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Hui Z, Deng H, Zhang X, Garrido C, Lirussi F, Ye XY, Xie T, Liu ZQ. Development and therapeutic potential of DNA-dependent protein kinase inhibitors. Bioorg Chem 2024; 150:107608. [PMID: 38981210 DOI: 10.1016/j.bioorg.2024.107608] [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: 05/04/2024] [Accepted: 06/28/2024] [Indexed: 07/11/2024]
Abstract
The deployment of DNA damage response (DDR) combats various forms of DNA damage, ensuring genomic stability. Cancer cells' propensity for genomic instability offers therapeutic opportunities to selectively kill cancer cells by suppressing the DDR pathway. DNA-dependent protein kinase (DNA-PK), a nuclear serine/threonine kinase, is crucial for the non-homologous end joining (NHEJ) pathway in the repair of DNA double-strand breaks (DSBs). Therefore, targeting DNA-PK is a promising cancer treatment strategy. This review elaborates on the structures of DNA-PK and its related large protein, as well as the development process of DNA-PK inhibitors, and recent advancements in their clinical application. We emphasize our analysis of the development process and structure-activity relationships (SARs) of DNA-PK inhibitors based on different scaffolds. We hope this review will provide practical information for researchers seeking to develop novel DNA-PK inhibitors in the future.
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Affiliation(s)
- Zi Hui
- Xiangya School of Pharmaceutical Sciences, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410013, P. R. China; School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-Cancer Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, P.R. China
| | - Haowen Deng
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Xuelei Zhang
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Carmen Garrido
- INSERM U1231, Label LipSTIC and Ligue Nationale contre le Cancer, Dijon, France; Faculté de médecine, Université de Bourgogne, Dijon, Centre de lutte contre le cancer Georges François Leclerc, 21000, Dijon, France
| | - Frédéric Lirussi
- INSERM U1231, Label LipSTIC and Ligue Nationale contre le Cancer, Dijon, France; Université de Franche Comté, France, University Hospital of Besançon (CHU), France
| | - Xiang-Yang Ye
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-Cancer Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, P.R. China.
| | - Tian Xie
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-Cancer Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, P.R. China.
| | - Zhao-Qian Liu
- Xiangya School of Pharmaceutical Sciences, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, 410013, P. R. China.
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Camfield S, Chakraborty S, Dwivedi SKD, Pramanik PK, Mukherjee P, Bhattacharya R. Secrets of DNA-PKcs beyond DNA repair. NPJ Precis Oncol 2024; 8:154. [PMID: 39043779 PMCID: PMC11266574 DOI: 10.1038/s41698-024-00655-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 07/15/2024] [Indexed: 07/25/2024] Open
Abstract
The canonical role of the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in repairing DNA double-strand breaks combined with its reported dysregulation in several malignancies has driven the development of DNA-PKcs inhibitors as therapeutics. However, until recently the relationship between DNA-PKcs and tumorigenesis has been primarily investigated with regard to its role in non-homologous end joining (NHEJ) repair. Emerging research has uncovered non-canonical DNA-PKcs functions involved with transcriptional regulation, telomere maintenance, metabolic regulation, and immune signaling all of which may also impinge on tumorigenesis. This review mainly discusses these non-canonical roles of DNA-PKcs in cellular biology and their potential contribution to tumorigenesis, as well as evaluating the implications of targeting DNA-PKcs for cancer therapy.
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Affiliation(s)
- Sydney Camfield
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Sayan Chakraborty
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Shailendra Kumar Dhar Dwivedi
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Pijush Kanti Pramanik
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Priyabrata Mukherjee
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Resham Bhattacharya
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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3
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Wu J, Song L, Lu M, Gao Q, Xu S, Zhou P, Ma T. The multifaceted functions of DNA-PKcs: implications for the therapy of human diseases. MedComm (Beijing) 2024; 5:e613. [PMID: 38898995 PMCID: PMC11185949 DOI: 10.1002/mco2.613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 06/21/2024] Open
Abstract
The DNA-dependent protein kinase (DNA-PK), catalytic subunit, also known as DNA-PKcs, is complexed with the heterodimer Ku70/Ku80 to form DNA-PK holoenzyme, which is well recognized as initiator in the nonhomologous end joining (NHEJ) repair after double strand break (DSB). During NHEJ, DNA-PKcs is essential for both DNA end processing and end joining. Besides its classical function in DSB repair, DNA-PKcs also shows multifaceted functions in various biological activities such as class switch recombination (CSR) and variable (V) diversity (D) joining (J) recombination in B/T lymphocytes development, innate immunity through cGAS-STING pathway, transcription, alternative splicing, and so on, which are dependent on its function in NHEJ or not. Moreover, DNA-PKcs deficiency has been proven to be related with human diseases such as neurological pathogenesis, cancer, immunological disorder, and so on through different mechanisms. Therefore, it is imperative to summarize the latest findings about DNA-PKcs and diseases for better targeting DNA-PKcs, which have shown efficacy in cancer treatment in preclinical models. Here, we discuss the multifaceted roles of DNA-PKcs in human diseases, meanwhile, we discuss the progresses of DNA-PKcs inhibitors and their potential in clinical trials. The most updated review about DNA-PKcs will hopefully provide insights and ideas to understand DNA-PKcs associated diseases.
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Affiliation(s)
- Jinghong Wu
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Liwei Song
- Department of Thoracic SurgeryBeijing Chest HospitalCapital Medical University, Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Mingjun Lu
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Qing Gao
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Shaofa Xu
- Department of Thoracic SurgeryBeijing Chest HospitalCapital Medical University, Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Ping‐Kun Zhou
- Beijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Teng Ma
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
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4
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Lohberger B, Barna S, Glänzer D, Eck N, Leithner A, Georg D. DNA-PKcs Inhibition Sensitizes Human Chondrosarcoma Cells to Carbon Ion Irradiation via Cell Cycle Arrest and Telomere Capping Disruption. Int J Mol Sci 2024; 25:6179. [PMID: 38892366 PMCID: PMC11173223 DOI: 10.3390/ijms25116179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 05/27/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
In order to overcome the resistance to radiotherapy in human chondrosarcoma cells, the prevention from efficient DNA repair with a combined treatment with the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) inhibitor AZD7648 was explored for carbon ion (C-ion) as well as reference photon (X-ray) irradiation (IR) using gene expression analysis, flow cytometry, protein phosphorylation, and telomere length shortening. Proliferation markers and cell cycle distribution changed significantly after combined treatment, revealing a prominent G2/M arrest. The expression of the G2/M checkpoint genes cyclin B, CDK1, and WEE1 was significantly reduced by IR alone and the combined treatment. While IR alone showed no effects, additional AZD7648 treatment resulted in a dose-dependent reduction in AKT phosphorylation and an increase in Chk2 phosphorylation. Twenty-four hours after IR, the key genes of DNA repair mechanisms were reduced by the combined treatment, which led to impaired DNA repair and increased radiosensitivity. A time-dependent shortening of telomere length was observed in both cell lines after combined treatment with AZD7648 and 8 Gy X-ray/C-ion IR. Our data suggest that the inhibition of DNA-PKcs may increase sensitivity to X-rays and C-ion IR by impairing its functional role in DNA repair mechanisms and telomere end protection.
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Affiliation(s)
- Birgit Lohberger
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036 Graz, Austria; (D.G.); (N.E.); (A.L.)
| | - Sandra Barna
- Department of Radiation Oncology, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria; (S.B.); (D.G.)
- MedAustron-Ion Therapy Center, Viktor-Kaplan Strasse 2, 2700 Wiener Neustadt, Austria
| | - Dietmar Glänzer
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036 Graz, Austria; (D.G.); (N.E.); (A.L.)
| | - Nicole Eck
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036 Graz, Austria; (D.G.); (N.E.); (A.L.)
| | - Andreas Leithner
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5-7, 8036 Graz, Austria; (D.G.); (N.E.); (A.L.)
| | - Dietmar Georg
- Department of Radiation Oncology, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria; (S.B.); (D.G.)
- MedAustron-Ion Therapy Center, Viktor-Kaplan Strasse 2, 2700 Wiener Neustadt, Austria
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5
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Ng YB, Akincilar SC. Shaping DNA damage responses: Therapeutic potential of targeting telomeric proteins and DNA repair factors in cancer. Curr Opin Pharmacol 2024; 76:102460. [PMID: 38776747 DOI: 10.1016/j.coph.2024.102460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 05/25/2024]
Abstract
Shelterin proteins regulate genomic stability by preventing inappropriate DNA damage responses (DDRs) at telomeres. Unprotected telomeres lead to persistent DDR causing cell cycle inhibition, growth arrest, and apoptosis. Cancer cells rely on DDR to protect themselves from DNA lesions and exogenous DNA-damaging agents such as chemotherapy and radiotherapy. Therefore, targeting DDR machinery is a promising strategy to increase the sensitivity of cancer cells to existing cancer therapies. However, the success of these DDR inhibitors depends on other mutations, and over time, patients develop resistance to these therapies. This suggests the need for alternative approaches. One promising strategy is co-inhibiting shelterin proteins with DDR molecules, which would offset cellular fitness in DNA repair in a mutation-independent manner. This review highlights the associations and dependencies of the shelterin complex with the DDR proteins and discusses potential co-inhibition strategies that might improve the therapeutic potential of current inhibitors.
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Affiliation(s)
- Yu Bin Ng
- Laboratory of NFκB Signalling, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A∗STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore
| | - Semih Can Akincilar
- Laboratory of NFκB Signalling, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A∗STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore.
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Zhang W, Zhang K, Shi J, Qiu H, Kan C, Ma Y, Hou N, Han F, Sun X. The impact of the senescent microenvironment on tumorigenesis: Insights for cancer therapy. Aging Cell 2024; 23:e14182. [PMID: 38650467 PMCID: PMC11113271 DOI: 10.1111/acel.14182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 04/25/2024] Open
Abstract
The growing global burden of cancer, especially among people aged 60 years and over, has become a key public health issue. This trend suggests the need for a deeper understanding of the various cancer types in order to develop universally effective treatments. A prospective area of research involves elucidating the interplay between the senescent microenvironment and tumor genesis. Currently, most oncology research focuses on adulthood and tends to ignore the potential role of senescent individuals on tumor progression. Senescent cells produce a senescence-associated secretory phenotype (SASP) that has a dual role in the tumor microenvironment (TME). While SASP components can remodel the TME and thus hinder tumor cell proliferation, they can also promote tumorigenesis and progression via pro-inflammatory and pro-proliferative mechanisms. To address this gap, our review seeks to investigate the influence of senescent microenvironment changes on tumor development and their potential implications for cancer therapies.
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Affiliation(s)
- Wenqiang Zhang
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
- Department of PathologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Kexin Zhang
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Junfeng Shi
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Hongyan Qiu
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Chengxia Kan
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Yujie Ma
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Ningning Hou
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Fang Han
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
- Department of PathologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
| | - Xiaodong Sun
- Department of Endocrinology and Metabolism, Clinical Research Center, Shandong Provincial Key Medical and Health Discipline of EndocrinologyAffiliated Hospital of Shandong Second Medical UniversityWeifangChina
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Prime SS, Darski P, Hunter KD, Cirillo N, Parkinson EK. A Review of the Repair of DNA Double Strand Breaks in the Development of Oral Cancer. Int J Mol Sci 2024; 25:4092. [PMID: 38612901 PMCID: PMC11012950 DOI: 10.3390/ijms25074092] [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: 02/28/2024] [Revised: 03/29/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024] Open
Abstract
We explore the possibility that defects in genes associated with the response and repair of DNA double strand breaks predispose oral potentially malignant disorders (OPMD) to undergo malignant transformation to oral squamous cell carcinoma (OSCC). Defects in the homologous recombination/Fanconi anemia (HR/FA), but not in the non-homologous end joining, causes the DNA repair pathway to appear to be consistent with features of familial conditions that are predisposed to OSCC (FA, Bloom's syndrome, Ataxia Telangiectasia); this is true for OSCC that occurs in young patients, sometimes with little/no exposure to classical risk factors. Even in Dyskeratosis Congenita, a disorder of the telomerase complex that is also predisposed to OSCC, attempts at maintaining telomere length involve a pathway with shared HR genes. Defects in the HR/FA pathway therefore appear to be pivotal in conditions that are predisposed to OSCC. There is also some evidence that abnormalities in the HR/FA pathway are associated with malignant transformation of sporadic cases OPMD and OSCC. We provide data showing overexpression of HR/FA genes in a cell-cycle-dependent manner in a series of OPMD-derived immortal keratinocyte cell lines compared to their mortal counterparts. The observations in this study argue strongly for an important role of the HA/FA DNA repair pathway in the development of OSCC.
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Affiliation(s)
- Stephen S. Prime
- Centre for Immunology and Regenerative Medicine, Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, UK;
| | - Piotr Darski
- Liverpool Head and Neck Centre, Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3BX, UK; (P.D.); (K.D.H.)
| | - Keith D. Hunter
- Liverpool Head and Neck Centre, Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3BX, UK; (P.D.); (K.D.H.)
| | - Nicola Cirillo
- Melbourne Dental School, University of Melbourne, 720 Swanson Street, Carlton, Melbourne, VIC 3053, Australia;
- School of Dentistry, University of Jordan, Amman 11942, Jordan
| | - E. Kenneth Parkinson
- Centre for Immunology and Regenerative Medicine, Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, UK;
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Lu M, Billerbeck S. Improving homology-directed repair by small molecule agents for genetic engineering in unconventional yeast?-Learning from the engineering of mammalian systems. Microb Biotechnol 2024; 17:e14398. [PMID: 38376092 PMCID: PMC10878012 DOI: 10.1111/1751-7915.14398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/08/2023] [Accepted: 12/21/2023] [Indexed: 02/21/2024] Open
Abstract
The ability to precisely edit genomes by deleting or adding genetic information enables the study of biological functions and the building of efficient cell factories. In many unconventional yeasts, such as those promising new hosts for cell factory design but also human pathogenic yeasts and food spoilers, this progress has been limited by the fact that most yeasts favour non-homologous end joining (NHEJ) over homologous recombination (HR) as a DNA repair mechanism, impairing genetic access to these hosts. In mammalian cells, small molecules that either inhibit proteins involved in NHEJ, enhance protein function in HR, or arrest the cell cycle in HR-dominant phases are regarded as promising agents for the simple and transient increase of HR-mediated genome editing without the need for a priori host engineering. Only a few of these chemicals have been applied to the engineering of yeast, although the targeted proteins are mostly conserved, making chemical agents a yet-underexplored area for enhancing yeast engineering. Here, we consolidate knowledge of the available small molecules that have been used to improve HR efficiency in mammalian cells and the few ones that have been used in yeast. We include available high-throughput-compatible NHEJ/HR quantification assays that could be used to screen for and isolate yeast-specific inhibitors.
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Affiliation(s)
- Min Lu
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenThe Netherlands
| | - Sonja Billerbeck
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenThe Netherlands
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9
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Khan H, Ochi T. Plant PAXX has an XLF-like function and stimulates DNA end joining by the Ku-DNA ligase IV/XRCC4 complex. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:58-68. [PMID: 37340932 DOI: 10.1111/tpj.16359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/14/2023] [Indexed: 06/22/2023]
Abstract
Non-homologous end joining (NHEJ) plays a major role in repairing DNA double-strand breaks and is key to genome stability and editing. The minimal core NHEJ proteins, namely Ku70, Ku80, DNA ligase IV and XRCC4, are conserved, but other factors vary in different eukaryote groups. In plants, the only known NHEJ proteins are the core factors, while the molecular mechanism of plant NHEJ remains unclear. Here, we report a previously unidentified plant ortholog of PAXX, the crystal structure of which showed a similar fold to human 'PAXX'. However, plant PAXX has similar molecular functions to human XLF, by directly interacting with Ku70/80 and XRCC4. This suggests that plant PAXX combines the roles of mammalian PAXX and XLF and that these functions merged into a single protein during evolution. This is consistent with a redundant function of PAXX and XLF in mammals.
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Affiliation(s)
- Hira Khan
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Takashi Ochi
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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10
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Torres-Montaner A. Interactions between the DNA Damage Response and the Telomere Complex in Carcinogenesis: A Hypothesis. Curr Issues Mol Biol 2023; 45:7582-7616. [PMID: 37754262 PMCID: PMC10527771 DOI: 10.3390/cimb45090478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 09/28/2023] Open
Abstract
Contrary to what was once thought, direct cancer originating from normal stem cells seems to be extremely rare. This is consistent with a preneoplastic period of telomere length reduction/damage in committed cells that becomes stabilized in transformation. Multiple observations suggest that telomere damage is an obligatory step preceding its stabilization. During tissue turnover, the telomeres of cells undergoing differentiation can be damaged as a consequence of defective DNA repair caused by endogenous or exogenous agents. This may result in the emergence of new mechanism of telomere maintenance which is the final outcome of DNA damage and the initial signal that triggers malignant transformation. Instead, transformation of stem cells is directly induced by primary derangement of telomere maintenance mechanisms. The newly modified telomere complex may promote survival of cancer stem cells, independently of telomere maintenance. An inherent resistance of stem cells to transformation may be linked to specific, robust mechanisms that help maintain telomere integrity.
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Affiliation(s)
- Antonio Torres-Montaner
- Department of Pathology, Queen’s Hospital, Rom Valley Way, Romford, London RM7 OAG, UK;
- Departamento de Bioquímica y Biologia Molecular, Universidad de Cadiz, Puerto Real, 11510 Cadiz, Spain
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11
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Kelly RD, Parmar G, Bayat L, Maitland MER, Lajoie GA, Edgell DR, Schild-Poulter C. Noncanonical functions of Ku may underlie essentiality in human cells. Sci Rep 2023; 13:12162. [PMID: 37500706 PMCID: PMC10374653 DOI: 10.1038/s41598-023-39166-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/20/2023] [Indexed: 07/29/2023] Open
Abstract
The Ku70/80 heterodimer is a key player in non-homologous end-joining DNA repair but is involved in other cellular functions like telomere regulation and maintenance, in which Ku's role is not fully characterized. It was previously reported that knockout of Ku80 in a human cell line results in lethality, but the underlying cause of Ku essentiality in human cells has yet to be fully explored. Here, we established conditional Ku70 knockout cells using CRISPR/Cas9 editing to study the essentiality of Ku70 function. While we observed loss of cell viability upon Ku depletion, we did not detect significant changes in telomere length, nor did we record lethal levels of DNA damage upon loss of Ku. Analysis of global proteome changes following Ku70 depletion revealed dysregulations of several cellular pathways including cell cycle/mitosis, RNA related processes, and translation/ribosome biogenesis. Our study suggests that the driving cause of loss of cell viability in Ku70 knockouts is not linked to the functions of Ku in DNA repair or at telomeres. Moreover, our data shows that loss of Ku affects multiple cellular processes and pathways and suggests that Ku plays critical roles in cellular processes beyond DNA repair and telomere maintenance to maintain cell viability.
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Affiliation(s)
- Rachel D Kelly
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Gursimran Parmar
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Laila Bayat
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Matthew E R Maitland
- Department of Biochemistry, Western University, London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Gilles A Lajoie
- Department of Biochemistry, Western University, London, ON, Canada
| | - David R Edgell
- Department of Biochemistry, Western University, London, ON, Canada
| | - Caroline Schild-Poulter
- Department of Biochemistry, Western University, London, ON, Canada.
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
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12
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Pennarun G, Picotto J, Bertrand P. Close Ties between the Nuclear Envelope and Mammalian Telomeres: Give Me Shelter. Genes (Basel) 2023; 14:genes14040775. [PMID: 37107534 PMCID: PMC10137478 DOI: 10.3390/genes14040775] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/18/2023] [Accepted: 03/20/2023] [Indexed: 04/29/2023] Open
Abstract
The nuclear envelope (NE) in eukaryotic cells is essential to provide a protective compartment for the genome. Beside its role in connecting the nucleus with the cytoplasm, the NE has numerous important functions including chromatin organization, DNA replication and repair. NE alterations have been linked to different human diseases, such as laminopathies, and are a hallmark of cancer cells. Telomeres, the ends of eukaryotic chromosomes, are crucial for preserving genome stability. Their maintenance involves specific telomeric proteins, repair proteins and several additional factors, including NE proteins. Links between telomere maintenance and the NE have been well established in yeast, in which telomere tethering to the NE is critical for their preservation and beyond. For a long time, in mammalian cells, except during meiosis, telomeres were thought to be randomly localized throughout the nucleus, but recent advances have uncovered close ties between mammalian telomeres and the NE that play important roles for maintaining genome integrity. In this review, we will summarize these connections, with a special focus on telomere dynamics and the nuclear lamina, one of the main NE components, and discuss the evolutionary conservation of these mechanisms.
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Affiliation(s)
- Gaëlle Pennarun
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
- Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
| | - Julien Picotto
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
- Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
| | - Pascale Bertrand
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
- Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
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13
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Chen W, Chiang J, Shang Z, Palchik G, Newman C, Zhang Y, Davis AJ, Lee H, Chen BPC. DNA-PKcs and ATM modulate mitochondrial ADP-ATP exchange as an oxidative stress checkpoint mechanism. EMBO J 2023; 42:e112094. [PMID: 36727301 PMCID: PMC10015379 DOI: 10.15252/embj.2022112094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 01/13/2023] [Accepted: 01/21/2023] [Indexed: 02/03/2023] Open
Abstract
DNA-PKcs is a key regulator of DNA double-strand break repair. Apart from its canonical role in the DNA damage response, DNA-PKcs is involved in the cellular response to oxidative stress (OS), but its exact role remains unclear. Here, we report that DNA-PKcs-deficient human cells display depolarized mitochondria membrane potential (MMP) and reoriented metabolism, supporting a role for DNA-PKcs in oxidative phosphorylation (OXPHOS). DNA-PKcs directly interacts with mitochondria proteins ANT2 and VDAC2, and formation of the DNA-PKcs/ANT2/VDAC2 (DAV) complex supports optimal exchange of ADP and ATP across mitochondrial membranes to energize the cell via OXPHOS and to maintain MMP. Moreover, we demonstrate that the DAV complex temporarily dissociates in response to oxidative stress to attenuate ADP-ATP exchange, a rate-limiting step for OXPHOS. Finally, we found that dissociation of the DAV complex is mediated by phosphorylation of DNA-PKcs at its Thr2609 cluster by ATM kinase. Based on these findings, we propose that the coordination between the DAV complex and ATM serves as a novel oxidative stress checkpoint to decrease ROS production from mitochondrial OXPHOS and to hasten cellular recovery from OS.
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Affiliation(s)
- Wei‐Min Chen
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
- Department of Life ScienceNational Taiwan UniversityTaipeiTaiwan
| | - Jui‐Chung Chiang
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
- Department of Life ScienceNational Taiwan UniversityTaipeiTaiwan
| | - Zengfu Shang
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
| | - Guillermo Palchik
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
| | - Ciara Newman
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
| | - Yuanyuan Zhang
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
| | - Anthony J Davis
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
| | - Hsinyu Lee
- Department of Life ScienceNational Taiwan UniversityTaipeiTaiwan
| | - Benjamin PC Chen
- Division of Molecular Radiation Biology, Department of Radiation OncologyUniversity of Texas Southwestern Medical Center at DallasDallasTXUSA
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14
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Chowdhury SG, Misra S, Karmakar P. Understanding the Impact of Obesity on Ageing in the Radiance of DNA Metabolism. J Nutr Health Aging 2023; 27:314-328. [PMID: 37248755 DOI: 10.1007/s12603-023-1912-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/22/2023] [Indexed: 05/31/2023]
Abstract
Ageing is a multi-factorial phenomenon which is considered as a major risk factor for the development of neurodegeneration, osteoporosis, cardiovascular disease, dementia, cancer, and other chronic diseases. Phenotypically, ageing is related with a combination of molecular, cellular, and physiological levels like genomic and epi-genomic alterations, loss of proteostasis, deregulation of cellular and subcellular function and mitochondrial dysfunction. Though, no single molecular mechanism accounts for the functional decline of different organ systems in older humans but accumulation of DNA damage or mutations is a dominant theory which contributes largely to the development of ageing and age-related diseases. However, mechanistic, and hierarchical order of these features of ageing has not been clarified yet. Scientific community now focus on the effect of obesity on accelerated ageing process. Obesity is a complex chronic disease that affects multiple organs and tissues. It can not only lead to various health conditions such as diabetes, cancer, and cardiovascular disease but also can decrease life expectancy which shows similar phenotype of ageing. Higher loads of DNA damage were also observed in the genome of obese people. Thus, inability of DNA damage repair may contribute to both ageing and obesity apart from cancer predisposition. The present review emphasizes on the involvement of molecular phenomenon of DNA metabolism in development of obesity and how it accelerates ageing in mammals.
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Affiliation(s)
- S G Chowdhury
- Parimal Karmakar, Department of Life Science and Biotechnology, Jadavpur University, Kolkata-700032, India.
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15
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ROS: Basic Concepts, Sources, Cellular Signaling, and its Implications in Aging Pathways. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1225578. [PMID: 36312897 PMCID: PMC9605829 DOI: 10.1155/2022/1225578] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/24/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022]
Abstract
Reactive oxygen species (ROS) are bioproducts of cellular metabolism. There is a range of molecules with oxidizing properties known as ROS. Despite those molecules being implied negatively in aging and numerous diseases, their key role in cellular signaling is evident. ROS control several biological processes such as inflammation, proliferation, and cell death. The redox signaling underlying these cellular events is one characteristic of the new generation of scientists aimed at defining the role of ROS in the cellular environment. The control of redox potential, which includes the balance of the sources of ROS and the antioxidant system, implies an important target for understanding the cells' fate derived from redox signaling. In this review, we summarized the chemical, the redox balance, the signaling, and the implications of ROS in biological aging.
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Telomeres and Their Neighbors. Genes (Basel) 2022; 13:genes13091663. [PMID: 36140830 PMCID: PMC9498494 DOI: 10.3390/genes13091663] [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: 08/23/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Abstract
Telomeres are essential structures formed from satellite DNA repeats at the ends of chromosomes in most eukaryotes. Satellite DNA repeat sequences are useful markers for karyotyping, but have a more enigmatic role in the eukaryotic cell. Much work has been done to investigate the structure and arrangement of repetitive DNA elements in classical models with implications for species evolution. Still more is needed until there is a complete picture of the biological function of DNA satellite sequences, particularly when considering non-model organisms. Celebrating Gregor Mendel’s anniversary by going to the roots, this review is designed to inspire and aid new research into telomeres and satellites with a particular focus on non-model organisms and accessible experimental and in silico methods that do not require specialized equipment or expensive materials. We describe how to identify telomere (and satellite) repeats giving many examples of published (and some unpublished) data from these techniques to illustrate the principles behind the experiments. We also present advice on how to perform and analyse such experiments, including details of common pitfalls. Our examples are a selection of recent developments and underexplored areas of research from the past. As a nod to Mendel’s early work, we use many examples from plants and insects, especially as much recent work has expanded beyond the human and yeast models traditional in telomere research. We give a general introduction to the accepted knowledge of telomere and satellite systems and include references to specialized reviews for the interested reader.
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17
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Kelm JM, Samarbakhsh A, Pillai A, VanderVere-Carozza PS, Aruri H, Pandey DS, Pawelczak KS, Turchi JJ, Gavande NS. Recent Advances in the Development of Non-PIKKs Targeting Small Molecule Inhibitors of DNA Double-Strand Break Repair. Front Oncol 2022; 12:850883. [PMID: 35463312 PMCID: PMC9020266 DOI: 10.3389/fonc.2022.850883] [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: 01/08/2022] [Accepted: 02/22/2022] [Indexed: 01/09/2023] Open
Abstract
The vast majority of cancer patients receive DNA-damaging drugs or ionizing radiation (IR) during their course of treatment, yet the efficacy of these therapies is tempered by DNA repair and DNA damage response (DDR) pathways. Aberrations in DNA repair and the DDR are observed in many cancer subtypes and can promote de novo carcinogenesis, genomic instability, and ensuing resistance to current cancer therapy. Additionally, stalled or collapsed DNA replication forks present a unique challenge to the double-strand DNA break (DSB) repair system. Of the various inducible DNA lesions, DSBs are the most lethal and thus desirable in the setting of cancer treatment. In mammalian cells, DSBs are typically repaired by the error prone non-homologous end joining pathway (NHEJ) or the high-fidelity homology directed repair (HDR) pathway. Targeting DSB repair pathways using small molecular inhibitors offers a promising mechanism to synergize DNA-damaging drugs and IR while selective inhibition of the NHEJ pathway can induce synthetic lethality in HDR-deficient cancer subtypes. Selective inhibitors of the NHEJ pathway and alternative DSB-repair pathways may also see future use in precision genome editing to direct repair of resulting DSBs created by the HDR pathway. In this review, we highlight the recent advances in the development of inhibitors of the non-phosphatidylinositol 3-kinase-related kinases (non-PIKKs) members of the NHEJ, HDR and minor backup SSA and alt-NHEJ DSB-repair pathways. The inhibitors described within this review target the non-PIKKs mediators of DSB repair including Ku70/80, Artemis, DNA Ligase IV, XRCC4, MRN complex, RPA, RAD51, RAD52, ERCC1-XPF, helicases, and DNA polymerase θ. While the DDR PIKKs remain intensely pursued as therapeutic targets, small molecule inhibition of non-PIKKs represents an emerging opportunity in drug discovery that offers considerable potential to impact cancer treatment.
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Affiliation(s)
- Jeremy M. Kelm
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, United States
| | - Amirreza Samarbakhsh
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, United States
| | - Athira Pillai
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, United States
| | | | - Hariprasad Aruri
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, United States
| | - Deepti S. Pandey
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, United States
| | | | - John J. Turchi
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States,NERx Biosciences, Indianapolis, IN, United States,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Navnath S. Gavande
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, United States,Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, United States,*Correspondence: Navnath S. Gavande, ; orcid.org/0000-0002-2413-0235
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18
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Transcriptome analysis of HEK 293T cells revealed different significance of the depletion of DNA-dependent protein kinase subunits, Ku70, Ku80, and DNA-PKcs. Biochimie 2022; 199:139-149. [DOI: 10.1016/j.biochi.2022.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/17/2022] [Accepted: 04/12/2022] [Indexed: 01/08/2023]
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Lee SH, Hromas R. Metnase and EEPD1: DNA Repair Functions and Potential Targets in Cancer Therapy. Front Oncol 2022; 12:808757. [PMID: 35155245 PMCID: PMC8831698 DOI: 10.3389/fonc.2022.808757] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022] Open
Abstract
Cells respond to DNA damage by activating signaling and DNA repair systems, described as the DNA damage response (DDR). Clarifying DDR pathways and their dysregulation in cancer are important for understanding cancer etiology, how cancer cells exploit the DDR to survive endogenous and treatment-related stress, and to identify DDR targets as therapeutic targets. Cancer is often treated with genotoxic chemicals and/or ionizing radiation. These agents are cytotoxic because they induce DNA double-strand breaks (DSBs) directly, or indirectly by inducing replication stress which causes replication fork collapse to DSBs. EEPD1 and Metnase are structure-specific nucleases, and Metnase is also a protein methyl transferase that methylates histone H3 and itself. EEPD1 and Metnase promote repair of frank, two-ended DSBs, and both promote the timely and accurate restart of replication forks that have collapsed to single-ended DSBs. In addition to its roles in HR, Metnase also promotes DSB repair by classical non-homologous recombination, and chromosome decatenation mediated by TopoIIα. Although mutations in Metnase and EEPD1 are not common in cancer, both proteins are frequently overexpressed, which may help tumor cells manage oncogenic stress or confer resistance to therapeutics. Here we focus on Metnase and EEPD1 DNA repair pathways, and discuss opportunities for targeting these pathways to enhance cancer therapy.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Sage J Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Suk-Hee Lee
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, United States
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Nahálková J. Focus on Molecular Functions of Anti-Aging Deacetylase SIRT3. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:21-34. [PMID: 35491023 DOI: 10.1134/s0006297922010035] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
SIRT3 is a protein lysine deacetylase with a prominent role in the maintenance of mitochondrial integrity, which is a vulnerable target in many diseases. Intriguingly, cellular aging is reversible just by SIRT3 overexpression, which raises many questions about the role of SIRT3 in the molecular anti-aging mechanisms. Therefore, functions of SIRT3 were analyzed through the interaction network of 407 substrates collected by data mining. Results of the pathway enrichment and gene function prediction confirmed functions in the primary metabolism and mitochondrial ATP production. However, it also suggested involvement in thermogenesis, brain-related neurodegenerative diseases Alzheimer's (AD), Parkinson's, Huntington's disease (HD), and non-alcoholic fatty liver disease. The protein node prioritization analysis identified subunits of the complex I of the mitochondrial respiratory chain (MRC) as the nodes with the main regulatory effect within the entire interaction network. Additional high-ranked nodes were succinate dehydrogenase subunit B (SDHB), complex II, and ATP5F1, complex V of MRC. The analysis supports existence of the NADH/NAD+ driven regulatory feedback loop between SIRT3, complex I (MRC), and acetyl-CoA synthetases, and existence of the nuclear substrates of SIRT3. Unexplored functions of SIRT3 substrates such as LMNA and LMNB; HIF-1a, p53, DNA-PK, and PARK7 are highlighted for further scientific advances. SIRT3 acts as a repressor of BACE1 through the SIRT3-LKB1-AMPK-CREB-PGC1A-PPARG-BACE1 (SIRT3-BACE1), which functions are fitted the best by the Circadian Clock pathway. It forms a new working hypothesis as the therapeutical target for AD treatment. Other important pathways linked to SIRT3 activity are highlighted for therapeutical interventions.
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Affiliation(s)
- Jarmila Nahálková
- Biochemistry, Molecular, and Cell Biology Unit, Biochemworld Co., Skyttorp, Uppsala County, 74394, Sweden.
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21
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Poláková E, Albanaz ATS, Zakharova A, Novozhilova TS, Gerasimov ES, Yurchenko V. Ku80 is involved in telomere maintenance but dispensable for genomic stability in Leishmania mexicana. PLoS Negl Trop Dis 2021; 15:e0010041. [PMID: 34965251 PMCID: PMC8716037 DOI: 10.1371/journal.pntd.0010041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/30/2021] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Telomeres are indispensable for genome stability maintenance. They are maintained by the telomere-associated protein complex, which include Ku proteins and a telomerase among others. Here, we investigated a role of Ku80 in Leishmania mexicana. Leishmania is a genus of parasitic protists of the family Trypanosomatidae causing a vector-born disease called leishmaniasis. METHODOLOGY/PRINCIPAL FINDINGS We used the previously established CRISPR/Cas9 system to mediate ablation of Ku80- and Ku70-encoding genes in L. mexicana. Complete knock-outs of both genes were confirmed by Southern blotting, whole-genome Illumina sequencing, and RT-qPCR. Resulting telomeric phenotypes were subsequently investigated using Southern blotting detection of terminal restriction fragments. The genome integrity in the Ku80- deficient cells was further investigated by whole-genome sequencing. Our work revealed that telomeres in the ΔKu80 L. mexicana are elongated compared to those of the wild type. This is a surprising finding considering that in another model trypanosomatid, Trypanosoma brucei, they are shortened upon ablation of the same gene. A telomere elongation phenotype has been documented in other species and associated with a presence of telomerase-independent alternative telomere lengthening pathway. Our results also showed that Ku80 appears to be not involved in genome stability maintenance in L. mexicana. CONCLUSION/SIGNIFICANCE Ablation of the Ku proteins in L. mexicana triggers telomere elongation, but does not have an adverse impact on genome integrity.
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Affiliation(s)
- Ester Poláková
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Amanda T. S. Albanaz
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Alexandra Zakharova
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | | | - Evgeny S. Gerasimov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, Moscow, Russia
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22
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Sui H, Hao M, Chang W, Imamichi T. The Role of Ku70 as a Cytosolic DNA Sensor in Innate Immunity and Beyond. Front Cell Infect Microbiol 2021; 11:761983. [PMID: 34746031 PMCID: PMC8566972 DOI: 10.3389/fcimb.2021.761983] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/06/2021] [Indexed: 12/24/2022] Open
Abstract
Human Ku70 is a well-known endogenous nuclear protein involved in the non-homologous end joining pathway to repair double-stranded breaks in DNA. However, Ku70 has been studied in multiple contexts and grown into a multifunctional protein. In addition to the extensive functional study of Ku70 in DNA repair process, many studies have emphasized the role of Ku70 in various other cellular processes, including apoptosis, aging, and HIV replication. In this review, we focus on discussing the role of Ku70 in inducing interferons and proinflammatory cytokines as a cytosolic DNA sensor. We explored the unique structure of Ku70 binding with DNA; illustrated, with evidence, how Ku70, as a nuclear protein, responds to extracellular DNA stimulation; and summarized the mechanisms of the Ku70-involved innate immune response pathway. Finally, we discussed several new strategies to modulate Ku70-mediated innate immune response and highlighted some potential physiological insights based on the role of Ku70 in innate immunity.
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Affiliation(s)
- Hongyan Sui
- Laboratory of Human Retrovirology and Immunoinformatics, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | | | | | - Tomozumi Imamichi
- Laboratory of Human Retrovirology and Immunoinformatics, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
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23
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Hromas R. The Safe Path at the Fork: Ensuring Replication-Associated DNA Double-Strand Breaks are Repaired by Homologous Recombination. Front Genet 2021; 12:748033. [PMID: 34646312 PMCID: PMC8502867 DOI: 10.3389/fgene.2021.748033] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/14/2021] [Indexed: 01/15/2023] Open
Abstract
Cells must replicate and segregate their DNA to daughter cells accurately to maintain genome stability and prevent cancer. DNA replication is usually fast and accurate, with intrinsic (proofreading) and extrinsic (mismatch repair) error-correction systems. However, replication forks slow or stop when they encounter DNA lesions, natural pause sites, and difficult-to-replicate sequences, or when cells are treated with DNA polymerase inhibitors or hydroxyurea, which depletes nucleotide pools. These challenges are termed replication stress, to which cells respond by activating DNA damage response signaling pathways that delay cell cycle progression, stimulate repair and replication fork restart, or induce apoptosis. Stressed forks are managed by rescue from adjacent forks, repriming, translesion synthesis, template switching, and fork reversal which produces a single-ended double-strand break (seDSB). Stressed forks also collapse to seDSBs when they encounter single-strand nicks or are cleaved by structure-specific nucleases. Reversed and cleaved forks can be restarted by homologous recombination (HR), but seDSBs pose risks of mis-rejoining by non-homologous end-joining (NHEJ) to other DSBs, causing genome rearrangements. HR requires resection of broken ends to create 3' single-stranded DNA for RAD51 recombinase loading, and resected ends are refractory to repair by NHEJ. This Mini Review highlights mechanisms that help maintain genome stability by promoting resection of seDSBs and accurate fork restart by HR.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Sage J Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, United States
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24
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Mechanism of Human Telomerase Reverse Transcriptase ( hTERT) Regulation and Clinical Impacts in Leukemia. Genes (Basel) 2021; 12:genes12081188. [PMID: 34440361 PMCID: PMC8392866 DOI: 10.3390/genes12081188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/09/2021] [Accepted: 05/17/2021] [Indexed: 01/03/2023] Open
Abstract
The proliferative capacity and continuous survival of cells are highly dependent on telomerase expression and the maintenance of telomere length. For this reason, elevated expression of telomerase has been identified in virtually all cancers, including leukemias; however, it should be noted that expression of telomerase is sometimes observed later in malignant development. This time point of activation is highly dependent on the type of leukemia and its causative factors. Many recent studies in this field have contributed to the elucidation of the mechanisms by which the various forms of leukemias increase telomerase activity. These include the dysregulation of telomerase reverse transcriptase (TERT) at various levels which include transcriptional, post-transcriptional, and post-translational stages. The pathways and biological molecules involved in these processes are also being deciphered with the advent of enabling technologies such as next-generation sequencing (NGS), ribonucleic acid sequencing (RNA-Seq), liquid chromatography-mass spectrometry (LCMS/MS), and many others. It has also been established that TERT possess diagnostic value as most adult cells do not express high levels of telomerase. Indeed, studies have shown that prognosis is not favorable in patients who have leukemias expressing high levels of telomerase. Recent research has indicated that targeting of this gene is able to control the survival of malignant cells and therefore offers a potential treatment for TERT-dependent leukemias. Here we review the mechanisms of hTERT regulation and deliberate their association in malignant states of leukemic cells. Further, we also cover the clinical implications of this gene including its use in diagnostic, prognostic, and therapeutic discoveries.
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Abbasi S, Parmar G, Kelly RD, Balasuriya N, Schild-Poulter C. The Ku complex: recent advances and emerging roles outside of non-homologous end-joining. Cell Mol Life Sci 2021; 78:4589-4613. [PMID: 33855626 PMCID: PMC11071882 DOI: 10.1007/s00018-021-03801-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/29/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022]
Abstract
Since its discovery in 1981, the Ku complex has been extensively studied under multiple cellular contexts, with most work focusing on Ku in terms of its essential role in non-homologous end-joining (NHEJ). In this process, Ku is well-known as the DNA-binding subunit for DNA-PK, which is central to the NHEJ repair process. However, in addition to the extensive study of Ku's role in DNA repair, Ku has also been implicated in various other cellular processes including transcription, the DNA damage response, DNA replication, telomere maintenance, and has since been studied in multiple contexts, growing into a multidisciplinary point of research across various fields. Some advances have been driven by clarification of Ku's structure, including the original Ku crystal structure and the more recent Ku-DNA-PKcs crystallography, cryogenic electron microscopy (cryoEM) studies, and the identification of various post-translational modifications. Here, we focus on the advances made in understanding the Ku heterodimer outside of non-homologous end-joining, and across a variety of model organisms. We explore unique structural and functional aspects, detail Ku expression, conservation, and essentiality in different species, discuss the evidence for its involvement in a diverse range of cellular functions, highlight Ku protein interactions and recent work concerning Ku-binding motifs, and finally, we summarize the clinical Ku-related research to date.
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Affiliation(s)
- Sanna Abbasi
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Gursimran Parmar
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Rachel D Kelly
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Nileeka Balasuriya
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Caroline Schild-Poulter
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada.
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26
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Shiromoto Y, Sakurai M, Minakuchi M, Ariyoshi K, Nishikura K. ADAR1 RNA editing enzyme regulates R-loop formation and genome stability at telomeres in cancer cells. Nat Commun 2021; 12:1654. [PMID: 33712600 PMCID: PMC7955049 DOI: 10.1038/s41467-021-21921-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 02/19/2021] [Indexed: 12/12/2022] Open
Abstract
ADAR1 is involved in adenosine-to-inosine RNA editing. The cytoplasmic ADAR1p150 edits 3'UTR double-stranded RNAs and thereby suppresses induction of interferons. Loss of this ADAR1p150 function underlies the embryonic lethality of Adar1 null mice, pathogenesis of the severe autoimmune disease Aicardi-Goutières syndrome, and the resistance developed in cancers to immune checkpoint blockade. In contrast, the biological functions of the nuclear-localized ADAR1p110 remain largely unknown. Here, we report that ADAR1p110 regulates R-loop formation and genome stability at telomeres in cancer cells carrying non-canonical variants of telomeric repeats. ADAR1p110 edits the A-C mismatches within RNA:DNA hybrids formed between canonical and non-canonical variant repeats. Editing of A-C mismatches to I:C matched pairs facilitates resolution of telomeric R-loops by RNase H2. This ADAR1p110-dependent control of telomeric R-loops is required for continued proliferation of telomerase-reactivated cancer cells, revealing the pro-oncogenic nature of ADAR1p110 and identifying ADAR1 as a promising therapeutic target of telomerase positive cancers.
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Affiliation(s)
| | - Masayuki Sakurai
- The Wistar Institute, Philadelphia, PA, USA.,Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | | | - Kentaro Ariyoshi
- The Wistar Institute, Philadelphia, PA, USA.,Integrated Center for Science and Humanities, Fukushima Medical University, Fukushima, Japan
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27
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Yue X, Bai C, Xie D, Ma T, Zhou PK. DNA-PKcs: A Multi-Faceted Player in DNA Damage Response. Front Genet 2020; 11:607428. [PMID: 33424929 PMCID: PMC7786053 DOI: 10.3389/fgene.2020.607428] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/01/2020] [Indexed: 12/17/2022] Open
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a member of the phosphatidylinositol 3-kinase related kinase family, which can phosphorylate more than 700 substrates. As the core enzyme, DNA-PKcs forms the active DNA-PK holoenzyme with the Ku80/Ku70 heterodimer to play crucial roles in cellular DNA damage response (DDR). Once DNA double strand breaks (DSBs) occur in the cells, DNA-PKcs is promptly recruited into damage sites and activated. DNA-PKcs is auto-phosphorylated and phosphorylated by Ataxia-Telangiectasia Mutated at multiple sites, and phosphorylates other targets, participating in a series of DDR and repair processes, which determine the cells' fates: DSBs NHEJ repair and pathway choice, replication stress response, cell cycle checkpoints, telomeres length maintenance, senescence, autophagy, etc. Due to the special and multi-faceted roles of DNA-PKcs in the cellular responses to DNA damage, it is important to precisely regulate the formation and dynamic of its functional complex and activities for guarding genomic stability. On the other hand, targeting DNA-PKcs has been considered as a promising strategy of exploring novel radiosensitizers and killing agents of cancer cells. Combining DNA-PKcs inhibitors with radiotherapy can effectively enhance the efficacy of radiotherapy, offering more possibilities for cancer therapy.
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Affiliation(s)
- Xiaoqiao Yue
- School of Public Health, University of South China, Hengyang, China.,Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Chenjun Bai
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Dafei Xie
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Teng Ma
- Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, China
| | - Ping-Kun Zhou
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
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28
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Gavande NS, VanderVere-Carozza PS, Pawelczak KS, Mendoza-Munoz P, Vernon TL, Hanakahi LA, Summerlin M, Dynlacht JR, Farmer AH, Sears CR, Nasrallah NA, Garrett J, Turchi JJ. Discovery and development of novel DNA-PK inhibitors by targeting the unique Ku-DNA interaction. Nucleic Acids Res 2020; 48:11536-11550. [PMID: 33119767 PMCID: PMC7672428 DOI: 10.1093/nar/gkaa934] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/02/2020] [Accepted: 10/09/2020] [Indexed: 01/05/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK) plays a critical role in the non-homologous end joining (NHEJ) repair pathway and the DNA damage response (DDR). DNA-PK has therefore been pursued for the development of anti-cancer therapeutics in combination with ionizing radiation (IR). We report the discovery of a new class of DNA-PK inhibitors that act via a novel mechanism of action, inhibition of the Ku-DNA interaction. We have developed a series of highly potent and specific Ku-DNA binding inhibitors (Ku-DBi's) that block the Ku-DNA interaction and inhibit DNA-PK kinase activity. Ku-DBi's directly interact with the Ku and inhibit in vitro NHEJ, cellular NHEJ, and potentiate the cellular activity of radiomimetic agents and IR. Analysis of Ku-null cells demonstrates that Ku-DBi's cellular activity is a direct result of Ku inhibition, as Ku-null cells are insensitive to Ku-DBi's. The utility of Ku-DBi's was also revealed in a CRISPR gene-editing model where we demonstrate that the efficiency of gene insertion events was increased in cells pre-treated with Ku-DBi's, consistent with inhibition of NHEJ and activation of homologous recombination to facilitate gene insertion. These data demonstrate the discovery and application of new series of compounds that modulate DNA repair pathways via a unique mechanism of action.
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Affiliation(s)
- Navnath S Gavande
- Department of Medicine, Indiana University School of Medicine, Indianapolis IN 46202, USA
- Department of Pharmaceutical Sciences, Wayne State University College of Pharmacy and Health Sciences, Detroit, MI 48201, USA
| | | | | | - Pamela Mendoza-Munoz
- Department of Medicine, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Tyler L Vernon
- Department of Medicine, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Leslyn A Hanakahi
- Department of Biopharmaceutical Sciences, University of Illinois College of Pharmacy, Rockford, IL 61107, USA
| | - Matthew Summerlin
- Department of Biopharmaceutical Sciences, University of Illinois College of Pharmacy, Rockford, IL 61107, USA
| | - Joseph R Dynlacht
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Annabelle H Farmer
- Department of Medicine, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Catherine R Sears
- Department of Medicine, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Nawar Al Nasrallah
- Department of Medicine, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Joy Garrett
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - John J Turchi
- Department of Medicine, Indiana University School of Medicine, Indianapolis IN 46202, USA
- NERx Biosciences, 212 W 10th St. Suite A480, Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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29
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Piekna-Przybylska D, Bambara RA, Maggirwar SB, Dewhurst S. G-quadruplex ligands targeting telomeres do not inhibit HIV promoter activity and cooperate with latency reversing agents in killing latently infected cells. Cell Cycle 2020; 19:2298-2313. [PMID: 32807015 DOI: 10.1080/15384101.2020.1796268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Altered telomere maintenance mechanism (TMM) is linked to increased DNA damage at telomeres and telomere uncapping. We previously showed that HIV-1 latent cells have altered TMM and are susceptible to ligands that target G-quadruplexes (G4) at telomeres. Susceptibility of latent cells to telomere targeting could potentially be used to support approaches to eradicate HIV reservoirs. However, G4 ligands also target G-quadruplexes in promoters blocking gene transcription. Since HIV promoter sequence can form G-quadruplexes, we investigated whether G4 ligands interfere with HIV-1 promoter activity and virus reactivation from latency, and whether telomere targeting could be combined with latency reversing agents (LRAs) to promote elimination of HIV reservoirs. Our results indicate that Sp1 binding region in HIV-1 promoter can adopt G4 structures in duplex DNA, and that in vitro binding of Sp1 to G-quadruplex is blocked by G4 ligand, suggesting that agents targeting telomeres interfere with virus reactivation. However, our studies show that G4 agents do not affect HIV-1 promoter activity in cell culture, and do not interfere with latency reversal. Importantly, primary memory CD4 + T cells infected with latent HIV-1 are more susceptible to combined treatment with LRAs and G4 ligands, indicating that drugs targeting TMM may enhance killing of HIV reservoirs. Using a cell-based DNA repair assay, we also found that HIV-1 infected cells have reduced efficiency of DNA mismatch repair (MMR), and base excision repair (BER), suggesting that altered TMM in latently infected cells could be associated with accumulation of DNA damage at telomeres and changes in telomeric caps.
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Affiliation(s)
- Dorota Piekna-Przybylska
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester , Rochester, NY, USA
| | - Robert A Bambara
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester , Rochester, NY, USA
| | - Sanjay B Maggirwar
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University , Washington, DC, USA
| | - Stephen Dewhurst
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester , Rochester, NY, USA
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30
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Anisenko A, Kan M, Shadrina O, Brattseva A, Gottikh M. Phosphorylation Targets of DNA-PK and Their Role in HIV-1 Replication. Cells 2020; 9:E1907. [PMID: 32824372 PMCID: PMC7464883 DOI: 10.3390/cells9081907] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 02/07/2023] Open
Abstract
The DNA dependent protein kinase (DNA-PK) is a trimeric nuclear complex consisting of a large protein kinase and the Ku heterodimer. The kinase activity of DNA-PK is required for efficient repair of DNA double-strand breaks (DSB) by non-homologous end joining (NHEJ). We also showed that the kinase activity of DNA-PK is essential for post-integrational DNA repair in the case of HIV-1 infection. Besides, DNA-PK is known to participate in such cellular processes as protection of mammalian telomeres, transcription, and some others where the need for its phosphorylating activity is not clearly elucidated. We carried out a systematic search and analysis of DNA-PK targets described in the literature and identified 67 unique DNA-PK targets phosphorylated in response to various in vitro and/or in vivo stimuli. A functional enrichment analysis of DNA-PK targets and determination of protein-protein associations among them were performed. For 27 proteins from these 67 DNA-PK targets, their participation in the HIV-1 life cycle was demonstrated. This information may be useful for studying the functioning of DNA-PK in various cellular processes, as well as in various stages of HIV-1 replication.
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Affiliation(s)
- Andrey Anisenko
- Chemistry Department and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia; (O.S.); (M.G.)
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia;; (M.K.); (A.B.)
| | - Marina Kan
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia;; (M.K.); (A.B.)
| | - Olga Shadrina
- Chemistry Department and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia; (O.S.); (M.G.)
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia;; (M.K.); (A.B.)
| | - Anna Brattseva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia;; (M.K.); (A.B.)
| | - Marina Gottikh
- Chemistry Department and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia; (O.S.); (M.G.)
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