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Németh E, Szüts D. The mutagenic consequences of defective DNA repair. DNA Repair (Amst) 2024; 139:103694. [PMID: 38788323 DOI: 10.1016/j.dnarep.2024.103694] [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: 03/22/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024]
Abstract
Multiple separate repair mechanisms safeguard the genome against various types of DNA damage, and their failure can increase the rate of spontaneous mutagenesis. The malfunction of distinct repair mechanisms leads to genomic instability through different mutagenic processes. For example, defective mismatch repair causes high base substitution rates and microsatellite instability, whereas homologous recombination deficiency is characteristically associated with deletions and chromosome instability. This review presents a comprehensive collection of all mutagenic phenotypes associated with the loss of each DNA repair mechanism, drawing on data from a variety of model organisms and mutagenesis assays, and placing greatest emphasis on systematic analyses of human cancer datasets. We describe the latest theories on the mechanism of each mutagenic process, often explained by reliance on an alternative repair pathway or the error-prone replication of unrepaired, damaged DNA. Aided by the concept of mutational signatures, the genomic phenotypes can be used in cancer diagnosis to identify defective DNA repair pathways.
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Affiliation(s)
- Eszter Németh
- Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary
| | - Dávid Szüts
- Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary.
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McMahon A, Zhao J, Yan S. Ubiquitin-mediated regulation of APE2 protein abundance. J Biol Chem 2024; 300:107337. [PMID: 38705397 PMCID: PMC11157268 DOI: 10.1016/j.jbc.2024.107337] [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: 10/30/2023] [Revised: 04/12/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024] Open
Abstract
APE2 plays important roles in the maintenance of genomic and epigenomic stability including DNA repair and DNA damage response. Accumulating evidence has suggested that APE2 is upregulated in multiple cancers at the protein and mRNA levels and that APE2 upregulation is correlative with higher and lower overall survival of cancer patients depending on tumor type. However, it remains unknown how APE2 protein abundance is maintained and regulated in cells. Here, we provide the first evidence of APE2 regulation via the posttranslational modification ubiquitin. APE2 is poly-ubiquitinated via K48-linked chains and degraded via the ubiquitin-proteasome system where K371 is the key residue within APE2 responsible for its ubiquitination and degradation. We further characterize MKRN3 as the E3 ubiquitin ligase for APE2 ubiquitination in cells and in vitro. In summary, this study offers the first definition of the APE2 proteostasis network and lays the foundation for future studies pertaining to the posttranslational modification regulation and functions of APE2 in genome integrity and cancer etiology/treatment.
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Affiliation(s)
- Anne McMahon
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Jianjun Zhao
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA; School of Data Science, University of North Carolina at Charlotte, Charlotte, North Carolina, USA; Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina, USA.
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Das D, Duncton MAJ, Georgiadis TM, Pellicena P, Clark J, Sobol RW, Georgiadis MM, King-Underwood J, Jobes DV, Chang C, Gao Y, Deacon AM, Wilson DM. A New Drug Discovery Platform: Application to DNA Polymerase Eta and Apurinic/Apyrimidinic Endonuclease 1. Int J Mol Sci 2023; 24:16637. [PMID: 38068959 PMCID: PMC10706420 DOI: 10.3390/ijms242316637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 12/18/2023] Open
Abstract
The ability to quickly discover reliable hits from screening and rapidly convert them into lead compounds, which can be verified in functional assays, is central to drug discovery. The expedited validation of novel targets and the identification of modulators to advance to preclinical studies can significantly increase drug development success. Our SaXPyTM ("SAR by X-ray Poses Quickly") platform, which is applicable to any X-ray crystallography-enabled drug target, couples the established methods of protein X-ray crystallography and fragment-based drug discovery (FBDD) with advanced computational and medicinal chemistry to deliver small molecule modulators or targeted protein degradation ligands in a short timeframe. Our approach, especially for elusive or "undruggable" targets, allows for (i) hit generation; (ii) the mapping of protein-ligand interactions; (iii) the assessment of target ligandability; (iv) the discovery of novel and potential allosteric binding sites; and (v) hit-to-lead execution. These advances inform chemical tractability and downstream biology and generate novel intellectual property. We describe here the application of SaXPy in the discovery and development of DNA damage response inhibitors against DNA polymerase eta (Pol η or POLH) and apurinic/apyrimidinic endonuclease 1 (APE1 or APEX1). Notably, our SaXPy platform allowed us to solve the first crystal structures of these proteins bound to small molecules and to discover novel binding sites for each target.
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Affiliation(s)
- Debanu Das
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Accelero Biostructures, Inc., San Carlos, CA 94070, USA
| | | | | | | | - Jennifer Clark
- Mitchell Cancer Institute and Department of Pharmacology, University of South Alabama, Mobile, AL 36604, USA
| | - Robert W. Sobol
- Mitchell Cancer Institute and Department of Pharmacology, University of South Alabama, Mobile, AL 36604, USA
- Department of Pathology & Laboratory Medicine, Warrant Alpert Medical School & Legorreta Cancer Center, Brown University, Providence, RI 02912, USA
| | - Millie M. Georgiadis
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | | | - David V. Jobes
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Mid-Atlantic BioTherapeutics, Inc., Doylestown, PA 18902, USA
| | - Caleb Chang
- Department of BioSciences, Rice University, Houston, TX 77251, USA
| | - Yang Gao
- Department of BioSciences, Rice University, Houston, TX 77251, USA
| | - Ashley M. Deacon
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Accelero Biostructures, Inc., San Carlos, CA 94070, USA
| | - David M. Wilson
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Biomedical Research Institute, Hasselt University, 3500 Diepenbeek, Belgium
- Belgium & Boost Scientific, 3550 Heusden-Zolder, Belgium
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