1
|
Osborne HC, Foster BM, Al-Hazmi H, Meyer S, Larrosa I, Schmidt CK. Small-Molecule Inhibition of CBX4/7 Hypersensitises Homologous Recombination-Impaired Cancer to Radiation by Compromising CtIP-Mediated DNA End Resection. Cancers (Basel) 2024; 16:2155. [PMID: 38893273 PMCID: PMC11172190 DOI: 10.3390/cancers16112155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
The therapeutic targeting of DNA repair pathways is an emerging concept in cancer treatment. Compounds that target specific DNA repair processes, such as those mending DNA double-strand breaks (DSBs), are therefore of therapeutic interest. UNC3866 is a small molecule that targets CBX4, a chromobox protein, and a SUMO E3 ligase. As a key modulator of DNA end resection-a prerequisite for DSB repair by homologous recombination (HR)-CBX4 promotes the functions of the DNA resection factor CtIP. Here, we show that treatment with UNC3866 markedly sensitises HR-deficient, NHEJ-hyperactive cancer cells to ionising radiation (IR), while it is non-toxic in selected HR-proficient cells. Consistent with UNC3866 targeting CtIP functions, it inhibits end-resection-dependent DNA repair including HR, alternative end joining (alt-EJ), and single-strand annealing (SSA). These findings raise the possibility that the UNC3866-mediated inhibition of end resection processes we define highlights a distinct vulnerability for the selective killing of HR-ineffective cancers.
Collapse
Affiliation(s)
- Hugh C. Osborne
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
| | - Benjamin M. Foster
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
| | - Hazim Al-Hazmi
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
| | - Stefan Meyer
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
- Department of Paediatric and Adolescent Oncology, Royal Manchester Children’s Hospital, Manchester M13 9WL, UK
- Department of Adolescent Oncology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, UK
| | - Igor Larrosa
- Department of Chemistry, University of Manchester, Chemistry Building, Oxford Road, Manchester M13 9PL, UK;
| | - Christine K. Schmidt
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health (FBMH), University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK; (H.C.O.); (B.M.F.); (H.A.-H.); (S.M.)
| |
Collapse
|
2
|
Bhachoo JS, Garvin AJ. SUMO and the DNA damage response. Biochem Soc Trans 2024; 52:773-792. [PMID: 38629643 PMCID: PMC11088926 DOI: 10.1042/bst20230862] [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: 12/08/2023] [Revised: 03/20/2024] [Accepted: 03/25/2024] [Indexed: 04/25/2024]
Abstract
The preservation of genome integrity requires specialised DNA damage repair (DDR) signalling pathways to respond to each type of DNA damage. A key feature of DDR is the integration of numerous post-translational modification signals with DNA repair factors. These modifications influence DDR factor recruitment to damaged DNA, activity, protein-protein interactions, and ultimately eviction to enable access for subsequent repair factors or termination of DDR signalling. SUMO1-3 (small ubiquitin-like modifier 1-3) conjugation has gained much recent attention. The SUMO-modified proteome is enriched with DNA repair factors. Here we provide a snapshot of our current understanding of how SUMO signalling impacts the major DNA repair pathways in mammalian cells. We highlight repeating themes of SUMO signalling used throughout DNA repair pathways including the assembly of protein complexes, competition with ubiquitin to promote DDR factor stability and ubiquitin-dependent degradation or extraction of SUMOylated DDR factors. As SUMO 'addiction' in cancer cells is protective to genomic integrity, targeting components of the SUMO machinery to potentiate DNA damaging therapy or exacerbate existing DNA repair defects is a promising area of study.
Collapse
Affiliation(s)
- Jai S. Bhachoo
- SUMO Biology Lab, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire LS2 9JT, U.K
| | - Alexander J. Garvin
- SUMO Biology Lab, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire LS2 9JT, U.K
| |
Collapse
|
3
|
Locke AJ, Abou Farraj R, Tran C, Zeinali E, Mashayekhi F, Ali JYH, Glover JNM, Ismail IH. The role of RNF138 in DNA end resection is regulated by ubiquitylation and CDK phosphorylation. J Biol Chem 2024; 300:105709. [PMID: 38309501 PMCID: PMC10910129 DOI: 10.1016/j.jbc.2024.105709] [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: 07/05/2023] [Revised: 01/02/2024] [Accepted: 01/18/2024] [Indexed: 02/05/2024] Open
Abstract
Double-strand breaks (DSBs) are DNA lesions that pose a significant threat to genomic stability. The repair of DSBs by the homologous recombination (HR) pathway is preceded by DNA end resection, the 5' to 3' nucleolytic degradation of DNA away from the DSB. We and others previously identified a role for RNF138, a really interesting new gene finger E3 ubiquitin ligase, in stimulating DNA end resection and HR. Yet, little is known about how RNF138's function is regulated in the context of DSB repair. Here, we show that RNF138 is phosphorylated at residue T27 by cyclin-dependent kinase (CDK) activity during the S and G2 phases of the cell cycle. We also observe that RNF138 is ubiquitylated constitutively, with ubiquitylation occurring in part on residue K158 and rising during the S/G2 phases. Interestingly, RNF138 ubiquitylation decreases upon genotoxic stress. By mutating RNF138 at residues T27, K158, and the previously identified S124 ataxia telangiectasia mutated phosphorylation site (Han et al., 2016, ref. 22), we find that post-translational modifications at all three positions mediate DSB repair. Cells expressing the T27A, K158R, and S124A variants of RNF138 are impaired in DNA end resection, HR activity, and are more sensitive to ionizing radiation compared to those expressing wildtype RNF138. Our findings shed more light on how RNF138 activity is controlled by the cell during HR.
Collapse
Affiliation(s)
- Andrew J Locke
- Division of Experimental Oncology, Department of Oncology, Faculty of Medicine & Dentistry, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Rabih Abou Farraj
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Caroline Tran
- Division of Experimental Oncology, Department of Oncology, Faculty of Medicine & Dentistry, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Elham Zeinali
- Division of Experimental Oncology, Department of Oncology, Faculty of Medicine & Dentistry, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Fatemeh Mashayekhi
- Division of Experimental Oncology, Department of Oncology, Faculty of Medicine & Dentistry, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Jana Yasser Hafez Ali
- Division of Experimental Oncology, Department of Oncology, Faculty of Medicine & Dentistry, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
| | - J N Mark Glover
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ismail Hassan Ismail
- Division of Experimental Oncology, Department of Oncology, Faculty of Medicine & Dentistry, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada; Biophysics Department, Faculty of Science, Cairo University, Giza, Egypt.
| |
Collapse
|
4
|
Han J, Mu Y, Huang J. Preserving genome integrity: The vital role of SUMO-targeted ubiquitin ligases. CELL INSIGHT 2023; 2:100128. [PMID: 38047137 PMCID: PMC10692494 DOI: 10.1016/j.cellin.2023.100128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 12/05/2023]
Abstract
Various post-translational modifications (PTMs) collaboratively fine-tune protein activities. SUMO-targeted ubiquitin E3 ligases (STUbLs) emerge as specialized enzymes that recognize SUMO-modified substrates through SUMO-interaction motifs and subsequently ubiquitinate them via the RING domain, thereby bridging the SUMO and ubiquitin signaling pathways. STUbLs participate in a wide array of molecular processes, including cell cycle regulation, DNA repair, replication, and mitosis, operating under both normal conditions and in response to challenges such as genotoxic stress. Their ability to catalyze various types of ubiquitin chains results in diverse proteolytic and non-proteolytic outcomes for target substrates. Importantly, STUbLs are strategically positioned in close proximity to SUMO proteases and deubiquitinases (DUBs), ensuring precise and dynamic control over their target proteins. In this review, we provide insights into the unique properties and indispensable roles of STUbLs, with a particular emphasis on their significance in preserving genome integrity in humans.
Collapse
Affiliation(s)
- Jinhua Han
- Institute of Geriatrics, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, 310030, Zhejiang, China
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Yanhua Mu
- National-Local Joint Engineering Research Center of Biodiagnosis & Biotherapy, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi, China
| | - Jun Huang
- Institute of Geriatrics, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, 310030, Zhejiang, China
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| |
Collapse
|
5
|
Yan J, Wu J, Wang Y, Di X, Jiang H, Wen D, Li D, Zhang S. A novel RBBP8(p.E281*) germline mutation is a predisposing mutation in familial hereditary cancer syndrome. J Mol Med (Berl) 2023; 101:1255-1265. [PMID: 37615686 DOI: 10.1007/s00109-023-02354-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/30/2023] [Accepted: 07/29/2023] [Indexed: 08/25/2023]
Abstract
Screening tumor susceptibility genes helps in identifying powerful biomarkers for hereditary cancer monitoring, prevention, and diagnosis, providing opportunities for understanding potential molecular mechanisms and biomarkers for the precise treatment of hereditary cancer syndromes. Whole-exome sequencing of blood and bioinformatics analysis uncovered a novel RBBP8(p.E281*) germline mutation in a family with hereditary cancer syndrome, which was verified by Sanger sequencing. Cell proliferation, colony formation, cell migration, and in vivo tumorigenesis were investigated by CCK8, colony formation, Transwell, and in vivo xenograft assays. Protein localization and interaction were detected by immunofluorescence, nuclear and cytoplasmic protein extraction kits, and Co-IP. A new heterozygous germline mutation of the RBBP8(p.E281*) gene was found to be associated with familial hereditary cancer syndrome. RBBP8-WT was mainly detected in the nucleus and interacts with BRCA1. In contrast, RBBP8(p.E281*) is mainly located in the cytoplasm, with no interaction with BRCA1. RBBP8(p.E281*) variant plays an oncogenic role in the cytoplasm in addition to its loss of function in the nucleus, which promotes breast cancer proliferation, in vivo tumorigenesis, and migration. Compared with the control group, RBBP8(p.E281*) showed elevated cell death in response to cisplatin and olaparib treatment. A novel RBBP8(p.E281*) germline mutation was identified from familial hereditary cancer syndrome. RBBP8(p.E281*) is not able to enter the nucleus or interact with BRCA1 through the lost binding motif, and RBBP8(p.E281*) variant appears to promote tumorigenesis in the cytoplasm in addition to its loss of function in the nucleus. RBBP8(p.E281*) variant may promote tumor susceptibility and serve as a precision medicine biomarker in familial hereditary cancer syndrome. KEY MESSAGES: RBBP8(p.E281*) is a susceptibility gene in this familial hereditary cancer syndrome RBBP8(p.E281*) lost its ability to enter the nucleus and the BRCA1 binding motif A novel RBBP8(p.E281*) germline mutation promotes breast cancer tumorigenesis Patients with RBBP8(p.E281*) germline mutation may benefit from Olaparib, Cisplatin.
Collapse
Affiliation(s)
- Jinhua Yan
- Department of Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, 410013, China
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410013, China
| | - Jinzheng Wu
- Department of Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, 410013, China
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410013, China
| | - Yang Wang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410013, China
| | - Xiaotang Di
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410013, China
| | - Hao Jiang
- Department of Biomedical Informatics, School of Life Sciences, Central South University, Changsha, 410013, China
| | - Doudou Wen
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410013, China
| | - Duo Li
- Department of Pathology, the Second Xiangya Hospital, Central South University, Changsha, 410013, China.
| | - Shubing Zhang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, 410013, China.
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, 410013, China.
| |
Collapse
|
6
|
Jeong SY, Hariharasudhan G, Kim MJ, Lim JY, Jung SM, Choi EJ, Chang IY, Kee Y, You HJ, Lee JH. SIAH2 regulates DNA end resection and replication fork recovery by promoting CtIP ubiquitination. Nucleic Acids Res 2022; 50:10469-10486. [PMID: 36155803 PMCID: PMC9561274 DOI: 10.1093/nar/gkac808] [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: 03/08/2022] [Revised: 08/19/2022] [Accepted: 09/10/2022] [Indexed: 11/16/2022] Open
Abstract
Human CtIP maintains genomic integrity primarily by promoting 5′ DNA end resection, an initial step of the homologous recombination (HR). A few mechanisms have been suggested as to how CtIP recruitment to damage sites is controlled, but it is likely that we do not yet have full understanding of the process. Here, we provide evidence that CtIP recruitment and functioning are controlled by the SIAH2 E3 ubiquitin ligase. We found that SIAH2 interacts and ubiquitinates CtIP at its N-terminal lysine residues. Mutating the key CtIP lysine residues impaired CtIP recruitment to DSBs and stalled replication forks, DSB end resection, overall HR repair capacity of cells, and recovery of stalled replication forks, suggesting that the SIAH2-induced ubiquitination is important for relocating CtIP to sites of damage. Depleting SIAH2 consistently phenocopied these results. Overall, our work suggests that SIAH2 is a new regulator of CtIP and HR repair, and emphasizes that SIAH2-mediated recruitment of the CtIP is an important step for CtIP’s function during HR repair.
Collapse
Affiliation(s)
- Seo-Yeon Jeong
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea.,Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Gurusamy Hariharasudhan
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Min-Ji Kim
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Ji-Yeon Lim
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea.,Department of Pharmacology, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Sung Mi Jung
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea.,Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Eun-Ji Choi
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea.,Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - In-Youb Chang
- Department of Anatomy, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Younghoon Kee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno-Joongang-daero, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Ho Jin You
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea.,Department of Pharmacology, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Jung-Hee Lee
- Laboratory of Genomic Instability and Cancer therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea.,Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| |
Collapse
|
7
|
Zhang T, Yang H, Zhou Z, Bai Y, Wang J, Wang W. Crosstalk between SUMOylation and ubiquitylation controls DNA end resection by maintaining MRE11 homeostasis on chromatin. Nat Commun 2022; 13:5133. [PMID: 36050397 PMCID: PMC9436968 DOI: 10.1038/s41467-022-32920-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 08/24/2022] [Indexed: 11/09/2022] Open
Abstract
DNA end resection is delicately regulated through various types of post-translational modifications to initiate homologous recombination, but the involvement of SUMOylation in this process remains incompletely understood. Here, we show that MRE11 requires SUMOylation to shield it from ubiquitin-mediated degradation when resecting damaged chromatin. Upon DSB induction, PIAS1 promotes MRE11 SUMOylation on chromatin to initiate DNA end resection. Then, MRE11 is deSUMOylated by SENP3 mainly after it has moved away from DSB sites. SENP3 deficiency results in MRE11 degradation failure and accumulation on chromatin, causing genome instability. We further show that cancer-related MRE11 mutants with impaired SUMOylation exhibit compromised DNA repair ability. Thus, we demonstrate that MRE11 SUMOylation in coordination with ubiquitylation is dynamically controlled by PIAS1 and SENP3 to facilitate DNA end resection and maintain genome stability. DNA end resection initiating DNA repair by homologous recombination needs to be delicately regulated. This study shows the interplay between SUMOylation and ubiquitylation maintains MRE11 homeostasis on chromatin, thus facilitating genome stability.
Collapse
Affiliation(s)
- Tao Zhang
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Han Yang
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Zenan Zhou
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Yongtai Bai
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Jiadong Wang
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Weibin Wang
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
| |
Collapse
|
8
|
Kolobynina KG, Rapp A, Cardoso MC. Chromatin Ubiquitination Guides DNA Double Strand Break Signaling and Repair. Front Cell Dev Biol 2022; 10:928113. [PMID: 35865631 PMCID: PMC9294282 DOI: 10.3389/fcell.2022.928113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
Chromatin is the context for all DNA-based molecular processes taking place in the cell nucleus. The initial chromatin structure at the site of the DNA damage determines both, lesion generation and subsequent activation of the DNA damage response (DDR) pathway. In turn, proceeding DDR changes the chromatin at the damaged site and across large fractions of the genome. Ubiquitination, besides phosphorylation and methylation, was characterized as an important chromatin post-translational modification (PTM) occurring at the DNA damage site and persisting during the duration of the DDR. Ubiquitination appears to function as a highly versatile “signal-response” network involving several types of players performing various functions. Here we discuss how ubiquitin modifiers fine-tune the DNA damage recognition and response and how the interaction with other chromatin modifications ensures cell survival.
Collapse
|
9
|
MRNIP condensates promote DNA double-strand break sensing and end resection. Nat Commun 2022; 13:2638. [PMID: 35551189 PMCID: PMC9098523 DOI: 10.1038/s41467-022-30303-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 04/25/2022] [Indexed: 01/07/2023] Open
Abstract
The rapid recognition of DNA double-strand breaks (DSBs) by the MRE11/RAD50/NBS1 (MRN) complex is critical for the initiation of DNA damage response and DSB end resection. Here, we show that MRN complex interacting protein (MRNIP) forms liquid-like condensates to promote homologous recombination-mediated DSB repair. The intrinsically disordered region is essential for MRNIP condensate formation. Mechanically, the MRN complex is compartmentalized and concentrated into MRNIP condensates in the nucleus. After DSB formation, MRNIP condensates move to the damaged DNA rapidly to accelerate the binding of DSB by the concentrated MRN complex, therefore inducing the autophosphorylation of ATM and subsequent activation of DNA damage response signaling. Meanwhile, MRNIP condensates-enhanced MRN complex loading further promotes DSB end resection. In addition, data from xenograft models and clinical samples confirm a correlation between MRNIP and radioresistance. Together, these results reveal an important role of MRNIP phase separation in DSB response and the MRN complex-mediated DSB end resection. The MRN complex is a critical sensor and processor of DNA double-strand breaks (DSBs). Here, the authors show that MRNIP forms liquid-like condensates to accelerate the MRN-mediated sensing and end resection of DSB, thereby promoting DSB repair.
Collapse
|
10
|
Fitieh A, Locke AJ, Mashayekhi F, Khaliqdina F, Sharma AK, Ismail IH. BMI-1 regulates DNA end resection and homologous recombination repair. Cell Rep 2022; 38:110536. [PMID: 35320715 DOI: 10.1016/j.celrep.2022.110536] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/12/2021] [Accepted: 02/28/2022] [Indexed: 11/03/2022] Open
Abstract
BMI-1 is an essential regulator of transcriptional silencing during development. Recently, the role of BMI-1 in the DNA damage response has gained much attention, but the exact mechanism of how BMI-1 participates in the process is unclear. Here, we establish a role for BMI-1 in the repair of DNA double-strand breaks by homologous recombination (HR), where it promotes DNA end resection. Mechanistically, BMI-1 mediates DNA end resection by facilitating the recruitment of CtIP, thus allowing RPA and RAD51 accumulation at DNA damage sites. Interestingly, treatment with transcription inhibitors rescues the DNA end resection defects of BMI-1-depleted cells, suggesting BMI-1-dependent transcriptional silencing mediates DNA end resection. Moreover, we find that H2A ubiquitylation at K119 (H2AK119ub) promotes end resection. Taken together, our results identify BMI-1-mediated transcriptional silencing and promotion of H2AK119ub deposition as essential regulators of DNA end resection and thus the progression of HR.
Collapse
Affiliation(s)
- Amira Fitieh
- Biophysics Department, Faculty of Science, Cairo University, 12613 Giza, Egypt; Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Andrew J Locke
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Fatemeh Mashayekhi
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Fajr Khaliqdina
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Ajit K Sharma
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Ismail Hassan Ismail
- Biophysics Department, Faculty of Science, Cairo University, 12613 Giza, Egypt; Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada.
| |
Collapse
|
11
|
Nickoloff JA, Sharma N, Taylor L, Allen SJ, Hromas R. Nucleases and Co-Factors in DNA Replication Stress Responses. DNA 2022; 2:68-85. [PMID: 36203968 PMCID: PMC9534323 DOI: 10.3390/dna2010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
DNA replication stress is a constant threat that cells must manage to proliferate and maintain genome integrity. DNA replication stress responses, a subset of the broader DNA damage response (DDR), operate when the DNA replication machinery (replisome) is blocked or replication forks collapse during S phase. There are many sources of replication stress, such as DNA lesions caused by endogenous and exogenous agents including commonly used cancer therapeutics, and difficult-to-replicate DNA sequences comprising fragile sites, G-quadraplex DNA, hairpins at trinucleotide repeats, and telomeres. Replication stress is also a consequence of conflicts between opposing transcription and replication, and oncogenic stress which dysregulates replication origin firing and fork progression. Cells initially respond to replication stress by protecting blocked replisomes, but if the offending problem (e.g., DNA damage) is not bypassed or resolved in a timely manner, forks may be cleaved by nucleases, inducing a DNA double-strand break (DSB) and providing a means to accurately restart stalled forks via homologous recombination. However, DSBs pose their own risks to genome stability if left unrepaired or misrepaired. Here we focus on replication stress response systems, comprising DDR signaling, fork protection, and fork processing by nucleases that promote fork repair and restart. Replication stress nucleases include MUS81, EEPD1, Metnase, CtIP, MRE11, EXO1, DNA2-BLM, SLX1-SLX4, XPF-ERCC1-SLX4, Artemis, XPG, and FEN1. Replication stress factors are important in cancer etiology as suppressors of genome instability associated with oncogenic mutations, and as potential cancer therapy targets to enhance the efficacy of chemo- and radiotherapeutics.
Collapse
Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Sage J. Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| |
Collapse
|
12
|
Cellular mechanism of action of 2-nitroimidzoles as hypoxia-selective therapeutic agents. Redox Biol 2022; 52:102300. [PMID: 35430547 PMCID: PMC9038562 DOI: 10.1016/j.redox.2022.102300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/05/2022] [Accepted: 03/18/2022] [Indexed: 02/06/2023] Open
Abstract
Solid tumours are often poorly oxygenated, which confers resistance to standard treatment modalities. Targeting hypoxic tumours requires compounds, such as nitroimidazoles (NIs), equipped with the ability to reach and become activated within diffusion limited tumour niches. NIs become selectively entrapped in hypoxic cells through bioreductive activation, and have shown promise as hypoxia directed therapeutics. However, little is known about their mechanism of action, hindering the broader clinical usage of NIs. Iodoazomycin arabinofuranoside (IAZA) and fluoroazomycin arabinofuranoside (FAZA) are clinically validated 2-NI hypoxic radiotracers with excellent tumour uptake properties. Hypoxic cancer cells have also shown preferential susceptibility to IAZA and FAZA treatment, making them ideal candidates for an in-depth study in a therapeutic setting. Using a head and neck cancer model, we show that hypoxic cells display higher sensitivity to IAZA and FAZA, where the drugs alter cell morphology, compromise DNA replication, slow down cell cycle progression and induce replication stress, ultimately leading to cytostasis. Effects of IAZA and FAZA on target cellular macromolecules (DNA, proteins and glutathione) were characterized to uncover potential mechanism(s) of action. Covalent binding of these NIs was only observed to cellular proteins, but not to DNA, under hypoxia. While protein levels remained unaffected, catalytic activities of NI target proteins, such as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the detoxification enzyme glutathione S-transferase (GST) were significantly curtailed in response to drug treatment under hypoxia. Intraperitoneal administration of IAZA was well-tolerated in mice and produced early (but transient) growth inhibition of subcutaneous mouse tumours. Hypoxic cells display preferential sensitivity to IAZA and FAZA. They alter cell morphology and induce cytostasis. IAZA and FAZA generate covalent adducts of proteins but not DNA. GAPDH and GST activities, but not protein levels, are significantly reduced.
Collapse
|
13
|
Hariharasudhan G, Jeong SY, Kim MJ, Jung SM, Seo G, Moon JR, Lee S, Chang IY, Kee Y, You H, Lee JH. OUP accepted manuscript. Nucleic Acids Res 2022; 50:1501-1516. [PMID: 35061896 PMCID: PMC8860612 DOI: 10.1093/nar/gkac009] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/23/2021] [Accepted: 01/13/2022] [Indexed: 11/24/2022] Open
Abstract
Homologous recombination (HR) is critical for error-free repair of DNA double-strand breaks. Chromatin loading of RAD51, a key protein that mediates the recombination, is a crucial step in the execution of the HR repair. Here, we present evidence that SUMOylation of RAD51 is crucial for the RAD51 recruitment to chromatin and HR repair. We found that topoisomerase 1-binding arginine/serine-rich protein (TOPORS) induces the SUMOylation of RAD51 at lysine residues 57 and 70 in response to DNA damaging agents. The SUMOylation was facilitated by an ATM-induced phosphorylation of TOPORS at threonine 515 upon DNA damage. Knockdown of TOPORS or expression of SUMOylation-deficient RAD51 mutants caused reduction in supporting normal RAD51 functions during the HR repair, suggesting the physiological importance of the modification. We found that the SUMOylation-deficient RAD51 reduces the association with its crucial binding partner BRCA2, explaining its deficiency in supporting the HR repair. These findings altogether demonstrate a crucial role for TOPORS-mediated RAD51 SUMOylation in promoting HR repair and genomic maintenance.
Collapse
Affiliation(s)
- Gurusamy Hariharasudhan
- Laboratory of Genomic Instability and Cancer Therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Seo-Yeon Jeong
- Laboratory of Genomic Instability and Cancer Therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
- Department of Pharmacology, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Min-Ji Kim
- Laboratory of Genomic Instability and Cancer Therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Sung Mi Jung
- Laboratory of Genomic Instability and Cancer Therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Gwanwoo Seo
- Laboratory of Genomic Instability and Cancer Therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
- Department of Pharmacology, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Ju-Ran Moon
- Laboratory of Genomic Instability and Cancer Therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Sumi Lee
- Laboratory of Genomic Instability and Cancer Therapeutics, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - In-Youb Chang
- Department of Anatomy, Chosun University School of Medicine, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
| | - Younghoon Kee
- Correspondence may also be addressed to Younghoon Kee. Tel: +82 53 785 1610;
| | - Ho Jin You
- Correspondence may also be addressed to Ho Jin You. Tel: +82 62 230 6337;
| | - Jung-Hee Lee
- To whom correspondence should be addressed. Tel: +82 62 230 6399;
| |
Collapse
|
14
|
SUMO-Based Regulation of Nuclear Positioning to Spatially Regulate Homologous Recombination Activities at Replication Stress Sites. Genes (Basel) 2021; 12:genes12122010. [PMID: 34946958 PMCID: PMC8701742 DOI: 10.3390/genes12122010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 12/20/2022] Open
Abstract
DNA lesions have properties that allow them to escape their nuclear compartment to achieve DNA repair in another one. Recent studies uncovered that the replication fork, when its progression is impaired, exhibits increased mobility when changing nuclear positioning and anchors to nuclear pore complexes, where specific types of homologous recombination pathways take place. In yeast models, increasing evidence points out that nuclear positioning is regulated by small ubiquitin-like modifier (SUMO) metabolism, which is pivotal to maintaining genome integrity at sites of replication stress. Here, we review how SUMO-based pathways are instrumental to spatially segregate the subsequent steps of homologous recombination during replication fork restart. In particular, we discussed how routing towards nuclear pore complex anchorage allows distinct homologous recombination pathways to take place at halted replication forks.
Collapse
|
15
|
Dhingra N, Zhao X. Advances in SUMO-based regulation of homologous recombination. Curr Opin Genet Dev 2021; 71:114-119. [PMID: 34333341 PMCID: PMC8671156 DOI: 10.1016/j.gde.2021.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 10/20/2022]
Abstract
Homologous Recombination (HR) is a critical DNA repair mechanism for a range of genome lesions. HR is responsible for mending DNA double strand breaks (DSBs) using intact template DNA. In addition, many HR proteins help cope with DNA lesions generated from DNA replication and telomere deficiency. The functions of HR proteins are often regulated by protein modifications that can quickly and reversibly adjust substrate proteins' attributes. Sumoylation is one of the prevalent modifications that affects all steps of the HR processes and exerts diverse regulation on substrates. This review aims to summarize the most recent advances in our understanding of SUMO-based HR regulation and highlight some key questions that remain to be elucidated.
Collapse
Affiliation(s)
- Nalini Dhingra
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| |
Collapse
|