1
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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] [MESH Headings] [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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2
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Nakatsuka E, Tan L, Cunneen B, Foster C, Lei YL, McLean K. Characterization of DNA damage repair pathway utilization in high-grade serous ovarian cancers yields rational therapeutic approaches. Transl Oncol 2024; 50:102119. [PMID: 39270525 DOI: 10.1016/j.tranon.2024.102119] [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: 06/04/2024] [Revised: 08/12/2024] [Accepted: 09/08/2024] [Indexed: 09/15/2024] Open
Abstract
While poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) have improved the prognosis of ovarian high-grade serous carcinoma (HGSC) tumors that are homologous recombination (HR) deficient (HRD), new therapeutic strategies are needed for tumors that are HR proficient (HRP) because they demonstrate greater resistance to current treatments and thus have poorer clinical outcomes. Additionally, clinical precautionary statements regarding potential risks associated with PARPi, such as myelodysplastic syndrome, highlight the need for combinatorial approaches that can lessen the dose and duration of PARPi treatment to reduce toxicities. Here, we evaluated DNA double-strand damage repair pathways in HRD and HRP ovarian cancer cell lines and found that in HRD cell lines, PARPi therapy reduced non-homologous end joining (NHEJ)-mediated repair, specifically due to decreased theta-mediated end-joining. The combination of PARPi with ATM serine/threonine kinase inhibitor (ATMi) suppressed both NHEJ and HR pathways in HRD and HRP cell lines, with synergistic increases in apoptosis and decreases in cell viability and colony formation. Interestingly, PARPi plus ATMi also decreased NF-κB p65 phosphorylation, which was not observed when PARPi was combined with inhibition of the ATR kinase (ATRi). These findings indicate that PARPi plus ATMi is a promising strategy for HGSC independent of underlying tumor HR status.
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Affiliation(s)
- Erika Nakatsuka
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Michigan, 1500 E. Medical Center Dr., Ann Arbor, MI 48109, USA
| | - Lijun Tan
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Michigan, 1500 E. Medical Center Dr., Ann Arbor, MI 48109, USA
| | - Brianna Cunneen
- Department of Gynecologic Oncology and Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY 14263, USA
| | - Caroline Foster
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Michigan, 1500 E. Medical Center Dr., Ann Arbor, MI 48109, USA
| | - Yu Leo Lei
- Department of Head and Neck Surgery, the University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; Department of Cancer Biology, the University of Texas M.D. Anderson Cancer Center, Houston, TX 77054, USA
| | - Karen McLean
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Michigan, 1500 E. Medical Center Dr., Ann Arbor, MI 48109, USA; Department of Gynecologic Oncology and Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY 14263, USA.
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3
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Aubuchon LN, Verma P. Endogenous base damage as a driver of genomic instability in homologous recombination-deficient cancers. DNA Repair (Amst) 2024; 141:103736. [PMID: 39096699 DOI: 10.1016/j.dnarep.2024.103736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 07/18/2024] [Accepted: 07/22/2024] [Indexed: 08/05/2024]
Abstract
Homologous recombination (HR) is a high-fidelity DNA double-strand break (DSB) repair pathway. Both familial and somatic loss of function mutation(s) in various HR genes predispose to a variety of cancer types, underscoring the importance of error-free repair of DSBs in human physiology. While environmental sources of DSBs have been known, more recent studies have begun to uncover the role of endogenous base damage in leading to these breaks. Base damage repair intermediates often consist of single-strand breaks, which if left unrepaired, can lead to DSBs as the replication fork encounters these lesions. This review summarizes various sources of endogenous base damage and how these lesions are repaired. We highlight how conversion of base repair intermediates, particularly those with 5'or 3' blocked ends, to DSBs can be a predominant source of genomic instability in HR-deficient cancers. We also discuss how endogenous base damage and ensuing DSBs can be exploited to enhance the efficacy of Poly (ADP-ribose) polymerase inhibitors (PARPi), that are widely used in the clinics for the regimen of HR-deficient cancers.
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Affiliation(s)
- Lindsey N Aubuchon
- Division of Oncology, Department of Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Cancer Biology Graduate Program, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Priyanka Verma
- Division of Oncology, Department of Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Cancer Biology Graduate Program, Washington University School of Medicine, St. Louis, MO 63110, USA.
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4
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Dibitetto D, Widmer CA, Rottenberg S. PARPi, BRCA, and gaps: controversies and future research. Trends Cancer 2024; 10:857-869. [PMID: 39004561 DOI: 10.1016/j.trecan.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/17/2024] [Accepted: 06/21/2024] [Indexed: 07/16/2024]
Abstract
In recent years, various poly(ADP-ribose) polymerase (PARP) inhibitors (PARPis) have been approved for the treatment of several cancers to target the vulnerability of homologous recombination (HR) deficiency (e.g., due to BRCA1/2 dysfunction). In this review we analyze the ongoing debates and recent breakthroughs in the use of PARPis for BRCA1/2-deficient cancers, juxtaposing the 'double-strand break (DSB)' and 'single-stranded DNA (ssDNA) gap' models of synthetic lethality induced by PARPis. We spotlight the complexity of this interaction, highlighting emerging research on the role of DNA polymerase theta (POLθ) and ssDNA gaps in shaping therapy responses. We scrutinize the clinical ramifications of these findings, especially concerning PARPi efficacy and resistance mechanisms, underscoring the heterogeneity of BRCA-mutated tumors and the urgent need for advanced research to bridge the gap between laboratory models and patient outcomes.
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Affiliation(s)
- Diego Dibitetto
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland; Bern Center for Precision Medicine and Cancer Therapy Research Cluster, Department for Biomedical Research, University of Bern, 3012 Bern, Switzerland; Molecular Oncology and DNA Damage Response Laboratory, Department of Experimental Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156 Milan, Italy.
| | - Carmen A Widmer
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland; Bern Center for Precision Medicine and Cancer Therapy Research Cluster, Department for Biomedical Research, University of Bern, 3012 Bern, Switzerland
| | - Sven Rottenberg
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland; Bern Center for Precision Medicine and Cancer Therapy Research Cluster, Department for Biomedical Research, University of Bern, 3012 Bern, Switzerland; Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands.
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5
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Kim Y, Min S, Kim S, Lee SY, Park YJ, Heo Y, Park SS, Park TJ, Lee JH, Kang HC, Ji JH, Cho H. PARP1-TRIM44-MRN loop dictates the response to PARP inhibitors. Nucleic Acids Res 2024:gkae756. [PMID: 39217466 DOI: 10.1093/nar/gkae756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 07/12/2024] [Accepted: 08/20/2024] [Indexed: 09/04/2024] Open
Abstract
PARP inhibitors (PARPi) show selective efficacy in tumors with homologous recombination repair (HRR)-defects but the activation mechanism of HRR pathway in PARPi-treated cells remains enigmatic. To unveil it, we searched for the mediator bridging PARP1 to ATM pathways by screening 211 human ubiquitin-related proteins. We discovered TRIM44 as a crucial mediator that recruits the MRN complex to damaged chromatin, independent of PARP1 activity. TRIM44 binds PARP1 and regulates the ubiquitination-PARylation balance of PARP1, which facilitates timely recruitment of the MRN complex for DSB repair. Upon exposure to PARPi, TRIM44 shifts its binding from PARP1 to the MRN complex via its ZnF UBP domain. Knockdown of TRIM44 in cells significantly enhances the sensitivity to olaparib and overcomes the resistance to olaparib induced by 53BP1 deficiency. These observations emphasize the central role of TRIM44 in tethering PARP1 to the ATM-mediated repair pathway. Suppression of TRIM44 may enhance PARPi effectiveness and broaden their use even to HR-proficient tumors.
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Affiliation(s)
- Yonghyeon Kim
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Sunwoo Min
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Soyeon Kim
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Seo Yun Lee
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon 24252, Republic of Korea
| | - Yeon-Ji Park
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Yungyeong Heo
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Soon Sang Park
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Tae Jun Park
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Jae-Ho Lee
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Ho Chul Kang
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Jae-Hoon Ji
- Department of Biochemistry and Structural Biology, The University of Texas Health San Antonio, TX 78229-3000, USA
| | - Hyeseong Cho
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
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Ramirez-Otero MA, Costanzo V. "Bridging the DNA divide": Understanding the interplay between replication- gaps and homologous recombination proteins RAD51 and BRCA1/2. DNA Repair (Amst) 2024; 141:103738. [PMID: 39084178 DOI: 10.1016/j.dnarep.2024.103738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 06/24/2024] [Accepted: 07/25/2024] [Indexed: 08/02/2024]
Abstract
A key but often neglected component of genomic instability is the emergence of single-stranded DNA (ssDNA) gaps during DNA replication in the absence of functional homologous recombination (HR) proteins, such as RAD51 and BRCA1/2. Research in prokaryotes has shed light on the dual role of RAD51's bacterial ortholog, RecA, in HR and the protection of replication forks, emphasizing its essential role in preventing the formation of ssDNA gaps, which is vital for cellular viability. This phenomenon was corroborated in eukaryotic cells deficient in HR, where the formation of ssDNA gaps within newly synthesized DNA and their subsequent processing by the MRE11 nuclease were observed. Without functional HR proteins, cells employ alternative ssDNA gap-filling mechanisms to ensure survival, though this compensatory response can compromise genomic stability. A notable example is the involvement of the translesion synthesis (TLS) polymerase POLζ, along with the repair protein POLθ, in the suppression of replicative ssDNA gaps. Persistent ssDNA gaps may result in replication fork collapse, chromosomal anomalies, and cell death, which contribute to cancer progression and resistance to therapy. Elucidating the processes that avert ssDNA gaps and safeguard replication forks is critical for enhancing cancer treatment approaches by exploiting the vulnerabilities of cancer cells in these pathways.
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Affiliation(s)
| | - Vincenzo Costanzo
- IFOM ETS - The AIRC Institute of Molecular Oncology, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy.
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7
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Schreuder A, Wendel TJ, Dorresteijn CGV, Noordermeer SM. (Single-stranded DNA) gaps in understanding BRCAness. Trends Genet 2024; 40:757-771. [PMID: 38789375 DOI: 10.1016/j.tig.2024.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024]
Abstract
The tumour-suppressive roles of BRCA1 and 2 have been attributed to three seemingly distinct functions - homologous recombination, replication fork protection, and single-stranded (ss)DNA gap suppression - and their relative importance is under debate. In this review, we examine the origin and resolution of ssDNA gaps and discuss the recent advances in understanding the role of BRCA1/2 in gap suppression. There are ample data showing that gap accumulation in BRCA1/2-deficient cells is linked to genomic instability and chemosensitivity. However, it remains unclear whether there is a causative role and the function of BRCA1/2 in gap suppression cannot unambiguously be dissected from their other functions. We therefore conclude that the three functions of BRCA1 and 2 are closely intertwined and not mutually exclusive.
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Affiliation(s)
- Anne Schreuder
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Tiemen J Wendel
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Carlo G V Dorresteijn
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands
| | - Sylvie M Noordermeer
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands.
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Blanch JR, Krishnamurthy M, McVey M. A non-tethering role for the Drosophila Pol θ linker domain in promoting damage resolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609911. [PMID: 39253446 PMCID: PMC11383001 DOI: 10.1101/2024.08.27.609911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
DNA polymerase theta (Pol θ) is an error-prone translesion polymerase that becomes crucial for DNA double-strand break repair when cells are deficient in homologous recombination or non-homologous end joining. In some organisms, Pol θ also promotes tolerance of DNA interstrand crosslinks. Due to its importance in DNA damage tolerance, Pol θ is an emerging target for treatment of cancer and disease. Prior work has characterized the functions of the Pol θ helicase-like and polymerase domains, but the roles of the linker domain are largely unknown. Here, we show that the Drosophila melanogaster Pol θ linker domain promotes egg development and is required for tolerance of DNA double-strand breaks and interstrand crosslinks. While a linker domain with scrambled amino acid residues is sufficient for DNA repair, replacement of the linker with part of the Homo sapiens Pol θ linker or a disordered region from the FUS RNA-binding protein does not restore function. These results demonstrate that the linker domain is not simply a random tether between the helicase-like and polymerase domains. Furthermore, they suggest that intrinsic amino acid residue properties, rather than protein interaction motifs, are more critical for Pol θ linker functions in DNA repair.
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9
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Valenza C, Marsicano RM, Trapani D, Curigliano G. PARP inhibitor resistant BRCA-mutated advanced breast cancer: current landscape and emerging treatments. Curr Opin Oncol 2024:00001622-990000000-00205. [PMID: 39246166 DOI: 10.1097/cco.0000000000001092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2024]
Abstract
PURPOSE OF REVIEW Patients with advanced breast cancer (aBC) treated with PARP inhibitors (PARPi) can eventually experience disease progression for emerging treatment resistance. This review aims to depict the treatment the molecular landscape, and the innovative therapies for patients with PARPi-resistant BRCA-mutated aBC. RECENT FINDINGS No specific therapy is specifically available in the setting post-PARPi-failure, with antibody-drug conjugates or nonplatinum-based chemotherapy (PBC) representing the best treatment options in this setting. Mechanisms of on-target PARPi resistance can be classified in reversions (60%) and nonreversion (40%); reverse mutations restore PARP functions. According to the first evidence of clinical validity, these alterations are associated with lower efficacy of PARPi and PBC. However, their clinical utility needs to be assessed. SUMMARY PARPi-resistant aBC represents a clinical unmet need due to the lack of specific targeted therapies and validated prognostic and predictive biomarkers. Constant efforts are required to better define the mechanisms of PARPi resistance and, consequently, develop biomarker-based treatment approach to prevent or overcame resistance.
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Affiliation(s)
- Carmine Valenza
- Division of New Drugs and Early Drug Development for Innovative Therapies, European Institute of Oncology, IRCCS
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Renato Maria Marsicano
- Division of New Drugs and Early Drug Development for Innovative Therapies, European Institute of Oncology, IRCCS
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Dario Trapani
- Division of New Drugs and Early Drug Development for Innovative Therapies, European Institute of Oncology, IRCCS
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Giuseppe Curigliano
- Division of New Drugs and Early Drug Development for Innovative Therapies, European Institute of Oncology, IRCCS
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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10
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Hanthi YW, Ramirez-Otero MA, Appleby R, De Antoni A, Joudeh L, Sannino V, Waked S, Ardizzoia A, Barra V, Fachinetti D, Pellegrini L, Costanzo V. RAD51 protects abasic sites to prevent replication fork breakage. Mol Cell 2024; 84:3026-3043.e11. [PMID: 39178838 DOI: 10.1016/j.molcel.2024.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/03/2024] [Accepted: 07/08/2024] [Indexed: 08/26/2024]
Abstract
Abasic sites are DNA lesions repaired by base excision repair. Cleavage of unrepaired abasic sites in single-stranded DNA (ssDNA) can lead to chromosomal breakage during DNA replication. How rupture of abasic DNA is prevented remains poorly understood. Here, using cryoelectron microscopy (cryo-EM), Xenopus laevis egg extracts, and human cells, we show that RAD51 nucleofilaments specifically recognize and protect abasic sites, which increase RAD51 association rate to DNA. In the absence of BRCA2 or RAD51, abasic sites accumulate as a result of DNA base methylation, oxidation, and deamination, inducing abasic ssDNA gaps that make replicating DNA fibers sensitive to APE1. RAD51 assembled on abasic DNA prevents abasic site cleavage by the MRE11-RAD50 complex, suppressing replication fork breakage triggered by an excess of abasic sites or POLθ polymerase inhibition. Our study highlights the critical role of BRCA2 and RAD51 in safeguarding against unrepaired abasic sites in DNA templates stemming from base alterations, ensuring genomic stability.
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Affiliation(s)
| | | | - Robert Appleby
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Anna De Antoni
- IFOM, The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Luay Joudeh
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | | | - Salli Waked
- IFOM, The AIRC Institute of Molecular Oncology, Milan, Italy
| | | | - Viviana Barra
- Institute Curie, PSL Research University, CNRS, UMR 144, 26 Rue d'Ulm, 75005 Paris, France
| | - Daniele Fachinetti
- Institute Curie, PSL Research University, CNRS, UMR 144, 26 Rue d'Ulm, 75005 Paris, France
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
| | - Vincenzo Costanzo
- IFOM, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy.
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11
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Mitri Z, Goodyear SM, Mills G. Strategies for the prevention or reversal of PARP inhibitor resistance. Expert Rev Anticancer Ther 2024:1-17. [PMID: 39145413 DOI: 10.1080/14737140.2024.2393251] [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: 06/06/2024] [Revised: 08/09/2024] [Accepted: 08/13/2024] [Indexed: 08/16/2024]
Abstract
INTRODUCTION Advances in our understanding of tumor biology shed light on hallmarks of cancer development and progression that include dysregulated DNA damage repair (DDR) machinery. Leveraging the underlying tumor genomic instability and tumor-specific defects in DDR, Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) induced DNA damage emerges as a novel non-chemotherapy therapeutic opportunity. PARPis are currently approved in multiple tumor types, with the largest benefit seen in tumors with homologous recombination repair (HRR) deficiency, including germline and somatic mutations in BRCA1/2 genes (BRCA) and other pathway members such as PALB2 and Rad51c. AREAS COVERED This review article summarizes the current approval landscape and known and proposed mechanisms of resistance to PARPi. Further, therapeutic strategies to overcome PARPi resistance are discussed, including ongoing clinical trials. EXPERT OPINION PARPi have proven to be a safe and effective therapy and represents a cornerstone treatment across multiple solid tumor types. Elucidating innate and acquired mechanisms of resistance, coupled with the emergence of novel therapeutic options to capitalize on the activity of PARPi and prevent or reverse the acquisition of resistance, provides an opportunity to further expand the role of PARPi in cancer therapy.
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Affiliation(s)
- Zahi Mitri
- Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Shaun M Goodyear
- Developmental and Cancer Biology, Knight Cancer Institute, Portland, OR, USA
| | - Gordon Mills
- Developmental and Cancer Biology, Knight Cancer Institute, Portland, OR, USA
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12
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Ito F, Li Z, Minakhin L, Chandramouly G, Tyagi M, Betsch R, Krais JJ, Taberi B, Vekariya U, Calbert M, Skorski T, Johnson N, Chen XS, Pomerantz RT. Structural basis for a Polθ helicase small-molecule inhibitor revealed by cryo-EM. Nat Commun 2024; 15:7003. [PMID: 39143110 PMCID: PMC11324745 DOI: 10.1038/s41467-024-51351-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 08/05/2024] [Indexed: 08/16/2024] Open
Abstract
DNA polymerase theta (Polθ) is a DNA helicase-polymerase protein that facilitates DNA repair and is synthetic lethal with homology-directed repair (HDR) factors. Thus, Polθ is a promising precision oncology drug-target in HDR-deficient cancers. Here, we characterize the binding and mechanism of action of a Polθ helicase (Polθ-hel) small-molecule inhibitor (AB25583) using cryo-EM. AB25583 exhibits 6 nM IC50 against Polθ-hel, selectively kills BRCA1/2-deficient cells, and acts synergistically with olaparib in cancer cells harboring pathogenic BRCA1/2 mutations. Cryo-EM uncovers predominantly dimeric Polθ-hel:AB25583 complex structures at 3.0-3.2 Å. The structures reveal a binding-pocket deep inside the helicase central-channel, which underscores the high specificity and potency of AB25583. The cryo-EM structures in conjunction with biochemical data indicate that AB25583 inhibits the ATPase activity of Polθ-hel helicase via an allosteric mechanism. These detailed structural data and insights about AB25583 inhibition pave the way for accelerating drug development targeting Polθ-hel in HDR-deficient cancers.
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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, CA, 90089, USA
| | - Ziyuan Li
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, CA, 90089, USA
| | - Leonid Minakhin
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Gurushankar Chandramouly
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Mrityunjay Tyagi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Robert Betsch
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - John J Krais
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Bernadette Taberi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Umeshkumar Vekariya
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Marissa Calbert
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Tomasz Skorski
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Neil Johnson
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, 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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13
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Lin X, Soni A, Hessenow R, Sun Y, Mladenov E, Guberina M, Stuschke M, Iliakis G. Talazoparib enhances resection at DSBs and renders HR-proficient cancer cells susceptible to Polθ inhibition. Radiother Oncol 2024; 200:110475. [PMID: 39147034 DOI: 10.1016/j.radonc.2024.110475] [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: 12/19/2023] [Revised: 07/02/2024] [Accepted: 08/12/2024] [Indexed: 08/17/2024]
Abstract
BACKGROUND AND PURPOSE The PARP inhibitor (PARPi), Talazoparib (BMN673), effectively and specifically radiosensitizes cancer cells. Radiosensitization is mediated by a shift in the repair of ionizing radiation (IR)-induced DNA double-strand breaks (DSBs) toward PARP1-independent, alternative end-joining (alt-EJ). DNA polymerase theta (Polθ) is a key component of this PARP1-independent alt-EJ pathway and we show here that its inhibition can further radiosensitize talazoparib-treated cells. The purpose of the present work is to explore mechanisms and dynamics underpinning enhanced talazoparib radiosensitization by Polθ inhibitors in HR-proficient cancer cells. METHODS AND MATERIALS Radiosensitization to PARPis, talazoparib, olaparib, rucaparib and veliparib was assessed by clonogenic survival. Polθ-proficient and -deficient cells were treated with PARPis and/or with the Polθ inhibitors ART558 or novobiocin. The role of DNA end-resection was studied by down-regulating CtIP and MRE11 expression using siRNAs. DSB repair was assessed by scoring γH2AX foci. The formation of chromosomal abnormalities was assessed as evidence of alt-EJ function using G2-specific cytogenetic analysis. RESULTS Talazoparib exerted pronounced radiosensitization that varied among the tested cancer cell lines; however, radiosensitization was undetectable in normal cells. Other commonly used PARPis, olaparib, veliparib, or rucaparib were ineffective radiosensitizers under our experimental conditions. Although genetic ablation or pharmacological inhibition of Polθ only mildly radiosensitized cancer cells, talazoparib-treated cells were markedly further radiosensitized. Mechanistically, talazoparib shunted DSBs to Polθ-dependent alt-EJ by enhancing DNA end-resection in a CtIP- and MRE11-dependent manner - an effect detectable at low, but not high IR doses. Chromosomal translocation analysis in talazoparib-treated cells exposed to Polθ inhibitors suggested that PARP1- and Polθ-dependent alt-EJ pathways may complement, but also back up each other. CONCLUSION We propose that talazoparib promotes low-dose, CtIP/MRE11-dependent resection and increases the reliance of irradiated HR-proficient cancer cells, on Polθ-mediated alt-EJ. The combination of Polθ inhibitors with talazoparib suppresses this option and causes further radiosensitization. The results suggest that Polθ inhibition may be exploited to maximize talazoparib radiosensitization of HR-proficient tumors in the clinic.
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Affiliation(s)
- Xixi Lin
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany; Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany
| | - Aashish Soni
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany; Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany.
| | - Razan Hessenow
- West German Proton Therapy Center Essen (WPE), University of Duisburg-Essen, 45147, Essen, Germany
| | - Yanjie Sun
- Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany; West German Proton Therapy Center Essen (WPE), University of Duisburg-Essen, 45147, Essen, Germany
| | - Emil Mladenov
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany; Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany
| | - Maja Guberina
- Department of Radiation Therapy, West German Cancer Center, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, German Cancer Research Center (DKFZ), 45147, Essen, Germany
| | - Martin Stuschke
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany; Department of Radiation Therapy, West German Cancer Center, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, German Cancer Research Center (DKFZ), 45147, Essen, Germany
| | - George Iliakis
- Division of Experimental Radiation Biology, Department of Radiation Therapy, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany; Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147, Essen, Germany.
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14
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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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15
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Previtali V, Bagnolini G, Ciamarone A, Ferrandi G, Rinaldi F, Myers SH, Roberti M, Cavalli A. New Horizons of Synthetic Lethality in Cancer: Current Development and Future Perspectives. J Med Chem 2024; 67:11488-11521. [PMID: 38955347 DOI: 10.1021/acs.jmedchem.4c00113] [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: 07/04/2024]
Abstract
In recent years, synthetic lethality has been recognized as a solid paradigm for anticancer therapies. The discovery of a growing number of synthetic lethal targets has led to a significant expansion in the use of synthetic lethality, far beyond poly(ADP-ribose) polymerase inhibitors used to treat BRCA1/2-defective tumors. In particular, molecular targets within DNA damage response have provided a source of inhibitors that have rapidly reached clinical trials. This Perspective focuses on the most recent progress in synthetic lethal targets and their inhibitors, within and beyond the DNA damage response, describing their design and associated therapeutic strategies. We will conclude by discussing the current challenges and new opportunities for this promising field of research, to stimulate discussion in the medicinal chemistry community, allowing the investigation of synthetic lethality to reach its full potential.
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Affiliation(s)
- Viola Previtali
- Computational & Chemical Biology, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Greta Bagnolini
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy
| | - Andrea Ciamarone
- Computational & Chemical Biology, Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy
| | - Giovanni Ferrandi
- Computational & Chemical Biology, Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy
| | - Francesco Rinaldi
- Computational & Chemical Biology, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Samuel Harry Myers
- Computational & Chemical Biology, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Marinella Roberti
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy
| | - Andrea Cavalli
- Computational & Chemical Biology, Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy
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16
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Harada N, Asada S, Jiang L, Nguyen H, Moreau L, Marina RJ, Adelman K, Iyer DR, D'Andrea AD. The splicing factor CCAR1 regulates the Fanconi anemia/BRCA pathway. Mol Cell 2024; 84:2618-2633.e10. [PMID: 39025073 PMCID: PMC11321822 DOI: 10.1016/j.molcel.2024.06.031] [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: 09/06/2023] [Revised: 05/15/2024] [Accepted: 06/25/2024] [Indexed: 07/20/2024]
Abstract
The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.
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Affiliation(s)
- Naoya Harada
- Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Shuhei Asada
- Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Lige Jiang
- Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Huy Nguyen
- Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Lisa Moreau
- Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Ryan J Marina
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Divya R Iyer
- Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA.
| | - Alan D D'Andrea
- Division of Radiation and Genome Stability, 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, Harvard Medical School, Boston, MA 02215, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA.
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17
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Liu Z, Jiang H, Lee SY, Kong N, Chan YW. FANCM promotes PARP inhibitor resistance by minimizing ssDNA gap formation and counteracting resection inhibition. Cell Rep 2024; 43:114464. [PMID: 38985669 DOI: 10.1016/j.celrep.2024.114464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/22/2024] [Accepted: 06/24/2024] [Indexed: 07/12/2024] Open
Abstract
Poly(ADP-ribose) polymerase inhibitors (PARPis) exhibit remarkable anticancer activity in tumors with homologous recombination (HR) gene mutations. However, the role of other DNA repair proteins in PARPi-induced lethality remains elusive. Here, we reveal that FANCM promotes PARPi resistance independent of the core Fanconi anemia (FA) complex. FANCM-depleted cells retain HR proficiency, acting independently of BRCA1 in response to PARPis. FANCM depletion leads to increased DNA damage in the second S phase after PARPi exposure, driven by elevated single-strand DNA (ssDNA) gap formation behind replication forks in the first S phase. These gaps arise from both 53BP1- and primase and DNA directed polymerase (PRIMPOL)-dependent mechanisms. Notably, FANCM-depleted cells also exhibit reduced resection of collapsed forks, while 53BP1 deletion restores resection and mitigates PARPi sensitivity. Our results suggest that FANCM counteracts 53BP1 to repair PARPi-induced DNA damage. Furthermore, FANCM depletion leads to increased chromatin bridges and micronuclei formation after PARPi treatment, elucidating the mechanism underlying extensive cell death in FANCM-depleted cells.
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Affiliation(s)
- Zeyuan Liu
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Huadong Jiang
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Sze Yuen Lee
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Nannan Kong
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Ying Wai Chan
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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18
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Willman GH, Xu H, Zeigler TM, McIntosh MT, Bhaduri-McIntosh S. Polymerase theta is a synthetic lethal target for killing Epstein-Barr virus lymphomas. J Virol 2024; 98:e0057224. [PMID: 38860782 PMCID: PMC11265443 DOI: 10.1128/jvi.00572-24] [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: 04/02/2024] [Accepted: 05/27/2024] [Indexed: 06/12/2024] Open
Abstract
Treatment options for Epstein-Barr virus (EBV)-cancers are limited, underscoring the need for new therapeutic approaches. We have previously shown that EBV-transformed cells and cancers lack homologous recombination (HR) repair, a prominent error-free pathway that repairs double-stranded DNA breaks; instead, EBV-transformed cells demonstrate genome-wide scars of the error-prone microhomology-mediated end joining (MMEJ) repair pathway. This suggests that EBV-cancers are vulnerable to synthetic lethal therapeutic approaches that target MMEJ repair. Indeed, we have previously found that targeting PARP, an enzyme that contributes to MMEJ, results in the death of EBV-lymphoma cells. With the emergence of clinical resistance to PARP inhibitors and the recent discovery of inhibitors of Polymerase theta (POLθ), the polymerase essential for MMEJ, we investigated the role of POLθ in EBV-lymphoma cells. We report that EBV-transformed cell lines, EBV-lymphoma cell lines, and EBV-lymphomas in AIDS patients demonstrate greater abundance of POLθ, driven by the EBV protein EBNA1, compared to EBV-uninfected primary lymphocytes and EBV-negative lymphomas from AIDS patients (a group that also abundantly expresses POLθ). We also find POLθ enriched at cellular DNA replication forks and exposure to the POLθ inhibitor Novobiocin impedes replication fork progress, impairs MMEJ-mediated repair of DNA double-stranded breaks, and kills EBV-lymphoma cells. Notably, cell killing is not due to Novobiocin-induced activation of the lytic/replicative phase of EBV. These findings support a role for POLθ not just in DNA repair but also DNA replication and as a therapeutic target in EBV-lymphomas and potentially other EBV-cancers as EBNA1 is expressed in all EBV-cancers.IMPORTANCEEpstein-Barr virus (EBV) contributes to ~2% of the global cancer burden. With a recent estimate of >200,000 deaths a year, identifying molecular vulnerabilities will be key to the management of these frequently aggressive and treatment-resistant cancers. Building on our earlier work demonstrating reliance of EBV-cancers on microhomology-mediated end-joining repair, we now report that EBV lymphomas and transformed B cell lines abundantly express the MMEJ enzyme POLθ that likely protects cellular replication forks and repairs replication-related cellular DNA breaks. Importantly also, we show that a newly identified POLθ inhibitor kills EBV-cancer cells, revealing a novel strategy to block DNA replication and repair of these aggressive cancers.
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Affiliation(s)
- Griffin H. Willman
- Division of Infectious Diseases, Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Huanzhou Xu
- Division of Infectious Diseases, Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Travis M. Zeigler
- Division of Infectious Diseases, Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Michael T. McIntosh
- Child Health Research Institute, Department of Pediatrics, University of Florida, Gainesville, Florida, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - Sumita Bhaduri-McIntosh
- Division of Infectious Diseases, Department of Pediatrics, University of Florida, Gainesville, Florida, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
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19
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Li X, Zou L. BRCAness, DNA gaps, and gain and loss of PARP inhibitor-induced synthetic lethality. J Clin Invest 2024; 134:e181062. [PMID: 39007266 PMCID: PMC11245158 DOI: 10.1172/jci181062] [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: 07/16/2024] Open
Abstract
Mutations in the tumor-suppressor genes BRCA1 and BRCA2 resulting in BRCA1/2 deficiency are frequently identified in breast, ovarian, prostate, pancreatic, and other cancers. Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPis) selectively kill BRCA1/2-deficient cancer cells by inducing synthetic lethality, providing an effective biomarker-guided strategy for targeted cancer therapy. However, a substantial fraction of cancer patients carrying BRCA1/2 mutations do not respond to PARPis, and most patients develop resistance to PARPis over time, highlighting a major obstacle to PARPi therapy in the clinic. Recent studies have revealed that changes of specific functional defects of BRCA1/2-deficient cells, particularly their defects in suppressing and protecting single-stranded DNA gaps, contribute to the gain or loss of PARPi-induced synthetic lethality. These findings not only shed light on the mechanism of action of PARPis, but also lead to revised models that explain how PARPis selectively kill BRCA-deficient cancer cells. Furthermore, new mechanistic principles of PARPi sensitivity and resistance have emerged from these studies, generating potentially useful guidelines for predicting the PARPi response and design therapies for overcoming PARPi resistance. In this Review, we will discuss these recent studies and put them in context with the classic views of PARPi-induced synthetic lethality, aiming to stimulate the development of new therapeutic strategies to overcome PARPi resistance and improve PARPi therapy.
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20
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Vekariya U, Minakhin L, Chandramouly G, Tyagi M, Kent T, Sullivan-Reed K, Atkins J, Ralph D, Nieborowska-Skorska M, Kukuyan AM, Tang HY, Pomerantz RT, Skorski T. PARG is essential for Polθ-mediated DNA end-joining by removing repressive poly-ADP-ribose marks. Nat Commun 2024; 15:5822. [PMID: 38987289 PMCID: PMC11236980 DOI: 10.1038/s41467-024-50158-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 06/27/2024] [Indexed: 07/12/2024] Open
Abstract
DNA polymerase theta (Polθ)-mediated end-joining (TMEJ) repairs DNA double-strand breaks and confers resistance to genotoxic agents. How Polθ is regulated at the molecular level to exert TMEJ remains poorly characterized. We find that Polθ interacts with and is PARylated by PARP1 in a HPF1-independent manner. PARP1 recruits Polθ to the vicinity of DNA damage via PARylation dependent liquid demixing, however, PARylated Polθ cannot perform TMEJ due to its inability to bind DNA. PARG-mediated de-PARylation of Polθ reactivates its DNA binding and end-joining activities. Consistent with this, PARG is essential for TMEJ and the temporal recruitment of PARG to DNA damage corresponds with TMEJ activation and dissipation of PARP1 and PAR. In conclusion, we show a two-step spatiotemporal mechanism of TMEJ regulation. First, PARP1 PARylates Polθ and facilitates its recruitment to DNA damage sites in an inactivated state. PARG subsequently activates TMEJ by removing repressive PAR marks on Polθ.
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Affiliation(s)
- Umeshkumar Vekariya
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Leonid Minakhin
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Gurushankar Chandramouly
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Mrityunjay Tyagi
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Tatiana Kent
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Katherine Sullivan-Reed
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Jessica Atkins
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Douglas Ralph
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Margaret Nieborowska-Skorska
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Anna-Mariya Kukuyan
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Facility, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Richard T Pomerantz
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA.
| | - Tomasz Skorski
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA.
- Department of Cancer and Cellular Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA.
- Nuclear Dynamics and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA, USA.
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21
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Dagar G, Gupta A, Shankar A, Chauhan R, Macha MA, Bhat AA, Das D, Goyal R, Bhoriwal S, Pandita RK, Prasad CP, Sarkar PS, Pandita TK, Singh M. The future of cancer treatment: combining radiotherapy with immunotherapy. Front Mol Biosci 2024; 11:1409300. [PMID: 39044839 PMCID: PMC11263218 DOI: 10.3389/fmolb.2024.1409300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/12/2024] [Indexed: 07/25/2024] Open
Abstract
Radiotherapy (RT) and immunotherapy (IT) are the powerful tools for cancer treatment which act through the stimulation of immune response, and evidence suggest that combinatorial actions of these therapies may augment each other's beneficial effect through complex synergistic mechanisms. These molecular strategies are designed to target rapidly dividing cancer cells by either directly or indirectly inducing DNA damage. However, when cells detect DNA damage, they activate a range of signalling pathways known as the DNA damage response (DDR) to repair. Strategies are being developed to interfere with the DDR pathways in cancer cells to ensure their damage-induced degeneration. The stability of a cell's genetic material is largely dependent on the efficacy of DNA repair and therefore, an in-depth understanding of DNA damages and repair mechanism(s) in cancer cells is important to develop a promising therapeutic strategies for ensuring the efficacy of damage-induced tumor cell death. In recent years, a wide range of small molecule drugs have been developed which are currently being employed to combat the DNA repair deficiencies associated with tumor cells. Sequential or concurrent use of these two modalities significantly enhances the anti-tumor response, however with a concurrent probability of increased incidence of symptomatic adverse effects. With advent of newer IT agents, and administration of higher doses of radiation per fraction, such effects are more difficult to predict owing to the paucity of randomized trial data. It is well established that anti cytotoxic-T-lymphocyte-associated antigen 4 (CTLA-4), anti- Programmed cell death protein 1(PD-1), anti-Programmed cell death one ligand 1 (PD-L1) can be safely administered with RT and many studies have demonstrated survival benefit with such combination for patients with metastatic malignancy. However, the biology of radioimmunotherapy (RT/IT) is still an open area where research need to be focused to determine optimum dosage specially the interaction of the RT/IT pathways to determine optimum dosing schedule. In the current article we have summarised the possible intracellular immunological events that might be triggered when RT and IT modalities are combined with the DDR antagonists and highlighted present clinical practices, outcome, and toxicity profile of this novel treatment strategy.
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Affiliation(s)
- Gunjan Dagar
- Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India
| | - Ashna Gupta
- Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India
| | - Abhishek Shankar
- Department of Radiation Oncology, All India Institute of Medical Sciences, New Delhi, India
| | - Ravi Chauhan
- Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India
| | - Muzafar A. Macha
- Watson-Crick Centre for Molecular Medicine, Islamic University of Science and Technology, Pulwama, Jammu And Kashmir, India
| | - Ajaz A. Bhat
- Department of Human Genetics-Precision Medicine in Diabetes, Obesity and Cancer Program, Sidra Medicine, Doha, Qatar
| | - Dayasagar Das
- Department of Medicine, NYU Langone Health, New York City, NY, United States
| | - Rajeev Goyal
- Department of Biochemistry, Lady Harding Medical College, New Delhi, India
| | - Sandeep Bhoriwal
- Department of Surgical Oncology, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Raj K. Pandita
- Center for Genomics and Precision Medicine, Texas A and M College of Medicine, Houston, TX, United States
| | - Chandra Prakash Prasad
- Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India
| | - Partha S. Sarkar
- Department of Neurobiology and Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States
| | - Tej K. Pandita
- Center for Genomics and Precision Medicine, Texas A and M College of Medicine, Houston, TX, United States
| | - Mayank Singh
- Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India
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22
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Sfeir A. Obscure DNA sequences unveil a new cancer target. Nat Struct Mol Biol 2024:10.1038/s41594-024-01347-x. [PMID: 38977900 DOI: 10.1038/s41594-024-01347-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Affiliation(s)
- Agnel Sfeir
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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23
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Bainbridge LJ, Daigaku Y. Adaptive use of error-prone DNA polymerases provides flexibility in genome replication during tumorigenesis. Cancer Sci 2024; 115:2125-2137. [PMID: 38651239 PMCID: PMC11247608 DOI: 10.1111/cas.16188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024] Open
Abstract
Human cells possess many different polymerase enzymes, which collaborate in conducting DNA replication and genome maintenance to ensure faithful duplication of genetic material. Each polymerase performs a specialized role, together providing a balance of accuracy and flexibility to the replication process. Perturbed replication increases the requirement for flexibility to ensure duplication of the entire genome. Flexibility is provided via the use of error-prone polymerases, which maintain the progression of challenged DNA replication at the expense of mutagenesis, an enabling characteristic of cancer. This review describes our recent understanding of mechanisms that alter the usage of polymerases during tumorigenesis and examines the implications of this for cell survival and tumor progression. Although expression levels of polymerases are often misregulated in cancers, this does not necessarily alter polymerase usage since an additional regulatory step may govern the use of these enzymes. We therefore also examine how the regulatory mechanisms of DNA polymerases, such as Rad18-mediated PCNA ubiquitylation, may impact the functionalization of error-prone polymerases to tolerate oncogene-induced replication stress. Crucially, it is becoming increasingly evident that cancer cells utilize error-prone polymerases to sustain ongoing replication in response to oncogenic mutations which inactivate key DNA replication and repair pathways, such as BRCA deficiency. This accelerates mutagenesis and confers chemoresistance, but also presents a dependency that can potentially be exploited by therapeutics.
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Affiliation(s)
- Lewis J. Bainbridge
- Cancer Genome Dynamics Project, Cancer InstituteJapanese Foundation for Cancer ResearchTokyoJapan
| | - Yasukazu Daigaku
- Cancer Genome Dynamics Project, Cancer InstituteJapanese Foundation for Cancer ResearchTokyoJapan
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24
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Kunihisa T, Inubushi S, Tanino H, Hoffman RM. Induction of the DNA-Repair Gene POLQ only in BRCA1-mutant Breast-Cancer Cells by Methionine Restriction. Cancer Genomics Proteomics 2024; 21:399-404. [PMID: 38944428 PMCID: PMC11215430 DOI: 10.21873/cgp.20458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 05/23/2024] [Accepted: 06/03/2024] [Indexed: 07/01/2024] Open
Abstract
BACKGROUND/AIM BRCA1/2 mutations in breast cancer cells impair homologous recombination and promote alternative end joining (Alt-EJ) for DNA-damage repair. DNA polymerase theta, encoded by POLQ, plays a crucial role in Alt-EJ, making it a potential therapeutic target, particularly in BRCA1/2-mutant cancers. Methionine restriction is a promising approach to target cancer cells due to their addiction to this amino acid. The present study investigated the expression of POLQ in BRCA1/2 wild-type and BRCA1-mutant breast cancer cells under methionine restriction. MATERIALS AND METHODS POLQ mRNA expression was measured using qRT-PCR in BRCA1/2 wild-type (MDA-MB-231) and BRCA1- mutant (HCC1937 and MDA-MB-436) breast-cancer cells under normal, or serum-restricted, or serum- and methionine-restricted conditions. RESULTS Compared to BRCA1/2 wild-type cells, BRCA1-mutant cells displayed significantly higher basal POLQ expression in normal medium. Methionine restriction further increased POLQ expression in the BRCA1-mutant cells but decreased it in the BRCA1/2 wild-type cells. CONCLUSION The present findings suggest that methionine restriction showed differential effects on POLQ expression, potentially impacting Alt-EJ activity, in BRCA1/2 wild-type and BRCA1-mutant breast-cancer cells. Further investigation is needed to explore the potential of combining methionine restriction with DNA-repair inhibitors, such as PARP inhibitors, to overcome drug resistance in BRCA1/2 mutant cancers.
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Affiliation(s)
- Tomonari Kunihisa
- Division of Breast and Endocrine Surgery, Graduate School of Medicine, Kobe University, Hyogo, Japan
| | - Sachiko Inubushi
- Division of Breast and Endocrine Surgery, Graduate School of Medicine, Kobe University, Hyogo, Japan
| | - Hirokazu Tanino
- Department of Thoracic and Cardiovascular Surgery, Wakayama Medical University, Wakayama, Japan
| | - Robert M Hoffman
- AntiCancer Inc, San Diego, CA, U.S.A.;
- Department of Surgery, University of California San Diego, La Jolla, CA, U.S.A
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25
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Németh E, Szüts D. The mutagenic consequences of defective DNA repair. DNA Repair (Amst) 2024; 139:103694. [PMID: 38788323 DOI: 10.1016/j.dnarep.2024.103694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024]
Abstract
Multiple separate repair mechanisms safeguard the genome against various types of DNA damage, and their failure can increase the rate of spontaneous mutagenesis. The malfunction of distinct repair mechanisms leads to genomic instability through different mutagenic processes. For example, defective mismatch repair causes high base substitution rates and microsatellite instability, whereas homologous recombination deficiency is characteristically associated with deletions and chromosome instability. This review presents a comprehensive collection of all mutagenic phenotypes associated with the loss of each DNA repair mechanism, drawing on data from a variety of model organisms and mutagenesis assays, and placing greatest emphasis on systematic analyses of human cancer datasets. We describe the latest theories on the mechanism of each mutagenic process, often explained by reliance on an alternative repair pathway or the error-prone replication of unrepaired, damaged DNA. Aided by the concept of mutational signatures, the genomic phenotypes can be used in cancer diagnosis to identify defective DNA repair pathways.
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Affiliation(s)
- Eszter Németh
- Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary
| | - Dávid Szüts
- Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary.
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26
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Laverty DJ, Gupta SK, Bradshaw GA, Hunter AS, Carlson BL, Calmo NM, Chen J, Tian S, Sarkaria JN, Nagel ZD. ATM inhibition exploits checkpoint defects and ATM-dependent double strand break repair in TP53-mutant glioblastoma. Nat Commun 2024; 15:5294. [PMID: 38906885 PMCID: PMC11192742 DOI: 10.1038/s41467-024-49316-8] [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: 12/20/2022] [Accepted: 05/28/2024] [Indexed: 06/23/2024] Open
Abstract
Determining the balance between DNA double strand break repair (DSBR) pathways is essential for understanding treatment response in cancer. We report a method for simultaneously measuring non-homologous end joining (NHEJ), homologous recombination (HR), and microhomology-mediated end joining (MMEJ). Using this method, we show that patient-derived glioblastoma (GBM) samples with acquired temozolomide (TMZ) resistance display elevated HR and MMEJ activity, suggesting that these pathways contribute to treatment resistance. We screen clinically relevant small molecules for DSBR inhibition with the aim of identifying improved GBM combination therapy regimens. We identify the ATM kinase inhibitor, AZD1390, as a potent dual HR/MMEJ inhibitor that suppresses radiation-induced phosphorylation of DSBR proteins, blocks DSB end resection, and enhances the cytotoxic effects of TMZ in treatment-naïve and treatment-resistant GBMs with TP53 mutation. We further show that a combination of G2/M checkpoint deficiency and reliance upon ATM-dependent DSBR renders TP53 mutant GBMs hypersensitive to TMZ/AZD1390 and radiation/AZD1390 combinations. This report identifies ATM-dependent HR and MMEJ as targetable resistance mechanisms in TP53-mutant GBM and establishes an approach for simultaneously measuring multiple DSBR pathways in treatment selection and oncology research.
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Affiliation(s)
- Daniel J Laverty
- Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | | | | | | | | | | | - Jiajia Chen
- Mayo Clinic, Rochester, MN, 55905, USA
- Shengjing Hospital of China Medical University, Shenyang, 110004, China
| | | | | | - Zachary D Nagel
- Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
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27
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Bessho T. Up-Regulation of Non-Homologous End-Joining by MUC1. Genes (Basel) 2024; 15:808. [PMID: 38927743 PMCID: PMC11203369 DOI: 10.3390/genes15060808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/10/2024] [Accepted: 06/15/2024] [Indexed: 06/28/2024] Open
Abstract
Ionizing radiation (IR) and chemotherapy with DNA-damaging drugs such as cisplatin are vital cancer treatment options. These treatments induce double-strand breaks (DSBs) as cytotoxic DNA damage; thus, the DSB repair activity in each cancer cell significantly influences the efficacy of the treatments. Pancreatic cancers are known to be resistant to these treatments, and the overexpression of MUC1, a member of the glycoprotein mucins, is associated with IR- and chemo-resistance. Therefore, we investigated the impact of MUC1 on DSB repair. This report examined the effect of the overexpression of MUC1 on homologous recombination (HR) and non-homologous end-joining (NHEJ) using cell-based DSB repair assays. In addition, the therapeutic potential of NHEJ inhibitors including HDAC inhibitors was also studied using pancreatic cancer cell lines. The MUC1-overexpression enhances NHEJ, while partially suppressing HR. Also, MUC1-overexpressed cancer cell lines are preferentially killed by a DNA-PK inhibitor and HDAC1/2 inhibitors. Altogether, MUC1 induces metabolic changes that create an imbalance between NHEJ and HR activities, and this imbalance can be a target for selective killing by HDAC inhibitors. This is a novel mechanism of MUC1-mediated IR-resistance and will form the basis for targeting MUC1-overexpressed pancreatic cancer.
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Affiliation(s)
- Tadayoshi Bessho
- The Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, NE 68198, USA
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28
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Saito S, Adachi N. Characterization and regulation of cell cycle-independent noncanonical gene targeting. Nat Commun 2024; 15:5044. [PMID: 38890315 PMCID: PMC11189520 DOI: 10.1038/s41467-024-49385-9] [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: 11/22/2023] [Accepted: 06/04/2024] [Indexed: 06/20/2024] Open
Abstract
Homology-dependent targeted DNA integration, generally referred to as gene targeting, provides a powerful tool for precise genome modification; however, its fundamental mechanisms remain poorly understood in human cells. Here we reveal a noncanonical gene targeting mechanism that does not rely on the homologous recombination (HR) protein Rad51. This mechanism is suppressed by Rad52 inhibition, suggesting the involvement of single-strand annealing (SSA). The SSA-mediated gene targeting becomes prominent when DSB repair by HR or end-joining pathways is defective and does not require isogenic DNA, permitting 5% sequence divergence. Intriguingly, loss of Msh2, loss of BLM, and induction of a target-site DNA break all significantly and synergistically enhance SSA-mediated targeted integration. Most notably, SSA-mediated integration is cell cycle-independent, occurring in the G1 phase as well. Our findings provide unequivocal evidence for Rad51-independent targeted integration and unveil multiple mechanisms to regulate SSA-mediated targeted as well as random integration.
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Affiliation(s)
- Shinta Saito
- Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Yokohama, 236-0027, Japan
| | - Noritaka Adachi
- Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Yokohama, 236-0027, Japan.
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29
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Frye CC, Tennant L, Yeager A, Azimzadeh P, Bhardwaj P, Xu Y, Liu J, Othoum G, Maher CA, Chernock R, Goedegebuure SP, Gillanders W, Olson JA, Brown TC. Overexpression of human DNA polymerase theta is a biomarker of aggressive and DNA repair-deficient papillary thyroid cancers. Surgery 2024:S0039-6060(24)00303-9. [PMID: 38897886 DOI: 10.1016/j.surg.2024.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 04/19/2024] [Accepted: 05/05/2024] [Indexed: 06/21/2024]
Abstract
BACKGROUND DNA polymerase theta (POLQ) is an enzyme that repairs double-strand DNA breaks. POLQ is overexpressed in several cancer types, and increased expression is associated with a poor prognosis. Ablating POLQ function in vitro increases drug sensitivity to agents that cause double-strand DNA breaks, including chemotherapies and ionizing radiation. POLQ's role in thyroid cancer remains poorly understood. METHODS Expression of POLQ and other genes of interest were analyzed in 513 papillary thyroid cancers (505 primary tumors and 8 metastatic lesions) and 59 normal thyroid samples available in the Cancer Genome Atlas. The Cancer Genome Atlas RNA and DNA sequencing data were queried with the Xena platform. The Recombination Proficiency Score was calculated to assess DNA repair efficiency. Other signaling events associated with thyroid tumorigenesis and clinical outcomes were analyzed. Univariate and multivariate analyses were performed. Treatment with the POLQ inhibitors ART558 and Novobiocin tested the effect of POLQ inhibition on in vitro thyroid cancer growth. RESULTS POLQ expression was increased in papillary thyroid cancers compared to normal thyroid tissue (P < .05). POLQ expression levels were inversely correlated with Recombination Proficiency Score levels (P < .05). POLQ expression was highest in tall cell papillary thyroid cancers and in metastases. Higher POLQ expression was also associated with dedifferentiation, BRAF signaling, and shorter progression-free intervals (P < .05). Treatment with POLQ inhibitors decreased in vitro thyroid cancer growth (P < .05). CONCLUSION These findings suggest that increased POLQ expression could serve as a valuable clinical marker and a potential therapeutic target in the treatment of thyroid cancer.
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Affiliation(s)
- C Corbin Frye
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO.
| | - Lena Tennant
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Ashley Yeager
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Pedram Azimzadeh
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Priya Bhardwaj
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Yifei Xu
- Department of Surgery, Division of Public Health Sciences, Washington University School of Medicine, St. Louis, MO
| | - Jingxia Liu
- Department of Surgery, Division of Public Health Sciences, Washington University School of Medicine, St. Louis, MO
| | - Ghofran Othoum
- Department of Medicine, Division of Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Christopher A Maher
- Department of Medicine, Division of Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Rebecca Chernock
- Department of Pathology and Immunology, Division of Anatomic and Molecular Pathology, Washington University School of Medicine, Saint Louis, MO
| | - S Peter Goedegebuure
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
| | - William Gillanders
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
| | - John A Olson
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Taylor C Brown
- Department of Surgery, Section of Surgical Oncology, Washington University School of Medicine, Saint Louis, MO
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30
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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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31
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Osborne HC, Foster BM, Al-Hazmi H, Meyer S, Larrosa I, Schmidt CK. Small-Molecule Inhibition of CBX4/7 Hypersensitises Homologous Recombination-Impaired Cancer to Radiation by Compromising CtIP-Mediated DNA End Resection. Cancers (Basel) 2024; 16:2155. [PMID: 38893273 PMCID: PMC11172190 DOI: 10.3390/cancers16112155] [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: 04/22/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
The therapeutic targeting of DNA repair pathways is an emerging concept in cancer treatment. Compounds that target specific DNA repair processes, such as those mending DNA double-strand breaks (DSBs), are therefore of therapeutic interest. UNC3866 is a small molecule that targets CBX4, a chromobox protein, and a SUMO E3 ligase. As a key modulator of DNA end resection-a prerequisite for DSB repair by homologous recombination (HR)-CBX4 promotes the functions of the DNA resection factor CtIP. Here, we show that treatment with UNC3866 markedly sensitises HR-deficient, NHEJ-hyperactive cancer cells to ionising radiation (IR), while it is non-toxic in selected HR-proficient cells. Consistent with UNC3866 targeting CtIP functions, it inhibits end-resection-dependent DNA repair including HR, alternative end joining (alt-EJ), and single-strand annealing (SSA). These findings raise the possibility that the UNC3866-mediated inhibition of end resection processes we define highlights a distinct vulnerability for the selective killing of HR-ineffective cancers.
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Affiliation(s)
- Hugh C. Osborne
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
| | - Benjamin M. Foster
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
| | - Hazim Al-Hazmi
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
| | - Stefan Meyer
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
- Department of Paediatric and Adolescent Oncology, Royal Manchester Children’s Hospital, Manchester M13 9WL, UK
- Department of Adolescent Oncology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, UK
| | - Igor Larrosa
- Department of Chemistry, University of Manchester, Chemistry Building, Oxford Road, Manchester M13 9PL, UK;
| | - Christine K. Schmidt
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
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32
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Dvořák Tomaštíková E, Vaculíková J, Štenclová V, Kaduchová K, Pobořilová Z, Paleček JJ, Pecinka A. The interplay of homology-directed repair pathways in the repair of zebularine-induced DNA-protein crosslinks in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 38824612 DOI: 10.1111/tpj.16863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/09/2024] [Accepted: 05/16/2024] [Indexed: 06/03/2024]
Abstract
DNA-protein crosslinks (DPCs) are highly toxic DNA lesions represented by proteins covalently bound to the DNA. Persisting DPCs interfere with fundamental genetic processes such as DNA replication and transcription. Cytidine analog zebularine (ZEB) has been shown to crosslink DNA METHYLTRANSFERASE1 (MET1). Recently, we uncovered a critical role of the SMC5/6-mediated SUMOylation in the repair of DPCs. In an ongoing genetic screen, we identified two additional candidates, HYPERSENSITIVE TO ZEBULARINE 2 and 3, that were mapped to REGULATOR OF TELOMERE ELONGATION 1 (RTEL1) and polymerase TEBICHI (TEB), respectively. By monitoring the growth of hze2 and hze3 plants in response to zebularine, we show the importance of homologous recombination (HR) factor RTEL1 and microhomology-mediated end-joining (MMEJ) polymerase TEB in the repair of MET1-DPCs. Moreover, genetic interaction and sensitivity assays showed the interdependency of SMC5/6 complex, HR, and MMEJ in the homology-directed repair of MET1-DPCs in Arabidopsis. Altogether, we provide evidence that MET1-DPC repair in plants is more complex than originally expected.
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Affiliation(s)
- Eva Dvořák Tomaštíková
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 31, Olomouc, 77900, Czech Republic
| | - Jitka Vaculíková
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 31, Olomouc, 77900, Czech Republic
- Faculty of Science, National Center for Biomolecular Research, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic
| | - Veronika Štenclová
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 31, Olomouc, 77900, Czech Republic
| | - Kateřina Kaduchová
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 31, Olomouc, 77900, Czech Republic
| | - Zuzana Pobořilová
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 31, Olomouc, 77900, Czech Republic
| | - Jan J Paleček
- Faculty of Science, National Center for Biomolecular Research, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 62500, Czech Republic
| | - Ales Pecinka
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 31, Olomouc, 77900, Czech Republic
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Zhang X, Joseph S, Wu D, Bowser JL, Vaziri C. The DNA Damage Response (DDR) landscape of endometrial cancer defines discrete disease subtypes and reveals therapeutic opportunities. NAR Cancer 2024; 6:zcae015. [PMID: 38596432 PMCID: PMC11000323 DOI: 10.1093/narcan/zcae015] [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: 11/20/2023] [Revised: 02/12/2024] [Accepted: 04/03/2024] [Indexed: 04/11/2024] Open
Abstract
Genome maintenance is an enabling characteristic that allows neoplastic cells to tolerate the inherent stresses of tumorigenesis and evade therapy-induced genotoxicity. Neoplastic cells also deploy many mis-expressed germ cell proteins termed Cancer Testes Antigens (CTAs) to promote genome maintenance and survival. Here, we present the first comprehensive characterization of the DNA Damage Response (DDR) and CTA transcriptional landscapes of endometrial cancer in relation to conventional histological and molecular subtypes. We show endometrial serous carcinoma (ESC), an aggressive endometrial cancer subtype, is defined by gene expression signatures comprising members of the Replication Fork Protection Complex (RFPC) and Fanconi Anemia (FA) pathway and CTAs with mitotic functions. DDR and CTA-based profiling also defines a subset of highly aggressive endometrioid endometrial carcinomas (EEC) with poor clinical outcomes that share similar profiles to ESC yet have distinct characteristics based on conventional histological and genomic features. Using an unbiased CRISPR-based genetic screen and a candidate gene approach, we confirm that DDR and CTA genes that constitute the ESC and related EEC gene signatures are required for proliferation and therapy-resistance of cultured endometrial cancer cells. Our study validates the use of DDR and CTA-based tumor classifiers and reveals new vulnerabilities of aggressive endometrial cancer where none currently exist.
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Affiliation(s)
- Xingyuan Zhang
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC - 27599, USA
| | - Sayali Joseph
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC - 27599, USA
| | - Di Wu
- Department of Biostatistics, University of North Carolina at Chapel Hill, School of Dentistry, Chapel Hill, NC - 27599, USA
| | - Jessica L Bowser
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC - 27599, USA
- UNC Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC - 27599, USA
| | - Cyrus Vaziri
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC - 27599, USA
- UNC Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC - 27599, USA
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Ordulu Z, Watkins J, Ritterhouse LL. Molecular Pathology of Ovarian Epithelial Neoplasms: Predictive, Prognostic, and Emerging Biomarkers. Clin Lab Med 2024; 44:199-219. [PMID: 38821641 DOI: 10.1016/j.cll.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
This review focuses on the diagnostic, prognostic, and predictive molecular biomarkers in ovarian epithelial neoplasms in the context of their morphologic classifications. Currently, most clinically actionable molecular findings are reported in high-grade serous carcinomas; however, the data on less common tumor types are rapidly accelerating. Overall, the advances in genomic knowledge over the last decade highlight the significance of integrating molecular findings with morphology in ovarian epithelial tumors for a wide-range of clinical applications, from assistance in diagnosis to predicting response to therapy.
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Affiliation(s)
- Zehra Ordulu
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02124, USA
| | - Jaclyn Watkins
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02124, USA
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Porrazzo A, Cassandri M, D'Alessandro A, Morciano P, Rota R, Marampon F, Cenci G. DNA repair in tumor radioresistance: insights from fruit flies genetics. Cell Oncol (Dordr) 2024; 47:717-732. [PMID: 38095764 DOI: 10.1007/s13402-023-00906-6] [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] [Accepted: 11/28/2023] [Indexed: 07/04/2024] Open
Abstract
BACKGROUND Radiation therapy (RT) is a key anti-cancer treatment that involves using ionizing radiation to kill tumor cells. However, this therapy can lead to short- and long-term adverse effects due to radiation exposure of surrounding normal tissue. The type of DNA damage inflicted by radiation therapy determines its effectiveness. High levels of genotoxic damage can lead to cell cycle arrest, senescence, and cell death, but many tumors can cope with this damage by activating protective mechanisms. Intrinsic and acquired radioresistance are major causes of tumor recurrence, and understanding these mechanisms is crucial for cancer therapy. The mechanisms behind radioresistance involve processes like hypoxia response, cell proliferation, DNA repair, apoptosis inhibition, and autophagy. CONCLUSION Here we briefly review the role of genetic and epigenetic factors involved in the modulation of DNA repair and DNA damage response that promote radioresistance. In addition, leveraging our recent results on the effects of low dose rate (LDR) of ionizing radiation on Drosophila melanogaster we discuss how this model organism can be instrumental in the identification of conserved factors involved in the tumor resistance to RT.
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Affiliation(s)
- Antonella Porrazzo
- Department of Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, 00146, Rome, Italy
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Matteo Cassandri
- Department of Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, 00146, Rome, Italy
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Andrea D'Alessandro
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, 00185, Rome, Italy
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, 00161, Rome, Italy
| | - Patrizia Morciano
- Dipartimento di Medicina Clinica, Sanità Pubblica, Scienze della Vita e dell'Ambiente, Università Degli Studi dell'Aquila, 67100, L'Aquila, Italy
- Laboratori Nazionali del Gran Sasso (LNGS), INFN, Assergi, 67100, L'Aquila, Italy
| | - Rossella Rota
- Department of Hematology and Oncology, Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, 00146, Rome, Italy
| | - Francesco Marampon
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Giovanni Cenci
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, 00185, Rome, Italy.
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, 00161, Rome, Italy.
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36
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Wang J, Sadeghi CA, Frock RL. DNA-PKcs suppresses illegitimate chromosome rearrangements. Nucleic Acids Res 2024; 52:5048-5066. [PMID: 38412274 PMCID: PMC11109964 DOI: 10.1093/nar/gkae140] [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: 07/11/2023] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 02/29/2024] Open
Abstract
Two DNA repair pathways, non-homologous end joining (NHEJ) and alternative end joining (A-EJ), are involved in V(D)J recombination and chromosome translocation. Previous studies reported distinct repair mechanisms for chromosome translocation, with NHEJ involved in humans and A-EJ in mice predominantly. NHEJ depends on DNA-PKcs, a critical partner in synapsis formation and downstream component activation. While DNA-PKcs inhibition promotes chromosome translocations harboring microhomologies in mice, its synonymous effect in humans is not known. We find partial DNA-PKcs inhibition in human cells leads to increased translocations and the continued involvement of a dampened NHEJ. In contrast, complete DNA-PKcs inhibition substantially increased microhomology-mediated end joining (MMEJ), thus bridging the two different translocation mechanisms between human and mice. Similar to a previous study on Ku70 deletion, DNA-PKcs deletion in G1/G0-phase mouse progenitor B cell lines, significantly impairs V(D)J recombination and generated higher rates of translocations as a consequence of dysregulated coding and signal end joining. Genetic DNA-PKcs inhibition suppresses NHEJ entirely, with repair phenotypically resembling Ku70-deficient A-EJ. In contrast, we find DNA-PKcs necessary in generating the near-exclusive MMEJ associated with Lig4 deficiency. Our study underscores DNA-PKcs in suppressing illegitimate chromosome rearrangement while also contributing to MMEJ in both species.
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Affiliation(s)
- Jinglong Wang
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cheyenne A Sadeghi
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Richard L Frock
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
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37
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Zhang Q, Chen C, Zou X, Wu W, Di Y, Li N, Fu A. Iron promotes ovarian cancer malignancy and advances platinum resistance by enhancing DNA repair via FTH1/FTL/POLQ/RAD51 axis. Cell Death Dis 2024; 15:329. [PMID: 38740757 PMCID: PMC11091064 DOI: 10.1038/s41419-024-06688-5] [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: 11/23/2023] [Revised: 04/13/2024] [Accepted: 04/16/2024] [Indexed: 05/16/2024]
Abstract
Iron is crucial for cell DNA synthesis and repair, but an excess of free iron can lead to oxidative stress and subsequent cell death. Although several studies suggest that cancer cells display characteristics of 'Iron addiction', an ongoing debate surrounds the question of whether iron can influence the malignant properties of ovarian cancer. In the current study, we initially found iron levels increase during spheroid formation. Furthermore, iron supplementation can promote cancer cell survival, cancer spheroid growth, and migration; vice versa, iron chelators inhibit this process. Notably, iron reduces the sensitivity of ovarian cancer cells to platinum as well. Mechanistically, iron downregulates DNA homologous recombination (HR) inhibitor polymerase theta (POLQ) and relieves its antagonism against the HR repair enzyme RAD51, thereby promoting DNA damage repair to resist chemotherapy-induced damage. Additionally, iron tightly regulated by ferritin (FTH1/FTL) which is indispensable for iron-triggered DNA repair. Finally, we discovered that iron chelators combined with platinum exhibit a synergistic inhibitory effect on ovarian cancer in vitro and in vivo. Our findings affirm the pro-cancer role of iron in ovarian cancer and reveal that iron advances platinum resistance by promoting DNA damage repair through FTH1/FTL/POLQ/RAD51 pathway. Our findings highlight the significance of iron depletion therapy, revealing a promising avenue for advancing ovarian cancer treatment.
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Affiliation(s)
- Qingyu Zhang
- Laboratory of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, Guangdong, China.
| | - Caiyun Chen
- Laboratory of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, Guangdong, China
| | - Xinxin Zou
- Laboratory of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, Guangdong, China
| | - Weifeng Wu
- Laboratory of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, Guangdong, China
| | - Yunbo Di
- Laboratory of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, Guangdong, China
| | - Ning Li
- The Marine Biomedical Research Institute of Guangdong Zhanjiang, Guangdong Medical University, Zhanjiang, 524023, China.
- Department of Hematology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, Guangdong, China.
| | - Aizhen Fu
- Laboratory of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, Guangdong, China.
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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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Morganti S, Marra A, De Angelis C, Toss A, Licata L, Giugliano F, Taurelli Salimbeni B, Berton Giachetti PPM, Esposito A, Giordano A, Bianchini G, Garber JE, Curigliano G, Lynce F, Criscitiello C. PARP Inhibitors for Breast Cancer Treatment: A Review. JAMA Oncol 2024; 10:658-670. [PMID: 38512229 DOI: 10.1001/jamaoncol.2023.7322] [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: 03/22/2024]
Abstract
Importance Poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors have revolutionized the treatment of patients with germline BRCA1/2-associated breast cancer, representing the first targeted therapy capable of improving outcomes in patients with hereditary tumors. However, resistance to PARP inhibitors occurs in almost all patients. Observations This narrative review summarizes the biological rationale behind the use of PARP inhibitors in breast cancer, as well as the available evidence, recent progress, and potential future applications of these agents. Recent studies have shown that the benefit of PARP inhibitors extends beyond patients with germline BRCA1/2-associated metastatic breast cancer to patients with somatic BRCA1/2 variants and to those with germline PALB2 alterations. Moreover, these agents proved to be effective both in the metastatic and adjuvant settings. However, patients with metastatic breast cancer usually do not achieve the long-term benefit from PARP inhibitors observed in other tumor types. Mechanisms of resistance have been identified, but how to effectively target them is largely unknown. Ongoing research is investigating both novel therapeutics and new combination strategies to overcome resistance. PARP1-selective inhibitors, by sparing the hematological toxic effects induced by the PARP2 blockade, are promising agents to be combined with chemotherapy, antibody-drug conjugates, and other targeted therapies. Conclusions and Relevance Although the efficacy of PARP inhibitors is well established, many questions persist. Future research should focus on identifying predictive biomarkers and therapeutic strategies to overcome resistance. Integrating well-designed translational efforts into all clinical studies is thereby crucial to laying the groundwork for future insights from ongoing research.
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Affiliation(s)
- Stefania Morganti
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | | | - Carmine De Angelis
- Department of Clinical Medicine and Surgery, University Federico II, Naples, Italy
- Laster and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas
| | - Angela Toss
- Department of Oncology and Hematology, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy
- Department of Medical and Surgical Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Luca Licata
- Department of Medical Oncology, San Raffaele Hospital, Milan, Italy
- School of Medicine and Surgery, Vita-Salute San Raffaele University, Milan, Italy
| | - Federica Giugliano
- European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
- INSERM U981-Molecular Predictors and New Targets in Oncology, PRISM Center for Precision Medicine, Gustave Roussy, Villejuif, France
| | | | | | - Angela Esposito
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Antonio Giordano
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Giampaolo Bianchini
- Department of Medical Oncology, San Raffaele Hospital, Milan, Italy
- School of Medicine and Surgery, Vita-Salute San Raffaele University, Milan, Italy
| | - Judy E Garber
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Giuseppe Curigliano
- European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Filipa Lynce
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Carmen Criscitiello
- European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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40
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Chatterjee S, Starrett GJ. Microhomology-mediated repair machinery and its relationship with HPV-mediated oncogenesis. J Med Virol 2024; 96:e29674. [PMID: 38757834 DOI: 10.1002/jmv.29674] [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: 12/30/2023] [Revised: 04/19/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024]
Abstract
Human Papillomaviruses (HPV) are a diverse family of non-enveloped dsDNA viruses that infect the skin and mucosal epithelia. Persistent HPV infections can lead to cancer frequently involving integration of the virus into the host genome, leading to sustained oncogene expression and loss of capsid and genome maintenance proteins. Microhomology-mediated double-strand break repair, a DNA double-stranded breaks repair pathway present in many organisms, was initially thought to be a backup but it's now seen as vital, especially in homologous recombination-deficient contexts. Increasing evidence has identified microhomology (MH) near HPV integration junctions, suggesting MH-mediated repair pathways drive integration. In this comprehensive review, we present a detailed summary of both the mechanisms underlying MH-mediated repair and the evidence for its involvement in HPV integration in cancer. Lastly, we highlight the involvement of these processes in the integration of other DNA viruses and the broader implications on virus lifecycles and host innate immune response.
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Affiliation(s)
- Subhajit Chatterjee
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gabriel J Starrett
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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41
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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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42
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Kong LR, Gupta K, Wu AJ, Perera D, Ivanyi-Nagy R, Ahmed SM, Tan TZ, Tan SLW, Fuddin A, Sundaramoorthy E, Goh GS, Wong RTX, Costa ASH, Oddy C, Wong H, Patro CPK, Kho YS, Huang XZ, Choo J, Shehata M, Lee SC, Goh BC, Frezza C, Pitt JJ, Venkitaraman AR. A glycolytic metabolite bypasses "two-hit" tumor suppression by BRCA2. Cell 2024; 187:2269-2287.e16. [PMID: 38608703 DOI: 10.1016/j.cell.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 02/01/2024] [Accepted: 03/07/2024] [Indexed: 04/14/2024]
Abstract
Knudson's "two-hit" paradigm posits that carcinogenesis requires inactivation of both copies of an autosomal tumor suppressor gene. Here, we report that the glycolytic metabolite methylglyoxal (MGO) transiently bypasses Knudson's paradigm by inactivating the breast cancer suppressor protein BRCA2 to elicit a cancer-associated, mutational single-base substitution (SBS) signature in nonmalignant mammary cells or patient-derived organoids. Germline monoallelic BRCA2 mutations predispose to these changes. An analogous SBS signature, again without biallelic BRCA2 inactivation, accompanies MGO accumulation and DNA damage in Kras-driven, Brca2-mutant murine pancreatic cancers and human breast cancers. MGO triggers BRCA2 proteolysis, temporarily disabling BRCA2's tumor suppressive functions in DNA repair and replication, causing functional haploinsufficiency. Intermittent MGO exposure incites episodic SBS mutations without permanent BRCA2 inactivation. Thus, a metabolic mechanism wherein MGO-induced BRCA2 haploinsufficiency transiently bypasses Knudson's two-hit requirement could link glycolysis activation by oncogenes, metabolic disorders, or dietary challenges to mutational signatures implicated in cancer evolution.
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Affiliation(s)
- Li Ren Kong
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Department of Pharmacology, National University of Singapore, Singapore 117600, Singapore
| | - Komal Gupta
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Andy Jialun Wu
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - David Perera
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK
| | | | - Syed Moiz Ahmed
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - Tuan Zea Tan
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - Shawn Lu-Wen Tan
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Institute of Molecular and Cell Biology (IMCB), A(∗)STAR, Singapore 138673, Singapore
| | | | | | | | | | - Ana S H Costa
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Callum Oddy
- Department of Oncology, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Hannan Wong
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - C Pawan K Patro
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - Yun Suen Kho
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore
| | - Xiao Zi Huang
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore
| | - Joan Choo
- Department of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Mona Shehata
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Department of Oncology, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Soo Chin Lee
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; Department of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Boon Cher Goh
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; Department of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Christian Frezza
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; University of Cologne, 50923 Köln, Germany
| | - Jason J Pitt
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; Genome Institute of Singapore, A(∗)STAR, Singapore 138673, Singapore
| | - Ashok R Venkitaraman
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Institute of Molecular and Cell Biology (IMCB), A(∗)STAR, Singapore 138673, Singapore; Department of Oncology, University of Cambridge, Cambridge CB2 0XZ, UK; Department of Medicine, National University of Singapore, Singapore 119228, Singapore.
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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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Fried W, Tyagi M, Minakhin L, Chandramouly G, Tredinnick T, Ramanjulu M, Auerbacher W, Calbert M, Rusanov T, Hoang T, Borisonnik N, Betsch R, Krais JJ, Wang Y, Vekariya UM, Gordon J, Morton G, Kent T, Skorski T, Johnson N, Childers W, Chen XS, Pomerantz RT. Discovery of a small-molecule inhibitor that traps Polθ on DNA and synergizes with PARP inhibitors. Nat Commun 2024; 15:2862. [PMID: 38580648 PMCID: PMC10997755 DOI: 10.1038/s41467-024-46593-1] [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: 08/14/2023] [Accepted: 03/04/2024] [Indexed: 04/07/2024] Open
Abstract
The DNA damage response (DDR) protein DNA Polymerase θ (Polθ) is synthetic lethal with homologous recombination (HR) factors and is therefore a promising drug target in BRCA1/2 mutant cancers. We discover an allosteric Polθ inhibitor (Polθi) class with 4-6 nM IC50 that selectively kills HR-deficient cells and acts synergistically with PARP inhibitors (PARPi) in multiple genetic backgrounds. X-ray crystallography and biochemistry reveal that Polθi selectively inhibits Polθ polymerase (Polθ-pol) in the closed conformation on B-form DNA/DNA via an induced fit mechanism. In contrast, Polθi fails to inhibit Polθ-pol catalytic activity on A-form DNA/RNA in which the enzyme binds in the open configuration. Remarkably, Polθi binding to the Polθ-pol:DNA/DNA closed complex traps the polymerase on DNA for more than forty minutes which elucidates the inhibitory mechanism of action. These data reveal a unique small-molecule DNA polymerase:DNA trapping mechanism that induces synthetic lethality in HR-deficient cells and potentiates the activity of PARPi.
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Affiliation(s)
- William Fried
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Mrityunjay Tyagi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Leonid Minakhin
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Gurushankar Chandramouly
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Taylor Tredinnick
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Mercy Ramanjulu
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA
| | - William Auerbacher
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Marissa Calbert
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
- Fels Cancer Institute for Personalized Medicine, Philadelphia, PA, USA
| | - Timur Rusanov
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | | | | | - Robert Betsch
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - John J Krais
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Yifan Wang
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Umeshkumar M Vekariya
- Fels Cancer Institute for Personalized Medicine, Philadelphia, PA, USA
- Department of Cancer and Cellular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - John Gordon
- Fels Cancer Institute for Personalized Medicine, Philadelphia, PA, USA
| | - George Morton
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA, USA
| | - Tatiana Kent
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Tomasz Skorski
- Fels Cancer Institute for Personalized Medicine, Philadelphia, PA, USA
- Department of Cancer and Cellular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Neil Johnson
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Wayne Childers
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA, USA
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA
| | - Richard T Pomerantz
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA.
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Peng Y, Zheng W, Chen Y, Lei X, Yang Z, Yang Y, Liang W, Sun K, Li G, Yu J. POLQ inhibition attenuates the stemness and ferroptosis resistance in gastric cancer cells via downregulation of dihydroorotate dehydrogenase. Cell Death Dis 2024; 15:248. [PMID: 38575587 PMCID: PMC10995193 DOI: 10.1038/s41419-024-06618-5] [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: 09/29/2023] [Revised: 03/14/2024] [Accepted: 03/18/2024] [Indexed: 04/06/2024]
Abstract
Gastric cancer (GC) contains subpopulations of cancer stem cells (CSCs), which are described as the main contributors in tumor initiation and metastasis. It is necessary to clarify the molecular mechanism underlying CSCs phenotype and develop novel biomarkers and therapeutic targets for gastric cancer. Here, we show that POLQ positively regulates stem cell-like characteristics of gastric cancer cells, knockdown of POLQ suppressed the stemness of GC cells in vitro and in vivo. Further mechanistic studies revealed that POLQ knockdown could downregulate the expression of dihydroorotate dehydrogenase (DHODH). DHODH overexpression rescued the reduced stemness resulted by POLQ knockdown. Furthermore, we found that POLQ expression correlated with resistance to ferroptosis, and POLQ inhibition renders gastric cancer cells more vulnerable to ferroptosis. Further investigation revealed that POLQ regulated DHODH expression via the transcription factors E2F4, thereby regulating ferroptosis resistance and stemness of gastric cancer cells. Given the importance of POLQ in stemness and ferroptosis resistance of GC, we further evaluated the therapeutic potential of POLQ inhibitor novobiocin, the results show that novobiocin attenuates the stemness of GC cells and increased ferroptosis sensitivity. Moreover, the combination of POLQ inhibitor and ferroptosis inducer synergistically suppressed MGC-803 xenograft tumor growth and diminished metastasis. Our results identify a POLQ-mediated stemness and ferroptosis defense mechanism and provide a new therapeutic strategy for gastric cancer.
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Affiliation(s)
- Yanmei Peng
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Wenbo Zheng
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Yuehong Chen
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Xuetao Lei
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Zhijing Yang
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Yuxuan Yang
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Weiqi Liang
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Kai Sun
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China.
| | - Guoxin Li
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China.
- Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China.
| | - Jiang Yu
- Department of General Surgery & Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor, Nanfang Hospital, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China.
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46
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Wang Y, Wang C, Liu J, Sun D, Meng F, Zhang M, Aliper A, Ren F, Zhavoronkov A, Ding X. Discovery of 3-hydroxymethyl-azetidine derivatives as potent polymerase theta inhibitors. Bioorg Med Chem 2024; 103:117662. [PMID: 38493730 DOI: 10.1016/j.bmc.2024.117662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/19/2024]
Abstract
Inhibition of the low fidelity DNA polymerase Theta (Polθ) is emerging as an attractive, synthetic-lethal antitumor strategy in BRCA-deficient tumors. Here we report the AI-enabled development of 3-hydroxymethyl-azetidine derivatives as a novel class of Polθ inhibitors featuring central scaffolding rings. Structure-based drug design first identified A7 as a lead compound, which was further optimized to the more potent derivative B3 and the metabolically stable deuterated compound C1. C1 exhibited significant antiproliferative properties in DNA repair-compromised cells and demonstrated favorable pharmacokinetics, showcasing that 3-hydroxymethyl-azetidine is an effective bio-isostere of pyrrolidin-3-ol and emphasizing the potential of AI in medicinal chemistry for precise molecular modifications.
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Affiliation(s)
- Yazhou Wang
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China
| | - Chao Wang
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China
| | - Jinxin Liu
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China
| | - Deheng Sun
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China
| | - Fanye Meng
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China
| | - Man Zhang
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China
| | - Alex Aliper
- Insilico Medicine AI Limited, Masdar City, Abu Dhabi 145748, United Arab Emirates
| | - Feng Ren
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China
| | - Alex Zhavoronkov
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China; Insilico Medicine AI Limited, Masdar City, Abu Dhabi 145748, United Arab Emirates
| | - Xiao Ding
- Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China.
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47
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Konstantinopoulos PA, Cheng SC, Lee EK, da Costa AABA, Gulhan D, Wahner Hendrickson AE, Kochupurakkal B, Kolin DL, Kohn EC, Liu JF, Penson RT, Stover EH, Curtis J, Sawyer H, Polak M, Chowdhury D, D'Andrea AD, Färkkilä A, Shapiro GI, Matulonis UA. Randomized Phase II Study of Gemcitabine With or Without ATR Inhibitor Berzosertib in Platinum-Resistant Ovarian Cancer: Final Overall Survival and Biomarker Analyses. JCO Precis Oncol 2024; 8:e2300635. [PMID: 38635934 DOI: 10.1200/po.23.00635] [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: 11/18/2023] [Revised: 12/28/2023] [Accepted: 02/29/2024] [Indexed: 04/20/2024] Open
Abstract
PURPOSE The multicenter, open-label, randomized phase 2 NCI-9944 study (NCT02595892) demonstrated that addition of ATR inhibitor (ATRi) berzosertib to gemcitabine increased progression-free survival (PFS) compared to gemcitabine alone (hazard ratio [HR]=0.57, one-sided log-rank P = .044, which met the one-sided significance level of 0.1 used for sample size calculation). METHODS We report here the final overall survival (OS) analysis and biomarker correlations (ATM expression by immunohistochemistry, mutational signature 3 and a genomic biomarker of replication stress) along with post-hoc exploratory analyses to adjust for crossover from gemcitabine to gemcitabine/berzosertib. RESULTS At the data cutoff of January 27, 2023 (>30 months of additional follow-up from the primary analysis), median OS was 59.4 weeks with gemcitabine/berzosertib versus 43.0 weeks with gemcitabine alone (HR 0.79, 90% CI 0.52 to 1.2, one-sided log-rank P = .18). An OS benefit with addition of berzosertib to gemcitabine was suggested in patients stratified into the platinum-free interval ≤3 months (N = 26) subgroup (HR, 0.48, 90% CI 0.22 to 1.01, one-sided log-rank P =.04) and in patients with ATM-negative/low (N = 24) tumors (HR, 0.50, 90% CI 0.23 to 1.08, one-sided log-rank P = .06). CONCLUSION The results of this follow-up analysis continue to support the promise of combined gemcitabine/ATRi therapy in platinum resistant ovarian cancer, an active area of investigation with several ongoing clinical trials.
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Affiliation(s)
| | - Su-Chun Cheng
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Elizabeth K Lee
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Alexandre André B A da Costa
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA
| | - Doga Gulhan
- Department of Biomedical Informatics and Ludwig Center at Harvard, Harvard Medical School, Boston, MA
| | | | - Bose Kochupurakkal
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA
| | - David L Kolin
- Department of Pathology, Brigham and Women's Hospital, Boston, MA
| | - Elise C Kohn
- Cancer Therapy Evaluation Program, National Cancer Institute, Bethesda, MD
| | - Joyce F Liu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Richard T Penson
- Department of Medical Oncology, Massachusetts General Hospital, Boston, MA
| | - Elizabeth H Stover
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Jennifer Curtis
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Hannah Sawyer
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Madeline Polak
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Dipanjan Chowdhury
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA
| | - Anniina Färkkilä
- Research Program in Systems Oncology, FIMM and HiLife, University of Helsinki, Helsinki, Finland
| | - Geoffrey I Shapiro
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Ursula A Matulonis
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
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48
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Ditonno F, Bianchi A, Malandra S, Porcaro AB, Fantinel E, Negrelli R, Ferro M, Milella M, Brunelli M, Autorino R, Cerruto MA, Veccia A, Antonelli A. PARP Inhibitors in Metastatic Prostate Cancer: A Comprehensive Systematic Review and Meta-analysis of Existing Evidence. Clin Genitourin Cancer 2024; 22:402-412.e17. [PMID: 38281877 DOI: 10.1016/j.clgc.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/05/2023] [Accepted: 12/16/2023] [Indexed: 01/30/2024]
Abstract
Poly (ADP-ribose) polymerase inhibitors (PARPi) represent an option in selected cases of metastatic castration-resistant prostate cancer (mCRPC). The aim of the present systematic review and meta-analysis is to evaluate the efficacy and safety of approved (Olaparib, Rucaparib) and investigational (Talazoparib, Niraparib, Veliparib) PARPi in mCRPC patients. Three databases were queried for studies analyzing oncological outcomes and adverse events of mCRPC patients receiving PARPi. Primary outcome was a PSA decline ≥ 50% from baseline. Secondary outcomes were objective response rate, progression-free survival (PFS), radiological PFS, overall survival (OS), conversion of circulating tumor cell count, and time to PSA progression. The number and rate of any grade adverse events (AEs), grade ≥ 3 AEs, and most common grade ≥ 3 AEs were registered. A subanalysis of outcomes per mutation type, prospective trials, and studies adopting combination therapies was performed. Overall, 31 studies were included in this systematic review, 28 of which are available for meta-analysis. The most frequently investigated drug was Olaparib. The most frequent mutation was BRCA2. A PSA decline rate of 43% (95% CI 0.32-0.54) was observed in the overall population. Mean OS was 15.9 (95% CI 12.9-19.0) months. In BRCA2 patients, PSA decline rate was 66% (95% CI 0.57-0.7) and OS 23.4 months (95% CI 22.8-24.1). Half of the patients suffered from grade 3 and 4 AEs (0.50 [95% CI 0.39-0.60]). Most common AEs were hematological, the most frequent being anemia (21.5%). PARP inhibitors represent a viable option for mCRPC patients. Current evidence suggests an increased effectiveness in homologous recombination repair (HRR) gene mutation carriers, especially BRCA2.
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Affiliation(s)
- Francesco Ditonno
- Department of Urology, University of Verona, Azienda Ospedaliera Universitaria Integrata (AOUI) Verona, Verona, Italy; Department of Urology, Rush University, Chicago, IL, USA
| | - Alberto Bianchi
- Department of Urology, University of Verona, Azienda Ospedaliera Universitaria Integrata (AOUI) Verona, Verona, Italy
| | - Sarah Malandra
- Department of Surgery, Dentistry, Pediatrics and Ginecology, University of Verona, Azienda Ospedaliera Universitaria Integrata (AOUI) Verona, Verona, Italy
| | - Antonio Benito Porcaro
- Department of Urology, University of Verona, Azienda Ospedaliera Universitaria Integrata (AOUI) Verona, Verona, Italy
| | - Emanuela Fantinel
- Section of Oncology, Department of Medicine, University of Verona, Azienda Ospedaliera Universitaria Integrata, Verona, Italy
| | - Riccardo Negrelli
- Department of Radiology, University of Verona, Azienda Ospedaliera Universitaria Integrata, Verona, Italy
| | - Matteo Ferro
- Department of Urology, European Institute of Oncology (IEO) IRCCS, Milan, Italy
| | - Michele Milella
- Section of Oncology, Department of Medicine, University of Verona, Azienda Ospedaliera Universitaria Integrata, Verona, Italy
| | - Matteo Brunelli
- Department of Diagnostic and Public Health, Section of Pathology, University of Verona, Italy
| | | | - Maria Angela Cerruto
- Department of Urology, University of Verona, Azienda Ospedaliera Universitaria Integrata (AOUI) Verona, Verona, Italy
| | - Alessandro Veccia
- Department of Urology, University of Verona, Azienda Ospedaliera Universitaria Integrata (AOUI) Verona, Verona, Italy.
| | - Alessandro Antonelli
- Department of Urology, University of Verona, Azienda Ospedaliera Universitaria Integrata (AOUI) Verona, Verona, Italy
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49
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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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50
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Kralemann LEM, van Tol N, Hooykaas PJJ, Tijsterman M. Molecular analysis of the role of polymerase theta in gene targeting in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:255-262. [PMID: 38402589 DOI: 10.1111/tpj.16689] [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: 10/16/2023] [Revised: 01/05/2024] [Accepted: 02/07/2024] [Indexed: 02/27/2024]
Abstract
Precise genetic modification can be achieved via a sequence homology-mediated process known as gene targeting (GT). Whilst established for genome engineering purposes, the application of GT in plants still suffers from a low efficiency for which an explanation is currently lacking. Recently reported reduced rates of GT in A. thaliana deficient in polymerase theta (Polθ), a core component of theta-mediated end joining (TMEJ) of DNA breaks, have led to the suggestion of a direct involvement of this enzyme in the homology-directed process. Here, by monitoring homology-driven gene conversion in plants with CRISPR reagent and donor sequences pre-integrated at random sites in the genome (in planta GT), we demonstrate that Polθ action is not required for GT, but instead suppresses the process, likely by promoting the repair of the DNA break by end-joining. This finding indicates that lack of donor integration explains the previously established reduced GT rates seen upon transformation of Polθ-deficient plants. Our study additionally provides insight into ectopic gene targeting (EGT), recombination events between donor and target that do not map to the target locus. EGT, which occurs at similar frequencies as "true" GT during transformation, was rare in our in planta GT experiments arguing that EGT predominantly results from target locus recombination with nonintegrated T-DNA molecules. By describing mechanistic features of GT our study provides directions for the improvement of precise genetic modification of plants.
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Affiliation(s)
- Lejon E M Kralemann
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Niels van Tol
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Paul J J Hooykaas
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Marcel Tijsterman
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
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