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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. [PMID: 38651239 DOI: 10.1111/cas.16188] [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: 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 Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yasukazu Daigaku
- Cancer Genome Dynamics Project, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
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2
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Sun M, Zhao B, Chen T, Yao L, Li X, Hu S, Chen C, Gao X, Tang C. Novel molecular typing reveals the risk of recurrence in patients with early-stage papillary thyroid cancer. Thyroid Res 2024; 17:7. [PMID: 38556856 PMCID: PMC10983671 DOI: 10.1186/s13044-024-00193-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/06/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND Papillary thyroid cancer (PTC) is an indolent disease with a favorable prognosis but characterized by a high recurrence rate. We aimed to improve precise stratification of recurrence risk in PTC patients with early stage using multi-gene signatures. PATIENTS AND METHODS The present study was performed using data from The Cancer Genome Atlas (TCGA) and multi-center datasets. Unsupervised consensus clustering was used to obtain the optimal molecular subtypes and least absolute shrinkage and selection operator (LASSO) analysis was performed to identify potential genes for the construction of recurrence signature. Kaplan-Meier survival analysis and the log-rank test was used to detect survival differences. Harrells concordance index (C-index) was used to assess the performance of the DNA damage repair (DDR) recurrence signature. RESULTS Through screening 8 candidate gene sets, the entire cohort was successfully stratified into two recurrence-related molecular subtypes based on DDR genes: DDR-high subtype and DDR-low subtype. The recurrence rate of DDR-high subtype was significantly lower than DDR-low subtype [HR = 0.288 (95%CI, 0.084-0.986), P = 0.047]. Further, a two-gene DDR recurrence signature was constructed, including PER1 and EME2. The high-risk group showed a significantly worse recurrence-free survival (RFS) than the low-risk group [HR = 10.647 (95%CI, 1.363-83.197), P = 0.024]. The multi-center data demonstrated that proportion of patients with low expression of PER1 and EME2 was higher in the recurrence group than those in the non-recurrence group. CONCLUSIONS These findings could help accurately and reliably identify PTC patients with high risk of recurrence so that they could receive more radical and aggressive treatment strategies and more rigorous surveillance practices.
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Affiliation(s)
- Mingyu Sun
- Department of Breast Surgery, Xuzhou Central Hospital, The Affiliated Xuzhou Hospital of Medical College of Southeast University, Xuzhou, 221009, China
| | - Bingqing Zhao
- Department of Plastic and Reconstructive Surgery, Tianjin Hospital of ITCWM Nankai Hospital, Tianjin, 300100, China
| | - Tao Chen
- The Xuzhou Clinical College of Xuzhou Medical University, Jiangsu, 221009, China
| | - Lijun Yao
- Department of Oncology, Suzhou Ninth People's Hospital, Suzhou, 215200, China
| | - Xiaoxin Li
- Department of Pathology, Xuzhou Central Hospital, The Affiliated Xuzhou Hospital of Medical College of Southeast University, Xuzhou, 221009, China
| | - Shaojun Hu
- Department of Oncology, Suzhou Ninth People's Hospital, Suzhou, 215200, China
| | - Chengling Chen
- Department of Breast Surgery, Xuzhou Central Hospital, The Affiliated Xuzhou Hospital of Medical College of Southeast University, Xuzhou, 221009, China.
| | - Xinbao Gao
- Department of Surgery for Vascular Thyroid and Hernia, Xuzhou Central Hospital, The Affiliated Xuzhou Hospital of Medical College of Southeast University, Xuzhou, 221009, China.
| | - Chuangang Tang
- Department of Breast Surgery, Xuzhou Central Hospital, The Affiliated Xuzhou Hospital of Medical College of Southeast University, Xuzhou, 221009, China.
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3
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Eckert KA. Nontraditional Roles of DNA Polymerase Eta Support Genome Duplication and Stability. Genes (Basel) 2023; 14:genes14010175. [PMID: 36672916 PMCID: PMC9858799 DOI: 10.3390/genes14010175] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
DNA polymerase eta (Pol η) is a Y-family polymerase and the product of the POLH gene. Autosomal recessive inheritance of POLH mutations is the cause of the xeroderma pigmentosum variant, a cancer predisposition syndrome. This review summarizes mounting evidence for expanded Pol η cellular functions in addition to DNA lesion bypass that are critical for maintaining genome stability. In vitro, Pol η displays efficient DNA synthesis through difficult-to-replicate sequences, catalyzes D-loop extensions, and utilizes RNA-DNA hybrid templates. Human Pol η is constitutively present at the replication fork. In response to replication stress, Pol η is upregulated at the transcriptional and protein levels, and post-translational modifications regulate its localization to chromatin. Numerous studies show that Pol η is required for efficient common fragile site replication and stability. Additionally, Pol η can be recruited to stalled replication forks through protein-protein interactions, suggesting a broader role in replication fork recovery. During somatic hypermutations, Pol η is recruited by mismatch repair proteins and is essential for VH gene A:T basepair mutagenesis. Within the global context of repeat-dense genomes, the recruitment of Pol η to perform specialized functions during replication could promote genome stability by interrupting pure repeat arrays with base substitutions. Alternatively, not engaging Pol η in genome duplication is costly, as the absence of Pol η leads to incomplete replication and increased chromosomal instability.
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Affiliation(s)
- Kristin A Eckert
- Gittlen Cancer Research Laboratories, Department of Pathology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17036, USA
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4
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Murakami Y, Kimura-Masuda K, Oda T, Matsumura I, Masuda Y, Ishihara R, Watanabe S, Kuroda Y, Kasamatsu T, Gotoh N, Takei H, Kobayashi N, Saitoh T, Murakami H, Handa H. MYC Causes Multiple Myeloma Progression via Attenuating TP53-Induced MicroRNA-34 Expression. Genes (Basel) 2022; 14:100. [PMID: 36672841 PMCID: PMC9859619 DOI: 10.3390/genes14010100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/31/2022] Open
Abstract
MicroRNAs (miRNAs and miRs) are small (19-25 base pairs) non-coding RNAs with the ability to modulate gene expression. Previously, we showed that the miR-34 family is downregulated in multiple myeloma (MM) as the cancer progressed. In this study, we aimed to clarify the mechanism of miRNA dysregulation in MM. We focused particularly on the interaction between MYC and the TP53-miR34 axis because there is a discrepancy between increased TP53 and decreased miR-34 expressions in MM. Using the nutlin-3 or Tet-on systems, we caused wild-type (WT) p53 protein accumulation in human MM cell lines (HMCLs) and observed upregulated miR-34 expression. Next, we found that treatment with an Myc inhibitor alone did not affect miR-34 expression levels, but when it was coupled with p53 accumulation, miR-34 expression increased. In contrast, forced MYC activation by the MYC-ER system reduced nutlin-3-induced miR-34 expression. We also observed that TP53 and MYC were negatively correlated with mature miR-34 expressions in the plasma cells of patients with MM. Our results suggest that MYC participates in the suppression of p53-dependent miRNA expressions. Because miRNA expression suppresses tumors, its inhibition leads to MM development and malignant transformation.
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Affiliation(s)
- Yuki Murakami
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Kei Kimura-Masuda
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Tsukasa Oda
- Laboratory of Mucosal Ecosystem Design, The Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8510, Japan
| | - Ikuko Matsumura
- Department of Hematology, Gunma University Graduate School of Medicine, Maebashi 371-8510, Japan
| | - Yuta Masuda
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
- Faculty of Medical Technology and Clinical Engineering, Gunma University of Health and Welfare, Maebashi 371-0823, Japan
| | - Rei Ishihara
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Saki Watanabe
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Yuko Kuroda
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Tetsuhiro Kasamatsu
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Nanami Gotoh
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Hisashi Takei
- Department of Hematology, Gunma University Graduate School of Medicine, Maebashi 371-8510, Japan
| | - Nobuhiko Kobayashi
- Department of Hematology, Gunma University Graduate School of Medicine, Maebashi 371-8510, Japan
| | - Takayuki Saitoh
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Maebashi 371-8510, Japan
| | - Hirokazu Murakami
- Faculty of Medical Technology and Clinical Engineering, Gunma University of Health and Welfare, Maebashi 371-0823, Japan
| | - Hiroshi Handa
- Department of Hematology, Gunma University Graduate School of Medicine, Maebashi 371-8510, Japan
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5
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Oda T, Nakamura R, Kasamatsu T, Gotoh N, Okuda K, Saitoh T, Handa H, Murakami H, Yamashita T. DNA-double strand breaks enhance the expression of major histocompatibility complex class II through the ATM-NF-κΒ-IRF1-CIITA pathway. Cancer Gene Ther 2022; 29:225-240. [PMID: 33619341 DOI: 10.1038/s41417-021-00302-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 01/18/2021] [Accepted: 01/28/2021] [Indexed: 01/31/2023]
Abstract
Major histocompatibility complex class II (MHC II) is important for the adaptive immune response because MHC II presents processed antigens to a cluster of differentiation 4 (CD4)-positive T-cells. Conventional doses of chemotherapeutic agents induce tumor cell death by causing DNA double-strand breaks (DSBs). However, cellular responses caused by sub-lethal doses of chemotherapeutic agents are poorly understood. In this study, using low doses of chemotherapeutic agents, we showed that DSBs enhanced the expression of MHC II on cells that originate from antigen-presenting cells (APCs). These agents induced the MHC class II transactivator (CIITA), the master regulator of MHC II, and interferon regulatory factor 1 (IRF1), a transcription factor for CIITA. Short hairpin RNA against IRF1 suppressed chemotherapeutic agent-induced CIITA expression, whereas exogenous expression of IRF1 induced CIITA. Inhibition of ataxia-telangiectasia mutated (ATM), a DSB-activated kinase, suppressed induction of IRF1, CIITA, and MHC II. Similar results were observed by inhibiting NF-κB, a downstream target of ATM. These results suggest that DSBs induce MHC II activity via the ATM-NF-κB-IRF1-CIITA pathway in cells that intrinsically present antigens. Additionally, chemotherapeutic agents induced T-cell regulatory molecules. Our findings suggest that chemotherapeutic agents enhance the antigen presentation activity of APCs for T-cell activation.
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Affiliation(s)
- Tsukasa Oda
- Laboratory of Molecular Genetics, The Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan. .,Center for Food Science and Wellness, Gunma University, Maebashi, Gunma, Japan.
| | - Ruri Nakamura
- Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan
| | - Tetsuhiro Kasamatsu
- Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan
| | - Nanami Gotoh
- Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan
| | - Keiko Okuda
- Department of Molecular Diagnostics and Therapeutics, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, Japan
| | - Takayuki Saitoh
- Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan
| | - Hiroshi Handa
- Graduate School of Medicine, Gunma University, Maebashi, Gunma, Japan
| | - Hirokazu Murakami
- Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan.,Gunma University of Health and Welfare, Maebashi, Gunma, Japan
| | - Takayuki Yamashita
- Laboratory of Molecular Genetics, The Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
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6
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Ahmadi SE, Rahimi S, Zarandi B, Chegeni R, Safa M. MYC: a multipurpose oncogene with prognostic and therapeutic implications in blood malignancies. J Hematol Oncol 2021; 14:121. [PMID: 34372899 PMCID: PMC8351444 DOI: 10.1186/s13045-021-01111-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/12/2021] [Indexed: 12/17/2022] Open
Abstract
MYC oncogene is a transcription factor with a wide array of functions affecting cellular activities such as cell cycle, apoptosis, DNA damage response, and hematopoiesis. Due to the multi-functionality of MYC, its expression is regulated at multiple levels. Deregulation of this oncogene can give rise to a variety of cancers. In this review, MYC regulation and the mechanisms by which MYC adjusts cellular functions and its implication in hematologic malignancies are summarized. Further, we also discuss potential inhibitors of MYC that could be beneficial for treating hematologic malignancies.
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Affiliation(s)
- Seyed Esmaeil Ahmadi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Rahimi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Bahman Zarandi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rouzbeh Chegeni
- Medical Laboratory Sciences Program, College of Health and Human Sciences, Northern Illinois University, DeKalb, IL, USA.
| | - Majid Safa
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.
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7
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Curti L, Campaner S. MYC-Induced Replicative Stress: A Double-Edged Sword for Cancer Development and Treatment. Int J Mol Sci 2021; 22:6168. [PMID: 34201047 PMCID: PMC8227504 DOI: 10.3390/ijms22126168] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/15/2022] Open
Abstract
MYC is a transcription factor that controls the expression of a large fraction of cellular genes linked to cell cycle progression, metabolism and differentiation. MYC deregulation in tumors leads to its pervasive genome-wide binding of both promoters and distal regulatory regions, associated with selective transcriptional control of a large fraction of cellular genes. This pairs with alterations of cell cycle control which drive anticipated S-phase entry and reshape the DNA-replication landscape. Under these circumstances, the fine tuning of DNA replication and transcription becomes critical and may pose an intrinsic liability in MYC-overexpressing cancer cells. Here, we will review the current understanding of how MYC controls DNA and RNA synthesis, discuss evidence of replicative and transcriptional stress induced by MYC and summarize preclinical data supporting the therapeutic potential of triggering replicative stress in MYC-driven tumors.
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Affiliation(s)
- Laura Curti
- Center for Genomic Science of IIT@CGS, Fondazione Istituto Italiano di Tecnologia (IIT), 20139 Milan, Italy
| | - Stefano Campaner
- Center for Genomic Science of IIT@CGS, Fondazione Istituto Italiano di Tecnologia (IIT), 20139 Milan, Italy
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8
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Calzetta NL, González Besteiro MA, Gottifredi V. PARP Activity Fine-tunes the DNA Replication Choreography of Chk1-depleted Cells. J Mol Biol 2021; 433:166949. [PMID: 33744317 DOI: 10.1016/j.jmb.2021.166949] [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: 12/29/2020] [Revised: 02/18/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022]
Abstract
Checkpoint Kinase 1 (Chk1) prevents DNA damage by adjusting the replication choreography in the face of replication stress. Chk1 depletion provokes slow and asymmetrical fork movement, yet the signals governing such changes remain unclear. We sought to investigate whether poly(ADP-ribose) polymerases (PARPs), key players of the DNA damage response, intervene in the DNA replication of Chk1-depleted cells. We demonstrate that PARP inhibition selectively alleviates the reduced fork elongation rates, without relieving fork asymmetry in Chk1-depleted cells. While the contribution of PARPs to fork elongation is not unprecedented, we found that their role in Chk1-depleted cells extends beyond fork movement. PARP-dependent fork deceleration induced mild dormant origin firing upon Chk1 depletion, augmenting the global rates of DNA synthesis. Thus, we have identified PARPs as novel regulators of replication fork dynamics in Chk1-depleted cells.
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Affiliation(s)
- Nicolás Luis Calzetta
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Marina Alejandra González Besteiro
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina.
| | - Vanesa Gottifredi
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina.
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9
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Tsao WC, Buj R, Aird KM, Sidorova JM, Eckert KA. Overexpression of oncogenic H-Ras in hTERT-immortalized and SV40-transformed human cells targets replicative and specialized DNA polymerases for depletion. PLoS One 2021; 16:e0251188. [PMID: 33961649 PMCID: PMC8104423 DOI: 10.1371/journal.pone.0251188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/21/2021] [Indexed: 11/26/2022] Open
Abstract
DNA polymerases play essential functions in replication fork progression and genome maintenance. DNA lesions and drug-induced replication stress result in up-regulation and re-localization of specialized DNA polymerases η and κ. Although oncogene activation significantly alters DNA replication dynamics, causing replication stress and genome instability, little is known about DNA polymerase expression and regulation in response to oncogene activation. Here, we investigated the consequences of mutant H-RASG12V overexpression on the regulation of DNA polymerases in h-TERT immortalized and SV40-transformed human cells. Focusing on DNA polymerases associated with the replication fork, we demonstrate that DNA polymerases are depleted in a temporal manner in response to H-RASG12V overexpression. The polymerases targeted for depletion, as cells display markers of senescence, include the Pol α catalytic subunit (POLA1), Pol δ catalytic and p68 subunits (POLD1 and POLD3), Pol η, and Pol κ. Both transcriptional and post-transcriptional mechanisms mediate this response. Pol η (POLH) depletion is sufficient to induce a senescence-like growth arrest in human foreskin fibroblast BJ5a cells, and is associated with decreased Pol α expression. Using an SV-40 transformed cell model, we observed cell cycle checkpoint signaling differences in cells with H-RasG12V-induced polymerase depletion, as compared to Pol η-deficient cells. Our findings contribute to our understanding of cellular events following oncogene activation and cellular transformation.
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Affiliation(s)
- Wei-chung Tsao
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Raquel Buj
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Katherine M. Aird
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
- Penn State Cancer Institute, Pennsylvania State University, Hershey, Pennsylvania, United States of America
| | - Julia M. Sidorova
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Kristin A. Eckert
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
- Penn State Cancer Institute, Pennsylvania State University, Hershey, Pennsylvania, United States of America
- * E-mail:
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10
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Nayak S, Calvo JA, Cantor SB. Targeting translesion synthesis (TLS) to expose replication gaps, a unique cancer vulnerability. Expert Opin Ther Targets 2021; 25:27-36. [PMID: 33416413 DOI: 10.1080/14728222.2021.1864321] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Introduction: Translesion synthesis (TLS) is a DNA damage tolerance (DDT) mechanism that employs error-prone polymerases to bypass replication blocking DNA lesions, contributing to a gain in mutagenesis and chemo-resistance. However, recent findings illustrate an emerging role for TLS in replication gap suppression (RGS), distinct from its role in post-replication gap filling. Here, TLS protects cells from replication stress (RS)-induced toxic single-stranded DNA (ssDNA) gaps that accumulate in the wake of active replication. Intriguingly, TLS-mediated RGS is specifically observed in several cancer cell lines and contributes to their survival. Thus, targeting TLS has the potential to uniquely eradicate tumors without harming non-cancer tissues. Areas Covered: This review provides an innovative perspective on the role of TLS beyond its canonical function of lesion bypass or post-replicative gap filling. We provide a comprehensive analysis that underscores the emerging role of TLS as a cancer adaptation necessary to overcome the replication stress response (RSR), an anti-cancer barrier. Expert Opinion: TLS RGS is critical for tumorigenesis and is a new hallmark of cancer. Although the exact mechanism and extent of TLS dependency in cancer is still emerging, TLS inhibitors have shown promise as an anti-cancer therapy in selectively targeting this unique cancer vulnerability.
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Affiliation(s)
- Sumeet Nayak
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School , Worcester, MA USA
| | - Jennifer A Calvo
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School , Worcester, MA USA
| | - Sharon B Cantor
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School , Worcester, MA USA
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11
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Unravelling roles of error-prone DNA polymerases in shaping cancer genomes. Oncogene 2021; 40:6549-6565. [PMID: 34663880 PMCID: PMC8639439 DOI: 10.1038/s41388-021-02032-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/01/2021] [Accepted: 09/20/2021] [Indexed: 12/12/2022]
Abstract
Mutagenesis is a key hallmark and enabling characteristic of cancer cells, yet the diverse underlying mutagenic mechanisms that shape cancer genomes are not understood. This review will consider the emerging challenge of determining how DNA damage response pathways-both tolerance and repair-act upon specific forms of DNA damage to generate mutations characteristic of tumors. DNA polymerases are typically the ultimate mutagenic effectors of DNA repair pathways. Therefore, understanding the contributions of DNA polymerases is critical to develop a more comprehensive picture of mutagenic mechanisms in tumors. Selection of an appropriate DNA polymerase-whether error-free or error-prone-for a particular DNA template is critical to the maintenance of genome stability. We review different modes of DNA polymerase dysregulation including mutation, polymorphism, and over-expression of the polymerases themselves or their associated activators. Based upon recent findings connecting DNA polymerases with specific mechanisms of mutagenesis, we propose that compensation for DNA repair defects by error-prone polymerases may be a general paradigm molding the mutational landscape of cancer cells. Notably, we demonstrate that correlation of error-prone polymerase expression with mutation burden in a subset of patient tumors from The Cancer Genome Atlas can identify mechanistic hypotheses for further testing. We contrast experimental approaches from broad, genome-wide strategies to approaches with a narrower focus on a few hundred base pairs of DNA. In addition, we consider recent developments in computational annotation of patient tumor data to identify patterns of mutagenesis. Finally, we discuss the innovations and future experiments that will develop a more comprehensive portrait of mutagenic mechanisms in human tumors.
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12
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Beyond Kinases: Targeting Replication Stress Proteins in Cancer Therapy. Trends Cancer 2020; 7:430-446. [PMID: 33203609 DOI: 10.1016/j.trecan.2020.10.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/19/2020] [Accepted: 10/26/2020] [Indexed: 12/13/2022]
Abstract
DNA replication stress describes a state of impaired replication fork progress that triggers a cellular stress response to maintain genome stability and complete DNA synthesis. Replication stress is a common state that must be tolerated in many cancers. One promising therapeutic approach is targeting replication stress response factors such as the ataxia telangiectasia and rad 3-related kinase (ATR) or checkpoint kinase 1 (CHK1) kinases that some cancers depend upon to survive endogenous replication stress. However, research revealing the complexity of the replication stress response suggests new genetic interactions and candidate therapeutic targets. Many of these candidates regulate DNA transactions around reversed replication forks, including helicases, nucleases and alternative polymerases that promote fork stability and restart. Here we review emerging strategies to exploit replication stress for cancer therapy.
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13
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Saha P, Mandal T, Talukdar AD, Kumar D, Kumar S, Tripathi PP, Wang QE, Srivastava AK. DNA polymerase eta: A potential pharmacological target for cancer therapy. J Cell Physiol 2020; 236:4106-4120. [PMID: 33184862 DOI: 10.1002/jcp.30155] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/21/2020] [Accepted: 11/02/2020] [Indexed: 12/24/2022]
Abstract
In the last two decades, intensive research has been carried out to improve the survival rates of cancer patients. However, the development of chemoresistance that ultimately leads to tumor relapse poses a critical challenge for the successful treatment of cancer patients. Many cancer patients experience tumor relapse and ultimately die because of treatment failure associated with acquired drug resistance. Cancer cells utilize multiple lines of self-defense mechanisms to bypass chemotherapy and radiotherapy. One such mechanism employed by cancer cells is translesion DNA synthesis (TLS), in which specialized TLS polymerases bypass the DNA lesion with the help of monoubiquitinated proliferating cell nuclear antigen. Among all TLS polymerases (Pol η, Pol ι, Pol κ, REV1, Pol ζ, Pol μ, Pol λ, Pol ν, and Pol θ), DNA polymerase eta (Pol η) is well studied and majorly responsible for the bypass of cisplatin and UV-induced DNA damage. TLS polymerases contribute to chemotherapeutic drug-induced mutations as well as therapy resistance. Therefore, targeting these polymerases presents a novel therapeutic strategy to combat chemoresistance. Mounting evidence suggests that inhibition of Pol η may have multiple impacts on cancer therapy such as sensitizing cancer cells to chemotherapeutics, suppressing drug-induced mutagenesis, and inhibiting the development of secondary tumors. Herein, we provide a general introduction of Pol η and its clinical implications in blocking acquired drug resistance. In addition; this review addresses the existing gaps and challenges of Pol η mediated TLS mechanisms in human cells. A better understanding of the Pol η mediated TLS mechanism will not merely establish it as a potential pharmacological target but also open possibilities to identify novel drug targets for future therapy.
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Affiliation(s)
- Priyanka Saha
- Cancer Biology & Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Tanima Mandal
- Cancer Biology & Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Anupam D Talukdar
- Department of Life Science and Bioinformatics, Assam University, Silchar, Assam, India
| | - Deepak Kumar
- Organic & Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Sanjay Kumar
- Division of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Andhra Pradesh, India
| | - Prem P Tripathi
- Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Qi-En Wang
- Department of Radiation Oncology, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Amit K Srivastava
- Cancer Biology & Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
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14
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Kurashima K, Kashiwagi H, Shimomura I, Suzuki A, Takeshita F, Mazevet M, Harata M, Yamashita T, Yamamoto Y, Kohno T, Shiotani B. SMARCA4 deficiency-associated heterochromatin induces intrinsic DNA replication stress and susceptibility to ATR inhibition in lung adenocarcinoma. NAR Cancer 2020; 2:zcaa005. [PMID: 34316685 PMCID: PMC8210217 DOI: 10.1093/narcan/zcaa005] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 03/28/2020] [Accepted: 04/16/2020] [Indexed: 12/31/2022] Open
Abstract
The SWI/SNF chromatin remodeling complex regulates transcription through the control of chromatin structure and is increasingly thought to play an important role in human cancer. Lung adenocarcinoma (LADC) patients frequently harbor mutations in SMARCA4, a core component of this multisubunit complex. Most of these mutations are loss-of-function mutations, which disrupt critical functions in the regulation of chromatin architecture and can cause DNA replication stress. This study reports that LADC cells deficient in SMARCA4 showed increased DNA replication stress and greater sensitivity to the ATR inhibitor (ATRi) in vitro and in vivo. Mechanistically, loss of SMARCA4 increased heterochromatin formation, resulting in stalled forks, a typical DNA replication stress. In the absence of SMARCA4, severe ATRi-induced single-stranded DNA, which caused replication catastrophe, was generated on nascent DNA near the reversed forks around heterochromatin in an Mre11-dependent manner. Thus, loss of SMARCA4 confers susceptibility to ATRi, both by increasing heterochromatin-associated replication stress and by allowing Mre11 to destabilize reversed forks. These two mechanisms synergistically increase susceptibility of SMARCA4-deficient LADC cells to ATRi. These results provide a preclinical basis for assessing SMARCA4 defects as a biomarker of ATRi efficacy.
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Affiliation(s)
- Kiminori Kurashima
- Division of Cellular Signaling, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
| | - Hideto Kashiwagi
- Division of Cellular Signaling, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
| | - Iwao Shimomura
- Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
- Department of Respirology, Graduate School of Medicine, Chiba University, Chiba-shi, Chiba 260-8670, Japan
| | - Ayako Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-shi, Chiba 277-8562, Japan
| | - Fumitaka Takeshita
- Department of Functional Analysis, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
| | - Marianne Mazevet
- Division of Cellular Signaling, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
| | - Masahiko Harata
- Graduate School of Agricultural Science, Tohoku University, Sendai-shi, Miyagi 980-0845, Japan
| | - Takayuki Yamashita
- Laboratory of Molecular Genetics, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi-shi, Gunma 371-8512, Japan
| | - Yusuke Yamamoto
- Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
| | - Takashi Kohno
- Division of Genome Biology, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
| | - Bunsyo Shiotani
- To whom correspondence should be addressed. Tel: +81 3 3547 5201 (Ext. 3681); Fax: +81 3 3543 9305;
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15
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ATR Inhibition Potentiates PARP Inhibitor Cytotoxicity in High Risk Neuroblastoma Cell Lines by Multiple Mechanisms. Cancers (Basel) 2020; 12:cancers12051095. [PMID: 32354033 PMCID: PMC7281288 DOI: 10.3390/cancers12051095] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/23/2020] [Indexed: 12/12/2022] Open
Abstract
Background: High risk neuroblastoma (HR-NB) is one the most difficult childhood cancers to cure. These tumours frequently present with DNA damage response (DDR) defects including loss or mutation of key DDR genes, oncogene-induced replication stress (RS) and cell cycle checkpoint dysfunction. Aim: To identify biomarkers of sensitivity to inhibition of Ataxia telangiectasia and Rad3 related (ATR), a DNA damage sensor, and poly (ADP-ribose) polymerase (PARP), which is required for single strand break repair. We also hypothesise that combining ATR and PARP inhibition is synergistic. Methods: Single agent sensitivity to VE-821 (ATR inhibitor) and olaparib (PARP inhibitor), and the combination, was determined using cell proliferation and clonogenic assays, in HR-NB cell lines. Basal expression of DDR proteins, including ataxia telangiectasia mutated (ATM) and ATR, was assessed using Western blotting. CHK1S345 and H2AXS129 phosphorylation was assessed using Western blotting to determine ATR activity and RS, respectively. RS and homologous recombination repair (HRR) activity was also measured by γH2AX and Rad51 foci formation using immunofluorescence. Results: MYCN amplification and/or low ATM protein expression were associated with sensitivity to VE-821 (p < 0.05). VE-821 was synergistic with olaparib (CI value 0.04-0.89) independent of MYCN or ATM status. Olaparib increased H2AXS129 phosphorylation which was further increased by VE-821. Olaparib-induced Rad51 foci formation was reduced by VE-821 suggesting inhibition of HRR. Conclusion: RS associated with MYCN amplification, ATR loss or PARP inhibition increases sensitivity to the ATR inhibitor VE-821. These findings suggest a potential therapeutic strategy for the treatment of HR-NB.
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González Besteiro MA, Calzetta NL, Loureiro SM, Habif M, Bétous R, Pillaire MJ, Maffia A, Sabbioneda S, Hoffmann JS, Gottifredi V. Chk1 loss creates replication barriers that compromise cell survival independently of excess origin firing. EMBO J 2019; 38:e101284. [PMID: 31294866 DOI: 10.15252/embj.2018101284] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 06/11/2019] [Accepted: 06/19/2019] [Indexed: 01/18/2023] Open
Abstract
The effectiveness of checkpoint kinase 1 (Chk1) inhibitors at killing cancer cells is considered to be fully dependent on their effect on DNA replication initiation. Chk1 inhibition boosts origin firing, presumably limiting the availability of nucleotides and in turn provoking the slowdown and subsequent collapse of forks, thus decreasing cell viability. Here we show that slow fork progression in Chk1-inhibited cells is not an indirect effect of excess new origin firing. Instead, fork slowdown results from the accumulation of replication barriers, whose bypass is impeded by CDK-dependent phosphorylation of the specialized DNA polymerase eta (Polη). Also in contrast to the linear model, the accumulation of DNA damage in Chk1-deficient cells depends on origin density but is largely independent of fork speed. Notwithstanding this, origin dysregulation contributes only mildly to the poor proliferation rates of Chk1-depleted cells. Moreover, elimination of replication barriers by downregulation of helicase components, but not their bypass by Polη, improves cell survival. Our results thus shed light on the molecular basis of the sensitivity of tumors to Chk1 inhibition.
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Affiliation(s)
- Marina A González Besteiro
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Nicolás L Calzetta
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Sofía M Loureiro
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Martín Habif
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Rémy Bétous
- Equipe «Labellisée LA LIGUE CONTRE LE CANCER», Laboratoire d'Excellence Toulouse Cancer LABEX TOUCAN - Cancer Research Center of Toulouse, Inserm U1037, CNRS ERL5294, University Paul Sabatier, Toulouse, France
| | - Marie-Jeanne Pillaire
- Equipe «Labellisée LA LIGUE CONTRE LE CANCER», Laboratoire d'Excellence Toulouse Cancer LABEX TOUCAN - Cancer Research Center of Toulouse, Inserm U1037, CNRS ERL5294, University Paul Sabatier, Toulouse, France
| | - Antonio Maffia
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" - CNR, Pavia, Italy
| | - Simone Sabbioneda
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza" - CNR, Pavia, Italy
| | - Jean-Sébastien Hoffmann
- Equipe «Labellisée LA LIGUE CONTRE LE CANCER», Laboratoire d'Excellence Toulouse Cancer LABEX TOUCAN - Cancer Research Center of Toulouse, Inserm U1037, CNRS ERL5294, University Paul Sabatier, Toulouse, France
| | - Vanesa Gottifredi
- Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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17
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Gallo D, Brown GW. Post-replication repair: Rad5/HLTF regulation, activity on undamaged templates, and relationship to cancer. Crit Rev Biochem Mol Biol 2019; 54:301-332. [PMID: 31429594 DOI: 10.1080/10409238.2019.1651817] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/12/2019] [Accepted: 07/31/2019] [Indexed: 12/18/2022]
Abstract
The eukaryotic post-replication repair (PRR) pathway allows completion of DNA replication when replication forks encounter lesions on the DNA template and are mediated by post-translational ubiquitination of the DNA sliding clamp proliferating cell nuclear antigen (PCNA). Monoubiquitinated PCNA recruits translesion synthesis (TLS) polymerases to replicate past DNA lesions in an error-prone manner while addition of K63-linked polyubiquitin chains signals for error-free template switching to the sister chromatid. Central to both branches is the E3 ubiquitin ligase and DNA helicase Rad5/helicase-like transcription factor (HLTF). Mutations in PRR pathway components lead to genomic rearrangements, cancer predisposition, and cancer progression. Recent studies have challenged the notion that the PRR pathway is involved only in DNA lesion tolerance and have shed new light on its roles in cancer progression. Molecular details of Rad5/HLTF recruitment and function at replication forks have emerged. Mounting evidence indicates that PRR is required during lesion-less replication stress, leading to TLS polymerase activity on undamaged templates. Analysis of PRR mutation status in human cancers and PRR function in cancer models indicates that down regulation of PRR activity is a viable strategy to inhibit cancer cell growth and reduce chemoresistance. Here, we review these findings, discuss how they change our views of current PRR models, and look forward to targeting the PRR pathway in the clinic.
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Affiliation(s)
- David Gallo
- Department of Biochemistry and Donnelly Centre, University of Toronto , Toronto , Canada
| | - Grant W Brown
- Department of Biochemistry and Donnelly Centre, University of Toronto , Toronto , Canada
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18
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Tonzi P, Huang TT. Role of Y-family translesion DNA polymerases in replication stress: Implications for new cancer therapeutic targets. DNA Repair (Amst) 2019; 78:20-26. [PMID: 30954011 DOI: 10.1016/j.dnarep.2019.03.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 03/26/2019] [Accepted: 03/28/2019] [Indexed: 12/18/2022]
Abstract
DNA replication stress, defined as the slowing or stalling of replication forks, is considered an emerging hallmark of cancer and a major contributor to genomic instability associated with tumorigenesis (Macheret and Halazonetis, 2015). Recent advances have been made in attempting to target DNA repair factors involved in alleviating replication stress to potentiate genotoxic treatments. Various inhibitors of ATR and Chk1, the two major kinases involved in the intra-S-phase checkpoint, are currently in Phase I and II clinical trials [2]. In addition, currently approved inhibitors of Poly-ADP Ribose Polymerase (PARP) show synthetic lethality in cells that lack double-strand break repair such as in BRCA1/2 deficient tumors [3]. These drugs have also been shown to exacerbate replication stress by creating a DNA-protein crosslink, termed PARP 'trapping', and this is now thought to contribute to the therapeutic efficacy. Translesion synthesis (TLS) is a mechanism whereby special repair DNA polymerases accommodate and tolerate various DNA lesions to allow for damage bypass and continuation of DNA replication (Yang and Gao, 2018). This class of proteins is best characterized by the Y-family, encompassing DNA polymerases (Pols) Kappa, Eta, Iota, and Rev1. While best studied for their ability to bypass physical lesions on the DNA, there is accumulating evidence for these proteins in coping with various natural replication fork barriers and alleviating replication stress. In this mini-review, we will highlight some of these recent advances, and discuss why targeting the TLS pathway may be a mechanism of enhancing cancer-associated replication stress. Exacerbation of replication stress can lead to increased genome instability, which can be toxic to cancer cells and represent a therapeutic vulnerability.
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Affiliation(s)
- Peter Tonzi
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Tony T Huang
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA.
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19
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Falquet B, Rass U. Structure-Specific Endonucleases and the Resolution of Chromosome Underreplication. Genes (Basel) 2019; 10:E232. [PMID: 30893921 PMCID: PMC6470701 DOI: 10.3390/genes10030232] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 12/11/2022] Open
Abstract
Complete genome duplication in every cell cycle is fundamental for genome stability and cell survival. However, chromosome replication is frequently challenged by obstacles that impede DNA replication fork (RF) progression, which subsequently causes replication stress (RS). Cells have evolved pathways of RF protection and restart that mitigate the consequences of RS and promote the completion of DNA synthesis prior to mitotic chromosome segregation. If there is entry into mitosis with underreplicated chromosomes, this results in sister-chromatid entanglements, chromosome breakage and rearrangements and aneuploidy in daughter cells. Here, we focus on the resolution of persistent replication intermediates by the structure-specific endonucleases (SSEs) MUS81, SLX1-SLX4 and GEN1. Their actions and a recently discovered pathway of mitotic DNA repair synthesis have emerged as important facilitators of replication completion and sister chromatid detachment in mitosis. As RS is induced by oncogene activation and is a common feature of cancer cells, any advances in our understanding of the molecular mechanisms related to chromosome underreplication have important biomedical implications.
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Affiliation(s)
- Benoît Falquet
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
- Faculty of Natural Sciences, University of Basel, Petersplatz 10, CH-4003 Basel, Switzerland.
| | - Ulrich Rass
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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20
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Tsao WC, Eckert KA. Detours to Replication: Functions of Specialized DNA Polymerases during Oncogene-induced Replication Stress. Int J Mol Sci 2018; 19:ijms19103255. [PMID: 30347795 PMCID: PMC6214091 DOI: 10.3390/ijms19103255] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 10/15/2018] [Accepted: 10/15/2018] [Indexed: 01/10/2023] Open
Abstract
Incomplete and low-fidelity genome duplication contribute to genomic instability and cancer development. Difficult-to-Replicate Sequences, or DiToRS, are natural impediments in the genome that require specialized DNA polymerases and repair pathways to complete and maintain faithful DNA synthesis. DiToRS include non B-DNA secondary structures formed by repetitive sequences, for example within chromosomal fragile sites and telomeres, which inhibit DNA replication under endogenous stress conditions. Oncogene activation alters DNA replication dynamics and creates oncogenic replication stress, resulting in persistent activation of the DNA damage and replication stress responses, cell cycle arrest, and cell death. The response to oncogenic replication stress is highly complex and must be tightly regulated to prevent mutations and tumorigenesis. In this review, we summarize types of known DiToRS and the experimental evidence supporting replication inhibition, with a focus on the specialized DNA polymerases utilized to cope with these obstacles. In addition, we discuss different causes of oncogenic replication stress and its impact on DiToRS stability. We highlight recent findings regarding the regulation of DNA polymerases during oncogenic replication stress and the implications for cancer development.
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Affiliation(s)
- Wei-Chung Tsao
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.
| | - Kristin A Eckert
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.
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