1
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Buehl CJ, Goff NJ, Hardwick SW, Gellert M, Blundell TL, Yang W, Chaplin AK, Meek K. Two distinct long-range synaptic complexes promote different aspects of end processing prior to repair of DNA breaks by non-homologous end joining. Mol Cell 2023; 83:698-714.e4. [PMID: 36724784 PMCID: PMC9992237 DOI: 10.1016/j.molcel.2023.01.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 11/29/2022] [Accepted: 01/06/2023] [Indexed: 02/03/2023]
Abstract
Non-homologous end joining is the major double-strand break repair (DSBR) pathway in mammals. DNA-PK is the hub and organizer of multiple steps in non-homologous end joining (NHEJ). Recent high-resolution structures show how two distinct NHEJ complexes "synapse" two DNA ends. One complex includes a DNA-PK dimer mediated by XLF, whereas a distinct DNA-PK dimer forms via a domain-swap mechanism where the C terminus of Ku80 from one DNA-PK protomer interacts with another DNA-PK protomer in trans. Remarkably, the distance between the two synapsed DNA ends in both dimers is the same (∼115 Å), which matches the distance observed in the initial description of an NHEJ long-range synaptic complex. Here, a mutational strategy is used to demonstrate distinct cellular function(s) of the two dimers: one promoting fill-in end processing, while the other promotes DNA end resection. Thus, the specific DNA-PK dimer formed (which may be impacted by DNA end structure) dictates the mechanism by which ends will be made ligatable.
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Affiliation(s)
- Christopher J Buehl
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Noah J Goff
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Steven W Hardwick
- CryoEM Facility, Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Martin Gellert
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Wei Yang
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Amanda K Chaplin
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK; Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
| | - Katheryn Meek
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA.
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2
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Bergstrand S, O'Brien EM, Coucoravas C, Hrossova D, Peirasmaki D, Schmidli S, Dhanjal S, Pederiva C, Siggens L, Mortusewicz O, O'Rourke JJ, Farnebo M. Small Cajal body-associated RNA 2 (scaRNA2) regulates DNA repair pathway choice by inhibiting DNA-PK. Nat Commun 2022; 13:1015. [PMID: 35197472 PMCID: PMC8866460 DOI: 10.1038/s41467-022-28646-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 01/25/2022] [Indexed: 12/20/2022] Open
Abstract
Evidence that long non-coding RNAs (lncRNAs) participate in DNA repair is accumulating, however, whether they can control DNA repair pathway choice is unknown. Here we show that the small Cajal body-specific RNA 2 (scaRNA2) can promote HR by inhibiting DNA-dependent protein kinase (DNA-PK) and, thereby, NHEJ. By binding to the catalytic subunit of DNA-PK (DNA-PKcs), scaRNA2 weakens its interaction with the Ku70/80 subunits, as well as with the LINP1 lncRNA, thereby preventing catalytic activation of the enzyme. Inhibition of DNA-PK by scaRNA2 stimulates DNA end resection by the MRN/CtIP complex, activation of ATM at DNA lesions and subsequent repair by HR. ScaRNA2 is regulated in turn by WRAP53β, which binds this RNA, sequestering it away from DNA-PKcs and allowing NHEJ to proceed. These findings reveal that RNA-dependent control of DNA-PK catalytic activity is involved in regulating whether the cell utilizes NHEJ or HR. Proper repair of DNA double-strand breaks is essential for genomic stability. Here, the authors report that a long non-coding RNA, scaRNA2, inhibits DNA-PK and thereby regulates the choice between error-prone NHEJ and error-free HR DNA repair.
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Affiliation(s)
- Sofie Bergstrand
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Stockholm, Sweden
| | - Eleanor M O'Brien
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Christos Coucoravas
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Dominika Hrossova
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Dimitra Peirasmaki
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Sandro Schmidli
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Soniya Dhanjal
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Chiara Pederiva
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Lee Siggens
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Stockholm, Sweden
| | - Oliver Mortusewicz
- Department of Oncology and Pathology, SciLife, Karolinska Institutet, Stockholm, Sweden
| | - Julienne J O'Rourke
- Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Marianne Farnebo
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Stockholm, Sweden. .,Department of Cell and Molecular biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden.
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3
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Yan Y, Yao S, Jia Z, Zhao J, Wang L. Iso-suillin-induced DNA damage leading to cell cycle arrest and apoptosis arised from p53 phosphorylation in A549 cells. Eur J Pharmacol 2021; 907:174299. [PMID: 34217708 DOI: 10.1016/j.ejphar.2021.174299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 06/22/2021] [Accepted: 06/29/2021] [Indexed: 01/10/2023]
Abstract
Extensive investigations have revealed that iso-suillin, a secondary metabolite isolated from Suillus flavus, could induce cell cycle arrest and apoptosis in human chronic myeloid leukemia K562 cells, human hepatocellular carcinoma SMMC-7721 cell line, and human small cell lung cancer H446 cell line in vitro. In the present study, human lung cancer A549 cells were used to reveal the mechanism of iso-suillin's effects on lung adenocarcinoma, which were detected both in vitro and in vivo. Results showed that iso-suillin potently inhibited A549 cell proliferation through an early G1 arrest. Iso-suillin also induced A549 cell apoptosis in vitro. Phosphorylation of p53 at serines 15 and 20 may be one of the pivotal factors for cell cycle arrest and apoptosis after treatment of iso-suillin in A549 cells. Moreover, in an A549 xenograft model, tumor growth and progression could be inhibited by iso-suillin. Body weight change and some vital organs toxicity was also roughly examined, no significant toxic effects of iso-suillin were shown (at a dose of 5 mg/kg for each administration). The in vitro and in vivo anti-tumor effects implied that iso-suillin may act as a tumor growth inhibitor, and its induction of p53 phosphorylation is pivotal for cell cycle arrest and apoptosis in A549 cells.
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Affiliation(s)
- Yongxin Yan
- The Basic Medical College, Hebei Medical University, Shijiazhuang, 050017, PR China
| | - Shengjie Yao
- The Basic Medical College, Hebei Medical University, Shijiazhuang, 050017, PR China
| | - Zhiqiang Jia
- The Basic Medical College, Hebei Medical University, Shijiazhuang, 050017, PR China
| | - Junxia Zhao
- The Basic Medical College, Hebei Medical University, Shijiazhuang, 050017, PR China.
| | - Li'an Wang
- The Life Science College, Hebei Normal University, Shijiazhuang, 050024, PR China
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4
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McPherson KS, Korzhnev DM. Targeting protein-protein interactions in the DNA damage response pathways for cancer chemotherapy. RSC Chem Biol 2021; 2:1167-1195. [PMID: 34458830 PMCID: PMC8342002 DOI: 10.1039/d1cb00101a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 06/20/2021] [Indexed: 12/11/2022] Open
Abstract
Cellular DNA damage response (DDR) is an extensive signaling network that orchestrates DNA damage recognition, repair and avoidance, cell cycle progression and cell death. DDR alteration is a hallmark of cancer, with the deficiency in one DDR capability often compensated by a dependency on alternative pathways endowing cancer cells with survival and growth advantage. Targeting these DDR pathways has provided multiple opportunities for the development of cancer therapies. Traditional drug discovery has mainly focused on catalytic inhibitors that block enzyme active sites, which limits the number of potential drug targets within the DDR pathways. This review article describes the emerging approach to the development of cancer therapeutics targeting essential protein-protein interactions (PPIs) in the DDR network. The overall strategy for the structure-based design of small molecule PPI inhibitors is discussed, followed by an overview of the major DNA damage sensing, DNA repair, and DNA damage tolerance pathways with a specific focus on PPI targets for anti-cancer drug design. The existing small molecule inhibitors of DDR PPIs are summarized that selectively kill cancer cells and/or sensitize cancers to front-line genotoxic therapies, and a range of new PPI targets are proposed that may lead to the development of novel chemotherapeutics.
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Affiliation(s)
- Kerry Silva McPherson
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center Farmington CT 06030 USA +1 860 679 3408 +1 860 679 2849
| | - Dmitry M Korzhnev
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center Farmington CT 06030 USA +1 860 679 3408 +1 860 679 2849
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5
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Tannous EA, Burgers PM. Novel insights into the mechanism of cell cycle kinases Mec1(ATR) and Tel1(ATM). Crit Rev Biochem Mol Biol 2021; 56:441-454. [PMID: 34151669 DOI: 10.1080/10409238.2021.1925218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
DNA replication is a highly precise process which usually functions in a perfect rhythm with cell cycle progression. However, cells are constantly faced with various kinds of obstacles such as blocks in DNA replication, lack of availability of precursors and improper chromosome alignment. When these problems are not addressed, they may lead to chromosome instability and the accumulation of mutations, and even cell death. Therefore, the cell has developed response mechanisms to keep most of these situations under control. Of the many factors that participate in this DNA damage response, members of the family of phosphatidylinositol 3-kinase-related protein kinases (PIKKs) orchestrate the response landscape. Our understanding of two members of the PIKK family, human ATR (yeast Mec1) and ATM (yeast Tel1), and their associated partner proteins, has shown substantial progress through recent biochemical and structural studies. Emerging structural information of these unique kinases show common features that reveal the mechanism of kinase activity.
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Affiliation(s)
- Elias A Tannous
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
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6
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Al-Ostoot FH, Sherapura A, Malojirao VH, Thirusangu P, Al-Muhimeed TI, Khanum SA, Prabhakar BT. Modulation of DNA damage response by targeting ATM kinase using newly synthesized di-phenoxy acetamide (DPA) analogs to induce anti-neoplasia. Pharmacol Rep 2021; 73:1344-1360. [PMID: 34109572 DOI: 10.1007/s43440-021-00292-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/21/2021] [Accepted: 05/31/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Imbalance and instability in the structure of the DNA have become major characteristics of cancer. In response to DNA damage, DNA damage response (DDR) protein, ataxia telangiectasia mutated (ATM), plays a pivotal role in the modulation of regulatory regions responsible for inhibition of apoptosis, thereby neoplastic progression. METHODS A new series of DPA (7a-t) were synthesized, characterized. Anti-proliferative studies to identify the lead compound were carried out by LDH and MTT assay. Apoptosis/DNA damage was measured through FACS, Annexin-v staining, TUNEL and Comet assay. Elucidation of molecular mechanism through immunoblot and further validation of the drug effect through in vivo approaches. RESULTS Initial in vitro anti-proliferative screening of Compounds DPA (7a-t) against multiple cancer cell lines identified Compound DPA (7n) as a potent cytotoxic molecule with IC50 value of 4.3 μM. Down the line, in vitro and in vivo evaluation of Compound DPA (7n) inferred that it has apoptotic inducing potentiality. Further, evaluation of molecular mechanism inferred that Compound DPA (7n) effectively modulates ATM phosphorylation only, eventually altering downstream signalling pathways. CONCLUSIONS Compound DPA (7n) emerged as a potent proapoptotic and anti-neoplastic agent by inhibiting ATM kinase activity both in vitro and in vivo. The conferring results ascertain that the drug could be developed as a new ATM kinase inhibitor with anti-cancer capacity.
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Affiliation(s)
- Fares Hezam Al-Ostoot
- Department of Chemistry, Yuvaraja's College, University of Mysore, Mysuru, India.,Department of Biochemistry, Faculty of Education and Science, Al-Baydha University, Al Bayda, Yemen
| | - Ankith Sherapura
- Molecular Biomedicine Laboratory, Postgraduate Department of Studies and Research in Biotechnology, Sahyadri Science College, Kuvempu University, Shivamogga, Karnataka, India
| | - Vikas H Malojirao
- Molecular Biomedicine Laboratory, Postgraduate Department of Studies and Research in Biotechnology, Sahyadri Science College, Kuvempu University, Shivamogga, Karnataka, India.,Department of Neurosurgery, Houston Methodist, Fannin Street, Houston, TX, USA
| | - Prabhu Thirusangu
- Molecular Biomedicine Laboratory, Postgraduate Department of Studies and Research in Biotechnology, Sahyadri Science College, Kuvempu University, Shivamogga, Karnataka, India.,Department of Experimental Pathology and Laboratory Medicine, Mayo Clinic, Rochester, MN, USA
| | - Tahani I Al-Muhimeed
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Shaukath Ara Khanum
- Department of Chemistry, Yuvaraja's College, University of Mysore, Mysuru, India.
| | - B T Prabhakar
- Molecular Biomedicine Laboratory, Postgraduate Department of Studies and Research in Biotechnology, Sahyadri Science College, Kuvempu University, Shivamogga, Karnataka, India.
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7
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Profilin-1; a novel regulator of DNA damage response and repair machinery in keratinocytes. Mol Biol Rep 2021; 48:1439-1452. [PMID: 33590416 PMCID: PMC7925496 DOI: 10.1007/s11033-021-06210-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/29/2021] [Indexed: 10/25/2022]
Abstract
Profilin-1 (PFN1) regulates actin polymerization and cytoskeletal growth. Despite the essential roles of PFN1 in cell integration, its subcellular function in keratinocyte has not been elucidated yet. Here we characterize the specific regulation of PFN1 in DNA damage response and repair machinery. PFN1 depletion accelerated DNA damage-mediated apoptosis exhibiting PTEN loss of function instigated by increased phosphorylated inactivation followed by high levels of AKT activation. PFN1 changed its predominant cytoplasmic localization to the nucleus upon DNA damage and subsequently restored the cytoplasmic compartment during the recovery time. Even though γH2AX was recruited at the sites of DNA double strand breaks in response to DNA damage, PFN1-deficient cells failed to recruit DNA repair factors, whereas control cells exhibited significant increases of these genes. Additionally, PFN1 depletion resulted in disruption of PTEN-AKT cascade upon DNA damage and CHK1-mediated cell cycle arrest was not recovered even after the recovery time exhibiting γH2AX accumulation. This might suggest PFN1 roles in regulating DNA damage response and repair machinery to protect cells from DNA damage. Future studies addressing the crosstalk and regulation of PTEN-related DNA damage sensing and repair pathway choice by PFN1 may further aid to identify new mechanistic insights for various DNA repair disorders.
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8
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Hu S, Hui Z, Lirussi F, Garrido C, Ye XY, Xie T. Small molecule DNA-PK inhibitors as potential cancer therapy: a patent review (2010-present). Expert Opin Ther Pat 2021; 31:435-452. [PMID: 33347360 DOI: 10.1080/13543776.2021.1866540] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: DNA-dependent protein kinase (DNA-PK) plays a crucial role in the repair of DSBs via non-homologous end joining (NHEJ). Several DNA-PK inhibitors are being investigated for potential anticancer treatment in clinical trials.Area covered: This review aims to give an overview of patents published since 2010 by analyzing the patent space and structure features of scaffolds used in those patents. It also discusses the recent clinical developments and provides perspectives on future challenges and directions in this field.Expert opinion: As a key component of the DNA damage response (DDR) pathway, DNA-PK appears to be a viable drug target for anticancer therapy. The clinical investigation of a DNA-PK inhibitor employs both a monotherapy and a combination strategy. In the combination strategy, a DNA-PK inhibitor is typically combined with a DSB inducer, radiation, a chemotherapy agent, or a PARP inhibitor, etc. Patent analyses suggest that diverse structures comprising different scaffolds from mono-heteroaryl to bicyclic heteroaryl to tricyclic heteroaryl are capable to achieve good DNA-PK inhibitory activity and good DNA-PK selectivity over other closely related enzymes. Several DNA-PK inhibitors are currently being evaluated in clinics, with the hope to get approval in the near future.
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Affiliation(s)
- Suwen Hu
- College of Pharmacy, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang Province, Zhejiang, People's Republic of China.,Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Zhejiang Province, People's Republic of China.,;cCollaborative Innovation Center of Chinese Medicines from Zhejiang Province, Zhejiang Province, People's Republic of China.,;dKey Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, Hangzhou, Zhejiang Province, People's Republic of China.,;eHangzhou Huadong Medicine Group, Pharmaceutical Research Institute Co. Ltd, Hanzhou City, Zhejiang Province, People's Republic of China
| | - Zi Hui
- College of Pharmacy, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang Province, Zhejiang, People's Republic of China.,Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Zhejiang Province, People's Republic of China.,;cCollaborative Innovation Center of Chinese Medicines from Zhejiang Province, Zhejiang Province, People's Republic of China.,;Key Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, Hangzhou, Zhejiang Province, People's Republic of China
| | - Frédéric Lirussi
- ;fINSERM, U1231, Label LipSTIC, and Ligue Nationale Contre Le Cancer, Dijon, France.,;gUniversité De Bourgogne-Franche Comté, I-SITE, France.,;hDepartment of Pharmacology-Toxicology & Metabolomics, University hospital of Besançon (CHU), 2 Boulevard Fleming, 25030 BESANCON, France
| | - Carmen Garrido
- ;INSERM, U1231, Label LipSTIC, and Ligue Nationale Contre Le Cancer, Dijon, France.,;Université De Bourgogne-Franche Comté, I-SITE, France.,;iAnti-cancer Center George-François Leclerc, CGFL, Dijon, France
| | - Xiang-Yang Ye
- College of Pharmacy, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang Province, Zhejiang, People's Republic of China.,Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Zhejiang Province, People's Republic of China.,;cCollaborative Innovation Center of Chinese Medicines from Zhejiang Province, Zhejiang Province, People's Republic of China.,;Key Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, Hangzhou, Zhejiang Province, People's Republic of China
| | - Tian Xie
- College of Pharmacy, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang Province, Zhejiang, People's Republic of China.,Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Zhejiang Province, People's Republic of China.,;cCollaborative Innovation Center of Chinese Medicines from Zhejiang Province, Zhejiang Province, People's Republic of China.,;Key Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, Hangzhou, Zhejiang Province, People's Republic of China
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9
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Activation of DNA damage response signaling in mammalian cells by ionizing radiation. Free Radic Res 2021; 55:581-594. [PMID: 33455476 DOI: 10.1080/10715762.2021.1876853] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cellular responses to DNA damage are fundamental to preserve genomic integrity during various endogenous and exogenous stresses. Following radiation therapy and chemotherapy, this DNA damage response (DDR) also determines development of carcinogenesis and therapeutic outcome. In humans, DNA damage activates a robust network of signal transduction cascades, driven primarily through phosphorylation events. These responses primarily involve two key non-redundant signal transducing proteins of phosphatidylinositol 3-kinase-like (PIKK) family - ATR and ATM, and their downstream kinases (hChk1 and hChk2). They further phosphorylate effectors proteins such as p53, Cdc25A and Cdc25C which function either to activate the DNA damage checkpoints and cell death mechanisms, or DNA repair pathways. Identification of molecular pathways that determine signaling after DNA damage and trigger DNA repair in response to differing types of DNA lesions allows for a far better understanding of the consequences of radiation and chemotherapy on normal and tumor cells. Here we highlight the network of DNA damage response pathways that are activated after treatment with different types of radiation. Further, we discuss regulation of cell cycle checkpoint and DNA repair processes in the context of DDR in response to radiation.
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10
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Güllülü Ö, Hehlgans S, Mayer BE, Gößner I, Petraki C, Hoffmann M, Dombrowsky MJ, Kunzmann P, Hamacher K, Strebhardt K, Fokas E, Rödel C, Münch C, Rödel F. A Spatial and Functional Interaction of a Heterotetramer Survivin-DNA-PKcs Complex in DNA Damage Response. Cancer Res 2021; 81:2304-2317. [PMID: 33408118 DOI: 10.1158/0008-5472.can-20-2931] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/19/2020] [Accepted: 12/28/2020] [Indexed: 11/16/2022]
Abstract
Substantial evidence has shown that overexpression of the inhibitor of apoptosis protein (IAP) survivin in human tumors correlates significantly with treatment resistance and poor patient prognosis. Survivin serves as a radiation resistance factor that impacts the DNA damage response by interacting with DNA-dependent protein kinase (DNA-PKcs). However, the complexity, molecular determinants, and functional consequences of this interrelationship remain largely unknown. By applying coimmunoprecipitation and flow cytometry-based Förster resonance energy transfer assays, we demonstrated a direct involvement of the survivin baculovirus IAP repeat domain in the regulation of radiation survival and DNA repair. This survivin-mediated activity required an interaction of residues S20 and W67 with the phosphoinositide 3-kinase (PI3K) domain of DNA-PKcs. In silico molecular docking and dynamics simulation analyses, in vitro kinase assays, and large-scale mass spectrometry suggested a heterotetrameric survivin-DNA-PKcs complex that results in a conformational change within the DNA-PKcs PI3K domain. Overexpression of survivin resulted in enhanced PI3K enzymatic activity and detection of differentially abundant phosphopeptides and proteins implicated in the DNA damage response. The survivin-DNA-PKcs interaction altered the S/T-hydrophobic motif substrate specificity of DNA-PKcs with a predominant usage of S/T-P phosphorylation sites and an increase of DNA-PKcs substrates including Foxo3. These data demonstrate that survivin differentially regulates DNA-PKcs-dependent radiation survival and DNA double-strand break repair via formation of a survivin-DNA-PKcs heterotetrameric complex. SIGNIFICANCE: These findings provide insight into survivin-mediated regulation of DNA-PKcs kinase and broaden our knowledge of the impact of survivin in modulating the cellular radiation response.See related commentary by Iliakis, p. 2270 GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/9/2304/F1.large.jpg.
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Affiliation(s)
- Ömer Güllülü
- Department of Radiotherapy and Oncology, University Hospital, Goethe University Frankfurt, Germany
| | - Stephanie Hehlgans
- Department of Radiotherapy and Oncology, University Hospital, Goethe University Frankfurt, Germany
| | - Benjamin E Mayer
- Department of Computational Biology and Simulation, Technical University of Darmstadt, Germany
| | - Ines Gößner
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, Germany
| | - Chrysi Petraki
- Department of Radiotherapy and Oncology, University Hospital, Goethe University Frankfurt, Germany
| | - Melanie Hoffmann
- Department of Radiotherapy and Oncology, University Hospital, Goethe University Frankfurt, Germany
| | - Maximilian J Dombrowsky
- Department of Computational Biology and Simulation, Technical University of Darmstadt, Germany
| | - Patrick Kunzmann
- Department of Computational Biology and Simulation, Technical University of Darmstadt, Germany
| | - Kay Hamacher
- Department of Computational Biology and Simulation, Technical University of Darmstadt, Germany
| | - Klaus Strebhardt
- Department of Obstetrics and Gynaecology, University Hospital, Goethe University Frankfurt, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,German Cancer Consortium (DKTK) partner site: Frankfurt, Frankfurt am Main, Germany
| | - Emmanouil Fokas
- Department of Radiotherapy and Oncology, University Hospital, Goethe University Frankfurt, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,German Cancer Consortium (DKTK) partner site: Frankfurt, Frankfurt am Main, Germany.,Frankfurt Cancer Institute (FCI), Theodor-Stern-Kai 7, Goethe University Frankfurt, Germany
| | - Claus Rödel
- Department of Radiotherapy and Oncology, University Hospital, Goethe University Frankfurt, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,German Cancer Consortium (DKTK) partner site: Frankfurt, Frankfurt am Main, Germany.,Frankfurt Cancer Institute (FCI), Theodor-Stern-Kai 7, Goethe University Frankfurt, Germany
| | - Christian Münch
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,German Cancer Consortium (DKTK) partner site: Frankfurt, Frankfurt am Main, Germany.,Frankfurt Cancer Institute (FCI), Theodor-Stern-Kai 7, Goethe University Frankfurt, Germany
| | - Franz Rödel
- Department of Radiotherapy and Oncology, University Hospital, Goethe University Frankfurt, Germany. .,German Cancer Research Center (DKFZ), Heidelberg, Germany.,German Cancer Consortium (DKTK) partner site: Frankfurt, Frankfurt am Main, Germany.,Frankfurt Cancer Institute (FCI), Theodor-Stern-Kai 7, Goethe University Frankfurt, Germany
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11
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Hepburn M, Saltzberg DJ, Lee L, Fang S, Atkinson C, Strynadka NCJ, Sali A, Lees-Miller SP, Schriemer DC. The active DNA-PK holoenzyme occupies a tensed state in a staggered synaptic complex. Structure 2021; 29:467-478.e6. [PMID: 33412091 DOI: 10.1016/j.str.2020.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/14/2020] [Accepted: 12/09/2020] [Indexed: 01/06/2023]
Abstract
In the non-homologous end-joining (NHEJ) of a DNA double-strand break, DNA ends are bound and protected by DNA-PK, which synapses across the break to tether the broken ends and initiate repair. There is little clarity surrounding the nature of the synaptic complex and the mechanism governing the transition to repair. We report an integrative structure of the synaptic complex at a precision of 13.5 Å, revealing a symmetric head-to-head arrangement with a large offset in the DNA ends and an extensive end-protection mechanism involving a previously uncharacterized plug domain. Hydrogen/deuterium exchange mass spectrometry identifies an allosteric pathway connecting DNA end-binding with the kinase domain that places DNA-PK under tension in the kinase-active state. We present a model for the transition from end-protection to repair, where the synaptic complex supports hierarchical processing of the ends and scaffold assembly, requiring displacement of the catalytic subunit and tension release through kinase activity.
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Affiliation(s)
- Morgan Hepburn
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Daniel J Saltzberg
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Sciences, and California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, CA 94158, USA
| | - Linda Lee
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Shujuan Fang
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
| | - Claire Atkinson
- Department of Biochemistry and Molecular Biology and High-Resolution Macromolecular Electron Microscopy Facility, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and High-Resolution Macromolecular Electron Microscopy Facility, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Sciences, and California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, CA 94158, USA
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada; Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada
| | - David C Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada; Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada; Department of Chemistry, University of Calgary, Calgary, AB, Canada.
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12
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Structural insights into the role of DNA-PK as a master regulator in NHEJ. GENOME INSTABILITY & DISEASE 2021; 2:195-210. [PMID: 34723130 PMCID: PMC8549938 DOI: 10.1007/s42764-021-00047-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/06/2021] [Accepted: 07/12/2021] [Indexed: 12/26/2022]
Abstract
DNA-dependent protein kinase catalytic subunit DNA-PKcs/PRKDC is the largest serine/threonine protein kinase of the phosphatidyl inositol 3-kinase-like protein kinase (PIKK) family and is the most highly expressed PIKK in human cells. With its DNA-binding partner Ku70/80, DNA-PKcs is required for regulated and efficient repair of ionizing radiation-induced DNA double-strand breaks via the non-homologous end joining (NHEJ) pathway. Loss of DNA-PKcs or other NHEJ factors leads to radiation sensitivity and unrepaired DNA double-strand breaks (DSBs), as well as defects in V(D)J recombination and immune defects. In this review, we highlight the contributions of the late Dr. Carl W. Anderson to the discovery and early characterization of DNA-PK. We furthermore build upon his foundational work to provide recent insights into the structure of NHEJ synaptic complexes, an evolutionarily conserved and functionally important YRPD motif, and the role of DNA-PKcs and its phosphorylation in NHEJ. The combined results identify DNA-PKcs as a master regulator that is activated by its detection of two double-strand DNA ends for a cascade of phosphorylation events that provide specificity and efficiency in assembling the synaptic complex for NHEJ.
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13
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Chen X, Xu X, Chen Y, Cheung JC, Wang H, Jiang J, de Val N, Fox T, Gellert M, Yang W. Structure of an activated DNA-PK and its implications for NHEJ. Mol Cell 2020; 81:801-810.e3. [PMID: 33385326 DOI: 10.1016/j.molcel.2020.12.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/17/2020] [Accepted: 12/07/2020] [Indexed: 02/06/2023]
Abstract
DNA-dependent protein kinase (DNA-PK), like all phosphatidylinositol 3-kinase-related kinases (PIKKs), is composed of conserved FAT and kinase domains (FATKINs) along with solenoid structures made of HEAT repeats. These kinases are activated in response to cellular stress signals, but the mechanisms governing activation and regulation remain unresolved. For DNA-PK, all existing structures represent inactive states with resolution limited to 4.3 Å at best. Here, we report the cryoelectron microscopy (cryo-EM) structures of DNA-PKcs (DNA-PK catalytic subunit) bound to a DNA end or complexed with Ku70/80 and DNA in both inactive and activated forms at resolutions of 3.7 Å overall and 3.2 Å for FATKINs. These structures reveal the sequential transition of DNA-PK from inactive to activated forms. Most notably, activation of the kinase involves previously unknown stretching and twisting within individual solenoid segments and loosens DNA-end binding. This unprecedented structural plasticity of helical repeats may be a general regulatory mechanism of HEAT-repeat proteins.
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Affiliation(s)
- Xuemin Chen
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiang Xu
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yun Chen
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joyce C Cheung
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Huaibin Wang
- Laboratory of Cell and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jiansen Jiang
- Laboratory of Membrane Proteins and Structural Biology, NHLBI, National Institutes of Health, Bethesda, MD 20892, USA
| | - Natalia de Val
- Cancer Research Technology Program Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc., Frederick, MD 21701, USA
| | - Tara Fox
- Cancer Research Technology Program Frederick National Laboratory for Cancer Research, Leidos Biomedical Research Inc., Frederick, MD 21701, USA
| | - Martin Gellert
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Wei Yang
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA.
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14
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Lees-Miller JP, Cobban A, Katsonis P, Bacolla A, Tsutakawa SE, Hammel M, Meek K, Anderson DW, Lichtarge O, Tainer JA, Lees-Miller SP. Uncovering DNA-PKcs ancient phylogeny, unique sequence motifs and insights for human disease. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 163:87-108. [PMID: 33035590 PMCID: PMC8021618 DOI: 10.1016/j.pbiomolbio.2020.09.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/12/2020] [Accepted: 09/29/2020] [Indexed: 01/26/2023]
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a key member of the phosphatidylinositol-3 kinase-like (PIKK) family of protein kinases with critical roles in DNA-double strand break repair, transcription, metastasis, mitosis, RNA processing, and innate and adaptive immunity. The absence of DNA-PKcs from many model organisms has led to the assumption that DNA-PKcs is a vertebrate-specific PIKK. Here, we find that DNA-PKcs is widely distributed in invertebrates, fungi, plants, and protists, and that threonines 2609, 2638, and 2647 of the ABCDE cluster of phosphorylation sites are highly conserved amongst most Eukaryotes. Furthermore, we identify highly conserved amino acid sequence motifs and domains that are characteristic of DNA-PKcs relative to other PIKKs. These include residues in the Forehead domain and a novel motif we have termed YRPD, located in an α helix C-terminal to the ABCDE phosphorylation site loop. Combining sequence with biochemistry plus structural data on human DNA-PKcs unveils conserved sequence and conformational features with functional insights and implications. The defined generally progressive DNA-PKcs sequence diversification uncovers conserved functionality supported by Evolutionary Trace analysis, suggesting that for many organisms both functional sites and evolutionary pressures remain identical due to fundamental cell biology. The mining of cancer genomic data and germline mutations causing human inherited disease reveal that robust DNA-PKcs activity in tumors is detrimental to patient survival, whereas germline mutations compromising function are linked to severe immunodeficiency and neuronal degeneration. We anticipate that these collective results will enable ongoing DNA-PKcs functional analyses with biological and medical implications.
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Affiliation(s)
- James P Lees-Miller
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Alexander Cobban
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Panagiotis Katsonis
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Albino Bacolla
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | - Susan E Tsutakawa
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Katheryn Meek
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, And Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI, 48824, USA
| | - Dave W Anderson
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Olivier Lichtarge
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - John A Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA; Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada.
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15
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de Oliveira TM, van Beek L, Shilliday F, Debreczeni JÉ, Phillips C. Cryo-EM: The Resolution Revolution and Drug Discovery. SLAS DISCOVERY 2020; 26:17-31. [PMID: 33016175 DOI: 10.1177/2472555220960401] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Single-particle cryogenic electron microscopy (cryo-EM) has been elevated to the mainstream of structural biology propelled by technological advancements in numerous fronts, including imaging analysis and the development of direct electron detectors. The drug discovery field has watched with (initial) skepticism and wonder at the progression of the technique and how it revolutionized the molecular understanding of previously intractable targets. This article critically assesses how cryo-EM has impacted drug discovery in diverse therapeutic areas. Targets that have been brought into the realm of structure-based drug design by cryo-EM and are thus reviewed here include membrane proteins like the GABAA receptor, several TRP channels, and G protein-coupled receptors, and multiprotein complexes like the ribosomes, the proteasome, and eIF2B. We will describe these studies highlighting the achievements, challenges, and caveats.
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Affiliation(s)
| | - Lotte van Beek
- Structure, Biophysics and FBLG, Discovery Sciences, AstraZeneca R&D, Cambridge, UK
| | - Fiona Shilliday
- Structure, Biophysics and FBLG, Discovery Sciences, AstraZeneca R&D, Cambridge, UK
| | - Judit É Debreczeni
- Structure, Biophysics and FBLG, Discovery Sciences, AstraZeneca R&D, Cambridge, UK
| | - Chris Phillips
- Structure, Biophysics and FBLG, Discovery Sciences, AstraZeneca R&D, Cambridge, UK
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16
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Hammel M, Rosenberg DJ, Bierma J, Hura GL, Thapar R, Lees-Miller SP, Tainer JA. Visualizing functional dynamicity in the DNA-dependent protein kinase holoenzyme DNA-PK complex by integrating SAXS with cryo-EM. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 163:74-86. [PMID: 32966823 DOI: 10.1016/j.pbiomolbio.2020.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/19/2020] [Accepted: 09/17/2020] [Indexed: 12/27/2022]
Abstract
Assembly of KU and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) at DNA double strand breaks (DSBs) forms DNA-PK holoenzyme as a critical initiating step for non-homologous end joining (NHEJ) repair of DSBs produced by radiation and chemotherapies. Advanced cryo-electron microscopy (cryo-EM) imaging together with breakthrough macromolecular X-ray crystal (MX) structures of KU and DNA-PKcs recently enabled visualization of the ∼600 kDa DNA-PK assembly at near atomic resolution. These important static structures provide the foundation for definition and interpretation of functional movements crucial to mechanistic understanding that can be tested through solution state structure analysis. We herein therefore leverage Cryo-EM and MX structures for the interpretation of synchrotron small-angle X-ray scattering (SAXS) data on DNA-PK conformations in solution to inform the structural mechanism for NHEJ initiation. SAXS, which measures thermodynamic solution-state conformational states and assemblies outside of cryo- and solid-state conditions, unveils the inherent flexibility of KU, DNA-PKcs and DNA-PK. The combined structural measurements reveal mobility of KU80 C-terminal region (KU80CTR), motion/plasticity of HEAT (DNA-PKcs Huntingtin, Elongation Factor 3, PP2 A, and TOR1) regions, allosteric switching upon DNA-PKcs autophosphorylation, and dimeric arrangements of DNA-PK assembly. Importantly, the results uncover displacement of the N-terminal HEAT domain during autophosphorylation as suitable for a regulated release mechanism of DNA-PKcs from DNA-PK to control unproductive access to toxic and mutagenic DNA repair intermediates. These integrated analyses show that the marriage of SAXS with cryo-EM leverages the strengths of both techniques to enable assessment of functional conformations and flexibility defining atomic-resolution molecular mechanisms for DSB repair.
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Affiliation(s)
- Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Daniel J Rosenberg
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA; Graduate Group in Biophysics, University of California, Berkeley, CA, 94720, USA
| | - Jan Bierma
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Gregory L Hura
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Roopa Thapar
- Department of Cancer Biology, Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, University of Calgary, Alberta, T2N 4N1, Canada
| | - John A Tainer
- Department of Cancer Biology, Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.
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17
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Lavin MF, Yeo AJ. Clinical potential of ATM inhibitors. Mutat Res 2020; 821:111695. [PMID: 32304909 DOI: 10.1016/j.mrfmmm.2020.111695] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 02/28/2020] [Accepted: 03/03/2020] [Indexed: 01/04/2023]
Abstract
The protein defective in the human genetic disorder ataxia-telangiectasia, ATM, plays a central role in responding to DNA double strand breaks and other lesions to protect the genome against DNA damage and in this way minimize the risk of mutations that can lead to abnormal cellular behaviour. Its function in normal cells is to protect the cell against genotoxic stress but inadvertently it can assist cancer cells by providing resistance against chemotherapeutic agents and thus favouring tumour growth and survival. However, it is now evident that ATM also functions in a DNA damage-independent fashion to protect the cell against other forms of stress such as oxidative and nutrient stress and this non-canonical mechanism may also be relevant to cancer susceptibility in individuals who lack a functional ATM gene. Thus the use of ATM inhibitors to combat resistance in tumours may extend beyond a role for this protein in the DNA damage response. Here, we provide some background on ATM and its activation and investigate the efficacy of ATM inhibitors in treating cancer.
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Affiliation(s)
- Martin F Lavin
- University of Queensland Centre for Clinical Research, University of Queensland, Brisbane, Australia.
| | - Abrey J Yeo
- University of Queensland Centre for Clinical Research, University of Queensland, Brisbane, Australia
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18
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Goldberg FW, Finlay MRV, Ting AKT, Beattie D, Lamont GM, Fallan C, Wrigley GL, Schimpl M, Howard MR, Williamson B, Vazquez-Chantada M, Barratt DG, Davies BR, Cadogan EB, Ramos-Montoya A, Dean E. The Discovery of 7-Methyl-2-[(7-methyl[1,2,4]triazolo[1,5- a]pyridin-6-yl)amino]-9-(tetrahydro-2 H-pyran-4-yl)-7,9-dihydro-8 H-purin-8-one (AZD7648), a Potent and Selective DNA-Dependent Protein Kinase (DNA-PK) Inhibitor. J Med Chem 2020; 63:3461-3471. [PMID: 31851518 DOI: 10.1021/acs.jmedchem.9b01684] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
DNA-PK is a key component within the DNA damage response, as it is responsible for recognizing and repairing double-strand DNA breaks (DSBs) via non-homologous end joining. Historically it has been challenging to identify inhibitors of the DNA-PK catalytic subunit (DNA-PKcs) with good selectivity versus the structurally related PI3 (lipid) and PI3K-related protein kinases. We screened our corporate collection for DNA-PKcs inhibitors with good PI3 kinase selectivity, identifying compound 1. Optimization focused on further improving selectivity while improving physical and pharmacokinetic properties, notably co-optimization of permeability and metabolic stability, to identify compound 16 (AZD7648). Compound 16 had no significant off-target activity in the protein kinome and only weak activity versus PI3Kα/γ lipid kinases. Monotherapy activity in murine xenograft models was observed, and regressions were observed when combined with inducers of DSBs (doxorubicin or irradiation) or PARP inhibition (olaparib). These data support progression into clinical studies (NCT03907969).
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Derek G Barratt
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0FZ, U.K
| | | | | | | | - Emma Dean
- Oncology R&D, AstraZeneca, Cambridge CB4 0FZ, U.K
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19
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Bacolla A, Tainer JA. DNA damage response mechanisms and structures fundamental to cancer research progress. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 147:1-3. [PMID: 31470026 DOI: 10.1016/j.pbiomolbio.2019.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Albino Bacolla
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Holcombe Blvd., Houston, TX, 77030, United States.
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Holcombe Blvd., Houston, TX, 77030, United States.
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