, using the same approach, we included the gene encoding a protein of diagnostic interest, the Bovine Herpesvirus 1 glycoprotein E, in the donor DNA. We obtained a stable clone able to secrete gE protein in fusion with GFP into the culture medium. This result was confirmed by ELISA and Western Blot analysis. This study confirms the suitability of this cell line for the production of proteins of diagnostic interest by stable gene expression in a mammalian system. These experiments will enable the technique to be developed from its proof of concept to more specific applications in the field of infectious disease diagnostics.
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Affiliation(s)
| | - Barbara Colitti
- Department of Veterinary Science, University of Turin, Largo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Luigi Bertolotti
- Department of Veterinary Science, University of Turin, Largo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Giulia Pezzoni
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 7, 25124, Brescia, Italy
| | - Eugenio Martignani
- Department of Veterinary Science, University of Turin, Largo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Maverick Melega
- Department of Veterinary Science, University of Turin, Largo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Emiliana Brocchi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 7, 25124, Brescia, Italy
| | - Sergio Rosati
- Department of Veterinary Science, University of Turin, Largo Braccini 2, 10095, Grugliasco, TO, Italy.
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135
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Cook AW, Toseland CP. The roles of nuclear myosin in the DNA damage response. J Biochem 2021; 169:265-271. [PMID: 33035317 DOI: 10.1093/jb/mvaa113] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/22/2020] [Indexed: 02/06/2023] Open
Abstract
Myosin within the nucleus has often been overlooked due to their importance in cytoplasmic processes and a lack of investigation. However, more recently, it has been shown that their nuclear roles are just as fundamental to cell function and survival with roles in transcription, DNA damage and viral replication. Myosins can act as molecular transporters and anchors that rely on their actin binding and ATPase capabilities. Their roles within the DNA damage response can varies from a transcriptional response, moving chromatin and stabilizing chromosome contacts. This review aims to highlight their key roles in the DNA damage response and how they impact nuclear organization and transcription.
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Affiliation(s)
- Alexander W Cook
- Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
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136
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Ackerson SM, Romney C, Schuck PL, Stewart JA. To Join or Not to Join: Decision Points Along the Pathway to Double-Strand Break Repair vs. Chromosome End Protection. Front Cell Dev Biol 2021; 9:708763. [PMID: 34322492 PMCID: PMC8311741 DOI: 10.3389/fcell.2021.708763] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/17/2021] [Indexed: 01/01/2023] Open
Abstract
The regulation of DNA double-strand breaks (DSBs) and telomeres are diametrically opposed in the cell. DSBs are considered one of the most deleterious forms of DNA damage and must be quickly recognized and repaired. Telomeres, on the other hand, are specialized, stable DNA ends that must be protected from recognition as DSBs to inhibit unwanted chromosome fusions. Decisions to join DNA ends, or not, are therefore critical to genome stability. Yet, the processing of telomeres and DSBs share many commonalities. Accordingly, key decision points are used to shift DNA ends toward DSB repair vs. end protection. Additionally, DSBs can be repaired by two major pathways, namely homologous recombination (HR) and non-homologous end joining (NHEJ). The choice of which repair pathway is employed is also dictated by a series of decision points that shift the break toward HR or NHEJ. In this review, we will focus on these decision points and the mechanisms that dictate end protection vs. DSB repair and DSB repair choice.
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Affiliation(s)
- Stephanie M Ackerson
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
| | - Carlan Romney
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
| | - P Logan Schuck
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
| | - Jason A Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
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137
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Sledzinski P, Dabrowska M, Nowaczyk M, Olejniczak M. Paving the way towards precise and safe CRISPR genome editing. Biotechnol Adv 2021; 49:107737. [PMID: 33785374 DOI: 10.1016/j.biotechadv.2021.107737] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 03/11/2021] [Accepted: 03/19/2021] [Indexed: 12/13/2022]
Abstract
As the possibilities of CRISPR-Cas9 technology have been revealed, we have entered a new era of research aimed at increasing its specificity and safety. This stage of technology development is necessary not only for its wider application in the clinic but also in basic research to better control the process of genome editing. Research during the past eight years has identified some factors influencing editing outcomes and led to the development of highly specific endonucleases, modified guide RNAs and computational tools supporting experiments. More recently, large-scale experiments revealed a previously overlooked feature: Cas9 can generate reproducible mutation patterns. As a result, it has become apparent that Cas9-induced double-strand break (DSB) repair is nonrandom and can be predicted to some extent. Here, we review the present state of knowledge regarding the specificity and safety of CRISPR-Cas9 technology to define gRNA, protein and target-related problems and solutions. These issues include sequence-specific off-target effects, immune responses, genetic variation and chromatin accessibility. We present new insights into the role of DNA repair in genome editing and define factors influencing editing outcomes. In addition, we propose practical guidelines for increasing the specificity of editing and discuss novel perspectives in improvement of this technology.
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Affiliation(s)
- Pawel Sledzinski
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland
| | - Magdalena Dabrowska
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland
| | - Mateusz Nowaczyk
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland
| | - Marta Olejniczak
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland.
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138
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Bossaert M, Pipier A, Riou JF, Noirot C, Nguyên LT, Serre RF, Bouchez O, Defrancq E, Calsou P, Britton S, Gomez D. Transcription-associated topoisomerase 2α (TOP2A) activity is a major effector of cytotoxicity induced by G-quadruplex ligands. eLife 2021; 10:65184. [PMID: 34180392 PMCID: PMC8279764 DOI: 10.7554/elife.65184] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 06/16/2021] [Indexed: 12/11/2022] Open
Abstract
G-quadruplexes (G4) are non-canonical DNA structures found in the genome of most species including human. Small molecules stabilizing these structures, called G4 ligands, have been identified and, for some of them, shown to induce cytotoxic DNA double-strand breaks. Through the use of an unbiased genetic approach, we identify here topoisomerase 2α (TOP2A) as a major effector of cytotoxicity induced by two clastogenic G4 ligands, pyridostatin and CX-5461, the latter molecule currently undergoing phase I/II clinical trials in oncology. We show that both TOP2 activity and transcription account for DNA break production following G4 ligand treatments. In contrast, clastogenic activity of these G4 ligands is countered by topoisomerase 1 (TOP1), which limits co-transcriptional G4 formation, and by factors promoting transcriptional elongation. Altogether our results support that clastogenic G4 ligands act as DNA structure-driven TOP2 poisons at transcribed regions bearing G4 structures.
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Affiliation(s)
- Madeleine Bossaert
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Angélique Pipier
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Jean-Francois Riou
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, CNRS, INSERM, Paris, France
| | - Céline Noirot
- INRAE, UR 875, Unité de Mathématique et Informatique Appliquées, Genotoul Bioinfo, Castanet-Tolosan, France
| | - Linh-Trang Nguyên
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | | | - Olivier Bouchez
- INRAE, US 1426, GeT-PlaGe, Genotoul, Castanet-Tolosan, France
| | - Eric Defrancq
- Département de Chimie Moléculaire, UMR CNRS 5250, Université Grenoble Alpes, Grenoble, France
| | - Patrick Calsou
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Sébastien Britton
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Dennis Gomez
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
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139
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Raina A, Sahu PK, Laskar RA, Rajora N, Sao R, Khan S, Ganai RA. Mechanisms of Genome Maintenance in Plants: Playing It Safe With Breaks and Bumps. Front Genet 2021; 12:675686. [PMID: 34239541 PMCID: PMC8258418 DOI: 10.3389/fgene.2021.675686] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/04/2021] [Indexed: 01/14/2023] Open
Abstract
Maintenance of genomic integrity is critical for the perpetuation of all forms of life including humans. Living organisms are constantly exposed to stress from internal metabolic processes and external environmental sources causing damage to the DNA, thereby promoting genomic instability. To counter the deleterious effects of genomic instability, organisms have evolved general and specific DNA damage repair (DDR) pathways that act either independently or mutually to repair the DNA damage. The mechanisms by which various DNA repair pathways are activated have been fairly investigated in model organisms including bacteria, fungi, and mammals; however, very little is known regarding how plants sense and repair DNA damage. Plants being sessile are innately exposed to a wide range of DNA-damaging agents both from biotic and abiotic sources such as ultraviolet rays or metabolic by-products. To escape their harmful effects, plants also harbor highly conserved DDR pathways that share several components with the DDR machinery of other organisms. Maintenance of genomic integrity is key for plant survival due to lack of reserve germline as the derivation of the new plant occurs from the meristem. Untowardly, the accumulation of mutations in the meristem will result in a wide range of genetic abnormalities in new plants affecting plant growth development and crop yield. In this review, we will discuss various DNA repair pathways in plants and describe how the deficiency of each repair pathway affects plant growth and development.
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Affiliation(s)
- Aamir Raina
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
- Botany Section, Women’s College, Aligarh Muslim University, Aligarh, India
| | - Parmeshwar K. Sahu
- Department of Genetics and Plant Breeding, Indira Gandhi Agriculture University, Raipur, India
| | | | - Nitika Rajora
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Richa Sao
- Department of Genetics and Plant Breeding, Indira Gandhi Agriculture University, Raipur, India
| | - Samiullah Khan
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
| | - Rais A. Ganai
- Watson-Crick Centre for Molecular Medicine, Islamic University of Science and Technology, Awantipora, India
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140
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Xu P, Liu Z, Liu Y, Ma H, Xu Y, Bao Y, Zhu S, Cao Z, Wu Z, Zhou Z, Wei W. Genome-wide interrogation of gene functions through base editor screens empowered by barcoded sgRNAs. Nat Biotechnol 2021; 39:1403-1413. [PMID: 34155407 DOI: 10.1038/s41587-021-00944-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 05/06/2021] [Indexed: 12/20/2022]
Abstract
Canonical CRISPR-knockout (KO) screens rely on Cas9-induced DNA double-strand breaks (DSBs) to generate targeted gene KOs. These methodologies may yield distorted results because DSB-associated effects are often falsely assumed to be consequences of gene perturbation itself, especially when high copy-number sites are targeted. In the present study, we report a DSB-independent, genome-wide CRISPR screening method, termed iBARed cytosine base editing-mediated gene KO (BARBEKO). This method leverages CRISPR cytosine base editors for genome-scale KO screens by perturbing gene start codons or splice sites, or by introducing premature termination codons. Furthermore, it is integrated with iBAR, a strategy we devised for improving screening quality and efficiency. By constructing such a cell library through lentiviral infection at a high multiplicity of infection (up to 10), we achieved efficient and accurate screening results with substantially reduced starting cells. More importantly, in comparison with Cas9-mediated fitness screens, BARBEKO screens are no longer affected by DNA cleavage-induced cytotoxicity in HeLa-, K562- or DSB-sensitive retinal pigmented epithelial 1 cells. We anticipate that BARBEKO offers a valuable tool to complement the current CRISPR-KO screens in various settings.
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Affiliation(s)
- Ping Xu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Zhiheng Liu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Ying Liu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Huazheng Ma
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.,Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Peking University, Beijing, China
| | - Yiyuan Xu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Ying Bao
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Shiyou Zhu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Zhongzheng Cao
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Zeguang Wu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Zhuo Zhou
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Wensheng Wei
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
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141
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Strubbe S, De Bruyne M, Pannicke U, Beyls E, Vandekerckhove B, Leclercq G, De Baere E, Bordon V, Vral A, Schwarz K, Haerynck F, Taghon T. A Novel Non-Coding Variant in DCLRE1C Results in Deregulated Splicing and Induces SCID Through the Generation of a Truncated ARTEMIS Protein That Fails to Support V(D)J Recombination and DNA Damage Repair. Front Immunol 2021; 12:674226. [PMID: 34220820 PMCID: PMC8248492 DOI: 10.3389/fimmu.2021.674226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/03/2021] [Indexed: 11/13/2022] Open
Abstract
Severe Combined Immune Deficiency (SCID) is a primary deficiency of the immune system in which opportunistic and recurring infections are often fatal during neonatal or infant life. SCID is caused by an increasing number of genetic defects that induce an abrogation of T lymphocyte development or function in which B and NK cells might be affected as well. Because of the increased availability and usage of next-generation sequencing (NGS), many novel variants in SCID genes are being identified and cause a heterogeneous disease spectrum. However, the molecular and functional implications of these new variants, of which some are non-coding, are often not characterized in detail. Using targeted NGS, we identified a novel homozygous c.465-1G>C splice acceptor site variant in the DCLRE1C gene in a T-B-NK+ SCID patient and fully characterized the molecular and functional impact. By performing a minigene splicing reporter assay, we revealed deregulated splicing of the DCLRE1C transcript since a cryptic splice acceptor in exon 7 was employed. This induced a frameshift and the generation of a p.Arg155Serfs*15 premature termination codon (PTC) within all DCLRE1C splice variants, resulting in the absence of full-length ARTEMIS protein. Consistently, a V(D)J recombination assay and a G0 micronucleus assay demonstrated the inability of the predicted mutant ARTEMIS protein to perform V(D)J recombination and DNA damage repair, respectively. Together, these experiments molecularly and functionally clarify how a newly identified c.465-1G>C variant in the DCLRE1C gene is responsible for inducing SCID. In a clinical context, this demonstrates how the experimental validation of new gene variants, that are identified by NGS, can facilitate the diagnosis of SCID which can be vital for implementing appropriate therapies.
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Affiliation(s)
- Steven Strubbe
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | | | - Ulrich Pannicke
- The Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Elien Beyls
- Department of Human Structure and Repair, Ghent University, Ghent, Belgium
| | - Bart Vandekerckhove
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent, Belgium
| | - Georges Leclercq
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent, Belgium
| | - Elfride De Baere
- Center for Medical Genetics Ghent (CMGG), Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Victoria Bordon
- Department of Internal Medicine and Pediatrics, Division of Pediatric Hemato-Oncology and Stem Cell Transplantation, Ghent University Hospital, Ghent, Belgium
| | - Anne Vral
- Department of Human Structure and Repair, Ghent University, Ghent, Belgium
| | - Klaus Schwarz
- The Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, Germa Red Cross Blood Service Baden-Württemberg - Hessen, Ulm, Germany
| | - Filomeen Haerynck
- Primary Immunodeficiency Research Lab, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium.,Department of Internal Medicine and Pediatrics, Division of Pediatric Immunology and Pulmonology, Ghent University Hospital, Ghent, Belgium
| | - Tom Taghon
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent, Belgium
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142
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Morton CR, Rzechorzek NJ, Maman JD, Kuramochi M, Sekiguchi H, Rambo R, Sasaki YC, Davies OR, Pellegrini L. Structural basis for the coiled-coil architecture of human CtIP. Open Biol 2021; 11:210060. [PMID: 34129781 PMCID: PMC8205527 DOI: 10.1098/rsob.210060] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The DNA repair factor CtIP has a critical function in double-strand break (DSB) repair by homologous recombination, promoting the assembly of the repair apparatus at DNA ends and participating in DNA-end resection. However, the molecular mechanisms of CtIP function in DSB repair remain unclear. Here, we present an atomic model for the three-dimensional architecture of human CtIP, derived from a multi-disciplinary approach that includes X-ray crystallography, small-angle X-ray scattering (SAXS) and diffracted X-ray tracking (DXT). Our data show that CtIP adopts an extended dimer-of-dimers structure, in agreement with a role in bridging distant sites on chromosomal DNA during the recombinational repair. The zinc-binding motif in the CtIP N-terminus alters dynamically the coiled-coil structure, with functional implications for the long-range interactions of CtIP with DNA. Our results provide a structural basis for the three-dimensional arrangement of chains in the CtIP tetramer, a key aspect of CtIP function in DNA DSB repair.
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Affiliation(s)
- C R Morton
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - N J Rzechorzek
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - J D Maman
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - M Kuramochi
- Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.,AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, Japan
| | - H Sekiguchi
- Centre for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - R Rambo
- Diamond Light Source, Didcot, Oxfordshire OX11 0DE, UK
| | - Y C Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.,AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, Japan.,Centre for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - O R Davies
- Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - L Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
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143
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Zhou Q, Howard ME, Tu X, Zhu Q, Denbeigh JM, Remmes NB, Herman MG, Beltran CJ, Yuan J, Greipp PT, Boughey JC, Wang L, Johnson N, Goetz MP, Sarkaria JN, Lou Z, Mutter RW. Inhibition of ATM Induces Hypersensitivity to Proton Irradiation by Upregulating Toxic End Joining. Cancer Res 2021; 81:3333-3346. [PMID: 33597272 PMCID: PMC8260463 DOI: 10.1158/0008-5472.can-20-2960] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/30/2020] [Accepted: 02/11/2021] [Indexed: 12/15/2022]
Abstract
Proton Bragg peak irradiation has a higher ionizing density than conventional photon irradiation or the entrance of the proton beam profile. Whether targeting the DNA damage response (DDR) could enhance vulnerability to the distinct pattern of damage induced by proton Bragg peak irradiation is currently unknown. Here, we performed genetic or pharmacologic manipulation of key DDR elements and evaluated DNA damage signaling, DNA repair, and tumor control in cell lines and xenografts treated with the same physical dose across a radiotherapy linear energy transfer spectrum. Radiotherapy consisted of 6 MV photons and the entrance beam or Bragg peak of a 76.8 MeV spot scanning proton beam. More complex DNA double-strand breaks (DSB) induced by Bragg peak proton irradiation preferentially underwent resection and engaged homologous recombination (HR) machinery. Unexpectedly, the ataxia-telangiectasia mutated (ATM) inhibitor, AZD0156, but not an inhibitor of ATM and Rad3-related, rendered cells hypersensitive to more densely ionizing proton Bragg peak irradiation. ATM inhibition blocked resection and shunted more DSBs to processing by toxic ligation through nonhomologous end-joining, whereas loss of DNA ligation via XRCC4 or Lig4 knockdown rescued resection and abolished the enhanced Bragg peak cell killing. Proton Bragg peak monotherapy selectively sensitized cell lines and tumor xenografts with inherent HR defects, and the repair defect induced by ATM inhibitor coadministration showed enhanced efficacy in HR-proficient models. In summary, inherent defects in HR or administration of an ATM inhibitor in HR-proficient tumors selectively enhances the relative biological effectiveness of proton Bragg peak irradiation. SIGNIFICANCE: Coadministration of an ATM inhibitor rewires DNA repair machinery to render cancer cells uniquely hypersensitive to DNA damage induced by the proton Bragg peak, which is characterized by higher density ionization.See related commentary by Nickoloff, p. 3156.
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Affiliation(s)
- Qin Zhou
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | | | - Xinyi Tu
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Qian Zhu
- Department of Oncology, Mayo Clinic, Rochester, Minnesota
| | - Janet M Denbeigh
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | | | - Michael G Herman
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Chris J Beltran
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Jian Yuan
- Department of Oncology, Mayo Clinic, Rochester, Minnesota
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Patricia T Greipp
- Division of Laboratory Genetics and Genomics, Mayo Clinic, Rochester, Minnesota
| | - Judy C Boughey
- Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Neil Johnson
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Matthew P Goetz
- Division of Medical Oncology, Mayo Clinic, Rochester, Minnesota
| | - Jann N Sarkaria
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Zhenkun Lou
- Department of Oncology, Mayo Clinic, Rochester, Minnesota.
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Robert W Mutter
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota.
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144
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Thompson MK, Sobol RW, Prakash A. Exploiting DNA Endonucleases to Advance Mechanisms of DNA Repair. BIOLOGY 2021; 10:530. [PMID: 34198612 PMCID: PMC8232306 DOI: 10.3390/biology10060530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 12/17/2022]
Abstract
The earliest methods of genome editing, such as zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALENs), utilize customizable DNA-binding motifs to target the genome at specific loci. While these approaches provided sequence-specific gene-editing capacity, the laborious process of designing and synthesizing recombinant nucleases to recognize a specific target sequence, combined with limited target choices and poor editing efficiency, ultimately minimized the broad utility of these systems. The discovery of clustered regularly interspaced short palindromic repeat sequences (CRISPR) in Escherichia coli dates to 1987, yet it was another 20 years before CRISPR and the CRISPR-associated (Cas) proteins were identified as part of the microbial adaptive immune system, by targeting phage DNA, to fight bacteriophage reinfection. By 2013, CRISPR/Cas9 systems had been engineered to allow gene editing in mammalian cells. The ease of design, low cytotoxicity, and increased efficiency have made CRISPR/Cas9 and its related systems the designer nucleases of choice for many. In this review, we discuss the various CRISPR systems and their broad utility in genome manipulation. We will explore how CRISPR-controlled modifications have advanced our understanding of the mechanisms of genome stability, using the modulation of DNA repair genes as examples.
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Affiliation(s)
- Marlo K. Thompson
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Robert W. Sobol
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
| | - Aishwarya Prakash
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
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145
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Navarro-Carrasco E, Lazo PA. VRK1 Depletion Facilitates the Synthetic Lethality of Temozolomide and Olaparib in Glioblastoma Cells. Front Cell Dev Biol 2021; 9:683038. [PMID: 34195200 PMCID: PMC8237761 DOI: 10.3389/fcell.2021.683038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022] Open
Abstract
Background Glioblastomas treated with temozolomide frequently develop resistance to pharmacological treatments. Therefore, there is a need to find alternative drug targets to reduce treatment resistance based on tumor dependencies. A possibility is to target simultaneously two proteins from different DNA-damage repair pathways to facilitate tumor cell death. Therefore, we tested whether targeting the human chromatin kinase VRK1 by RNA interference can identify this protein as a novel molecular target to reduce the dependence on temozolomide in combination with olaparib, based on synthetic lethality. Materials and Methods Depletion of VRK1, an enzyme that regulates chromatin dynamic reorganization and facilitates resistance to DNA damage, was performed in glioblastoma cells treated with temozolomide, an alkylating agent used for GBM treatment; and olaparib, an inhibitor of PARP-1, used as sensitizer. Two genetically different human glioblastoma cell lines, LN-18 and LN-229, were used for these experiments. The effect on the DNA-damage response was followed by determination of sequential steps in this process: H4K16ac, γH2AX, H4K20me2, and 53BP1. Results The combination of temozolomide and olaparib increased DNA damage detected by labeling free DNA ends, and chromatin relaxation detected by H4K16ac. The combination of both drugs, at lower doses, resulted in an increase in the DNA damage response detected by the formation of γH2AX and 53BP1 foci. VRK1 depletion did not prevent the generation of DNA damage in TUNEL assays, but significantly impaired the DNA damage response induced by temozolomide and olaparib, and mediated by γH2AX, H4K20me2, and 53BP1. The combination of these drugs in VRK1 depleted cells resulted in an increase of glioblastoma cell death detected by annexin V and the processing of PARP-1 and caspase-3. Conclusion Depletion of the chromatin kinase VRK1 promotes tumor cell death at lower doses of a combination of temozolomide and olaparib treatments, and can be a novel alternative target for therapies based on synthetic lethality.
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Affiliation(s)
- Elena Navarro-Carrasco
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca-IBSAL, Hospital Universitario de Salamanca, Salamanca, Spain
| | - Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca-IBSAL, Hospital Universitario de Salamanca, Salamanca, Spain
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146
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Orhan E, Velazquez C, Tabet I, Sardet C, Theillet C. Regulation of RAD51 at the Transcriptional and Functional Levels: What Prospects for Cancer Therapy? Cancers (Basel) 2021; 13:2930. [PMID: 34208195 PMCID: PMC8230762 DOI: 10.3390/cancers13122930] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 01/07/2023] Open
Abstract
The RAD51 recombinase is a critical effector of Homologous Recombination (HR), which is an essential DNA repair mechanism for double-strand breaks. The RAD51 protein is recruited onto the DNA break by BRCA2 and forms homopolymeric filaments that invade the homologous chromatid and use it as a template for repair. RAD51 filaments are detectable by immunofluorescence as distinct foci in the cell nucleus, and their presence is a read out of HR proficiency. RAD51 is an essential gene, protecting cells from genetic instability. Its expression is low and tightly regulated in normal cells and, contrastingly, elevated in a large fraction of cancers, where its level of expression and activity have been linked with sensitivity to genotoxic treatment. In particular, BRCA-deficient tumors show reduced or obliterated RAD51 foci formation and increased sensitivity to platinum salt or PARP inhibitors. However, resistance to treatment sets in rapidly and is frequently based on a complete or partial restoration of RAD51 foci formation. Consequently, RAD51 could be a highly valuable therapeutic target. Here, we review the multiple levels of regulation that impact the transcription of the RAD51 gene, as well as the post-translational modifications that determine its expression level, recruitment on DNA damage sites and the efficient formation of homofilaments. Some of these regulation levels may be targeted and their impact on cancer cell survival discussed.
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Affiliation(s)
- Esin Orhan
- IRCM, Institut de Recherche en Cancérologie de Montpellier U1194 INSERM, Université de Montpellier, 34090 Montpellier, France; (E.O.); (I.T.); (C.S.)
| | | | - Imene Tabet
- IRCM, Institut de Recherche en Cancérologie de Montpellier U1194 INSERM, Université de Montpellier, 34090 Montpellier, France; (E.O.); (I.T.); (C.S.)
| | - Claude Sardet
- IRCM, Institut de Recherche en Cancérologie de Montpellier U1194 INSERM, Université de Montpellier, 34090 Montpellier, France; (E.O.); (I.T.); (C.S.)
| | - Charles Theillet
- IRCM, Institut de Recherche en Cancérologie de Montpellier U1194 INSERM, Université de Montpellier, 34090 Montpellier, France; (E.O.); (I.T.); (C.S.)
- ICM, Institut du Cancer de Montpellier, 34090 Montpellier, France;
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147
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Repair pathway choice for double-strand breaks. Essays Biochem 2021; 64:765-777. [PMID: 32648897 DOI: 10.1042/ebc20200007] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 12/20/2022]
Abstract
Deoxyribonucleic acid (DNA) is at a constant risk of damage from endogenous substances, environmental radiation, and chemical stressors. DNA double-strand breaks (DSBs) pose a significant threat to genomic integrity and cell survival. There are two major pathways for DSB repair: nonhomologous end-joining (NHEJ) and homologous recombination (HR). The extent of DNA end resection, which determines the length of the 3' single-stranded DNA (ssDNA) overhang, is the primary factor that determines whether repair is carried out via NHEJ or HR. NHEJ, which does not require a 3' ssDNA tail, occurs throughout the cell cycle. 53BP1 and the cofactors PTIP or RIF1-shieldin protect the broken DNA end, inhibit long-range end resection and thus promote NHEJ. In contrast, HR mainly occurs during the S/G2 phase and requires DNA end processing to create a 3' tail that can invade a homologous region, ensuring faithful gene repair. BRCA1 and the cofactors CtIP, EXO1, BLM/DNA2, and the MRE11-RAD50-NBS1 (MRN) complex promote DNA end resection and thus HR. DNA resection is influenced by the cell cycle, the chromatin environment, and the complexity of the DNA end break. Herein, we summarize the key factors involved in repair pathway selection for DSBs and discuss recent related publications.
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Druggable binding sites in the multicomponent assemblies that characterise DNA double-strand-break repair through non-homologous end joining. Essays Biochem 2021; 64:791-806. [PMID: 32579168 PMCID: PMC7588668 DOI: 10.1042/ebc20190092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 02/07/2023]
Abstract
Non-homologous end joining (NHEJ) is one of the two principal damage repair pathways for DNA double-strand breaks in cells. In this review, we give a brief overview of the system including a discussion of the effects of deregulation of NHEJ components in carcinogenesis and resistance to cancer therapy. We then discuss the relevance of targeting NHEJ components pharmacologically as a potential cancer therapy and review previous approaches to orthosteric regulation of NHEJ factors. Given the limited success of previous investigations to develop inhibitors against individual components, we give a brief discussion of the recent advances in computational and structural biology that allow us to explore different targets, with a particular focus on modulating protein-protein interaction interfaces. We illustrate this discussion with three examples showcasing some current approaches to developing protein-protein interaction inhibitors to modulate the assembly of NHEJ multiprotein complexes in space and time.
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Sweeney CL, Pavel-Dinu M, Choi U, Brault J, Liu T, Koontz S, Li L, Theobald N, Lee J, Bello EA, Wu X, Meis RJ, Dahl GA, Porteus MH, Malech HL, De Ravin SS. Correction of X-CGD patient HSPCs by targeted CYBB cDNA insertion using CRISPR/Cas9 with 53BP1 inhibition for enhanced homology-directed repair. Gene Ther 2021; 28:373-390. [PMID: 33712802 PMCID: PMC8232036 DOI: 10.1038/s41434-021-00251-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/09/2021] [Accepted: 02/24/2021] [Indexed: 01/31/2023]
Abstract
X-linked chronic granulomatous disease is an immunodeficiency characterized by defective production of microbicidal reactive oxygen species (ROS) by phagocytes. Causative mutations occur throughout the 13 exons and splice sites of the CYBB gene, resulting in loss of gp91phox protein. Here we report gene correction by homology-directed repair in patient hematopoietic stem/progenitor cells (HSPCs) using CRISPR/Cas9 for targeted insertion of CYBB exon 1-13 or 2-13 cDNAs from adeno-associated virus donors at endogenous CYBB exon 1 or exon 2 sites. Targeted insertion of exon 1-13 cDNA did not restore physiologic gp91phox levels, consistent with a requirement for intron 1 in CYBB expression. However, insertion of exon 2-13 cDNA fully restored gp91phox and ROS production upon phagocyte differentiation. Addition of a woodchuck hepatitis virus post-transcriptional regulatory element did not further enhance gp91phox expression in exon 2-13 corrected cells, indicating that retention of intron 1 was sufficient for optimal CYBB expression. Targeted correction was increased ~1.5-fold using i53 mRNA to transiently inhibit nonhomologous end joining. Following engraftment in NSG mice, corrected HSPCs generated phagocytes with restored gp91phox and ROS production. Our findings demonstrate the utility of tailoring donor design and targeting strategies to retain regulatory elements needed for optimal expression of the target gene.
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Affiliation(s)
- Colin L Sweeney
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Mara Pavel-Dinu
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Uimook Choi
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Julie Brault
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Taylor Liu
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sherry Koontz
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | | | - Narda Theobald
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Janet Lee
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ezekiel A Bello
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Xiaolin Wu
- Cancer Research Technology Program, Leidos Biomedical Research Inc., Frederick, MD, USA
| | | | | | - Matthew H Porteus
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA.
| | - Harry L Malech
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Suk See De Ravin
- Genetic Immunotherapy Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Gajek A, Gralewska P, Marczak A, Rogalska A. Current Implications of microRNAs in Genome Stability and Stress Responses of Ovarian Cancer. Cancers (Basel) 2021; 13:cancers13112690. [PMID: 34072593 PMCID: PMC8199164 DOI: 10.3390/cancers13112690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/16/2022] Open
Abstract
Genomic alterations and aberrant DNA damage signaling are hallmarks of ovarian cancer (OC), the leading cause of mortality among gynecological cancers worldwide. Owing to the lack of specific symptoms and late-stage diagnosis, survival chances of patients are significantly reduced. Poly (ADP-ribose) polymerase (PARP) inhibitors and replication stress response inhibitors present attractive therapeutic strategies for OC. Recent research has focused on ovarian cancer-associated microRNAs (miRNAs) that play significant regulatory roles in various cellular processes. While miRNAs have been shown to participate in regulation of tumorigenesis and drug responses through modulating the DNA damage response (DDR), little is known about their potential influence on sensitivity to chemotherapy. The main objective of this review is to summarize recent findings on the utility of miRNAs as cancer biomarkers, in particular, ovarian cancer, and their regulation of DDR or modified replication stress response proteins. We further discuss the suppressive and promotional effects of various miRNAs on ovarian cancer and their participation in cell cycle disturbance, response to DNA damage, and therapeutic functions in multiple cancer types, with particular focus on ovarian cancer. Improved understanding of the mechanisms by which miRNAs regulate drug resistance should facilitate the development of effective combination therapies for ovarian cancer.
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