1
|
Cybulla E, Wallace S, Meroni A, Jackson J, Agashe S, Tennakoon M, Limbu M, Quinet A, Lomonosova E, Noia H, Tirman S, Wood M, Lemacon D, Fuh K, Zou L, Vindigni A. A RAD18-UBC13-PALB2-RNF168 axis mediates replication fork recovery in BRCA1-deficient cancer cells. Nucleic Acids Res 2024:gkae563. [PMID: 38943334 DOI: 10.1093/nar/gkae563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 05/24/2024] [Accepted: 06/21/2024] [Indexed: 07/01/2024] Open
Abstract
BRCA1/2 proteins function in genome stability by promoting repair of double-stranded DNA breaks through homologous recombination and by protecting stalled replication forks from nucleolytic degradation. In BRCA1/2-deficient cancer cells, extensively degraded replication forks can be rescued through distinct fork recovery mechanisms that also promote cell survival. Here, we identified a novel pathway mediated by the E3 ubiquitin ligase RAD18, the E2-conjugating enzyme UBC13, the recombination factor PALB2, the E3 ubiquitin ligase RNF168 and PCNA ubiquitination that promotes fork recovery in BRCA1- but not BRCA2-deficient cells. We show that this pathway does not promote fork recovery by preventing replication fork reversal and degradation in BRCA1-deficient cells. We propose a mechanism whereby the RAD18-UBC13-PALB2-RNF168 axis facilitates resumption of DNA synthesis by promoting re-annealing of the complementary single-stranded template strands of the extensively degraded forks, thereby allowing re-establishment of a functional replication fork. We also provide preliminary evidence for the potential clinical relevance of this novel fork recovery pathway in BRCA1-mutated cancers, as RAD18 is over-expressed in BRCA1-deficient cancers, and RAD18 loss compromises cell viability in BRCA1-deficient cancer cells.
Collapse
Affiliation(s)
- Emily Cybulla
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Sierra Wallace
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Alice Meroni
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Jessica Jackson
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Sumedha Agashe
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Mithila Tennakoon
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Mangsi Limbu
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Annabel Quinet
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Elena Lomonosova
- Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Hollie Noia
- Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Stephanie Tirman
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Matthew Wood
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Delphine Lemacon
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Katherine Fuh
- Division of Gynecologic Oncology, Department of Ob/Gyn and Reproductive Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Lee Zou
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27708, USA
| | - Alessandro Vindigni
- Division of Oncology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| |
Collapse
|
2
|
Wu J, Jiang Y, Zhang Q, Mao X, Wu T, Hao M, Zhang S, Meng Y, Wan X, Qiu L, Han J. KDM6A-SND1 interaction maintains genomic stability by protecting the nascent DNA and contributes to cancer chemoresistance. Nucleic Acids Res 2024:gkae487. [PMID: 38850159 DOI: 10.1093/nar/gkae487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 05/22/2024] [Accepted: 05/26/2024] [Indexed: 06/10/2024] Open
Abstract
Genomic instability is one of the hallmarks of cancer. While loss of histone demethylase KDM6A increases the risk of tumorigenesis, its specific role in maintaining genomic stability remains poorly understood. Here, we propose a mechanism in which KDM6A maintains genomic stability independently on its demethylase activity. This occurs through its interaction with SND1, resulting in the establishment of a protective chromatin state that prevents replication fork collapse by recruiting of RPA and Ku70 to nascent DNA strand. Notably, KDM6A-SND1 interaction is up-regulated by KDM6A SUMOylation, while KDM6AK90A mutation almost abolish the interaction. Loss of KDM6A or SND1 leads to increased enrichment of H3K9ac and H4K8ac but attenuates the enrichment of Ku70 and H3K4me3 at nascent DNA strand. This subsequently results in enhanced cellular sensitivity to genotoxins and genomic instability. Consistent with these findings, knockdown of KDM6A and SND1 in esophageal squamous cell carcinoma (ESCC) cells increases genotoxin sensitivity. Intriguingly, KDM6A H101D & P110S, N1156T and D1216N mutations identified in ESCC patients promote genotoxin resistance via increased SND1 association. Our finding provides novel insights into the pivotal role of KDM6A-SND1 in genomic stability and chemoresistance, implying that targeting KDM6A and/or its interaction with SND1 may be a promising strategy to overcome the chemoresistance.
Collapse
Affiliation(s)
- Jian Wu
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yixin Jiang
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Qin Zhang
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xiaobing Mao
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Tong Wu
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Mengqiu Hao
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Su Zhang
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yang Meng
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xiaowen Wan
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Lei Qiu
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Junhong Han
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| |
Collapse
|
3
|
Teresa BGD, Ayala-Zambrano C, González-Suárez M, Molina B, Torres L, Rodríguez A, Frías S. Reversion from basal histone H4 hypoacetylation at the replication fork increases DNA damage in FANCA deficient cells. PLoS One 2024; 19:e0298032. [PMID: 38820384 PMCID: PMC11142588 DOI: 10.1371/journal.pone.0298032] [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: 01/04/2024] [Accepted: 01/16/2024] [Indexed: 06/02/2024] Open
Abstract
The FA/BRCA pathway safeguards DNA replication by repairing interstrand crosslinks (ICL) and maintaining replication fork stability. Chromatin structure, which is in part regulated by histones posttranslational modifications (PTMs), has a role in maintaining genomic integrity through stabilization of the DNA replication fork and promotion of DNA repair. An appropriate balance of PTMs, especially acetylation of histones H4 in nascent chromatin, is required to preserve a stable DNA replication fork. To evaluate the acetylation status of histone H4 at the replication fork of FANCA deficient cells, we compared histone acetylation status at the DNA replication fork of isogenic FANCA deficient and FANCA proficient cell lines by using accelerated native immunoprecipitation of nascent DNA (aniPOND) and in situ protein interactions in the replication fork (SIRF) assays. We found basal hypoacetylation of multiple residues of histone H4 in FA replication forks, together with increased levels of Histone Deacetylase 1 (HDAC1). Interestingly, high-dose short-term treatment with mitomycin C (MMC) had no effect over H4 acetylation abundance at the replication fork. However, chemical inhibition of histone deacetylases (HDAC) with Suberoylanilide hydroxamic acid (SAHA) induced acetylation of the FANCA deficient DNA replication forks to levels comparable to their isogenic control counterparts. This forced permanence of acetylation impacted FA cells homeostasis by inducing DNA damage and promoting G2 cell cycle arrest. Altogether, this caused reduced RAD51 foci formation and increased markers of replication stress, including phospho-RPA-S33. Hypoacetylation of the FANCA deficient replication fork, is part of the cellular phenotype, the perturbation of this feature by agents that prevent deacetylation, such as SAHA, have a deleterious effect over the delicate equilibrium they have reached to perdure despite a defective FA/BRCA pathway.
Collapse
Affiliation(s)
- Benilde García-de Teresa
- Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Ciudad de México, Mexico
- Doctorado en Ciencias Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Ciudad de México, Mexico
| | - Cecilia Ayala-Zambrano
- Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Ciudad de México, Mexico
- Doctorado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Mexico City, Ciudad de México, Mexico
| | - Mirna González-Suárez
- Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Ciudad de México, Mexico
| | - Bertha Molina
- Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Ciudad de México, Mexico
| | - Leda Torres
- Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Ciudad de México, Mexico
| | - Alfredo Rodríguez
- Laboratorio de Falla Medular y Carcinogénesis, Unidad de Genética de la Nutrición, Instituto Nacional de Pediatría, Mexico City, Ciudad de México, Mexico
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Mexico City, Ciudad de México, Mexico
| | - Sara Frías
- Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Ciudad de México, Mexico
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Mexico City, Ciudad de México, Mexico
| |
Collapse
|
4
|
Herr LM, Schaffer ED, Fuchs KF, Datta A, Brosh RM. Replication stress as a driver of cellular senescence and aging. Commun Biol 2024; 7:616. [PMID: 38777831 PMCID: PMC11111458 DOI: 10.1038/s42003-024-06263-w] [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: 12/13/2023] [Accepted: 04/29/2024] [Indexed: 05/25/2024] Open
Abstract
Replication stress refers to slowing or stalling of replication fork progression during DNA synthesis that disrupts faithful copying of the genome. While long considered a nexus for DNA damage, the role of replication stress in aging is under-appreciated. The consequential role of replication stress in promotion of organismal aging phenotypes is evidenced by an extensive list of hereditary accelerated aging disorders marked by molecular defects in factors that promote replication fork progression and operate uniquely in the replication stress response. Additionally, recent studies have revealed cellular pathways and phenotypes elicited by replication stress that align with designated hallmarks of aging. Here we review recent advances demonstrating the role of replication stress as an ultimate driver of cellular senescence and aging. We discuss clinical implications of the intriguing links between cellular senescence and aging including application of senotherapeutic approaches in the context of replication stress.
Collapse
Affiliation(s)
- Lauren M Herr
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Ethan D Schaffer
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Kathleen F Fuchs
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Arindam Datta
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Robert M Brosh
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
| |
Collapse
|
5
|
Tian T, Chen J, Zhao H, Li Y, Xia F, Huang J, Han J, Liu T. UFL1 triggers replication fork degradation by MRE11 in BRCA1/2-deficient cells. Nat Chem Biol 2024:10.1038/s41589-024-01611-7. [PMID: 38649452 DOI: 10.1038/s41589-024-01611-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
The stabilization of stalled forks has emerged as a crucial mechanism driving resistance to poly(ADP-ribose) polymerase (PARP) inhibitors in BRCA1/2-deficient tumors. Here, we identify UFL1, a UFM1-specific E3 ligase, as a pivotal regulator of fork stability and the response to PARP inhibitors in BRCA1/2-deficient cells. On replication stress, UFL1 localizes to stalled forks and catalyzes the UFMylation of PTIP, a component of the MLL3/4 methyltransferase complex, specifically at lysine 148. This modification facilitates the assembly of the PTIP-MLL3/4 complex, resulting in the enrichment of H3K4me1 and H3K4me3 at stalled forks and subsequent recruitment of the MRE11 nuclease. Consequently, loss of UFL1, disruption of PTIP UFMylation or overexpression of the UFM1 protease UFSP2 protects nascent DNA strands from extensive degradation and confers resistance to PARP inhibitors in BRCA1/2-deficient cells. These findings provide mechanistic insights into the processes underlying fork instability in BRCA1/2-deficient cells and offer potential therapeutic avenues for the treatment of BRCA1/2-deficient tumors.
Collapse
Affiliation(s)
- Tian Tian
- Zhejiang Key Laboratory of Geriatrics and Geriatrics Institute of Zhejiang Province, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, China
- The MOE Key Laboratory of Biosystems Homeostasis and Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Junliang Chen
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, Shaoxing, China
| | - Huacun Zhao
- Department of Cell Biology, and Department of General Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yulin Li
- The MOE Key Laboratory of Biosystems Homeostasis and Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Feiyu Xia
- Department of Cell Biology, and Department of General Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Huang
- Zhejiang Key Laboratory of Geriatrics and Geriatrics Institute of Zhejiang Province, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, China
- The MOE Key Laboratory of Biosystems Homeostasis and Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, Shaoxing, China
- Cancer Center, Zhejiang University, Hangzhou, China
| | - Jinhua Han
- Zhejiang Key Laboratory of Geriatrics and Geriatrics Institute of Zhejiang Province, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ting Liu
- Zhejiang Key Laboratory of Geriatrics and Geriatrics Institute of Zhejiang Province, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, China.
- Department of Cell Biology, and Department of General Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| |
Collapse
|
6
|
Muñoz S, Barroso S, Badra-Fajardo N, Marqueta-Gracia JJ, García-Rubio ML, Ubieto-Capella P, Méndez J, Aguilera A. SIN3A histone deacetylase action counteracts MUS81 to promote stalled fork stability. Cell Rep 2024; 43:113778. [PMID: 38341854 PMCID: PMC10915396 DOI: 10.1016/j.celrep.2024.113778] [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: 07/19/2023] [Revised: 12/09/2023] [Accepted: 01/26/2024] [Indexed: 02/13/2024] Open
Abstract
During genome duplication, replication forks (RFs) can be stalled by different obstacles or by depletion of replication factors or nucleotides. A limited number of histone post-translational modifications at stalled RFs are involved in RF protection and restart. Provided the recent observation that the SIN3A histone deacetylase complex reduces transcription-replication conflicts, we explore the role of the SIN3A complex in protecting RFs under stressed conditions. We observe that Sin3A protein is enriched at replicating DNA in the presence of hydroxyurea. In this situation, Sin3A-depleted cells show increased RF stalling, H3 acetylation, and DNA breaks at stalled RFs. Under Sin3A depletion, RF recovery is impaired, and DNA damage accumulates. Importantly, these effects are partially dependent on the MUS81 endonuclease, which promotes DNA breaks and MRE11-dependent DNA degradation of such breaks. We propose that chromatin deacetylation triggered by the SIN3A complex limits MUS81 cleavage of stalled RFs, promoting genome stability when DNA replication is challenged.
Collapse
Affiliation(s)
- Sergio Muñoz
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Sonia Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Nibal Badra-Fajardo
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - José Javier Marqueta-Gracia
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - María L García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Patricia Ubieto-Capella
- Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Juan Méndez
- Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain.
| |
Collapse
|
7
|
Dansu DK, Sauma S, Huang D, Li M, Moyon S, Casaccia P. The epigenetic landscape of oligodendrocyte progenitors changes with time. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579145. [PMID: 38501119 PMCID: PMC10946295 DOI: 10.1101/2024.02.06.579145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
SUMMARY Dansu et al. identify distinct histone H4 modifications as potential mechanism underlying the functional differences between adult and neonatal progenitors. While H4K8ac favors the expression of differentiation genes, their expression is halted by H4K20me3. Adult oligodendrocyte progenitors (aOPCs) generate myelinating oligodendrocytes, like neonatal progenitors (nOPCs), but they also display unique functional features. Here, using RNA-sequencing, unbiased histone proteomics analysis and ChIP-sequencing, we define the transcripts and histone marks underlying the unique properties of aOPCs. We describe the lower proliferative capacity and higher levels of expression of oligodendrocyte specific genes in aOPCs compared to nOPCs, as well as the greater levels of H4 histone marks. We also report increased occupancy of the H4K8ac mark at chromatin locations corresponding to oligodendrocyte-specific transcription factors and lipid metabolism genes. Pharmacological inhibition of H4K8ac deposition reduces the levels of these transcripts in aOPCs, rendering their transcriptome more similar to nOPCs. The repressive H4K20me3 mark is also higher in aOPCs compared to nOPCs and pharmacological inhibition of its deposition results in increased levels of genes related to the mature oligodendrocyte state. Overall, this study identifies two histone marks which are important for the unique transcriptional and functional identity of aOPCs.
Collapse
|
8
|
Guh CL, Lei KH, Chen YA, Jiang YZ, Chang HY, Liaw H, Li HW, Yen HY, Chi P. RAD51 paralogs synergize with RAD51 to protect reversed forks from cellular nucleases. Nucleic Acids Res 2023; 51:11717-11731. [PMID: 37843130 PMCID: PMC10681713 DOI: 10.1093/nar/gkad856] [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: 04/14/2023] [Revised: 09/12/2023] [Accepted: 09/23/2023] [Indexed: 10/17/2023] Open
Abstract
Fork reversal is a conserved mechanism to prevent stalled replication forks from collapsing. Formation and protection of reversed forks are two crucial steps in ensuring fork integrity and stability. Five RAD51 paralogs, namely, RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3, which share sequence and structural similarity to the recombinase RAD51, play poorly defined mechanistic roles in these processes. Here, using purified BCDX2 (RAD51BCD-XRCC2) and CX3 (RAD51C-XRCC3) complexes and in vitro reconstituted biochemical systems, we mechanistically dissect their functions in forming and protecting reversed forks. We show that both RAD51 paralog complexes lack fork reversal activities. Whereas CX3 exhibits modest fork protection activity, BCDX2 significantly synergizes with RAD51 to protect DNA against attack by the nucleases MRE11 and EXO1. DNA protection is contingent upon the ability of RAD51 to form a functional nucleoprotein filament on DNA. Collectively, our results provide evidence for a hitherto unknown function of RAD51 paralogs in synergizing with RAD51 nucleoprotein filament to prevent degradation of stressed replication forks.
Collapse
Affiliation(s)
- Chia-Lun Guh
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Kai-Hang Lei
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Yi-An Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yi-Zhen Jiang
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Hao-Yen Chang
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Hungjiun Liaw
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Wen Li
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Hsin-Yung Yen
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
9
|
Bitler BG, Bailey CA, Yamamoto TM, McMellen A, Kim H, Watson ZL. Targeting BRPF3 moderately reverses olaparib resistance in high grade serous ovarian carcinoma. Mol Carcinog 2023; 62:1717-1730. [PMID: 37493106 PMCID: PMC10592327 DOI: 10.1002/mc.23610] [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: 11/09/2022] [Revised: 07/06/2023] [Accepted: 07/11/2023] [Indexed: 07/27/2023]
Abstract
PARP inhibitors (PARPi) kill cancer cells by stalling DNA replication and preventing DNA repair, resulting in a critical accumulation of DNA damage. Resistance to PARPi is a growing clinical problem in the treatment of high grade serous ovarian carcinoma (HGSOC). Acetylation of histone H3 lysine 14 (H3K14ac) and associated histone acetyltransferases (HATs) and epigenetic readers have known functions in DNA repair and replication. Our objectives are to examine their expression and activities in the context of PARPi-resistant HGSOC, and to determine if targeting H3K14ac or associated proteins has therapeutic potential. Using mass spectrometry profiling of histone modifications, we observed increased H3K14ac enrichment in PARPi-resistant HGSOC cells relative to isogenic PARPi-sensitive lines. By reverse-transcriptase quantitative PCR and RNA-seq, we also observed altered expression of numerous HATs in PARPi-resistant HGSOC cells and a PARPi-resistant PDX model. Knockdown of HATs only modestly altered PARPi response, although knockdown and inhibition of PCAF significantly increased resistance. Pharmacologic inhibition of HBO1 depleted H3K14ac but did not affect PARPi response. However, knockdown and inhibition of BRPF3, a bromodomain and PHD-finger containing protein that is known to interact in a complex with HBO1, did reduce PARPi resistance. This study demonstrates that depletion of H3K14ac does not affect PARPi response in HGSOC. Our data suggest that the bromodomain function of HAT proteins, such as PCAF, or accessory proteins, such as BRPF3, may play a more direct role compared to direct HATs function in PARPi response.
Collapse
Affiliation(s)
- Benjamin G. Bitler
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Courtney A. Bailey
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Tomomi M. Yamamoto
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Alexandra McMellen
- Section of Hematology, Oncology, and Bone Marrow Transplantation, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Hyunmin Kim
- Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Zachary L. Watson
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| |
Collapse
|
10
|
Lee RS, Sad K, Fawwal DV, Spangle JM. Emerging Role of Epigenetic Modifiers in Breast Cancer Pathogenesis and Therapeutic Response. Cancers (Basel) 2023; 15:4005. [PMID: 37568822 PMCID: PMC10417282 DOI: 10.3390/cancers15154005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 08/04/2023] [Accepted: 08/05/2023] [Indexed: 08/13/2023] Open
Abstract
Breast cancer pathogenesis, treatment, and patient outcomes are shaped by tumor-intrinsic genomic alterations that divide breast tumors into molecular subtypes. These molecular subtypes often dictate viable therapeutic interventions and, ultimately, patient outcomes. However, heterogeneity in therapeutic response may be a result of underlying epigenetic features that may further stratify breast cancer patient outcomes. In this review, we examine non-genetic mechanisms that drive functional changes to chromatin in breast cancer to contribute to cell and tumor fitness and highlight how epigenetic activity may inform the therapeutic response. We conclude by providing perspectives on the future of therapeutic targeting of epigenetic enzymes, an approach that holds untapped potential to improve breast cancer patient outcomes.
Collapse
Affiliation(s)
- Richard Sean Lee
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA; (R.S.L.); (K.S.); (D.V.F.)
- Department of Biology, Emory College, Atlanta, GA 30322, USA
| | - Kirti Sad
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA; (R.S.L.); (K.S.); (D.V.F.)
| | - Dorelle V. Fawwal
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA; (R.S.L.); (K.S.); (D.V.F.)
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University School of Medicine, Atlanta, GA 30311, USA
| | - Jennifer Marie Spangle
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA; (R.S.L.); (K.S.); (D.V.F.)
| |
Collapse
|
11
|
Dabin J, Mori M, Polo SE. The DNA damage response in the chromatin context: A coordinated process. Curr Opin Cell Biol 2023; 82:102176. [PMID: 37301060 DOI: 10.1016/j.ceb.2023.102176] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 05/03/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023]
Abstract
In the cell nucleus, DNA damage signaling and repair machineries operate on a chromatin substrate, the integrity of which is critical for cell function and viability. Here, we review recent advances in deciphering the tight coordination between chromatin maintenance and the DNA damage response (DDR). We discuss how the DDR impacts chromatin marks, organization and mobility, and, in turn, how chromatin alterations actively contribute to the DDR, providing additional levels of regulation. We present our current knowledge of the molecular bases of these critical processes in physiological and pathological conditions, and also highlight open questions that emerge in this expanding field.
Collapse
Affiliation(s)
- Juliette Dabin
- Epigenetics and Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, 35 rue Hélène Brion, 75013 Paris, France
| | - Margherita Mori
- Epigenetics and Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, 35 rue Hélène Brion, 75013 Paris, France
| | - Sophie E Polo
- Epigenetics and Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, 35 rue Hélène Brion, 75013 Paris, France.
| |
Collapse
|
12
|
Yano K, Shiotani B. Emerging strategies for cancer therapy by ATR inhibitors. Cancer Sci 2023. [PMID: 37189251 DOI: 10.1111/cas.15845] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/19/2023] [Accepted: 04/29/2023] [Indexed: 05/17/2023] Open
Abstract
DNA replication stress (RS) causes genomic instability and vulnerability in cancer cells. To counteract RS, cells have evolved various mechanisms involving the ATR kinase signaling pathway, which regulates origin firing, cell cycle checkpoints, and fork stabilization to secure the fidelity of replication. However, ATR signaling also alleviates RS to support cell survival by driving RS tolerance, thereby contributing to therapeutic resistance. Cancer cells harboring genetic mutations and other changes that disrupt normal DNA replication increase the risk of DNA damage and the levels of RS, conferring addiction to ATR activity for sustainable replication and susceptibility to therapeutic approaches using ATR inhibitors (ATRis). Therefore, clinical trials are currently being conducted to evaluate the efficacy of ATRis as monotherapies or in combination with other drugs and biomarkers. In this review, we discuss recent advances in the elucidation of the mechanisms by which ATR functions in the RS response and its therapeutic relevance when utilizing ATRis.
Collapse
Affiliation(s)
- Kimiyoshi Yano
- Laboratory of Genome Stress Signaling, National Cancer Center Research Institute, Tokyo, Japan
| | - Bunsyo Shiotani
- Laboratory of Genome Stress Signaling, National Cancer Center Research Institute, Tokyo, Japan
| |
Collapse
|
13
|
Lee SY, Kim JJ, Miller KM. Single-Cell Analysis of Histone Acetylation Dynamics at Replication Forks Using PLA and SIRF. Methods Mol Biol 2023; 2589:345-360. [PMID: 36255636 DOI: 10.1007/978-1-0716-2788-4_23] [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] [Indexed: 06/16/2023]
Abstract
Genome integrity is constantly challenged by various processes including DNA damage, structured DNA, transcription, and DNA-protein crosslinks. During DNA replication, active replication forks that encounter these obstacles can result in their stalling and collapse. Accurate DNA replication requires the ability of forks to navigate these threats, which is aided by DNA repair proteins. Histone acetylation participates in this process through an ability to signal and recruit proteins to regions of replicating DNA. For example, the histone acetyltransferase PCAF promotes the recruitment of the DNA repair factors MRE11 and EXO1 to stalled forks by acetylating histone H4 at lysine 8 (H4K8ac). These highly dynamic processes can be detected and analyzed using a modified proximity ligation assay (PLA) method, known as SIRF (in situ protein interactions with nascent DNA replication forks). This single-cell assay combines PLA with EdU-coupled Click-iT chemistry reactions and fluorescence microscopy to detect these interactions at sites of replicating DNA. Here we provide a detailed protocol utilizing SIRF that detects the HAT PCAF and histone acetylation at replication forks. This technique provides a robust methodology to determine protein recruitment and modifications at the replication fork with single-cell resolution.
Collapse
Affiliation(s)
- Seo Yun Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Jae Jin Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon, Republic of Korea.
| | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
- Livestrong Cancer Institutes, Dell Medical School, The University of Texas at Austin, Austin, TX, USA.
| |
Collapse
|
14
|
Lemay JF, St-Hilaire E, Ronato DA, Gao Y, Bélanger F, Gezzar-Dandashi S, Kimenyi Ishimwe AB, Sawchyn C, Lévesque D, McQuaid M, Boisvert FM, Mallette FA, Masson JY, Drobetsky EA, Wurtele H. A genome-wide screen identifies SCAI as a modulator of the UV-induced replicative stress response. PLoS Biol 2022; 20:e3001543. [PMID: 36215310 PMCID: PMC9584372 DOI: 10.1371/journal.pbio.3001543] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 10/20/2022] [Accepted: 09/05/2022] [Indexed: 11/23/2022] Open
Abstract
Helix-destabilizing DNA lesions induced by environmental mutagens such as UV light cause genomic instability by strongly blocking the progression of DNA replication forks (RFs). At blocked RF, single-stranded DNA (ssDNA) accumulates and is rapidly bound by Replication Protein A (RPA) complexes. Such stretches of RPA-ssDNA constitute platforms for recruitment/activation of critical factors that promote DNA synthesis restart. However, during periods of severe replicative stress, RPA availability may become limiting due to inordinate sequestration of this multifunctional complex on ssDNA, thereby negatively impacting multiple vital RPA-dependent processes. Here, we performed a genome-wide screen to identify factors that restrict the accumulation of RPA-ssDNA during UV-induced replicative stress. While this approach revealed some expected "hits" acting in pathways such as nucleotide excision repair, translesion DNA synthesis, and the intra-S phase checkpoint, it also identified SCAI, whose role in the replicative stress response was previously unappreciated. Upon UV exposure, SCAI knock-down caused elevated accumulation of RPA-ssDNA during S phase, accompanied by reduced cell survival and compromised RF progression. These effects were independent of the previously reported role of SCAI in 53BP1-dependent DNA double-strand break repair. We also found that SCAI is recruited to UV-damaged chromatin and that its depletion promotes nascent DNA degradation at stalled RF. Finally, we (i) provide evidence that EXO1 is the major nuclease underlying ssDNA formation and DNA replication defects in SCAI knockout cells and, consistent with this, (ii) demonstrate that SCAI inhibits EXO1 activity on a ssDNA gap in vitro. Taken together, our data establish SCAI as a novel regulator of the UV-induced replicative stress response in human cells.
Collapse
Affiliation(s)
- Jean-François Lemay
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
| | - Edlie St-Hilaire
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
| | - Daryl A. Ronato
- Genome Stability Laboratory, CHU de Québec Research Center, Oncology Division; Department of Molecular Biology, Medical Biochemistry and Pathology; Laval University Cancer Research Center, Québec City, Québec, Canada
| | - Yuandi Gao
- Genome Stability Laboratory, CHU de Québec Research Center, Oncology Division; Department of Molecular Biology, Medical Biochemistry and Pathology; Laval University Cancer Research Center, Québec City, Québec, Canada
| | - François Bélanger
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
| | - Sari Gezzar-Dandashi
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
- Molecular Biology Program, Université de Montréal, Montréal, Québec, Canada
| | - Aimé Boris Kimenyi Ishimwe
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
- Molecular Biology Program, Université de Montréal, Montréal, Québec, Canada
| | - Christina Sawchyn
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Dominique Lévesque
- Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Mary McQuaid
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
| | | | - Frédérick A. Mallette
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
- Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Québec Research Center, Oncology Division; Department of Molecular Biology, Medical Biochemistry and Pathology; Laval University Cancer Research Center, Québec City, Québec, Canada
| | - Elliot A. Drobetsky
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
- Department of Medicine, Université de Montréal, Montréal, Québec, Canada
- * E-mail: (EAD); (HW)
| | - Hugo Wurtele
- Centre de recherche, de l’Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada
- Department of Medicine, Université de Montréal, Montréal, Québec, Canada
- * E-mail: (EAD); (HW)
| |
Collapse
|
15
|
The mismatch recognition protein MutSα promotes nascent strand degradation at stalled replication forks. Proc Natl Acad Sci U S A 2022; 119:e2201738119. [PMID: 36161943 PMCID: PMC9546528 DOI: 10.1073/pnas.2201738119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DNA mismatch repair (MMR) is well known for its role in maintaining replication fidelity by correcting mispairs generated during replication. Here, we identify an unusual MMR function to promote genome instability in the replication stress response. Under replication stress, binding of the mismatch recognition protein MutSα to replication forks blocks the loading of fork protection factors FANCD2 and BRCA1 to replication forks and promotes the recruitment of exonuclease MRE11 onto DNA to nascent strand degradation. This MutSα-dependent MRE11-catalyzed DNA degradation causes DNA breaks and chromosome abnormalities, contributing to an ultramutator phenotype. Mismatch repair (MMR) is a replication-coupled DNA repair mechanism and plays multiple roles at the replication fork. The well-established MMR functions include correcting misincorporated nucleotides that have escaped the proofreading activity of DNA polymerases, recognizing nonmismatched DNA adducts, and triggering a DNA damage response. In an attempt to determine whether MMR regulates replication progression in cells expressing an ultramutable DNA polymerase ɛ (Polɛ), carrying a proline-to-arginine substitution at amino acid 286 (Polɛ-P286R), we identified an unusual MMR function in response to hydroxyurea (HU)-induced replication stress. Polɛ-P286R cells treated with hydroxyurea exhibit increased MRE11-catalyzed nascent strand degradation. This degradation by MRE11 depends on the mismatch recognition protein MutSα and its binding to stalled replication forks. Increased MutSα binding at replication forks is also associated with decreased loading of replication fork protection factors FANCD2 and BRCA1, suggesting blockage of these fork protection factors from loading to replication forks by MutSα. We find that the MutSα-dependent MRE11-catalyzed fork degradation induces DNA breaks and various chromosome abnormalities. Therefore, unlike the well-known MMR functions of ensuring replication fidelity, the newly identified MMR activity of promoting genome instability may also play a role in cancer avoidance by eliminating rogue cells.
Collapse
|
16
|
Targeting Homologous Recombination Deficiency in Ovarian Cancer with PARP Inhibitors: Synthetic Lethal Strategies That Impact Overall Survival. Cancers (Basel) 2022; 14:cancers14194621. [PMID: 36230543 PMCID: PMC9563432 DOI: 10.3390/cancers14194621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/09/2022] [Accepted: 09/21/2022] [Indexed: 11/23/2022] Open
Abstract
Simple Summary Synthetic lethality approaches to cancer therapy involves combining events to cause cancer cell death. Using this strategy, major advances have occurred in the treatment of women with ovarian cancer who have defects in the Homologous Recombination Repair (HRR) pathway. When the HRR pathway is defective, due to mutations or epigenetic changes in genes such as BRCA1 or BRCA2, cells can no longer accurately repair double strand breaks (DSBs). Capitalising on this weakness, pharmacological inhibition of poly (ADP-ribose) polymerase (PARP) that function to repair single strand breaks (SSBs) leads to synthetic lethality in cells with defective HRR. PARP inhibitors (PARPis) including olaparib, niraparib and rucaparib are approved for the clinical management of women with ovarian cancer. Understanding and overcoming issues of acquired resistance to PARPis, extending these strategies to benefit more patients and combining PARPis with other drugs, including immunotherapies, are of high priority in the field today. Abstract The advent of molecular targeted therapies has made a significant impact on survival of women with ovarian cancer who have defects in homologous recombination repair (HRR). High-grade serous ovarian cancer (HGSOC) is the most common histological subtype of ovarian cancer, with over 50% displaying defective HRR. Poly ADP ribose polymerases (PARPs) are a family of enzymes that catalyse the transfer of ADP-ribose to target proteins, functioning in fundamental cellular processes including transcription, chromatin remodelling and DNA repair. In cells with deficient HRR, PARP inhibitors (PARPis) cause synthetic lethality leading to cell death. Despite the major advances that PARPis have heralded for women with ovarian cancer, questions and challenges remain, including: can the benefits of PARPis be brought to a wider range of women with ovarian cancer; can other drugs in clinical use function in a similar way or with greater efficacy than currently clinically approved PARPis; what can we learn from long-term responders to PARPis; can PARPis sensitise ovarian cancer cells to immunotherapy; and can synthetic lethal strategies be employed more broadly to develop new therapies for women with ovarian cancer. We examine these, and other, questions with focus on improving outcomes for women with ovarian cancer.
Collapse
|
17
|
Abstract
General control nonderepressible 5 protein (Gcn5) and its homologs, including p300/CBP-associated factor (PCAF), are lysine acetyltransferases that modify both histone and non-histone proteins using acetyl coenzyme A as a donor substrate. While decades of studies have uncovered a vast network of cellular processes impacted by these acetyltransferases, including gene transcription and metabolism, far less is known about how these enzymes are themselves regulated. In this review, we summarize the type and functions of posttranslational modifications proposed to control Gcn5 in both yeast and human cells. We further outline common themes, open questions, and strategies to guide future work.
Collapse
|
18
|
Wang N, Yang Y, Jin D, Zhang Z, Shen K, Yang J, Chen H, Zhao X, Yang L, Lu H. PARP inhibitor resistance in breast and gynecological cancer: Resistance mechanisms and combination therapy strategies. Front Pharmacol 2022; 13:967633. [PMID: 36091750 PMCID: PMC9455597 DOI: 10.3389/fphar.2022.967633] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/04/2022] [Indexed: 12/02/2022] Open
Abstract
Breast cancer and gynecological tumors seriously endanger women’s physical and mental health, fertility, and quality of life. Due to standardized surgical treatment, chemotherapy, and radiotherapy, the prognosis and overall survival of cancer patients have improved compared to earlier, but the management of advanced disease still faces great challenges. Recently, poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) have been clinically approved for breast and gynecological cancer patients, significantly improving their quality of life, especially of patients with BRCA1/2 mutations. However, drug resistance faced by PARPi therapy has hindered its clinical promotion. Therefore, developing new drug strategies to resensitize cancers affecting women to PARPi therapy is the direction of our future research. Currently, the effects of PARPi in combination with other drugs to overcome drug resistance are being studied. In this article, we review the mechanisms of PARPi resistance and summarize the current combination of clinical trials that can improve its resistance, with a view to identify the best clinical treatment to save the lives of patients.
Collapse
Affiliation(s)
- Nannan Wang
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yan Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
| | - Dongdong Jin
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Zhengzhou Key Laboratory of Endometrial Disease Prevention and Treatment, Zhengzhou, China
| | - Zhenan Zhang
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ke Shen
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jing Yang
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Huanhuan Chen
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xinyue Zhao
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Li Yang
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Zhengzhou Key Laboratory of Endometrial Disease Prevention and Treatment, Zhengzhou, China
- *Correspondence: Li Yang, ; Huaiwu Lu,
| | - Huaiwu Lu
- Department of Gynaecological Oncology, Sun Yat Sen Memorial Hospital, Guangzhou, China
- *Correspondence: Li Yang, ; Huaiwu Lu,
| |
Collapse
|
19
|
Structural mechanism of endonucleolytic processing of blocked DNA ends and hairpins by Mre11-Rad50. Mol Cell 2022; 82:3513-3522.e6. [DOI: 10.1016/j.molcel.2022.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 06/10/2022] [Accepted: 07/23/2022] [Indexed: 11/17/2022]
|
20
|
Chen YJC, Koutelou E, Dent SY. Now open: Evolving insights to the roles of lysine acetylation in chromatin organization and function. Mol Cell 2022; 82:716-727. [PMID: 35016034 PMCID: PMC8857060 DOI: 10.1016/j.molcel.2021.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 12/17/2022]
Abstract
Protein acetylation is conserved across phylogeny and has been recognized as one of the most prominent post-translational modifications since its discovery nearly 60 years ago. Histone acetylation is an active mark characteristic of open chromatin, but acetylation on specific lysine residues and histone variants occurs in different biological contexts and can confer various outcomes. The significance of acetylation events is indicated by the associations of lysine acetyltransferases, deacetylases, and acetyl-lysine readers with developmental disorders and pathologies. Recent advances have uncovered new roles of acetylation regulators in chromatin-centric events, which emphasize the complexity of these functional networks. In this review, we discuss mechanisms and dynamics of acetylation in chromatin organization and DNA-templated processes, including gene transcription and DNA repair and replication.
Collapse
Affiliation(s)
- Ying-Jiun C. Chen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.,Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Evangelia Koutelou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.,Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Sharon Y.R. Dent
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.,Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.,Correspondence:
| |
Collapse
|
21
|
Xia L, Liu Y, Zhang Z, Gong Y, Yu T, Zhao D, Qiu W, Wang Y, Zhang J. Modulation of IL-6 Expression by KLF4-Mediated Transactivation and PCAF-Mediated Acetylation in Sublytic C5b-9-Induced Rat Glomerular Mesangial Cells. Front Immunol 2022; 12:779667. [PMID: 35046941 PMCID: PMC8761757 DOI: 10.3389/fimmu.2021.779667] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/06/2021] [Indexed: 12/17/2022] Open
Abstract
Interleukin-6 (IL-6) overproduction has been considered to contribute to inflammatory damage of glomerular mesangial cells (GMCs) in human mesangial proliferative glomerulonephritis (MsPGN) and its rat model called Thy-1 nephritis (Thy-1N). However, the regulatory mechanisms of IL-6 expression in GMCs upon sublytic C5b-9 timulation remain poorly understood. We found that Krüppel-like factor 4 (KLF4) bound to the IL-6 promoter (−618 to −126 nt) and activated IL-6 gene transcription. Furthermore, lysine residue 224 of KLF4 was acetylated by p300/CBP-associated factor (PCAF), which was important for KLF4-mediated transactivation. Moreover, lysine residue 5 on histone H2B and lysine residue 9 on histone H3 at the IL-6 promoter were also acetylated by PCAF, which resulted in an increase in IL-6 transcription. Besides, NF-κB activation promoted IL-6 expression by elevating the expression of PCAF. Overall, these findings suggest that sublytic C5b-9-induced the expression of IL-6 involves KLF4-mediated transactivation, PCAF-mediated acetylation of KLF4 and histones, and NF-κB activation in GMCs.
Collapse
Affiliation(s)
- Lu Xia
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Yu Liu
- Department of Microbiology and Immunology, Jiangsu Health Vocational College, Nanjing, China
| | - Zhiwei Zhang
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Yajuan Gong
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Tianyi Yu
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Dan Zhao
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Wen Qiu
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Yingwei Wang
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Jing Zhang
- Department of Immunology, Nanjing Medical University, Nanjing, China.,Key Laboratory of Immunological Environment and Disease, Nanjing Medical University, Nanjing, China.,Key Laboratory of Antibody Technology of Ministry of Health, Nanjing Medical University, Nanjing, China
| |
Collapse
|
22
|
Dolce V, Dusi S, Giannattasio M, Joseph CR, Fumasoni M, Branzei D. Parental histone deposition on the replicated strands promotes error-free DNA damage tolerance and regulates drug resistance. Genes Dev 2022; 36:167-179. [PMID: 35115379 PMCID: PMC8887126 DOI: 10.1101/gad.349207.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/12/2022] [Indexed: 11/24/2022]
Abstract
In this study, Dolce et al. investigated connections between Ctf4-mediated processes involved in drug resistance, and conducted a suppressor screen of ctf4Δ sensitivity to the methylating agent MMS. Their findings demonstrate a chromatin-based drug resistance mechanism in which defects in parental histone transfer after replication fork passage impair error-free recombination bypass and lead to up-regulation of TLS-mediated mutagenesis and drug resistance. Ctf4 is a conserved replisome component with multiple roles in DNA metabolism. To investigate connections between Ctf4-mediated processes involved in drug resistance, we conducted a suppressor screen of ctf4Δ sensitivity to the methylating agent MMS. We uncovered that mutations in Dpb3 and Dpb4 components of polymerase ε result in the development of drug resistance in ctf4Δ via their histone-binding function. Alleviated sensitivity to MMS of the double mutants was not associated with rescue of ctf4Δ defects in sister chromatid cohesion, replication fork architecture, or template switching, which ensures error-free replication in the presence of genotoxic stress. Strikingly, the improved viability depended on translesion synthesis (TLS) polymerase-mediated mutagenesis, which was drastically increased in ctf4 dpb3 double mutants. Importantly, mutations in Mcm2–Ctf4–Polα and Dpb3–Dpb4 axes of parental (H3–H4)2 deposition on lagging and leading strands invariably resulted in reduced error-free DNA damage tolerance through gap filling by template switch recombination. Overall, we uncovered a chromatin-based drug resistance mechanism in which defects in parental histone transfer after replication fork passage impair error-free recombination bypass and lead to up-regulation of TLS-mediated mutagenesis and drug resistance.
Collapse
Affiliation(s)
- Valeria Dolce
- Istituto FIRC (Fondazione Italiana per la Ricerca sul Cancro) di Oncologia Molecolare (IFOM), the FIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Sabrina Dusi
- Istituto FIRC (Fondazione Italiana per la Ricerca sul Cancro) di Oncologia Molecolare (IFOM), the FIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Michele Giannattasio
- Istituto FIRC (Fondazione Italiana per la Ricerca sul Cancro) di Oncologia Molecolare (IFOM), the FIRC Institute of Molecular Oncology, 20139 Milan, Italy.,Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, 20122 Milan, Italy
| | - Chinnu Rose Joseph
- Istituto FIRC (Fondazione Italiana per la Ricerca sul Cancro) di Oncologia Molecolare (IFOM), the FIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Marco Fumasoni
- Istituto FIRC (Fondazione Italiana per la Ricerca sul Cancro) di Oncologia Molecolare (IFOM), the FIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Dana Branzei
- Istituto FIRC (Fondazione Italiana per la Ricerca sul Cancro) di Oncologia Molecolare (IFOM), the FIRC Institute of Molecular Oncology, 20139 Milan, Italy.,Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), 27100 Pavia, Italy
| |
Collapse
|
23
|
Wootton J, Soutoglou E. Chromatin and Nuclear Dynamics in the Maintenance of Replication Fork Integrity. Front Genet 2022; 12:773426. [PMID: 34970302 PMCID: PMC8712883 DOI: 10.3389/fgene.2021.773426] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
Replication of the eukaryotic genome is a highly regulated process and stringent control is required to maintain genome integrity. In this review, we will discuss the many aspects of the chromatin and nuclear environment that play key roles in the regulation of both unperturbed and stressed replication. Firstly, the higher order organisation of the genome into A and B compartments, topologically associated domains (TADs) and sub-nuclear compartments has major implications in the control of replication timing. In addition, the local chromatin environment defined by non-canonical histone variants, histone post-translational modifications (PTMs) and enrichment of factors such as heterochromatin protein 1 (HP1) plays multiple roles in normal S phase progression and during the repair of replicative damage. Lastly, we will cover how the spatial organisation of stalled replication forks facilitates the resolution of replication stress.
Collapse
Affiliation(s)
- Jack Wootton
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Evi Soutoglou
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| |
Collapse
|
24
|
Yan S, Gao S, Zhou P. Multi-functions of exonuclease 1 in DNA damage response and cancer susceptibility. RADIATION MEDICINE AND PROTECTION 2021. [DOI: 10.1016/j.radmp.2021.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
25
|
Abstract
DNA double-strand breaks (DSBs) are cytotoxic lesions that threaten genome integrity and cell viability. Typically, cells repair DSBs by either nonhomologous end joining (NHEJ) or homologous recombination (HR). The relative use of these two pathways depends on many factors, including cell cycle stage and the nature of the DNA ends. A critical determinant of repair pathway selection is the initiation of 5'→3' nucleolytic degradation of DNA ends, a process referred to as DNA end resection. End resection is essential to create single-stranded DNA overhangs, which serve as the substrate for the Rad51 recombinase to initiate HR and are refractory to NHEJ repair. Here, we review recent insights into the mechanisms of end resection, how it is regulated, and the pathological consequences of its dysregulation.
Collapse
Affiliation(s)
- Petr Cejka
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), 6500 Bellinzona, Switzerland; .,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zürich, Switzerland
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA; .,Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| |
Collapse
|
26
|
Lee SY, Kim JJ, Miller KM. Bromodomain proteins: protectors against endogenous DNA damage and facilitators of genome integrity. Exp Mol Med 2021; 53:1268-1277. [PMID: 34548613 PMCID: PMC8492697 DOI: 10.1038/s12276-021-00673-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/13/2021] [Indexed: 12/11/2022] Open
Abstract
Endogenous DNA damage is a major contributor to mutations, which are drivers of cancer development. Bromodomain (BRD) proteins are well-established participants in chromatin-based DNA damage response (DDR) pathways, which maintain genome integrity from cell-intrinsic and extrinsic DNA-damaging sources. BRD proteins are most well-studied as regulators of transcription, but emerging evidence has revealed their importance in other DNA-templated processes, including DNA repair and replication. How BRD proteins mechanistically protect cells from endogenous DNA damage through their participation in these pathways remains an active area of investigation. Here, we review several recent studies establishing BRD proteins as key influencers of endogenous DNA damage, including DNA–RNA hybrid (R-loops) formation during transcription and participation in replication stress responses. As endogenous DNA damage is known to contribute to several human diseases, including neurodegeneration, immunodeficiencies, cancer, and aging, the ability of BRD proteins to suppress DNA damage and mutations is likely to provide new insights into the involvement of BRD proteins in these diseases. Although many studies have focused on BRD proteins in transcription, evidence indicates that BRD proteins have emergent functions in DNA repair and genome stability and are participants in the etiology and treatment of diseases involving endogenous DNA damage. Bromodomain (BRD) proteins, known to regulate gene expression, switching particular genes on and off, also play key roles in repairing DNA damage, and studying them may help identify treatments for various diseases, including cancer. DNA damage can occur during normal cellular metabolism, for example, during copying DNA and gene expression. DNA damage is implicated in tumor formation as well as in neurodegeneration, immunodeficiency, and aging. Seo Yun Lee and colleagues at The University of Texas at Austin, USA, have reviewed new results showing how BRD proteins function in repairing DNA damage. They report that when DNA is damaged during copying in BRD-deficient cells, tumors can result. They also report that defects in BRD proteins are often present in cancers. Studying how BRD proteins function in both healthy and diseased cells could help to identify new therapies.
Collapse
Affiliation(s)
- Seo Yun Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Jae Jin Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA. .,Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon, Korea.
| | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA. .,Livestrong Cancer Institutes, Dell Medical School, The University of Texas at Austin, Austin, TX, USA.
| |
Collapse
|
27
|
ZGRF1 promotes end resection of DNA homologous recombination via forming complex with BRCA1/EXO1. Cell Death Discov 2021; 7:260. [PMID: 34552057 PMCID: PMC8458317 DOI: 10.1038/s41420-021-00633-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/16/2021] [Accepted: 08/26/2021] [Indexed: 11/08/2022] Open
Abstract
To maintain genomic stability, the mammalian cells has evolved a coordinated response to DNA damage, including activation of DNA repair and cell cycle checkpoint processes. Exonuclease 1 (EXO1)-dependent excision of DNA ends is important for the initiation of homologous recombination (HR) repair of DNA breaks, which is thought to play a key role in activating the ATR-CHK1 pathway to induce G2/M cell cycle arrest. But the mechanism is still not fully understood. Here, we report that ZGRF1 forms complexes with EXO1 as well as other repair proteins and promotes DNA repair through HR. ZGRF1 is recruited to DNA damage sites in a MDC1-RNF8-BRCA1 dependent manner. Furthermore, ZGRF1 is important for the recruitment of RPA2 to DNA damage sites and the following ATR-CHK1 mediated G2/M checkpoint in response to irradiation. ZGRF1 null cells show increased sensitivity to many DNA-damaging agents, especially PARPi and irradiation. Collectively,our findings identify ZGRF1 as a novel regulator of DNA end resection and G2/M checkpoint. ZGRF1 is a potential target of radiation and PARPi cancer therapy.
Collapse
|
28
|
Bowry A, Kelly RDW, Petermann E. Hypertranscription and replication stress in cancer. Trends Cancer 2021; 7:863-877. [PMID: 34052137 DOI: 10.1016/j.trecan.2021.04.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/23/2021] [Accepted: 04/30/2021] [Indexed: 12/18/2022]
Abstract
Replication stress results from obstacles to replication fork progression, including ongoing transcription, which can cause transcription-replication conflicts. Oncogenic signaling can promote global increases in transcription activity, also termed hypertranscription. Despite the widely accepted importance of oncogene-induced hypertranscription, its study remains neglected compared with other causes of replication stress and genomic instability in cancer. A growing number of recent studies are reporting that oncogenes, such as RAS, and targeted cancer treatments, such as bromodomain and extraterminal motif (BET) bromodomain inhibitors, increase global transcription, leading to R-loop accumulation, transcription-replication conflicts, and the activation of replication stress responses. Here we discuss our mechanistic understanding of hypertranscription-induced replication stress and the resulting cellular responses, in the context of oncogenes and targeted cancer therapies.
Collapse
Affiliation(s)
- Akhil Bowry
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Richard D W Kelly
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Eva Petermann
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| |
Collapse
|
29
|
Replication stress: from chromatin to immunity and beyond. Curr Opin Genet Dev 2021; 71:136-142. [PMID: 34455237 DOI: 10.1016/j.gde.2021.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/08/2021] [Accepted: 08/12/2021] [Indexed: 12/25/2022]
Abstract
Replication stress (RS) is a hallmark of cancer cells that is associated with increased genomic instability. RS occurs when replication forks encounter obstacles along the DNA. Stalled forks are signaled by checkpoint kinases that prevent fork collapse and coordinate fork repair pathways. Fork restart also depends on chromatin remodelers to increase the accessibility of nascent chromatin to recombination and repair factors. In this review, we discuss recent findings on the causes and consequences of RS, with a focus on endogenous replication impediments and their impact on fork velocity. We also discuss recent studies on the interplay between stalled forks and innate immunity, which extends the RS response beyond cell boundaries and opens new avenues for cancer therapy.
Collapse
|
30
|
Thakar T, Moldovan GL. The emerging determinants of replication fork stability. Nucleic Acids Res 2021; 49:7224-7238. [PMID: 33978751 PMCID: PMC8287955 DOI: 10.1093/nar/gkab344] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/18/2021] [Accepted: 04/20/2021] [Indexed: 12/21/2022] Open
Abstract
A universal response to replication stress is replication fork reversal, where the nascent complementary DNA strands are annealed to form a protective four-way junction allowing forks to avert DNA damage while replication stress is resolved. However, reversed forks are in turn susceptible to nucleolytic digestion of the regressed nascent DNA arms and rely on dedicated mechanisms to protect their integrity. The most well studied fork protection mechanism involves the BRCA pathway and its ability to catalyze RAD51 nucleofilament formation on the reversed arms of stalled replication forks. Importantly, the inability to prevent the degradation of reversed forks has emerged as a hallmark of BRCA deficiency and underlies genome instability and chemosensitivity in BRCA-deficient cells. In the past decade, multiple factors underlying fork stability have been discovered. These factors either cooperate with the BRCA pathway, operate independently from it to augment fork stability in its absence, or act as enablers of fork degradation. In this review, we examine these novel determinants of fork stability, explore the emergent conceptual underpinnings underlying fork protection, as well as the impact of fork protection on cellular viability and cancer therapy.
Collapse
Affiliation(s)
- Tanay Thakar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| |
Collapse
|
31
|
Técher H, Pasero P. The Replication Stress Response on a Narrow Path Between Genomic Instability and Inflammation. Front Cell Dev Biol 2021; 9:702584. [PMID: 34249949 PMCID: PMC8270677 DOI: 10.3389/fcell.2021.702584] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
The genome of eukaryotic cells is particularly at risk during the S phase of the cell cycle, when megabases of chromosomal DNA are unwound to generate two identical copies of the genome. This daunting task is executed by thousands of micro-machines called replisomes, acting at fragile structures called replication forks. The correct execution of this replication program depends on the coordinated action of hundreds of different enzymes, from the licensing of replication origins to the termination of DNA replication. This review focuses on the mechanisms that ensure the completion of DNA replication under challenging conditions of endogenous or exogenous origin. It also covers new findings connecting the processing of stalled forks to the release of small DNA fragments into the cytoplasm, activating the cGAS-STING pathway. DNA damage and fork repair comes therefore at a price, which is the activation of an inflammatory response that has both positive and negative impacts on the fate of stressed cells. These new findings have broad implications for the etiology of interferonopathies and for cancer treatment.
Collapse
Affiliation(s)
- Hervé Técher
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, Montpellier, France
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, Montpellier, France
| |
Collapse
|
32
|
Andronikou C, Rottenberg S. Studying PAR-Dependent Chromatin Remodeling to Tackle PARPi Resistance. Trends Mol Med 2021; 27:630-642. [PMID: 34030964 DOI: 10.1016/j.molmed.2021.04.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/12/2022]
Abstract
Histone eviction and chromatin relaxation are important processes for efficient DNA repair. Poly(ADP) ribose (PAR) polymerase 1 (PARP1) is a key mediator of this process, and disruption of PARP1 activity has a direct impact on chromatin structure. PARP inhibitors (PARPis) have been established as a treatment for BRCA1- or BRCA2-deficient tumors. Unfortunately, PARPi resistance occurs in many patients and the underlying mechanisms are not fully understood. In particular, it remains unclear how chromatin remodelers and histone chaperones compensate for the loss of the PARylation signal. In this Opinion article, we summarize currently known mechanisms of PARPi resistance. We discuss how the study of PARP1-mediated chromatin remodeling may help in further understanding PARPi resistance and finding new therapeutic approaches to overcome it.
Collapse
Affiliation(s)
- Christina Andronikou
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, The Netherlands; Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Sven Rottenberg
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, The Netherlands; Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern, Switzerland; Bern Center for Precision Medicine, University of Bern, Bern, Switzerland.
| |
Collapse
|
33
|
Abstract
In this issue of Molecular Cell, Kim et al., 2020 report that PCAF is a fork-associated histone acetyltransferase (HAT) that regulates the stability of stalled forks and the response to PARP inhibition in BRCA1/2-deficient cells.
Collapse
|