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Bazan Russo TD, Mujacic C, Di Giovanni E, Vitale MC, Ferrante Bannera C, Randazzo U, Contino S, Bono M, Gristina V, Galvano A, Perez A, Badalamenti G, Russo A, Bazan V, Incorvaia L. Polθ: emerging synthetic lethal partner in homologous recombination-deficient tumors. Cancer Gene Ther 2024:10.1038/s41417-024-00815-2. [PMID: 39122831 DOI: 10.1038/s41417-024-00815-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 07/22/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024]
Abstract
The most remarkable finding in synthetic lethality (SL) is the hypersensitivity to PARP inhibitors (PARPis) of the tumors harboring defects in genes involved in homologous repair (HR) such as BRCA1/2. Despite initial responsiveness to PARPi, the penetrance of the synthetic lethal interactions between BRCA1/2 genes and PARPi is incomplete. Thus, a significant proportion of HR-defective tumors experience intrinsic or acquired resistance, representing a key challenge of clinical research. An expanded concept of SL is opening new ways and includes novel forms of genetic interactions, investigating not only traditional SL of pairs genes but also SL between biological pathways that regulate the same essential survival cell function. In this context, recent research showed that HR and theta-mediated end-joining (TMEJ) pathways exhibit SL. DNA polymerase theta (Polθ) is encoded by the POLQ gene and is a key component of the TMEJ, an essential backup pathway, intrinsically mutagenic, to repair resected double-strand breaks (DSBs) when the non-homologous end joining (NHEJ) and HR are impaired. Polθ is broadly expressed in normal tissues, overexpressed in several cancers, and typically associated with poor outcomes and shorter relapse-free survival. Notably, HR-deficient tumor cells present the characteristic mutational signatures of the error-prone TMEJ pathway. According to this observation, the loss of HR proteins, such as BRCA1 or BRCA2, contributes to increasing the TMEJ-specific genomic profile, suggesting synthetic lethal interactions between loss of the POLQ and HR genes, and resulting in the emerging interest for Polθ as a potential therapeutic target in BRCA1/2-associated tumors.This review summarizes the converging roles of the POLQ and HR genes in DNA DSB repair, the early-stage clinical trials using Polθ inhibitor to treat HR-defective tumors and to overcome BRCA-reversion mutations responsible for therapeutic resistance, and the novel pleiotropic effects of Polθ, paving the way for the development of unexplored synthetic lethality strategies.
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Affiliation(s)
- Tancredi Didier Bazan Russo
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Clarissa Mujacic
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Emilia Di Giovanni
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Maria Concetta Vitale
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Carla Ferrante Bannera
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Ugo Randazzo
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Silvia Contino
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Marco Bono
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Valerio Gristina
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Antonio Galvano
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Alessandro Perez
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Giuseppe Badalamenti
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy.
| | - Antonio Russo
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy.
| | - Viviana Bazan
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
| | - Lorena Incorvaia
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), Section of Medical Oncology, University of Palermo, 90127, Palermo, Italy
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Yang K, Zhu L, Liu C, Zhou D, Zhu Z, Xu N, Li W. Current status and prospect of the DNA double-strand break repair pathway in colorectal cancer development and treatment. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167438. [PMID: 39059591 DOI: 10.1016/j.bbadis.2024.167438] [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: 12/16/2023] [Revised: 07/18/2024] [Accepted: 07/18/2024] [Indexed: 07/28/2024]
Abstract
Colorectal cancer (CRC) is one of the most common malignancies worldwide. Double-strand break (DSB) is the most severe type of DNA damage. However, few reviews have thoroughly examined the involvement of DSB in CRC. Latest researches demonstrated that DSB repair plays an important role in CRC. For example, DSB-related genes such as BRCA1, Ku-70 and DNA polymerase theta (POLQ) are associated with the occurrence of CRC, and POLQ even showed to affect the prognosis and resistance for radiotherapy in CRC. This review comprehensively summarizes the DSB role in CRC, explores the mechanisms and discusses the association with CRC treatment. Four pathways for DSB have been demonstrated. 1. Nonhomologous end joining (NHEJ) is the major pathway. Its core genes including Ku70 and Ku80 bind to broken ends and recruit repair factors to form a complex that mediates the connection of DNA breaks. 2. Homologous recombination (HR) is another important pathway. Its key genes including BRCA1 and BRCA2 are involved in finding, pairing, and joining broken ends, and ensure the restoration of breaks in a normal double-stranded DNA structure. 3. Single-strand annealing (SSA) pathway, and 4. POLθ-mediated end-joining (alt-EJ) is a backup pathway. This paper elucidates roles of the DSB repair pathways in CRC, which could contribute to the development of potential new treatment approaches and provide new opportunities for CRC treatment and more individualized treatment options based on therapeutic strategies targeting these DNA repair pathways.
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Affiliation(s)
- Kexin Yang
- Department of Colorectal Surgery, the Third Affiliated Hospital of Kunming Medical University, Yunnan Cancer Hospital, Kunming 650106, China; Kunming Medical University, Kunming 650500, China
| | - Lihua Zhu
- Department of Surgical Oncology, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, China; Kunming Medical University, Kunming 650500, China
| | - Chang Liu
- Department of Surgical Oncology, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
| | - Dayang Zhou
- Department of Surgical Oncology, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
| | - Zhu Zhu
- Department of Surgical Oncology, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
| | - Ning Xu
- Department of Colorectal Surgery, the Third Affiliated Hospital of Kunming Medical University, Yunnan Cancer Hospital, Kunming 650106, China; Department of Surgical Oncology, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, China; Kunming Medical University, Kunming 650500, China.
| | - Wenliang Li
- Department of Colorectal Surgery, the Third Affiliated Hospital of Kunming Medical University, Yunnan Cancer Hospital, Kunming 650106, China; Kunming Medical University, Kunming 650500, China.
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Ito F, Li Z, Minakhin L, Khant HA, Pomerantz RT, Chen XS. Structural Basis for Polθ-Helicase DNA Binding and Microhomology-Mediated End-Joining. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597860. [PMID: 38895274 PMCID: PMC11185775 DOI: 10.1101/2024.06.07.597860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
DNA double-strand breaks (DSBs) present a critical threat to genomic integrity, often precipitating genomic instability and oncogenesis. Repair of DSBs predominantly occurs through homologous recombination (HR) and non-homologous end joining (NHEJ). In HR-deficient cells, DNA polymerase theta (Polθ) becomes critical for DSB repair via microhomology-mediated end joining (MMEJ), also termed theta-mediated end joining (TMEJ). Thus, Polθ is synthetically lethal with BRCA1/2 and other HR factors, underscoring its potential as a therapeutic target in HR-deficient cancers. However, the molecular mechanisms governing Polθ-mediated MMEJ remain poorly understood. Here we present a series of cryo-electron microscopy structures of the Polθ helicase domain (Polθ-hel) in complex with DNA containing 3'-overhang. The structures reveal the sequential conformations adopted by Polθ-hel during the critical phases of DNA binding, microhomology searching, and microhomology annealing. The stepwise conformational changes within the Polθ-hel subdomains and its functional dimeric state are pivotal for aligning the 3'-overhangs, facilitating the microhomology search and subsequent annealing necessary for DSB repair via MMEJ. Our findings illustrate the essential molecular switches within Polθ-hel that orchestrate the MMEJ process in DSB repair, laying the groundwork for the development of targeted therapies against the Polθ-hel.
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Affiliation(s)
- Fumiaki Ito
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, 90089, USA
- Department of Microbiology, Immunology and Molecular Genetics
- California NanoSystems Institute, University of California, Los Angeles, CA90095, USA
| | - Ziyuan Li
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, 90089, USA
| | - Leonid Minakhin
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Htet A. Khant
- USC Center of Excellence for Nano-Imaging, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Richard T. Pomerantz
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Xiaojiang S. Chen
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, 90089, USA
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Thomas C, Avalos-Irving L, Victorino J, Green S, Andrews M, Rodrigues N, Ebirim S, Mudd A, Towle-Weicksel JB. Melanoma-Derived DNA Polymerase Theta Variants Exhibit Altered DNA Polymerase Activity. Biochemistry 2024; 63:1107-1117. [PMID: 38671548 PMCID: PMC11080051 DOI: 10.1021/acs.biochem.3c00670] [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: 11/29/2023] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 04/28/2024]
Abstract
DNA polymerase θ (Pol θ or POLQ) is primarily involved in repairing double-stranded breaks in DNA through an alternative pathway known as microhomology-mediated end joining (MMEJ) or theta-mediated end joining (TMEJ). Unlike other DNA repair polymerases, Pol θ is thought to be highly error-prone yet critical for cell survival. We have identified several POLQ gene variants from human melanoma tumors that experience altered DNA polymerase activity, including a propensity for incorrect nucleotide selection and reduced polymerization rates compared to WT Pol θ. Variants are 30-fold less efficient at incorporating a nucleotide during repair and up to 70-fold less accurate at selecting the correct nucleotide opposite a templating base. This suggests that aberrant Pol θ has reduced DNA repair capabilities and may also contribute to increased mutagenesis. Moreover, the variants were identified in established tumors, suggesting that cancer cells may use mutated polymerases to promote metastasis and drug resistance.
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Affiliation(s)
- Corey Thomas
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Lisbeth Avalos-Irving
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Jorge Victorino
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Sydney Green
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Morgan Andrews
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Naisha Rodrigues
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Sarah Ebirim
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Ayden Mudd
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Jamie B. Towle-Weicksel
- Department of Physical Sciences, Rhode Island College, 600 Mount Pleasant Avenue, Providence, Rhode Island 02908, United States
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Zerio CJ, Bai Y, Sosa-Alvarado BA, Guzi T, Lander GC. Human polymerase theta helicase positions DNA microhomologies for double-strand break repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591388. [PMID: 38712090 PMCID: PMC11071473 DOI: 10.1101/2024.04.26.591388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
DNA double-strand breaks occur in all human cells on a daily basis and must be repaired with high fidelity to minimize genomic instability1. Deficiencies in high-fidelity DNA repair by homologous recombination lead to dependence on DNA polymerase theta, which identifies DNA microhomologies in 3' single-stranded DNA overhangs and anneals them to initiate error-prone double-strand break repair. The resulting genomic instability is associated with numerous cancers, thereby making this polymerase an attractive therapeutic target2,3. However, despite the biomedical importance of polymerase theta, the molecular details of how it initiates DNA break repair remain unclear4,5. Here we present cryo-electron microscopy structures of the polymerase theta helicase domain bound to microhomology-containing DNA, revealing DNA-induced rearrangements of the helicase that enable DNA repair. Our structures show that DNA-bound helicase dimers facilitate a microhomology search that positions 3' single-stranded DNA ends in proximity to align complementary base pairs and anneal DNA microhomology. We define the molecular determinants that enable the polymerase theta helicase domain to identify and pair DNA microhomologies to initiate mutagenic DNA repair, providing mechanistic insights into therapeutic targeting of these interactions.
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Affiliation(s)
- Christopher J. Zerio
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
| | | | | | | | - Gabriel C. Lander
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
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Jones KM, Bryan A, McCunn E, Lantz PE, Blalock H, Ojeda IC, Mehta K, Cosper PF. The Causes and Consequences of DNA Damage and Chromosomal Instability Induced by Human Papillomavirus. Cancers (Basel) 2024; 16:1662. [PMID: 38730612 PMCID: PMC11083350 DOI: 10.3390/cancers16091662] [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: 03/31/2024] [Revised: 04/18/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024] Open
Abstract
High-risk human papillomaviruses (HPVs) are the main cause of cervical, oropharyngeal, and anogenital cancers, which are all treated with definitive chemoradiation therapy when locally advanced. HPV proteins are known to exploit the host DNA damage response to enable viral replication and the epithelial differentiation protocol. This has far-reaching consequences for the host genome, as the DNA damage response is critical for the maintenance of genomic stability. HPV+ cells therefore have increased DNA damage, leading to widespread genomic instability, a hallmark of cancer, which can contribute to tumorigenesis. Following transformation, high-risk HPV oncoproteins induce chromosomal instability, or chromosome missegregation during mitosis, which is associated with a further increase in DNA damage, particularly due to micronuclei and double-strand break formation. Thus, HPV induces significant DNA damage and activation of the DNA damage response in multiple contexts, which likely affects radiation sensitivity and efficacy. Here, we review how HPV activates the DNA damage response, how it induces chromosome missegregation and micronuclei formation, and discuss how these factors may affect radiation response. Understanding how HPV affects the DNA damage response in the context of radiation therapy may help determine potential mechanisms to improve therapeutic response.
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Affiliation(s)
- Kathryn M. Jones
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Ava Bryan
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Emily McCunn
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Pate E. Lantz
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
| | - Hunter Blalock
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
- University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Isabel C. Ojeda
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
- University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Kavi Mehta
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53705, USA
- Carbone Cancer Center, University of Wisconsin, Madison, WI 53705, USA
| | - Pippa F. Cosper
- Department of Human Oncology, University of Wisconsin, Madison, WI 53705, USA
- Carbone Cancer Center, University of Wisconsin, Madison, WI 53705, USA
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Fijen C, Drogalis Beckham L, Terino D, Li Y, Ramsden DA, Wood RD, Doublié S, Rothenberg E. Sequential requirements for distinct Polθ domains during theta-mediated end joining. Mol Cell 2024; 84:1460-1474.e6. [PMID: 38640894 PMCID: PMC11031631 DOI: 10.1016/j.molcel.2024.03.010] [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: 03/29/2023] [Revised: 01/10/2024] [Accepted: 03/12/2024] [Indexed: 04/21/2024]
Abstract
DNA polymerase θ (Polθ) plays a central role in a DNA double-strand break repair pathway termed theta-mediated end joining (TMEJ). TMEJ functions by pairing short-sequence "microhomologies" (MHs) in single-stranded DNA at each end of a break and subsequently initiating DNA synthesis. It is not known how the Polθ helicase domain (HD) and polymerase domain (PD) operate to bring together MHs and facilitate repair. To resolve these transient processes in real time, we utilized in vitro single-molecule FRET approaches and biochemical analyses. We find that the Polθ-HD mediates the initial capture of two ssDNA strands, bringing them in close proximity. The Polθ-PD binds and stabilizes pre-annealed MHs to form a synaptic complex (SC) and initiate repair synthesis. Individual synthesis reactions show that Polθ is inherently non-processive, accounting for complex mutational patterns during TMEJ. Binding of Polθ-PD to stem-loop-forming sequences can substantially limit synapsis, depending on the available dNTPs and sequence context.
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Affiliation(s)
- Carel Fijen
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA.
| | - Lea Drogalis Beckham
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Dante Terino
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Yuzhen Li
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Dale A Ramsden
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA.
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Stroik S, Luthman AJ, Ramsden DA. Templated insertions-DNA repair gets acrobatic. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2024; 65 Suppl 1:82-89. [PMID: 37438951 PMCID: PMC10962320 DOI: 10.1002/em.22564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/28/2023] [Accepted: 07/07/2023] [Indexed: 07/14/2023]
Abstract
Deletions associated with the repair of DNA double-strand breaks is a source of genetic alternation and a recognized source of disease-causing mutagenesis. Theta-mediated end joining is a DNA repair mechanism, which guarantees deletions by its employment of microhomology (MH) alignment to facilitate end joining. A lesser-characterized templated insertion ability of this pathway, on the other hand, is associated with both deletion and insertion. This mechanism is characterized by at least one round of polymerase θ-mediated synthesis, which does not result in successful repair, followed by a subsequent round of polymerase engagement and synthesis that does lead to repair. Here we focus on the mechanisms by which polymerase θ introduces these insertions-direct, inverse, and a new class which we have termed strand switching. We observe this new class of templated insertions at multiple loci and across multiple species, often at a comparable frequency to those previously characterized. Templated insertion mutations are often enriched in cancer genomes and repeat expansion disorders. This repair mechanism thus contributes to disease-associated mutagenesis, and may plausibly even promote disease. Characterization of the types of polymerase θ-dependent insertions can provide new insight into these diseases and clinical promise for treatment.
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Affiliation(s)
- Susanna Stroik
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Adam J. Luthman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill NC, USA
| | - Dale A. Ramsden
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Merker L, Feller L, Dorn A, Puchta H. Deficiency of both classical and alternative end-joining pathways leads to a synergistic defect in double-strand break repair but not to an increase in homology-dependent gene targeting in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:242-254. [PMID: 38179887 DOI: 10.1111/tpj.16604] [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: 04/03/2023] [Revised: 10/13/2023] [Accepted: 12/12/2023] [Indexed: 01/06/2024]
Abstract
In eukaryotes, double-strand breaks (DSBs) are either repaired by homologous recombination (HR) or non-homologous end-joining (NHEJ). In somatic plant cells, HR is very inefficient. Therefore, the vast majority of DSBs are repaired by two different pathways of NHEJ. The classical (cNHEJ) pathway depends on the heterodimer KU70/KU80, while polymerase theta (POLQ) is central to the alternative (aNHEJ) pathway. Surprisingly, Arabidopsis plants are viable, even when both pathways are impaired. However, they exhibit severe growth retardation and reduced fertility. Analysis of mitotic anaphases indicates that the double mutant is characterized by a dramatic increase in chromosome fragmentation due to defective DSB repair. In contrast to the single mutants, the double mutant was found to be highly sensitive to the DSB-inducing genotoxin bleomycin. Thus, both pathways can complement for each other efficiently in DSB repair. We speculated that in the absence of both NHEJ pathways, HR might be enhanced. This would be especially attractive for gene targeting (GT) in which predefined changes are introduced using a homologous template. Unexpectedly, the polq single mutant as well as the double mutant showed significantly lower GT frequencies in comparison to wildtype plants. Accordingly, we were able to show that elimination of both NHEJ pathways does not pose an attractive approach for Agrobacterium-mediated GT. However, our results clearly indicate that a loss of cNHEJ leads to an increase in GT frequency, which is especially drastic and attractive for practical applications, in which the in planta GT strategy is used.
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Affiliation(s)
- Laura Merker
- Joseph Gottlieb Kölreuter Institute for Plant Sciences, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Laura Feller
- Joseph Gottlieb Kölreuter Institute for Plant Sciences, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Annika Dorn
- Joseph Gottlieb Kölreuter Institute for Plant Sciences, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Holger Puchta
- Joseph Gottlieb Kölreuter Institute for Plant Sciences, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
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Ma L, Chen W, Yang M, Ha S, Xiong S, Zhu J, Xiang H, Luo G. Discovery and Proof of Concept of Potent Dual Polθ/PARP Inhibitors for Efficient Treatment of Homologous Recombination-Deficient Tumors. J Med Chem 2024; 67:3606-3625. [PMID: 38375763 DOI: 10.1021/acs.jmedchem.3c02096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
DNA polymerase theta (Polθ) has recently emerged as a new attractive synthetic lethal target involved in DNA damage repair. Inactivating Polθ alone or in combination with PARP inhibitors has demonstrated substantial therapeutic potential against tumors with homologous recombination (HR) defects such as alternation of BRCA genes. Herein, we report the design and proof of concept of a highly potent dual Polθ/PARP inhibitor 25d, which exhibited low nanomolar inhibitory activities against both Polθ and PARP1. Compared to combination treatment, 25d demonstrated superior antitumor efficacy in both MDA-MB-436 cells and xenografts by inducing more DNA damage and apoptosis. Importantly, 25d retained sensitivity in PARP inhibitor-resistant MDA-MB-436 cells with 53BP1 defect. Altogether, these findings illustrate the potential advantages of 25d, a first-in-class dual Polθ/PARP inhibitor, over monotherapy in treating HR-deficient tumors, including those with acquired PARP inhibitor resistance.
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Affiliation(s)
- Luyu Ma
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Wei Chen
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Ming Yang
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Si Ha
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Shuangshuang Xiong
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Jiacheng Zhu
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Hua Xiang
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Guoshun Luo
- State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, College of Pharmacy, China Pharmaceutical University, Nanjing 211198, P. R. China
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Sallmyr A, Bhandari SK, Naila T, Tomkinson AE. Mammalian DNA ligases; roles in maintaining genome integrity. J Mol Biol 2024; 436:168276. [PMID: 37714297 PMCID: PMC10843057 DOI: 10.1016/j.jmb.2023.168276] [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: 06/18/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/17/2023]
Abstract
The joining of breaks in the DNA phosphodiester backbone is essential for genome integrity. Breaks are generated during normal processes such as DNA replication, cytosine demethylation during differentiation, gene rearrangement in the immune system and germ cell development. In addition, they are generated either directly by a DNA damaging agent or indirectly due to damage excision during repair. Breaks are joined by a DNA ligase that catalyzes phosphodiester bond formation at DNA nicks with 3' hydroxyl and 5' phosphate termini. Three human genes encode ATP-dependent DNA ligases. These enzymes have a conserved catalytic core consisting of three subdomains that encircle nicked duplex DNA during ligation. The DNA ligases are targeted to different nuclear DNA transactions by specific protein-protein interactions. Both DNA ligase IIIα and DNA ligase IV form stable complexes with DNA repair proteins, XRCC1 and XRCC4, respectively. There is functional redundancy between DNA ligase I and DNA ligase IIIα in DNA replication, excision repair and single-strand break repair. Although DNA ligase IV is a core component of the major double-strand break repair pathway, non-homologous end joining, the other enzymes participate in minor, alternative double-strand break repair pathways. In contrast to the nucleus, only DNA ligase IIIα is present in mitochondria and is essential for maintaining the mitochondrial genome. Human immunodeficiency syndromes caused by mutations in either LIG1 or LIG4 have been described. Preclinical studies with DNA ligase inhibitors have identified potentially targetable abnormalities in cancer cells and evidence that DNA ligases are potential targets for cancer therapy.
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Affiliation(s)
- Annahita Sallmyr
- University of New Mexico Comprehensive Cancer Center and the Departments of Internal Medicine, and Molecular Genetics & Microbiology, University of New Mexico Health Sciences Center, United States
| | - Seema Khattri Bhandari
- University of New Mexico Comprehensive Cancer Center and the Departments of Internal Medicine, and Molecular Genetics & Microbiology, University of New Mexico Health Sciences Center, United States
| | - Tasmin Naila
- University of New Mexico Comprehensive Cancer Center and the Departments of Internal Medicine, and Molecular Genetics & Microbiology, University of New Mexico Health Sciences Center, United States
| | - Alan E Tomkinson
- University of New Mexico Comprehensive Cancer Center and the Departments of Internal Medicine, and Molecular Genetics & Microbiology, University of New Mexico Health Sciences Center, United States.
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12
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Hinch R, Donnelly P, Hinch AG. Meiotic DNA breaks drive multifaceted mutagenesis in the human germ line. Science 2023; 382:eadh2531. [PMID: 38033082 PMCID: PMC7615360 DOI: 10.1126/science.adh2531] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 09/29/2023] [Indexed: 12/02/2023]
Abstract
Meiotic recombination commences with hundreds of programmed DNA breaks; however, the degree to which they are accurately repaired remains poorly understood. We report that meiotic break repair is eightfold more mutagenic for single-base substitutions than was previously understood, leading to de novo mutation in one in four sperm and one in 12 eggs. Its impact on indels and structural variants is even higher, with 100- to 1300-fold increases in rates per break. We uncovered new mutational signatures and footprints relative to break sites, which implicate unexpected biochemical processes and error-prone DNA repair mechanisms, including translesion synthesis and end joining in meiotic break repair. We provide evidence that these mechanisms drive mutagenesis in human germ lines and lead to disruption of hundreds of genes genome wide.
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Affiliation(s)
- Robert Hinch
- Big Data Institute, University of Oxford; Oxford, UK
| | - Peter Donnelly
- Wellcome Centre for Human Genetics, University of Oxford; Oxford, UK
- Genomics plc; Oxford, UK
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13
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Godneeva B, Fejes Tóth K, Quan B, Chou TF, Aravin AA. Impact of Germline Depletion of Bonus on Chromatin State in Drosophila Ovaries. Cells 2023; 12:2629. [PMID: 37998364 PMCID: PMC10670193 DOI: 10.3390/cells12222629] [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: 10/18/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023] Open
Abstract
Gene expression is controlled via complex regulatory mechanisms involving transcription factors, chromatin modifications, and chromatin regulatory factors. Histone modifications, such as H3K27me3, H3K9ac, and H3K27ac, play an important role in controlling chromatin accessibility and transcriptional output. In vertebrates, the Transcriptional Intermediary Factor 1 (TIF1) family of proteins play essential roles in transcription, cell differentiation, DNA repair, and mitosis. Our study focused on Bonus, the sole member of the TIF1 family in Drosophila, to investigate its role in organizing epigenetic modifications. Our findings demonstrated that depleting Bonus in ovaries leads to a mild reduction in the H3K27me3 level over transposon regions and alters the distribution of active H3K9ac marks on specific protein-coding genes. Additionally, through mass spectrometry analysis, we identified novel interacting partners of Bonus in ovaries, such as PolQ, providing a comprehensive understanding of the associated molecular pathways. Furthermore, our research revealed Bonus's interactions with the Polycomb Repressive Complex 2 and its co-purification with select histone acetyltransferases, shedding light on the underlying mechanisms behind these changes in chromatin modifications.
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Affiliation(s)
- Baira Godneeva
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Katalin Fejes Tóth
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Baiyi Quan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Tsui-Fen Chou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alexei A. Aravin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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14
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Thomas C, Avalos-Irving L, Victorino J, Green S, Andrews M, Rodrigues N, Ebirim S, Mudd A, Towle-Weicksel JB. Melanoma-derived DNA polymerase theta variants exhibit altered DNA polymerase activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.566933. [PMID: 38014040 PMCID: PMC10680777 DOI: 10.1101/2023.11.14.566933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
DNA Polymerase θ (Pol θ or POLQ) is primarily involved in repairing double-stranded breaks in DNA through the alternative pathway known as microhomology-mediated end joining (MMEJ) or theta-mediated end joining (TMEJ). Unlike other DNA repair polymerases, Pol θ is thought to be highly error prone, yet critical for cell survival. We have identified several mutations in the POLQ gene from human melanoma tumors. Through biochemical analysis, we have demonstrated that all three cancer-associated variants experienced altered DNA polymerase activity including a propensity for incorrect nucleotide selection and reduced polymerization rates compared to WT Pol θ. Moreover, the variants are 30 fold less efficient at incorporating a nucleotide during repair and up to 70 fold less accurate at selecting the correct nucleotide opposite a templating base. Taken together, this suggests that aberrant Pol θ has reduced DNA repair capabilities and may also contribute to increased mutagenesis. While this may be beneficial to normal cell survival, the variants were identified in established tumors suggesting that cancer cells may use this promiscuous polymerase to its advantage to promote metastasis and drug resistance.
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15
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Syed A, Filandr F, Patterson-Fortin J, Bacolla A, Ravindranathan R, Zhou J, McDonald D, Albuhluli M, Verway-Cohen A, Newman J, Tsai MS, Jones D, Schriemer D, D’Andrea A, Tainer J. Novobiocin blocks nucleic acid binding to Polθ and inhibits stimulation of its ATPase activity. Nucleic Acids Res 2023; 51:9920-9937. [PMID: 37665033 PMCID: PMC10570058 DOI: 10.1093/nar/gkad727] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/10/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023] Open
Abstract
Polymerase theta (Polθ) acts in DNA replication and repair, and its inhibition is synthetic lethal in BRCA1 and BRCA2-deficient tumor cells. Novobiocin (NVB) is a first-in-class inhibitor of the Polθ ATPase activity, and it is currently being tested in clinical trials as an anti-cancer drug. Here, we investigated the molecular mechanism of NVB-mediated Polθ inhibition. Using hydrogen deuterium exchange-mass spectrometry (HX-MS), biophysical, biochemical, computational and cellular assays, we found NVB is a non-competitive inhibitor of ATP hydrolysis. NVB sugar group deletion resulted in decreased potency and reduced HX-MS interactions, supporting a specific NVB binding orientation. Collective results revealed that NVB binds to an allosteric site to block DNA binding, both in vitro and in cells. Comparisons of The Cancer Genome Atlas (TCGA) tumors and matched controls implied that POLQ upregulation in tumors stems from its role in replication stress responses to increased cell proliferation: this can now be tested in fifteen tumor types by NVB blocking ssDNA-stimulation of ATPase activity, required for Polθ function at replication forks and DNA damage sites. Structural and functional insights provided in this study suggest a path for developing NVB derivatives with improved potency for Polθ inhibition by targeting ssDNA binding with entropically constrained small molecules.
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Affiliation(s)
- Aleem Syed
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Frantisek Filandr
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jeffrey Patterson-Fortin
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ramya Ravindranathan
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Jia Zhou
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Drew T McDonald
- Biological and System Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Mohammed E Albuhluli
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Amy Verway-Cohen
- Biological and System Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Joseph A Newman
- Center for Medicines Discovery, University of Oxford, OX1 3QU, UK
| | - Miaw-Sheue Tsai
- Biological and System Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Darin E Jones
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - David C Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Alan D D’Andrea
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - John A Tainer
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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16
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Akash S, Bayıl I, Hossain MS, Islam MR, Hosen ME, Mekonnen AB, Nafidi HA, Bin Jardan YA, Bourhia M, Bin Emran T. Novel computational and drug design strategies for inhibition of human papillomavirus-associated cervical cancer and DNA polymerase theta receptor by Apigenin derivatives. Sci Rep 2023; 13:16565. [PMID: 37783745 PMCID: PMC10545697 DOI: 10.1038/s41598-023-43175-x] [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: 05/05/2023] [Accepted: 09/20/2023] [Indexed: 10/04/2023] Open
Abstract
The present study deals with the advanced in-silico analyses of several Apigenin derivatives to explore human papillomavirus-associated cervical cancer and DNA polymerase theta inhibitor properties by molecular docking, molecular dynamics, QSAR, drug-likeness, PCA, a dynamic cross-correlation matrix and quantum calculation properties. The initial literature study revealed the potent antimicrobial and anticancer properties of Apigenin, prompting the selection of its potential derivatives to investigate their abilities as inhibitors of human papillomavirus-associated cervical cancer and DNA polymerase theta. In silico molecular docking was employed to streamline the findings, revealing promising energy-binding interactions between all Apigenin derivatives and the targeted proteins. Notably, Apigenin 4'-O-Rhamnoside and Apigenin-4'-Alpha-L-Rhamnoside demonstrated higher potency against the HPV45 oncoprotein E7 (PDB ID 2EWL), while Apigenin and Apigenin 5-O-Beta-D-Glucopyranoside exhibited significant binding energy against the L1 protein in humans. Similarly, a binding affinity range of - 7.5 kcal/mol to - 8.8 kcal/mol was achieved against DNA polymerase theta, indicating the potential of Apigenin derivatives to inhibit this enzyme (PDB ID 8E23). This finding was further validated through molecular dynamic simulation for 100 ns, analyzing parameters such as RMSD, RMSF, SASA, H-bond, and RoG profiles. The results demonstrated the stability of the selected compounds during the simulation. After passing the stability testing, the compounds underwent screening for ADMET, pharmacokinetics, and drug-likeness properties, fulfilling all the necessary criteria. QSAR, PCA, dynamic cross-correlation matrix, and quantum calculations were conducted, yielding satisfactory outcomes. Since this study utilized in silico computational approaches and obtained outstanding results, further validation is crucial. Therefore, additional wet-lab experiments should be conducted under in vivo and in vitro conditions to confirm the findings.
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Affiliation(s)
- Shopnil Akash
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Birulia, Ashulia, Dhaka, 1216, Bangladesh.
| | - Imren Bayıl
- Department of Bioinformatics and Computational Biology, Gaziantep University, Gaziantep, Turkey
| | - Md Saddam Hossain
- Department of Biomedical Engineering, Faculty of Engineering & Technology, Islamic University, Kushtia, Bangladesh
| | - Md Rezaul Islam
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Birulia, Ashulia, Dhaka, 1216, Bangladesh
| | - Md Eram Hosen
- Professor Joarder DNA and Chromosome Research Laboratory, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | | | - Hiba-Allah Nafidi
- Department of Food Science, Faculty of Agricultural and Food Sciences, Laval University, 2325, Quebec City, QC, G1V 0A6, Canada
| | - Yousef A Bin Jardan
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed Bourhia
- Department of Chemistry and Biochemistry, Faculty of Medicine and Pharmacy, Ibn Zohr University, 70000, Laayoune, Morocco
| | - Talha Bin Emran
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School & Legorreta Cancer Center, Brown University, Providence, RI 02912, United States.
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17
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Brambati A, Sacco O, Porcella S, Heyza J, Kareh M, Schmidt JC, Sfeir A. RHINO directs MMEJ to repair DNA breaks in mitosis. Science 2023; 381:653-660. [PMID: 37440612 PMCID: PMC10561558 DOI: 10.1126/science.adh3694] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/30/2023] [Indexed: 07/15/2023]
Abstract
Nonhomologous end-joining (NHEJ) and homologous recombination (HR) are the primary pathways for repairing DNA double-strand breaks (DSBs) during interphase, whereas microhomology-mediated end-joining (MMEJ) has been regarded as a backup mechanism. Through CRISPR-Cas9-based synthetic lethal screens in cancer cells, we identified subunits of the 9-1-1 complex (RAD9A-RAD1-HUS1) and its interacting partner, RHINO, as crucial MMEJ factors. We uncovered an unexpected function for RHINO in restricting MMEJ to mitosis. RHINO accumulates in M phase, undergoes Polo-like kinase 1 (PLK1) phosphorylation, and interacts with polymerase θ (Polθ), enabling its recruitment to DSBs for subsequent repair. Additionally, we provide evidence that MMEJ activity in mitosis repairs persistent DSBs that originate in S phase. Our findings offer insights into the synthetic lethal relationship between the genes POLQ and BRCA1 and BRAC2 and the synergistic effect of Polθ and poly(ADP-ribose) polymerase (PARP) inhibitors.
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Affiliation(s)
- Alessandra Brambati
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center; New York, NY, USA
| | - Olivia Sacco
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center; New York, NY, USA
| | - Sarina Porcella
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center; New York, NY, USA
| | - Joshua Heyza
- Institute for Quantitative Health Sciences and Engineering, Michigan State University; East Lansing, MI, USA
- Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University; East Lansing, MI, USA
| | - Mike Kareh
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center; New York, NY, USA
| | - Jens C. Schmidt
- Institute for Quantitative Health Sciences and Engineering, Michigan State University; East Lansing, MI, USA
- Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University; East Lansing, MI, USA
| | - Agnel Sfeir
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center; New York, NY, USA
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18
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Sengupta A, Das K, Jha N, Akhter Y, Kumar A. Molecular evolution steered structural adaptations in the DNA polymerase III α subunit of halophilic bacterium Salinibacter ruber. Extremophiles 2023; 27:20. [PMID: 37481762 DOI: 10.1007/s00792-023-01306-2] [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: 03/14/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023]
Abstract
A significant portion of the earth has a salty environment, and the literature on bacterial survival mechanisms in salty environments is limited. During molecular evolution, halophiles increase acidic amino acid residues on their protein surfaces which leads to a negatively charged surface potential that helps them to maintain the protein integrity and protect them from denaturation by competing with salt ions. Through protein family analysis, we have investigated the molecular-level adaptive features of DNA polymerase III's catalytic subunit (alpha) and its structure-function relationship. This study throws light on the novel understanding of halophilic bacterial replication and the molecular basis of salt adaptation. Comparisons of the amino acid contents and electronegativity of halophilic and mesophilic bacterial proteins revealed adaptations that allow halophilic bacteria to thrive in high salt concentrations. A significantly lower isoelectric point of halophilic bacterial proteins indicates the acidic nature. Also, an abundance of disordered regions in halophiles suggests the requirement of the salt ions that play a crucial role in their stable protein folding. Despite having similar topology, mesophilic and halophilic proteins, a set of very prominent molecular modifications was observed in the alpha subunit of halophiles.
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Affiliation(s)
- Aveepsa Sengupta
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India
| | - Kunwali Das
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India
| | - Nidhi Jha
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India
| | - Yusuf Akhter
- Department of Biotechnology, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226025, India.
| | - Ashutosh Kumar
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India.
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19
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Ravindran F, Jain A, Desai S, Menon N, Srivastava K, Bawa PS, Sateesh K, Srivatsa N, Raghunath SK, Srinivasan S, Choudhary B. Whole-exome sequencing of Indian prostate cancer reveals a novel therapeutic target: POLQ. J Cancer Res Clin Oncol 2023; 149:2451-2462. [PMID: 35737091 DOI: 10.1007/s00432-022-04111-0] [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: 04/21/2022] [Accepted: 06/03/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE Prostate cancer is the second most common cancer diagnosed worldwide and the third most common cancer among men in India. This study's objective was to characterise the mutational landscape of Indian prostate cancer using whole-exome sequencing to identify population-specific polymorphisms. METHODS Whole-exome sequencing was performed of 58 treatment-naive primary prostate tumors of Indian origin. Multiple computational and statistical analyses were used to profile the known common mutations, other deleterious mutations, driver genes, prognostic biomarkers, and gene signatures unique to each clinical parameter. Cox analysis was performed to validate survival-associated genes. McNemar test identified genes significant to recurrence and receiver-operating characteristic (ROC) analysis was conducted to determine its accuracy. OncodriveCLUSTL algorithm was used to deduce driver genes. The druggable target identified was modeled with its known inhibitor using Autodock. RESULTS TP53 was the most commonly mutated gene in our cohort. Three novel deleterious variants unique to the Indian prostate cancer subtype were identified: POLQ, FTHL17, and OR8G1. COX regression analysis identified ACSM5, a mitochondrial gene responsible for survival. CYLC1 gene, which encodes for sperm head cytoskeletal protein, was identified as an unfavorable prognostic biomarker indicative of recurrence. The novel POLQ mutant, also identified as a driver gene, was evaluated as the druggable target in this study. POLQ, a DNA repair enzyme implicated in various cancer types, is overexpressed and is associated with a poor prognosis. The mutant POLQ was subjected to structural analysis and modeled with its known inhibitor novobiocin resulting in decreased binding efficiency necessitating the development of a better drug. CONCLUSION In this pilot study, the molecular profiling using multiple computational and statistical analyses revealed distinct polymorphisms in the Indian prostate cancer cohort. The mutational signatures identified provide a valuable resource for prognostic stratification and targeted treatment strategies for Indian prostate cancer patients. The DNA repair enzyme, POLQ, was identified as the druggable target in this study.
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Affiliation(s)
- Febina Ravindran
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India
| | - Anika Jain
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India
| | - Sagar Desai
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India
- Manipal Academy of Higher Education, Manipal, India
| | - Navjoth Menon
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India
| | - Kriti Srivastava
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India
| | - Pushpinder Singh Bawa
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India
| | - K Sateesh
- Healthcare Global Enterprises Ltd, Cancer Centre, Bangalore, India
| | - N Srivatsa
- Healthcare Global Enterprises Ltd, Cancer Centre, Bangalore, India
| | - S K Raghunath
- Healthcare Global Enterprises Ltd, Cancer Centre, Bangalore, India
| | - Subhashini Srinivasan
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronic City Phase 1, Bangalore, Karnataka, India.
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20
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Pismataro MC, Astolfi A, Barreca ML, Pacetti M, Schenone S, Bandiera T, Carbone A, Massari S. Small Molecules Targeting DNA Polymerase Theta (POLθ) as Promising Synthetic Lethal Agents for Precision Cancer Therapy. J Med Chem 2023; 66:6498-6522. [PMID: 37134182 DOI: 10.1021/acs.jmedchem.2c02101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Synthetic lethality (SL) is an innovative strategy in targeted anticancer therapy that exploits tumor genetic vulnerabilities. This topic has come to the forefront in recent years, as witnessed by the increased number of publications since 2007. The first proof of concept for the effectiveness of SL was provided by the approval of poly(ADP-ribose)polymerase inhibitors, which exploit a SL interaction in BRCA-deficient cells, although their use is limited by resistance. Searching for additional SL interactions involving BRCA mutations, the DNA polymerase theta (POLθ) emerged as an exciting target. This review summarizes, for the first time, the POLθ polymerase and helicase inhibitors reported to date. Compounds are described focusing on chemical structure and biological activity. With the aim to enable further drug discovery efforts in interrogating POLθ as a target, we propose a plausible pharmacophore model for POLθ-pol inhibitors and provide a structural analysis of the known POLθ ligand binding sites.
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Affiliation(s)
- Maria Chiara Pismataro
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Andrea Astolfi
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Maria Letizia Barreca
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Martina Pacetti
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Silvia Schenone
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy
| | - Tiziano Bandiera
- D3 PharmaChemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Anna Carbone
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy
| | - Serena Massari
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
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21
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Rogers CB, Kram RE, Lin K, Myers CL, Sobeck A, Hendrickson EA, Bielinsky AK. Fanconi anemia-associated chromosomal radial formation is dependent on POLθ-mediated alternative end joining. Cell Rep 2023; 42:112428. [PMID: 37086407 DOI: 10.1016/j.celrep.2023.112428] [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: 10/13/2022] [Revised: 01/25/2023] [Accepted: 04/07/2023] [Indexed: 04/23/2023] Open
Abstract
Activation of the Fanconi anemia (FA) pathway after treatment with mitomycin C (MMC) is essential for preventing chromosome translocations termed "radials." When replication forks stall at MMC-induced interstrand crosslinks (ICLs), the FA pathway is activated to orchestrate ICL unhooking and repair of the DNA break intermediates. However, in FA-deficient cells, how ICL-associated breaks are resolved in a manner that leads to radials is unclear. Here, we demonstrate that MMC-induced radials are dependent on DNA polymerase theta (POLθ)-mediated alternative end joining (A-EJ). Specifically, we show that radials observed in FANCD2-/- cells are dependent on POLθ and DNA ligase III and occur independently of classical non-homologous end joining. Furthermore, treatment of FANCD2-/- cells with POLθ inhibitors abolishes radials and leads to the accumulation of breaks co-localizing with common fragile sites. Uniformly, these observations implicate A-EJ in radial formation and provide mechanistic insights into the treatment of FA pathway-deficient cancers with POLθ inhibitors.
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Affiliation(s)
- Colette B Rogers
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rachel E Kram
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kevin Lin
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alexandra Sobeck
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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22
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Yi G, Sung Y, Kim C, Ra JS, Hirakawa H, Kato T, Fujimori A, Kim H, Takata KI. DNA polymerase θ-mediated repair of high LET radiation-induced complex DNA double-strand breaks. Nucleic Acids Res 2023; 51:2257-2269. [PMID: 36805268 PMCID: PMC10018357 DOI: 10.1093/nar/gkad076] [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: 07/19/2022] [Revised: 01/21/2023] [Accepted: 01/25/2023] [Indexed: 02/22/2023] Open
Abstract
DNA polymerase θ (POLQ) is a unique DNA polymerase that is able to perform microhomology-mediated end-joining as well as translesion synthesis (TLS) across an abasic (AP) site and thymine glycol (Tg). However, the biological significance of the TLS activity is currently unknown. Herein we provide evidence that the TLS activity of POLQ plays a critical role in repairing complex DNA double-strand breaks (DSBs) induced by high linear energy transfer (LET) radiation. Radiotherapy with high LET radiation such as carbon ions leads to more deleterious biological effects than corresponding doses of low LET radiation such as X-rays. High LET-induced DSBs are considered to be complex, carrying additional DNA damage such as AP site and Tg in close proximity to the DSB sites. However, it is not clearly understood how complex DSBs are processed in mammalian cells. We demonstrated that genetic disruption of POLQ results in an increase of chromatid breaks and enhanced cellular sensitivity following treatment with high LET radiation. At the biochemical level, POLQ was able to bypass an AP site and Tg during end-joining and was able to anneal two single-stranded DNA tails when DNA lesions were located outside the microhomology. This study offers evidence that POLQ is directly involved in the repair of complex DSBs.
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Affiliation(s)
- Geunil Yi
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Yubin Sung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Chanwoo Kim
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Hirokazu Hirakawa
- Department of Charged Particle Therapy Research, Institute for Quantum Medical Science, Chiba 263-8555, Japan
| | - Takamitsu A Kato
- Department of Environmental & Radiological Health Sciences, Colorado State University, Colorado 80523, USA
| | - Akira Fujimori
- Department of Charged Particle Therapy Research, Institute for Quantum Medical Science, Chiba 263-8555, Japan
| | - Hajin Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Kei-ichi Takata
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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23
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Brambati A, Sacco O, Porcella S, Heyza J, Kareh M, Schmidt JC, Sfeir A. RHINO restricts MMEJ activity to mitosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.16.532763. [PMID: 36993461 PMCID: PMC10055031 DOI: 10.1101/2023.03.16.532763] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
DNA double-strand breaks (DSBs) are toxic lesions that can lead to genome instability if not properly repaired. Breaks incurred in G1 phase of the cell cycle are predominantly fixed by non-homologous end-joining (NHEJ), while homologous recombination (HR) is the primary repair pathway in S and G2. Microhomology-mediated end-joining (MMEJ) is intrinsically error-prone and considered a backup DSB repair pathway that becomes essential when HR and NHEJ are compromised. In this study, we uncover MMEJ as the major DSB repair pathway in M phase. Using CRISPR/Cas9-based synthetic lethal screens, we identify subunits of the 9-1-1 complex (RAD9A-HUS1-RAD1) and its interacting partner, RHINO, as critical MMEJ factors. Mechanistically, we show that the function of 9-1-1 and RHINO in MMEJ is inconsistent with their well-established role in ATR signaling. Instead, RHINO plays an unexpected and essential role in directing mutagenic repair to M phase by directly binding to Polymerase theta (Polθ) and promoting its recruitment to DSBs in mitosis. In addition, we provide evidence that mitotic MMEJ repairs persistent DNA damage that originates in S phase but is not repaired by HR. The latter findings could explain the synthetic lethal relationship between POLQ and BRCA1/2 and the synergistic effect of Polθ and PARP inhibitors. In summary, our study identifies MMEJ as the primary pathway for repairing DSBs during mitosis and highlights an unanticipated role for RHINO in directing mutagenic repair to M phase.
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24
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Multifaceted Nature of DNA Polymerase θ. Int J Mol Sci 2023; 24:ijms24043619. [PMID: 36835031 PMCID: PMC9962433 DOI: 10.3390/ijms24043619] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/26/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023] Open
Abstract
DNA polymerase θ belongs to the A family of DNA polymerases and plays a key role in DNA repair and damage tolerance, including double-strand break repair and DNA translesion synthesis. Pol θ is often overexpressed in cancer cells and promotes their resistance to chemotherapeutic agents. In this review, we discuss unique biochemical properties and structural features of Pol θ, its multiple roles in protection of genome stability and the potential of Pol θ as a target for cancer treatment.
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25
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Patterson-Fortin J, D'Andrea AD. Targeting Polymerase Theta (POLθ) for Cancer Therapy. Cancer Treat Res 2023; 186:285-298. [PMID: 37978141 DOI: 10.1007/978-3-031-30065-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Polymerase theta (POLθ) is the critical multi-domain enzyme in microhomology-mediated end-joining DNA double-stranded break repair. POLθ is expressed at low levels in normal tissue but is often overexpressed in cancers, especially in DNA repair deficient cancers, such as homologous-recombination cancers, rendering them exquisitely sensitive to POLθ inhibition secondary to synthetic lethality. Development of POLθ inhibitors is an active area of investigation with inhibitors of the N-terminal helicase domain or the C-terminal polymerase domain currently in clinical trial. Here, we review POLθ-mediated microhomology-mediated end-joining, the development of POLθ inhibitors, and the potential clinical uses of POLθ inhibitors.
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Affiliation(s)
- Jeffrey Patterson-Fortin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
- Harvard Medical School, Center for DNA Damage and Repair, Susan F. Smith Center for Women's Cancers (SFSCWC), The Fuller-American Cancer Society, Dana-Farber Cancer Institute, HIM 243, 450 Brookline Ave., Boston, MA, 02215, USA.
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26
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Abstract
DNA polymerase θ (Pol θ) is a DNA repair enzyme widely conserved in animals and plants. Pol θ uses short DNA sequence homologies to initiate repair of double-strand breaks by theta-mediated end joining. The DNA polymerase domain of Pol θ is at the C terminus and is connected to an N-terminal DNA helicase-like domain by a central linker. Pol θ is crucial for maintenance of damaged genomes during development, protects DNA against extensive deletions, and limits loss of heterozygosity. The cost of using Pol θ for genome protection is that a few nucleotides are usually deleted or added at the repair site. Inactivation of Pol θ often enhances the sensitivity of cells to DNA strand-breaking chemicals and radiation. Since some homologous recombination-defective cancers depend on Pol θ for growth, inhibitors of Pol θ may be useful in treating such tumors.
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Affiliation(s)
- Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, Texas, USA;
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA;
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27
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Mann A, Ramirez-Otero MA, De Antoni A, Hanthi YW, Sannino V, Baldi G, Falbo L, Schrempf A, Bernardo S, Loizou J, Costanzo V. POLθ prevents MRE11-NBS1-CtIP-dependent fork breakage in the absence of BRCA2/RAD51 by filling lagging-strand gaps. Mol Cell 2022; 82:4218-4231.e8. [PMID: 36400008 DOI: 10.1016/j.molcel.2022.09.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/16/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022]
Abstract
POLθ promotes repair of DNA double-strand breaks (DSBs) resulting from collapsed forks in homologous recombination (HR) defective tumors. Inactivation of POLθ results in synthetic lethality with the loss of HR genes BRCA1/2, which induces under-replicated DNA accumulation. However, it is unclear whether POLθ-dependent DNA replication prevents HR-deficiency-associated lethality. Here, we isolated Xenopus laevis POLθ and showed that it processes stalled Okazaki fragments, directly visualized by electron microscopy, thereby suppressing ssDNA gaps accumulating on lagging strands in the absence of RAD51 and preventing fork reversal. Inhibition of POLθ DNA polymerase activity leaves fork gaps unprotected, enabling their cleavage by the MRE11-NBS1-CtIP endonuclease, which produces broken forks with asymmetric single-ended DSBs, hampering BRCA2-defective cell survival. These results reveal a POLθ-dependent genome protection function preventing stalled forks rupture and highlight possible resistance mechanisms to POLθ inhibitors.
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Affiliation(s)
- Anjali Mann
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Miguel Angel Ramirez-Otero
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Anna De Antoni
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Yodhara Wijesekara Hanthi
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Vincenzo Sannino
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Giorgio Baldi
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Lucia Falbo
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Anna Schrempf
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | - Sara Bernardo
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | - Joanna Loizou
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | - Vincenzo Costanzo
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy.
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28
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Baxter JS, Zatreanu D, Pettitt SJ, Lord CJ. Resistance to DNA repair inhibitors in cancer. Mol Oncol 2022; 16:3811-3827. [PMID: 35567571 PMCID: PMC9627783 DOI: 10.1002/1878-0261.13224] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/25/2022] [Accepted: 05/12/2022] [Indexed: 12/24/2022] Open
Abstract
The DNA damage response (DDR) represents a complex network of proteins which detect and repair DNA damage, thereby maintaining the integrity of the genome and preventing the transmission of mutations and rearranged chromosomes to daughter cells. Faults in the DDR are a known driver and hallmark of cancer. Furthermore, inhibition of DDR enzymes can be used to treat the disease. This is exemplified by PARP inhibitors (PARPi) used to treat cancers with defects in the homologous recombination DDR pathway. A series of novel DDR targets are now also under pre-clinical or clinical investigation, including inhibitors of ATR kinase, WRN helicase or the DNA polymerase/helicase Polθ (Pol-Theta). Drug resistance is a common phenomenon that impairs the overall effectiveness of cancer treatments and there is already some understanding of how resistance to PARPi occurs. Here, we discuss how an understanding of PARPi resistance could inform how resistance to new drugs targeting the DDR emerges. We also discuss potential strategies that could limit the impact of these therapy resistance mechanisms in cancer.
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Affiliation(s)
- Joseph S. Baxter
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
| | - Diana Zatreanu
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
| | - Stephen J. Pettitt
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
| | - Christopher J. Lord
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
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29
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Liddiard K, Aston-Evans AN, Cleal K, Hendrickson E, Baird D. POLQ suppresses genome instability and alterations in DNA repeat tract lengths. NAR Cancer 2022; 4:zcac020. [PMID: 35774233 PMCID: PMC9241439 DOI: 10.1093/narcan/zcac020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/19/2022] [Accepted: 06/10/2022] [Indexed: 11/26/2022] Open
Abstract
DNA polymerase theta (POLQ) is a principal component of the alternative non-homologous end-joining (ANHEJ) DNA repair pathway that ligates DNA double-strand breaks. Utilizing independent models of POLQ insufficiency during telomere-driven crisis, we found that POLQ - /- cells are resistant to crisis-induced growth deceleration despite sustaining inter-chromosomal telomere fusion frequencies equivalent to wild-type (WT) cells. We recorded longer telomeres in POLQ - / - than WT cells pre- and post-crisis, notwithstanding elevated total telomere erosion and fusion rates. POLQ - /- cells emerging from crisis exhibited reduced incidence of clonal gross chromosomal abnormalities in accordance with increased genetic heterogeneity. High-throughput sequencing of telomere fusion amplicons from POLQ-deficient cells revealed significantly raised frequencies of inter-chromosomal fusions with correspondingly depreciated intra-chromosomal recombinations. Long-range interactions culminating in telomere fusions with centromere alpha-satellite repeats, as well as expansions in HSAT2 and HSAT3 satellite and contractions in ribosomal DNA repeats, were detected in POLQ - / - cells. In conjunction with the expanded telomere lengths of POLQ - /- cells, these results indicate a hitherto unrealized capacity of POLQ for regulation of repeat arrays within the genome. Our findings uncover novel considerations for the efficacy of POLQ inhibitors in clinical cancer interventions, where potential genome destabilizing consequences could drive clonal evolution and resistant disease.
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Affiliation(s)
- Kate Liddiard
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
| | - Alys N Aston-Evans
- Dementia Research Institute, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK
| | - Kez Cleal
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Duncan M Baird
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
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30
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Drzewiecka M, Barszczewska-Pietraszek G, Czarny P, Skorski T, Śliwiński T. Synthetic Lethality Targeting Polθ. Genes (Basel) 2022; 13:genes13061101. [PMID: 35741863 PMCID: PMC9223150 DOI: 10.3390/genes13061101] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/06/2022] [Accepted: 06/11/2022] [Indexed: 01/27/2023] Open
Abstract
Research studies regarding synthetic lethality (SL) in human cells are primarily motivated by the potential of this phenomenon to be an effective, but at the same time, safe to the patient's anti-cancer chemotherapy. Among the factors that are targets for the induction of the synthetic lethality effect, those involved in DNA repair seem to be the most relevant. Specifically, when mutation in one of the canonical DNA double-strand break (DSB) repair pathways occurs, which is a frequent event in cancer cells, the alternative pathways may be a promising target for the elimination of abnormal cells. Currently, inhibiting RAD52 and/or PARP1 in the tumor cells that are deficient in the canonical repair pathways has been the potential target for inducing the effect of synthetic lethality. Unfortunately, the development of resistance to commonly used PARP1 inhibitors (PARPi) represents the greatest obstacle to working out a successful treatment protocol. DNA polymerase theta (Polθ), encoded by the POLQ gene, plays a key role in an alternative DSB repair pathway-theta-mediated end joining (TMEJ). Thus, it is a promising target in the treatment of tumors harboring deficiencies in homologous recombination repair (HRR), where its inhibition can induce SL. In this review, the authors discuss the current state of knowledge on Polθ as a potential target for synthetic lethality-based anticancer therapies.
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Affiliation(s)
- Małgorzata Drzewiecka
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland; (M.D.); (G.B.-P.)
| | - Gabriela Barszczewska-Pietraszek
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland; (M.D.); (G.B.-P.)
| | - Piotr Czarny
- Department of Medical Biochemistry, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Tomasz Skorski
- Fels Cancer Institute for Personalized Medicine, Departament of Cancer and Cellular Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
- Correspondence: (T.S.); (T.Ś.); Tel.: +1-215-707-9157 (T.S.); +48-42-635-44-86 (T.Ś.)
| | - Tomasz Śliwiński
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland; (M.D.); (G.B.-P.)
- Correspondence: (T.S.); (T.Ś.); Tel.: +1-215-707-9157 (T.S.); +48-42-635-44-86 (T.Ś.)
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31
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Vanson S, Li Y, Wood RD, Doublié S. Probing the structure and function of polymerase θ helicase-like domain. DNA Repair (Amst) 2022; 116:103358. [PMID: 35753097 PMCID: PMC10329254 DOI: 10.1016/j.dnarep.2022.103358] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/09/2022] [Accepted: 06/09/2022] [Indexed: 11/19/2022]
Abstract
DNA Polymerase θ is the key actuator of the recently identified double-strand break repair pathway, theta-mediated end joining (TMEJ). It is the only known polymerase to have a 3-domain architecture containing an independently functional family A DNA polymerase tethered by a long central region to an N-terminal helicase-like domain (HLD). Full-length polymerase θ and the isolated HLD hydrolyze ATP in the presence of DNA, but no processive DNA duplex unwinding has been observed. Based on sequence and structure conservation, the HLD is classified as a member of helicase superfamily II and, more specifically, the Ski2-like family. The specific subdomain composition and organization most closely resemble that of archaeal DNA repair helicases Hel308 and Hjm. The underlying structural basis as to why the HLD is not able to processively unwind duplex DNA, despite its similarity to bona fide helicases, remains elusive. Activities of the HLD include ATP hydrolysis, protein displacement, and annealing of complementary DNA. These observations have led to speculation about the role of the HLD within the context of double-strand break repair via TMEJ, such as removal of single-stranded DNA binding proteins like RPA and RAD51 and microhomology alignment. This review summarizes the structural classification and organization of the polymerase θ HLD and its homologs and explores emerging data on its biochemical activities. We conclude with a simple, speculative model for the HLD's role in TMEJ.
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Affiliation(s)
- Scott Vanson
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA
| | - Yuzhen Li
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX 77230, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX 77230, USA.
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA.
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32
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Bai W, Zhao B, Gu M, Dong J. Alternative end-joining in BCR gene rearrangements and translocations. Acta Biochim Biophys Sin (Shanghai) 2022; 54:782-795. [PMID: 35593472 PMCID: PMC9828324 DOI: 10.3724/abbs.2022051] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Programmed DNA double-strand breaks (DSBs) occur during antigen receptor gene recombination, namely V(D)J recombination in developing B lymphocytes and class switch recombination (CSR) in mature B cells. Repair of these DSBs by classical end-joining (c-NHEJ) enables the generation of diverse BCR repertoires for efficient humoral immunity. Deletion of or mutation in c-NHEJ genes in mice and humans confer various degrees of primary immune deficiency and predisposition to lymphoid malignancies that often harbor oncogenic chromosomal translocations. In the absence of c-NHEJ, alternative end-joining (A-EJ) catalyzes robust CSR and to a much lesser extent, V(D)J recombination, but the mechanisms of A-EJ are only poorly defined. In this review, we introduce recent advances in the understanding of A-EJ in the context of V(D)J recombination and CSR with emphases on DSB end processing, DNA polymerases and ligases, and discuss the implications of A-EJ to lymphoid development and chromosomal translocations.
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Affiliation(s)
- Wanyu Bai
- Department of ImmunologyZhongshan School of MedicineSun Yat-sen UniversityGuangzhou510080China,Key Laboratory of Tropical Disease Control (Sun Yat-sen University)Ministry of EducationGuangzhou510080China
| | - Bo Zhao
- Department of ImmunologyZhongshan School of MedicineSun Yat-sen UniversityGuangzhou510080China,Key Laboratory of Tropical Disease Control (Sun Yat-sen University)Ministry of EducationGuangzhou510080China
| | - Mingyu Gu
- Department of ImmunologyZhongshan School of MedicineSun Yat-sen UniversityGuangzhou510080China,Key Laboratory of Tropical Disease Control (Sun Yat-sen University)Ministry of EducationGuangzhou510080China
| | - Junchao Dong
- Department of ImmunologyZhongshan School of MedicineSun Yat-sen UniversityGuangzhou510080China,Key Laboratory of Tropical Disease Control (Sun Yat-sen University)Ministry of EducationGuangzhou510080China,Correspondence address. Tel: +86-20-87330571; E-mail:
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33
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Abstract
Significance: The small, multicopy mitochondrial genome (mitochondrial DNA [mtDNA]) is essential for efficient energy production, as alterations in its coding information or a decrease in its copy number disrupt mitochondrial ATP synthesis. However, the mitochondrial replication machinery encounters numerous challenges that may limit its ability to duplicate this important genome and that jeopardize mtDNA stability, including various lesions in the DNA template, topological stress, and an insufficient nucleotide supply. Recent Advances: An ever-growing array of DNA repair or maintenance factors are being reported to localize to the mitochondria. We review current knowledge regarding the mitochondrial factors that may contribute to the tolerance or repair of various types of changes in the mitochondrial genome, such as base damage, incorporated ribonucleotides, and strand breaks. We also discuss the newly discovered link between mtDNA instability and activation of the innate immune response. Critical Issues: By which mechanisms do mitochondria respond to challenges that threaten mtDNA maintenance? What types of mtDNA damage are repaired, and when are the affected molecules degraded instead? And, finally, which forms of mtDNA instability trigger an immune response, and how? Future Directions: Further work is required to understand the contribution of the DNA repair and damage-tolerance factors present in the mitochondrial compartment, as well as the balance between mtDNA repair and degradation. Finally, efforts to understand the events underlying mtDNA release into the cytosol are warranted. Pursuing these and many related avenues can improve our understanding of what goes wrong in mitochondrial disease. Antioxid. Redox Signal. 36, 885-905.
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Affiliation(s)
- Gustavo Carvalho
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Bruno Marçal Repolês
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Isabela Mendes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
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34
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Schaub JM, Soniat MM, Finkelstein IJ. Polymerase theta-helicase promotes end joining by stripping single-stranded DNA-binding proteins and bridging DNA ends. Nucleic Acids Res 2022; 50:3911-3921. [PMID: 35357490 PMCID: PMC9023281 DOI: 10.1093/nar/gkac119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 01/20/2022] [Accepted: 03/29/2022] [Indexed: 01/20/2023] Open
Abstract
Homologous recombination-deficient cancers rely on DNA polymerase Theta (Polθ)-Mediated End Joining (TMEJ), an alternative double-strand break repair pathway. Polθ is the only vertebrate polymerase that encodes an N-terminal superfamily 2 (SF2) helicase domain, but the role of this helicase domain in TMEJ remains unclear. Using single-molecule imaging, we demonstrate that Polθ-helicase (Polθ-h) is a highly processive single-stranded DNA (ssDNA) motor protein that can efficiently strip Replication Protein A (RPA) from ssDNA. Polθ-h also has a limited capacity for disassembling RAD51 filaments but is not processive on double-stranded DNA. Polθ-h can bridge two non-complementary DNA strands in trans. PARylation of Polθ-h by PARP-1 resolves these DNA bridges. We conclude that Polθ-h removes RPA and RAD51 filaments and mediates bridging of DNA overhangs to aid in polymerization by the Polθ polymerase domain.
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Affiliation(s)
- Jeffrey M Schaub
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Michael M Soniat
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
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35
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PrimPol: A Breakthrough among DNA Replication Enzymes and a Potential New Target for Cancer Therapy. Biomolecules 2022; 12:biom12020248. [PMID: 35204749 PMCID: PMC8961649 DOI: 10.3390/biom12020248] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/29/2022] [Accepted: 02/02/2022] [Indexed: 02/01/2023] Open
Abstract
DNA replication can encounter blocking obstacles, leading to replication stress and genome instability. There are several mechanisms for evading this blockade. One mechanism consists of repriming ahead of the obstacles, creating a new starting point; in humans, PrimPol is responsible for carrying out this task. PrimPol is a primase that operates in both the nucleus and mitochondria. In contrast with conventional primases, PrimPol is a DNA primase able to initiate DNA synthesis de novo using deoxynucleotides, discriminating against ribonucleotides. In vitro, PrimPol can act as a DNA primase, elongating primers that PrimPol itself sythesizes, or as translesion synthesis (TLS) DNA polymerase, elongating pre-existing primers across lesions. However, the lack of evidence for PrimPol polymerase activity in vivo suggests that PrimPol only acts as a DNA primase. Here, we provide a comprehensive review of human PrimPol covering its biochemical properties and structure, in vivo function and regulation, and the processes that take place to fill the gap-containing lesion that PrimPol leaves behind. Finally, we explore the available data on human PrimPol expression in different tissues in physiological conditions and its role in cancer.
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36
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Ramsden DA, Carvajal-Garcia J, Gupta GP. Mechanism, cellular functions and cancer roles of polymerase-theta-mediated DNA end joining. Nat Rev Mol Cell Biol 2022; 23:125-140. [PMID: 34522048 DOI: 10.1038/s41580-021-00405-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 02/08/2023]
Abstract
Cellular pathways that repair chromosomal double-strand breaks (DSBs) have pivotal roles in cell growth, development and cancer. These DSB repair pathways have been the target of intensive investigation, but one pathway - alternative end joining (a-EJ) - has long resisted elucidation. In this Review, we highlight recent progress in our understanding of a-EJ, especially the assignment of DNA polymerase theta (Polθ) as the predominant mediator of a-EJ in most eukaryotes, and discuss a potential molecular mechanism by which Polθ-mediated end joining (TMEJ) occurs. We address possible cellular functions of TMEJ in resolving DSBs that are refractory to repair by non-homologous end joining (NHEJ), DSBs generated following replication fork collapse and DSBs present owing to stalling of repair by homologous recombination. We also discuss how these context-dependent cellular roles explain how TMEJ can both protect against and cause genome instability, and the emerging potential of Polθ as a therapeutic target in cancer.
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Affiliation(s)
- Dale A Ramsden
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Juan Carvajal-Garcia
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gaorav P Gupta
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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37
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Feng W, Smith CM, Simpson DA, Gupta GP. Targeting Non-homologous and Alternative End Joining Repair to Enhance Cancer Radiosensitivity. Semin Radiat Oncol 2021; 32:29-41. [PMID: 34861993 DOI: 10.1016/j.semradonc.2021.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Many cancer therapies, including radiotherapy, induce DSBs as the major driving mechanism for inducing cancer cell death. Thus, modulating DSB repair has immense potential for radiosensitization, although such interventions must be carefully designed to be tumor selective to ensure that normal tissue toxicities are not also increased. Here, we review mechanisms of error-prone DSB repair through a highly efficient process called end joining. There are two major pathways of end-joining repair: non-homologous end joining (NHEJ) and alternative end joining (a-EJ), both of which can be selectively upregulated in cancer and thus represent attractive therapeutic targets for radiosensitization. These EJ pathways each have therapeutically targetable pioneer factors - DNA-dependent protein kinase catalytic subunit (DNA-PKcs) for NHEJ and DNA Polymerase Theta (Pol θ) for a-EJ. We summarize the current status of therapeutic targeting of NHEJ and a-EJ to enhance the effects of radiotherapy - focusing on challenges that must be overcome and opportunities that require further exploration. By leveraging preclinical insights into mechanisms of altered DSB repair programs in cancer, selective radiosensitization through NHEJ and/or a-EJ targeting remains a highly attractive avenue for ongoing and future clinical investigation.
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Affiliation(s)
| | - Chelsea M Smith
- Lineberger Comprehensive Cancer Center; Pathobiology and Translational Science Graduate Program
| | | | - Gaorav P Gupta
- Lineberger Comprehensive Cancer Center; Pathobiology and Translational Science Graduate Program; Department of Radiation Oncology; Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC.
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38
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Llorens-Agost M, Ensminger M, Le HP, Gawai A, Liu J, Cruz-García A, Bhetawal S, Wood RD, Heyer WD, Löbrich M. POLθ-mediated end joining is restricted by RAD52 and BRCA2 until the onset of mitosis. Nat Cell Biol 2021; 23:1095-1104. [PMID: 34616022 PMCID: PMC8675436 DOI: 10.1038/s41556-021-00764-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 08/30/2021] [Indexed: 01/25/2023]
Abstract
BRCA2-mutant cells are defective in homologous recombination, making them vulnerable to the inactivation of other pathways for the repair of DNA double-strand breaks (DSBs). This concept can be clinically exploited but is currently limited due to insufficient knowledge about how DSBs are repaired in the absence of BRCA2. We show that DNA polymerase θ (POLθ)-mediated end joining (TMEJ) repairs DSBs arising during the S phase in BRCA2-deficient cells only after the onset of the ensuing mitosis. This process is regulated by RAD52, whose loss causes the premature usage of TMEJ and the formation of chromosomal fusions. Purified RAD52 and BRCA2 proteins both block the DNA polymerase function of POLθ, suggesting a mechanism explaining their synthetic lethal relationships. We propose that the delay of TMEJ until mitosis ensures the conversion of originally one-ended DSBs into two-ended DSBs. Mitotic chromatin condensation might further serve to juxtapose correct break ends and limit chromosomal fusions.
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Affiliation(s)
- Marta Llorens-Agost
- Radiation Biology and DNA Repair, Technical University of Darmstadt, Darmstadt, Germany
| | - Michael Ensminger
- Radiation Biology and DNA Repair, Technical University of Darmstadt, Darmstadt, Germany
| | - Hang Phuong Le
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, USA
| | - Anugrah Gawai
- Radiation Biology and DNA Repair, Technical University of Darmstadt, Darmstadt, Germany
| | - Jie Liu
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, USA
| | - Andrés Cruz-García
- Radiation Biology and DNA Repair, Technical University of Darmstadt, Darmstadt, Germany
| | - Sarita Bhetawal
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX, USA
| | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX, USA
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, USA
| | - Markus Löbrich
- Radiation Biology and DNA Repair, Technical University of Darmstadt, Darmstadt, Germany.
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39
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Prodhomme MK, Péricart S, Pommier RM, Morel AP, Brunac AC, Franchet C, Moyret-Lalle C, Brousset P, Puisieux A, Hoffmann JS, Tissier A. Opposite Roles for ZEB1 and TMEJ in the Regulation of Breast Cancer Genome Stability. Front Cell Dev Biol 2021; 9:727429. [PMID: 34458275 PMCID: PMC8388841 DOI: 10.3389/fcell.2021.727429] [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: 06/18/2021] [Accepted: 07/23/2021] [Indexed: 12/22/2022] Open
Abstract
Breast cancer cells frequently acquire mutations in faithful DNA repair genes, as exemplified by BRCA-deficiency. Moreover, overexpression of an inaccurate DNA repair pathway may also be at the origin of the genetic instability arising during the course of cancer progression. The specific gain in expression of POLQ, encoding the error-prone DNA polymerase Theta (POLθ) involved in theta-mediated end joining (TMEJ), is associated with a characteristic mutational signature. To gain insight into the mechanistic regulation of POLQ expression, this review briefly presents recent findings on the regulation of POLQ in the claudin-low breast tumor subtype, specifically expressing transcription factors involved in epithelial-to-mesenchymal transition (EMT) such as ZEB1 and displaying a paucity in genomic abnormality.
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Affiliation(s)
- Mélanie K Prodhomme
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
| | - Sarah Péricart
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Roxane M Pommier
- Gilles Thomas Bioinformatics Platform, Centre Léon Bérard, Cancer Research Centre of Lyon, Lyon, France
| | - Anne-Pierre Morel
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
| | - Anne-Cécile Brunac
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Camille Franchet
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Caroline Moyret-Lalle
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
| | - Pierre Brousset
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Alain Puisieux
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,Institut Curie, Versailles Saint-Quentin-en-Yvelines University, PSL Research University, Paris, France
| | - Jean-Sébastien Hoffmann
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Toulouse, France
| | - Agnès Tissier
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Centre of Lyon, Équipe Labellisée Ligue Contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,LabEx DEVweCAN, Université de Lyon, Lyon, France
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40
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Zahn KE, Jensen RB. Polymerase θ Coordinates Multiple Intrinsic Enzymatic Activities during DNA Repair. Genes (Basel) 2021; 12:1310. [PMID: 34573292 PMCID: PMC8470613 DOI: 10.3390/genes12091310] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 11/16/2022] Open
Abstract
The POLQ gene encodes DNA polymerase θ, a 2590 amino acid protein product harboring DNA-dependent ATPase, template-dependent DNA polymerase, dNTP-dependent endonuclease, and 5'-dRP lyase functions. Polymerase θ participates at an essential step of a DNA double-strand break repair pathway able to join 5'-resected substrates by locating and pairing microhomologies present in 3'-overhanging single-stranded tails, cleaving the extraneous 3'-DNA by dNTP-dependent end-processing, before extending the nascent 3' end from the microhomology annealing site. Metazoans require polymerase θ for full resistance to DNA double-strand break inducing agents but can survive knockout of the POLQ gene. Cancer cells with compromised homologous recombination, or other DNA repair defects, over-utilize end-joining by polymerase θ and often over-express the POLQ gene. This dependency points to polymerase θ as an ideal drug target candidate and multiple drug-development programs are now preparing to enter clinical trials with small-molecule inhibitors. Specific inhibitors of polymerase θ would not only be predicted to treat BRCA-mutant cancers, but could thwart accumulated resistance to current standard-of-care cancer therapies and overcome PARP-inhibitor resistance in patients. This article will discuss synthetic lethal strategies targeting polymerase θ in DNA damage-response-deficient cancers and summarize data, describing molecular structures and enzymatic functions.
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Affiliation(s)
- Karl E. Zahn
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Repare Therapeutics, 7210 Rue Frederick Banting, Montreal, QC H4S 2A1, Canada
| | - Ryan B. Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
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41
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Chen XS, Pomerantz RT. DNA Polymerase θ: A Cancer Drug Target with Reverse Transcriptase Activity. Genes (Basel) 2021; 12:1146. [PMID: 34440316 PMCID: PMC8391894 DOI: 10.3390/genes12081146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 12/11/2022] Open
Abstract
The emergence of precision medicine from the development of Poly (ADP-ribose) polymerase (PARP) inhibitors that preferentially kill cells defective in homologous recombination has sparked wide interest in identifying and characterizing additional DNA repair enzymes that are synthetic lethal with HR factors. DNA polymerase theta (Polθ) is a validated anti-cancer drug target that is synthetic lethal with HR factors and other DNA repair proteins and confers cellular resistance to various genotoxic cancer therapies. Since its initial characterization as a helicase-polymerase fusion protein in 2003, many exciting and unexpected activities of Polθ in microhomology-mediated end-joining (MMEJ) and translesion synthesis (TLS) have been discovered. Here, we provide a short review of Polθ's DNA repair activities and its potential as a drug target and highlight a recent report that reveals Polθ as a naturally occurring reverse transcriptase (RT) in mammalian cells.
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Affiliation(s)
- Xiaojiang S. Chen
- Molecular and Computational Biology, USC Dornsife Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA;
| | - Richard T. Pomerantz
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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42
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Zatreanu D, Robinson HMR, Alkhatib O, Boursier M, Finch H, Geo L, Grande D, Grinkevich V, Heald RA, Langdon S, Majithiya J, McWhirter C, Martin NMB, Moore S, Neves J, Rajendra E, Ranzani M, Schaedler T, Stockley M, Wiggins K, Brough R, Sridhar S, Gulati A, Shao N, Badder LM, Novo D, Knight EG, Marlow R, Haider S, Callen E, Hewitt G, Schimmel J, Prevo R, Alli C, Ferdinand A, Bell C, Blencowe P, Bot C, Calder M, Charles M, Curry J, Ekwuru T, Ewings K, Krajewski W, MacDonald E, McCarron H, Pang L, Pedder C, Rigoreau L, Swarbrick M, Wheatley E, Willis S, Wong AC, Nussenzweig A, Tijsterman M, Tutt A, Boulton SJ, Higgins GS, Pettitt SJ, Smith GCM, Lord CJ. Polθ inhibitors elicit BRCA-gene synthetic lethality and target PARP inhibitor resistance. Nat Commun 2021; 12:3636. [PMID: 34140467 PMCID: PMC8211653 DOI: 10.1038/s41467-021-23463-8] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/30/2021] [Indexed: 02/05/2023] Open
Abstract
To identify approaches to target DNA repair vulnerabilities in cancer, we discovered nanomolar potent, selective, low molecular weight (MW), allosteric inhibitors of the polymerase function of DNA polymerase Polθ, including ART558. ART558 inhibits the major Polθ-mediated DNA repair process, Theta-Mediated End Joining, without targeting Non-Homologous End Joining. In addition, ART558 elicits DNA damage and synthetic lethality in BRCA1- or BRCA2-mutant tumour cells and enhances the effects of a PARP inhibitor. Genetic perturbation screening revealed that defects in the 53BP1/Shieldin complex, which cause PARP inhibitor resistance, result in in vitro and in vivo sensitivity to small molecule Polθ polymerase inhibitors. Mechanistically, ART558 increases biomarkers of single-stranded DNA and synthetic lethality in 53BP1-defective cells whilst the inhibition of DNA nucleases that promote end-resection reversed these effects, implicating these in the synthetic lethal mechanism-of-action. Taken together, these observations describe a drug class that elicits BRCA-gene synthetic lethality and PARP inhibitor synergy, as well as targeting a biomarker-defined mechanism of PARPi-resistance.
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Affiliation(s)
- Diana Zatreanu
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Helen M R Robinson
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Omar Alkhatib
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Marie Boursier
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Harry Finch
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Lerin Geo
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Diego Grande
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Vera Grinkevich
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Robert A Heald
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Sophie Langdon
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Jayesh Majithiya
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Claire McWhirter
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Niall M B Martin
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Shaun Moore
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Joana Neves
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Eeson Rajendra
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Marco Ranzani
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Theresia Schaedler
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Martin Stockley
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Kimberley Wiggins
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
| | - Rachel Brough
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Sandhya Sridhar
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Aditi Gulati
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Nan Shao
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Luned M Badder
- The Breast Cancer Now Research Unit, King's College London, London, UK
| | - Daniela Novo
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Eleanor G Knight
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Rebecca Marlow
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Research Unit, King's College London, London, UK
| | - Syed Haider
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Elsa Callen
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | | | - Joost Schimmel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Remko Prevo
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, UK
| | - Christina Alli
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Amanda Ferdinand
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Cameron Bell
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Peter Blencowe
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Chris Bot
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Mathew Calder
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Mark Charles
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Jayne Curry
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Tennyson Ekwuru
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Katherine Ewings
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Wojciech Krajewski
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Ellen MacDonald
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Hollie McCarron
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Leon Pang
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Chris Pedder
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Laurent Rigoreau
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Martin Swarbrick
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Ed Wheatley
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Simon Willis
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Ai Ching Wong
- Cancer Research UK, Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Andre Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew Tutt
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
- The Breast Cancer Now Research Unit, King's College London, London, UK
| | - Simon J Boulton
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK
- The Francis Crick Institute, London, UK
| | - Geoff S Higgins
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, UK
| | - Stephen J Pettitt
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
| | - Graeme C M Smith
- Artios Pharma, The Glenn Berge Building, Babraham Research Campus, Cambridge, UK.
| | - Christopher J Lord
- CRUK Gene Function Laboratory, The Institute of Cancer Research, London, UK.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
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43
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Zhou J, Gelot C, Pantelidou C, Li A, Yücel H, Davis RE, Farkkila A, Kochupurakkal B, Syed A, Shapiro GI, Tainer JA, Blagg BSJ, Ceccaldi R, D’Andrea AD. A first-in-class Polymerase Theta Inhibitor selectively targets Homologous-Recombination-Deficient Tumors. NATURE CANCER 2021; 2:598-610. [PMID: 34179826 PMCID: PMC8224818 DOI: 10.1038/s43018-021-00203-x] [Citation(s) in RCA: 155] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
DNA polymerase theta (POLθ) is synthetic lethal with Homologous Recombination (HR) deficiency and thus a candidate target for HR-deficient cancers. Through high-throughput small molecule screens we identified the antibiotic Novobiocin (NVB) as a specific POLθ inhibitor that selectively kills HR-deficient tumor cells in vitro and in vivo. NVB directly binds to the POLθ ATPase domain, inhibits its ATPase activity, and phenocopies POLθ depletion. NVB kills HR-deficient breast and ovarian tumors in GEMM, xenograft and PDX models. Increased POLθ levels predict NVB sensitivity, and BRCA-deficient tumor cells with acquired resistance to PARP inhibitors (PARPi) are sensitive to NVB in vitro and in vivo. Mechanistically, NVB-mediated cell death in PARPi-resistant cells arises from increased double-strand break end resection, leading to accumulation of single-strand DNA intermediates and non-functional RAD51 foci. Our results demonstrate that NVB may be useful alone or in combination with PARPi in treating HR-deficient tumors, including those with acquired PARPi resistance. (151/150).
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Affiliation(s)
- Jia Zhou
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Camille Gelot
- Inserm U830, PSL Research University, Institut Curie, 75005, Paris, France
| | - Constantia Pantelidou
- Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Adam Li
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Hatice Yücel
- Inserm U830, PSL Research University, Institut Curie, 75005, Paris, France
| | - Rachel E. Davis
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Anniina Farkkila
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Bose Kochupurakkal
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Aleem Syed
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Geoffrey I. Shapiro
- Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.,Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA, USA
| | - John A. Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Brian S. J. Blagg
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Raphael Ceccaldi
- Inserm U830, PSL Research University, Institut Curie, 75005, Paris, France.,Corresponding authors: Alan D. D’Andrea, M.D., Director, Susan F. Smith Center for Women’s Cancers (SFSCWC), Director, Center for DNA Damage and Repair, Dana-Farber Cancer Institute, The Fuller-American Cancer Society Professor, Harvard Medical School, Phone: 617-632-2080, , Raphael Ceccaldi, Institut Curie, 75005, Paris, France, Phone: +33 (0)1 56 24 69 49,
| | - Alan D. D’Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA.,Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA, USA.,Susan F. Smith Center for Women’s Cancers, Dana-Farber Cancer Institute, Boston, MA, USA.,Corresponding authors: Alan D. D’Andrea, M.D., Director, Susan F. Smith Center for Women’s Cancers (SFSCWC), Director, Center for DNA Damage and Repair, Dana-Farber Cancer Institute, The Fuller-American Cancer Society Professor, Harvard Medical School, Phone: 617-632-2080, , Raphael Ceccaldi, Institut Curie, 75005, Paris, France, Phone: +33 (0)1 56 24 69 49,
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44
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Maiorano D, El Etri J, Franchet C, Hoffmann JS. Translesion Synthesis or Repair by Specialized DNA Polymerases Limits Excessive Genomic Instability upon Replication Stress. Int J Mol Sci 2021; 22:3924. [PMID: 33920223 PMCID: PMC8069355 DOI: 10.3390/ijms22083924] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/02/2021] [Accepted: 04/06/2021] [Indexed: 12/15/2022] Open
Abstract
DNA can experience "replication stress", an important source of genome instability, induced by various external or endogenous impediments that slow down or stall DNA synthesis. While genome instability is largely documented to favor both tumor formation and heterogeneity, as well as drug resistance, conversely, excessive instability appears to suppress tumorigenesis and is associated with improved prognosis. These findings support the view that karyotypic diversity, necessary to adapt to selective pressures, may be limited in tumors so as to reduce the risk of excessive instability. This review aims to highlight the contribution of specialized DNA polymerases in limiting extreme genetic instability by allowing DNA replication to occur even in the presence of DNA damage, to either avoid broken forks or favor their repair after collapse. These mechanisms and their key regulators Rad18 and Polθ not only offer diversity and evolutionary advantage by increasing mutagenic events, but also provide cancer cells with a way to escape anti-cancer therapies that target replication forks.
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Affiliation(s)
- Domenico Maiorano
- Institute of Human Genetics, UMR9002, CNRS-University of Montpellier, 34396 Montpellier, France; (D.M.); (J.E.E.)
| | - Jana El Etri
- Institute of Human Genetics, UMR9002, CNRS-University of Montpellier, 34396 Montpellier, France; (D.M.); (J.E.E.)
| | - Camille Franchet
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France;
| | - Jean-Sébastien Hoffmann
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France;
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Zahn KE, Jensen RB, Wood RD, Doublié S. WITHDRAWN: Human DNA polymerase θ harbors DNA end-trimming activity critical for DNA repair. Mol Cell 2021; 81:1534-1547.e4. [PMID: 33577776 PMCID: PMC8231307 DOI: 10.1016/j.molcel.2021.01.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/24/2020] [Accepted: 01/15/2021] [Indexed: 12/12/2022]
Abstract
Cancers with hereditary defects in homologous recombination rely on DNA polymerase θ (pol θ) for repair of DNA double-strand breaks. During end joining, pol θ aligns microhomology tracts internal to 5'-resected broken ends. An unidentified nuclease trims the 3' ends before synthesis can occur. Here we report that a nuclease activity, which differs from the proofreading activity often associated with DNA polymerases, is intrinsic to the polymerase domain of pol θ. Like the DNA synthesis activity, the nuclease activity requires conserved metal-binding residues, metal ions, and dNTPs and is inhibited by ddNTPs or chain-terminated DNA. Our data indicate that pol θ repurposes metal ions in the polymerase active site for endonucleolytic cleavage and that the polymerase-active and end-trimming conformations of the enzyme are distinct. We reveal a nimble strategy of substrate processing that allows pol θ to trim or extend DNA depending on the DNA repair context.
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Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave., Burlington, VT 05405, USA; Department of Therapeutic Radiology, Yale University, New Haven, CT 06510, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale University, New Haven, CT 06510, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 78957, USA.
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave., Burlington, VT 05405, USA.
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46
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DNA-damage tolerance through PCNA ubiquitination and sumoylation. Biochem J 2021; 477:2655-2677. [PMID: 32726436 DOI: 10.1042/bcj20190579] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/08/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022]
Abstract
DNA-damage tolerance (DDT) is employed by eukaryotic cells to bypass replication-blocking lesions induced by DNA-damaging agents. In budding yeast Saccharomyces cerevisiae, DDT is mediated by RAD6 epistatic group genes and the central event for DDT is sequential ubiquitination of proliferating cell nuclear antigen (PCNA), a DNA clamp required for replication and DNA repair. DDT consists of two parallel pathways: error-prone DDT is mediated by PCNA monoubiquitination, which recruits translesion synthesis DNA polymerases to bypass lesions with decreased fidelity; and error-free DDT is mediated by K63-linked polyubiquitination of PCNA at the same residue of monoubiquitination, which facilitates homologous recombination-mediated template switch. Interestingly, the same PCNA residue is also subjected to sumoylation, which leads to inhibition of unwanted recombination at replication forks. All three types of PCNA posttranslational modifications require dedicated conjugating and ligation enzymes, and these enzymes are highly conserved in eukaryotes, from yeast to human.
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47
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Schrempf A, Slyskova J, Loizou JI. Targeting the DNA Repair Enzyme Polymerase θ in Cancer Therapy. Trends Cancer 2021; 7:98-111. [PMID: 33109489 DOI: 10.1016/j.trecan.2020.09.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/21/2022]
Abstract
Targeted cancer therapies represent a milestone towards personalized treatment as they function via inhibition of cancer-specific alterations. Polymerase θ (POLQ), an error-prone translesion polymerase, also involved in DNA double-strand break (DSB) repair, is often upregulated in cancer. POLQ is synthetic lethal with various DNA repair genes, including known cancer drivers such as BRCA1/2, making it essential in homologous recombination-deficient cancers. Thus, POLQ represents a promising target in cancer therapy and efforts for the development of POLQ inhibitors are actively underway with first clinical trials due to start in 2021. This review summarizes the journey of POLQ from a backup DNA repair enzyme to a promising therapeutic target for cancer treatment.
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Affiliation(s)
- Anna Schrempf
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna, Austria; Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
| | - Jana Slyskova
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna, Austria; Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria.
| | - Joanna I Loizou
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna, Austria; Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria.
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48
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Patterson-Fortin J, D'Andrea AD. Exploiting the Microhomology-Mediated End-Joining Pathway in Cancer Therapy. Cancer Res 2020; 80:4593-4600. [PMID: 32651257 PMCID: PMC7641946 DOI: 10.1158/0008-5472.can-20-1672] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/13/2020] [Accepted: 07/07/2020] [Indexed: 01/16/2023]
Abstract
Repair of DNA double-strand breaks (DSB) is performed by two major pathways, homology-dependent repair and classical nonhomologous end-joining. Recent studies have identified a third pathway, microhomology-mediated end-joining (MMEJ). MMEJ has similarities to homology-dependent repair, in that repair is initiated with end resection, leading to single-stranded 3' ends, which require microhomology upstream and downstream of the DSB. Importantly, the MMEJ pathway is commonly upregulated in cancers, especially in homologous recombination-deficient cancers, which display a distinctive mutational signature. Here, we review the molecular process of MMEJ as well as new targets and approaches exploiting the MMEJ pathway in cancer therapy.
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Affiliation(s)
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, Massachusetts
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Hwang T, Reh S, Dunbayev Y, Zhong Y, Takata Y, Shen J, McBride KM, Murnane JP, Bhak J, Lee S, Wood RD, Takata KI. Defining the mutation signatures of DNA polymerase θ in cancer genomes. NAR Cancer 2020; 2:zcaa017. [PMID: 32885167 PMCID: PMC7454005 DOI: 10.1093/narcan/zcaa017] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 01/25/2023] Open
Abstract
DNA polymerase theta (POLQ)-mediated end joining (TMEJ) is a distinct pathway for mediating DNA double-strand break (DSB) repair. TMEJ is required for the viability of BRCA-mutated cancer cells. It is crucial to identify tumors that rely on POLQ activity for DSB repair, because such tumors are defective in other DSB repair pathways and have predicted sensitivity to POLQ inhibition and to cancer therapies that produce DSBs. We define here the POLQ-associated mutation signatures in human cancers, characterized by short insertions and deletions in a specific range of microhomologies. By analyzing 82 COSMIC (Catalogue of Somatic Mutations in Cancer) signatures, we found that BRCA-mutated cancers with a higher level of POLQ expression have a greatly enhanced representation of the small insertion and deletion signature 6, as well as single base substitution signature 3. Using human cancer cells with disruptions of POLQ, we further show that TMEJ dominates end joining of two separated DSBs (distal EJ). Templated insertions with microhomology are enriched in POLQ-dependent distal EJ. The use of this signature analysis will aid in identifying tumors relying on POLQ activity.
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Affiliation(s)
- Taejoo Hwang
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Shelley Reh
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Yerkin Dunbayev
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Yi Zhong
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Yoko Takata
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Jianjun Shen
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Kevin M McBride
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - John P Murnane
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jong Bhak
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Semin Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Kei-Ichi Takata
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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50
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Silvestri R, Landi S. DNA polymerases in the risk and prognosis of colorectal and pancreatic cancers. Mutagenesis 2020; 34:363-374. [PMID: 31647559 DOI: 10.1093/mutage/gez031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/17/2019] [Indexed: 12/30/2022] Open
Abstract
Human cancers arise from the alteration of genes involved in important pathways that mainly affect cell growth and proliferation. DNA replication and DNA damages recognition and repair are among these pathways and DNA polymerases that take part in these processes are frequently involved in cancer onset and progression. For example, damaging alterations within the proofreading domain of replicative polymerases, often reported in patients affected by colorectal cancer (CRC), are considered risk factors and drivers of carcinogenesis as they can lead to the accumulation of several mutations throughout the genome. Thus, replicative polymerases can be involved in cancer when losses of their physiological functions occur. On the contrary, reparative polymerases are often involved in cancer precisely because of their physiological role. In fact, their ability to repair and bypass DNA damages, which confers genome stability, can also counteract the effect of most anticancer drugs. In addition, the altered expression can characterise some type of cancers, which exacerbates this aspect. For example, all of the DNA polymerases involved a damage bypass mechanism, known as translesion synthesis, with the only exception of polymerase theta, are downregulated in CRC. Conversely, in pancreatic ductal adenocarcinoma (PDAC), most of these polymerase result upregulated. This suggests that different types of cancer can rely on different reparative polymerases to acquire drug resistance. Here we will examine all of the aspects that link DNA polymerases with CRC and PDAC.
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Affiliation(s)
| | - Stefano Landi
- Department of Biology, University of Pisa, Pisa, Italy
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