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Donati E, Vidossich P, De Vivo M. Molecular Mechanism of Phosphate Steering for DNA Binding, Cleavage Localization, and Substrate Release in Nucleases. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elisa Donati
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
| | - Pietro Vidossich
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
| | - Marco De Vivo
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
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Zhong G, Wang Y, Wei H, Chen M, Lin H, Huang Z, Huang J, Wang S, Lin J. The Clinical Significance of the Expression of FEN1 in Primary Osteosarcoma. Int J Gen Med 2021; 14:6477-6485. [PMID: 34675615 PMCID: PMC8504935 DOI: 10.2147/ijgm.s335817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/29/2021] [Indexed: 12/17/2022] Open
Abstract
PURPOSE The aim of this research was to investigate the clinical significance of the expression of flap structure-specific endonuclease 1 (FEN1) in primary osteosarcoma. METHODS The expression of FEN1 was detected by immunohistochemistry analysis. The association of the expression of FEN1 in osteosarcoma with clinicopathological parameters was analyzed by using χ 2 test or Fisher's exact test. Survival analyses were performed by Kaplan-Meier method and Cox proportional hazards regression model. RESULTS Of the 40 osteosarcoma patients, 19 (47.5%) patients presented with FEN1 high expression, while in the non-neoplastic bone specimens, the FEN1 high expression was observed in 10% (3/30), the positive expression rate in osteosarcoma patients was significantly higher than that of non-neoplastic bone specimens (P< 0.01). Univariate analysis indicated that the progression-free survival (PFS) and overall survival (OS) were correlated with the expression level of FEN1 (PFS, P < 0.001; OS, P = 0.002), Enneking staging (PFS, P = 0.026; OS, P = 0.044) and chemotherapy response (PFS, P = 0.019; OS, P = 0.031). Multivariate analysis demonstrated that FEN1 expression was an independent prognostic factor for the PFS (HR = 4.73, P = 0.002) and OS (HR = 4.01, P = 0.038) of osteosarcoma patients. CONCLUSION This study showed that FEN1 was overexpressed in osteosarcoma patients and positively associated with poor prognosis of osteosarcoma patients. Further studies should focus on the relative mechanisms and the targeted FEN1 therapies for osteosarcoma.
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Affiliation(s)
- Guangxian Zhong
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Yunqing Wang
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Hongxiang Wei
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Meifang Chen
- The Health Management Center, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Huangfeng Lin
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Zhen Huang
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Jinlong Huang
- Department of Hematology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Shenglin Wang
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
| | - Jianhua Lin
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, People’s Republic of China
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Tian Y, Zhu Q, Sun Z, Geng D, Lin B, Su X, He J, Guo M, Xu H, Zhao Y, Qin W, Wang PG, Wen L, Yi W. One-Step Enzymatic Labeling Reveals a Critical Role of O-GlcNAcylation in Cell-Cycle Progression and DNA Damage Response. Angew Chem Int Ed Engl 2021; 60:26128-26135. [PMID: 34590401 DOI: 10.1002/anie.202110053] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Indexed: 12/26/2022]
Abstract
O-linked N-acetylglucosamine (O-GlcNAcylation) is a ubiquitous post-translational modification of proteins that is essential for cell function. Perturbation of O-GlcNAcylation leads to altered cell-cycle progression and DNA damage response. However, the underlying mechanisms are poorly understood. Here, we develop a highly sensitive one-step enzymatic strategy for capture and profiling O-GlcNAcylated proteins in cells. Using this strategy, we discover that flap endonuclease 1 (FEN1), an essential enzyme in DNA synthesis, is a novel substrate for O-GlcNAcylation. FEN1 O-GlcNAcylation is dynamically regulated during the cell cycle. O-GlcNAcylation at the serine 352 of FEN1 disrupts its interaction with Proliferating Cell Nuclear Antigen (PCNA) at the replication foci, and leads to altered cell cycle, defects in DNA replication, accumulation of DNA damage, and enhanced sensitivity to DNA damage agents. Thus, our study provides a sensitive method for profiling O-GlcNAcylated proteins, and reveals an unknown mechanism of O-GlcNAcylation in regulating cell cycle progression and DNA damage response.
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Affiliation(s)
- Yinping Tian
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, School of Medicine, Zhejiang University, Hangzhou, China.,MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Qiang Zhu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zeyu Sun
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Didi Geng
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Bingyi Lin
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaoling Su
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jiahui He
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Miao Guo
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Hong Xu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ye Zhao
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Weijie Qin
- National Center for Protein Sciences Beijing, State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Peng George Wang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Liuqing Wen
- Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wen Yi
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, School of Medicine, Zhejiang University, Hangzhou, China.,MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
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54
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Rad27 and Exo1 function in different excision pathways for mismatch repair in Saccharomyces cerevisiae. Nat Commun 2021; 12:5568. [PMID: 34552065 PMCID: PMC8458276 DOI: 10.1038/s41467-021-25866-z] [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: 02/19/2021] [Accepted: 08/31/2021] [Indexed: 11/20/2022] Open
Abstract
Eukaryotic DNA Mismatch Repair (MMR) involves redundant exonuclease 1 (Exo1)-dependent and Exo1-independent pathways, of which the Exo1-independent pathway(s) is not well understood. The exo1Δ440-702 mutation, which deletes the MutS Homolog 2 (Msh2) and MutL Homolog 1 (Mlh1) interacting peptides (SHIP and MIP boxes, respectively), eliminates the Exo1 MMR functions but is not lethal in combination with rad27Δ mutations. Analyzing the effect of different combinations of the exo1Δ440-702 mutation, a rad27Δ mutation and the pms1-A99V mutation, which inactivates an Exo1-independent MMR pathway, demonstrated that each of these mutations inactivates a different MMR pathway. Furthermore, it was possible to reconstitute a Rad27- and Msh2-Msh6-dependent MMR reaction in vitro using a mispaired DNA substrate and other MMR proteins. Our results demonstrate Rad27 defines an Exo1-independent eukaryotic MMR pathway that is redundant with at least two other MMR pathways. Defects in DNA mismatch repair (MMR) have been linked to inherited and sporadic cancers. Here the authors demonstrate that the DNA repair protein Rad27 (human FEN1) functions in one of three redundant mispair excision pathways, where its flap endonuclease activity catalyzes mispair excision.
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55
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Sobhy MA, Tehseen M, Takahashi M, Bralić A, De Biasio A, Hamdan SM. Implementing fluorescence enhancement, quenching, and FRET for investigating flap endonuclease 1 enzymatic reaction at the single-molecule level. Comput Struct Biotechnol J 2021; 19:4456-4471. [PMID: 34471492 PMCID: PMC8385120 DOI: 10.1016/j.csbj.2021.07.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/23/2021] [Accepted: 07/25/2021] [Indexed: 11/24/2022] Open
Abstract
Flap endonuclease 1 (FEN1) is an important component of the intricate molecular machinery for DNA replication and repair. FEN1 is a structure-specific 5' nuclease that cleaves nascent single-stranded 5' flaps during the maturation of Okazaki fragments. Here, we review our research primarily applying single-molecule fluorescence to resolve important mechanistic aspects of human FEN1 enzymatic reaction. The methodology presented in this review is aimed as a guide for tackling other biomolecular enzymatic reactions by fluorescence enhancement, quenching, and FRET and their combinations. Using these methods, we followed in real-time the structures of the substrate and product and 5' flap cleavage during catalysis. We illustrate that FEN1 actively bends the substrate to verify its features and continues to mold it to induce a protein disorder-to-order transitioning that controls active site assembly. This mechanism suppresses off-target cleavage of non-cognate substrates and promotes their dissociation with an accuracy that was underestimated from bulk assays. We determined that product release in FEN1 after the 5' flap release occurs in two steps; a brief binding to the bent nicked-product followed by longer binding to the unbent nicked-product before dissociation. Based on our cryo-electron microscopy structure of the human lagging strand replicase bound to FEN1, we propose how this two-step product release mechanism may regulate the final steps during the maturation of Okazaki fragments.
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Affiliation(s)
- Mohamed A Sobhy
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Muhammad Tehseen
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Masateru Takahashi
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Amer Bralić
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Alfredo De Biasio
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, Lancaster Rd, Leicester LE1 7HB, UK
| | - Samir M Hamdan
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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56
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Wilson DM, Deacon AM, Duncton MAJ, Pellicena P, Georgiadis MM, Yeh AP, Arvai AS, Moiani D, Tainer JA, Das D. Fragment- and structure-based drug discovery for developing therapeutic agents targeting the DNA Damage Response. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 163:130-142. [PMID: 33115610 PMCID: PMC8666131 DOI: 10.1016/j.pbiomolbio.2020.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/13/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022]
Abstract
Cancer will directly affect the lives of over one-third of the population. The DNA Damage Response (DDR) is an intricate system involving damage recognition, cell cycle regulation, DNA repair, and ultimately cell fate determination, playing a central role in cancer etiology and therapy. Two primary therapeutic approaches involving DDR targeting include: combinatorial treatments employing anticancer genotoxic agents; and synthetic lethality, exploiting a sporadic DDR defect as a mechanism for cancer-specific therapy. Whereas, many DDR proteins have proven "undruggable", Fragment- and Structure-Based Drug Discovery (FBDD, SBDD) have advanced therapeutic agent identification and development. FBDD has led to 4 (with ∼50 more drugs under preclinical and clinical development), while SBDD is estimated to have contributed to the development of >200, FDA-approved medicines. Protein X-ray crystallography-based fragment library screening, especially for elusive or "undruggable" targets, allows for simultaneous generation of hits plus details of protein-ligand interactions and binding sites (orthosteric or allosteric) that inform chemical tractability, downstream biology, and intellectual property. Using a novel high-throughput crystallography-based fragment library screening platform, we screened five diverse proteins, yielding hit rates of ∼2-8% and crystal structures from ∼1.8 to 3.2 Å. We consider current FBDD/SBDD methods and some exemplary results of efforts to design inhibitors against the DDR nucleases meiotic recombination 11 (MRE11, a.k.a., MRE11A), apurinic/apyrimidinic endonuclease 1 (APE1, a.k.a., APEX1), and flap endonuclease 1 (FEN1).
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Affiliation(s)
- David M Wilson
- Hasselt University, Biomedical Research Institute, Diepenbeek, Belgium; Boost Scientific, Heusden-Zolder, Belgium; XPose Therapeutics Inc., San Carlos, CA, USA
| | - Ashley M Deacon
- Accelero Biostructures Inc., San Francisco, CA, USA; XPose Therapeutics Inc., San Carlos, CA, USA
| | | | | | - Millie M Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA; XPose Therapeutics Inc., San Carlos, CA, USA
| | - Andrew P Yeh
- Accelero Biostructures Inc., San Francisco, CA, USA
| | - Andrew S Arvai
- Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Davide Moiani
- Department of Cancer Biology, MD Anderson Cancer Center, Houston, TX, USA; Department of Molecular and Cellular Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - John A Tainer
- Department of Cancer Biology, MD Anderson Cancer Center, Houston, TX, USA; Department of Molecular and Cellular Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - Debanu Das
- Accelero Biostructures Inc., San Francisco, CA, USA; XPose Therapeutics Inc., San Carlos, CA, USA.
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57
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Wei L, Ploss A. Mechanism of Hepatitis B Virus cccDNA Formation. Viruses 2021; 13:v13081463. [PMID: 34452329 PMCID: PMC8402782 DOI: 10.3390/v13081463] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) remains a major medical problem affecting at least 257 million chronically infected patients who are at risk of developing serious, frequently fatal liver diseases. HBV is a small, partially double-stranded DNA virus that goes through an intricate replication cycle in its native cellular environment: human hepatocytes. A critical step in the viral life-cycle is the conversion of relaxed circular DNA (rcDNA) into covalently closed circular DNA (cccDNA), the latter being the major template for HBV gene transcription. For this conversion, HBV relies on multiple host factors, as enzymes capable of catalyzing the relevant reactions are not encoded in the viral genome. Combinations of genetic and biochemical approaches have produced findings that provide a more holistic picture of the complex mechanism of HBV cccDNA formation. Here, we review some of these studies that have helped to provide a comprehensive picture of rcDNA to cccDNA conversion. Mechanistic insights into this critical step for HBV persistence hold the key for devising new therapies that will lead not only to viral suppression but to a cure.
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58
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Mohanty BK, Karam JA, Howley BV, Dalton AC, Grelet S, Dincman T, Streitfeld WS, Yoon JH, Balakrishnan L, Chazin WJ, Long DT, Howe PH. Heterogeneous nuclear ribonucleoprotein E1 binds polycytosine DNA and monitors genome integrity. Life Sci Alliance 2021; 4:4/9/e202000995. [PMID: 34272328 PMCID: PMC8321654 DOI: 10.26508/lsa.202000995] [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: 12/15/2020] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/24/2022] Open
Abstract
hnRNP E1 binds polycytosine tracts of DNA and monitors genome integrity. Heterogeneous nuclear ribonucleoprotein E1 (hnRNP E1) is a tumor suppressor protein that binds site- and structure-specifically to RNA sequences to regulate mRNA stability, facilitate alternative splicing, and suppress protein translation on several metastasis-associated mRNAs. Here, we show that hnRNP E1 binds polycytosine-rich DNA tracts present throughout the genome, including those at promoters of several oncogenes and telomeres and monitors genome integrity. It binds DNA in a site- and structure-specific manner. hnRNP E1-knockdown cells displayed increased DNA damage signals including γ-H2AX at its binding sites and also showed increased mutations. UV and hydroxyurea treatment of hnRNP E1-knockdown cells exacerbated the basal DNA damage signals with increased cell cycle arrest, activation of checkpoint proteins, and monoubiquitination of proliferating cell nuclear antigen despite no changes in deubiquitinating enzymes. DNA damage caused by genotoxin treatment localized to hnRNP E1 binding sites. Our work suggests that hnRNP E1 facilitates functions of DNA integrity proteins at polycytosine tracts and monitors DNA integrity at these sites.
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Affiliation(s)
- Bidyut K Mohanty
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Joseph Aq Karam
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Breege V Howley
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Annamarie C Dalton
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Simon Grelet
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA.,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Toros Dincman
- Division of Hematology and Oncology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - William S Streitfeld
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Je-Hyun Yoon
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Lata Balakrishnan
- Department of Biology, School of Science, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - David T Long
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Philip H Howe
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA .,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
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Zhu Y, Dai H, Wang Y, Liang Y, Feng W, Yuan Y. Targeting FEN1 Suppresses the Proliferation of Chronic Myeloid Leukemia Cells Through Regulating Alternative End-Joining Pathways. DNA Cell Biol 2021; 40:1101-1111. [PMID: 34156283 DOI: 10.1089/dna.2021.0239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Chronic myeloid leukemia (CML) is characterized by the formation of the BCR-ABL fusion gene. The BCR-ABL protein leads to an increased level of reactive oxygen species, which is a major cause of endogenous DNA double-strand breaks (DSBs). CML cells are prone to rely on a highly mutagenic alternative end-joining (Alt-EJ) pathway to cope with enhanced DSBs, which aggravates chromosomal instability. Hence, targeting dysregulated DNA repair proteins provides new insights into cancer treatment. In this study, we discovered the abnormal upregulation of Flap endonuclease 1 (FEN1) in CML, as well as FEN1's participation in the error-prone Alt-EJ repair pathway and its interplay with DNA Ligase1 and proliferating cell nuclear antigen in DSB repair. Knockdown of FEN1 by shRNA not only inhibited the proliferation and induced apoptosis but also enhanced the efficacy of imatinib (IM) in drug-resistant CML cell K562/G01. Moreover, excessive DSB accumulation was detected after FEN1 inhibition. In summary, our results demonstrated that FEN1 is a promising therapeutic target in CML treatment. This work extends the understanding of regulating abnormal DSB repair for cancer treatment.
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Affiliation(s)
- Yalin Zhu
- Department of Laboratory Medicine, Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China
| | - Hongdan Dai
- Department of Laboratory Medicine, Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China
| | - Yonghong Wang
- Department of Laboratory Medicine, Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China
| | - Yang Liang
- Department of Laboratory Medicine, Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China
| | - Wenli Feng
- Department of Laboratory Medicine, Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China
| | - Ying Yuan
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Asada K, Sakaue F, Nagata T, Zhang JC, Yoshida-Tanaka K, Abe A, Nawa M, Nishina K, Yokota T. Short DNA/RNA heteroduplex oligonucleotide interacting proteins are key regulators of target gene silencing. Nucleic Acids Res 2021; 49:4864-4876. [PMID: 33928345 PMCID: PMC8136785 DOI: 10.1093/nar/gkab258] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 03/25/2021] [Accepted: 04/23/2021] [Indexed: 01/31/2023] Open
Abstract
Antisense oligonucleotide (ASO)-based therapy is one of the next-generation therapy, especially targeting neurological disorders. Many cases of ASO-dependent gene expression suppression have been reported. Recently, we developed a tocopherol conjugated DNA/RNA heteroduplex oligonucleotide (Toc-HDO) as a new type of drug. Toc-HDO is more potent, stable, and efficiently taken up by the target tissues compared to the parental ASO. However, the detailed mechanisms of Toc-HDO, including its binding proteins, are unknown. Here, we developed native gel shift assays with fluorescence-labeled nucleic acids samples extracted from mice livers. These assays revealed two Toc-HDO binding proteins, annexin A5 (ANXA5) and carbonic anhydrase 8 (CA8). Later, we identified two more proteins, apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) and flap structure-specific endonuclease 1 (FEN1) by data mining. shRNA knockdown studies demonstrated that all four proteins regulated Toc-HDO activity in Hepa1-6, mouse hepatocellular cells. In vitro binding assays and fluorescence polarization assays with purified recombinant proteins characterized the identified proteins and pull-down assays with cell lysates demonstrated the protein binding to the Toc-HDO and ASO in a biological environment. Taken together, our findings provide a brand new molecular biological insight as well as future directions for HDO-based disease therapy.
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Affiliation(s)
- Ken Asada
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Fumika Sakaue
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Tetsuya Nagata
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Ji-chun Zhang
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Kie Yoshida-Tanaka
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Aya Abe
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Makiko Nawa
- Laboratory of Cytometry and Proteome Research, Nanken-Kyoten and Research Core Center, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Kazutaka Nishina
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Takanori Yokota
- Department of Neurology and Neurological Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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Zangouei AS, Alimardani M, Moghbeli M. MicroRNAs as the critical regulators of Doxorubicin resistance in breast tumor cells. Cancer Cell Int 2021; 21:213. [PMID: 33858435 PMCID: PMC8170947 DOI: 10.1186/s12935-021-01873-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/08/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Chemotherapy is one of the most common treatment options for breast cancer (BC) patients. However, about half of the BC patients are chemotherapeutic resistant. Doxorubicin (DOX) is considered as one of the first line drugs in the treatment of BC patients whose function is negatively affected by multi drug resistance. Due to the severe side effects of DOX, it is very important to diagnose the DOX resistant BC patients. Therefore, assessment of molecular mechanisms involved in DOX resistance can improve the clinical outcomes in BC patients by introducing the novel therapeutic and diagnostic molecular markers. MicroRNAs (miRNAs) as members of the non-coding RNAs family have pivotal roles in various cellular processes including cell proliferation and apoptosis. Therefore, aberrant miRNAs functions and expressions can be associated with tumor progression, metastasis, and drug resistance. Moreover, due to miRNAs stability in body fluids, they can be considered as non-invasive diagnostic markers for the DOX response in BC patients. MAIN BODY In the present review, we have summarized all of the miRNAs that have been reported to be associated with DOX resistance in BC for the first time in the world. CONCLUSIONS Since, DOX has severe side effects; it is required to distinguish the non DOX-responders from responders to improve the clinical outcomes of BC patients. This review highlights the miRNAs as pivotal regulators of DOX resistance in breast tumor cells. Moreover, the present review paves the way of introducing a non-invasive panel of prediction markers for DOX response among BC patients.
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Affiliation(s)
- Amir Sadra Zangouei
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maliheh Alimardani
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Medical Genetics and Molecular Medicine, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Meysam Moghbeli
- Department of Medical Genetics and Molecular Medicine, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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Yang H, Wang C, Xu E, Wei W, Liu Y, Liu S. Dual-Mode FEN1 Activity Detection Based on Nt.BstNBI-Induced Tandem Signal Amplification. Anal Chem 2021; 93:6567-6572. [PMID: 33847477 DOI: 10.1021/acs.analchem.1c00829] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Flap endonuclease 1 (FEN1) is a structure-specific nuclease that cleaves the 5' single-stranded protrusion (also known as 5' flap) during Okazaki fragment processing. It is overexpressed in various types of human cancer cells and has been considered as an important biomarker for cancer diagnosis. However, conventional methods for FEN1 assay usually suffer from complicated platform and laborious procedures with a limited sensitivity. Here, we developed a dual-signal method for sensitive detection of FEN1 on the basis of duplex-specific nuclease actuated cyclic enzymatic repairing-mediated signal amplification. Once the 5' flap of the double-flap DNA substrate was cleaved by target FEN1, the cleaved 5' flap initiated strand-displacement amplification to produce plenty of G-rich DNA (G) sequences. These G sequences that self-assembled into G-quadruplexes in the presence of hemin revealed horseradish-peroxidase-like catalytic activities as well as fluorescence enhancement of thioflavin T. The UV-vis signal showed a good linear relationship with the logarithm of FEN1 activity ranging from 0.03 to 1.5 U with a detection limit of 0.01 U. The fluorescence signal correlated linearly with the logarithm of FEN1 activity ranging from 0.001 to 1.5 U with a detection limit of 0.75 mU. In addition, FEN1 can be visualized not only by colorimetry but also by fluorescence (under ice-water mixture conditions). This reliable, accurate, and convenient method would be a potential powerful tool in point-of-care testing applications and therapeutic response assessment.
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Affiliation(s)
- Haitang Yang
- Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Chenchen Wang
- Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Ensheng Xu
- Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Wei Wei
- Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Yong Liu
- Henan Key Laboratory of Polyoxometalate Chemistry, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
| | - Songqin Liu
- Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
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A bibliometric analysis of researches on flap endonuclease 1 from 2005 to 2019. BMC Cancer 2021; 21:374. [PMID: 33827468 PMCID: PMC8028219 DOI: 10.1186/s12885-021-08101-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 03/24/2021] [Indexed: 12/21/2022] Open
Abstract
Background Flap endonuclease 1 (FEN1) is a structure-specific nuclease that plays a role in a variety of DNA metabolism processes. FEN1 is important for maintaining genomic stability and regulating cell growth and development. It is associated with the occurrence and development of several diseases, especially cancers. There is a lack of systematic bibliometric analyses focusing on research trends and knowledge structures related to FEN1. Purpose To analyze hotspots, the current state and research frontiers performed for FEN1 over the past 15 years. Methods Publications were retrieved from the Web of Science Core Collection (WoSCC) database, analyzing publication dates ranging from 2005 to 2019. VOSviewer1.6.15 and Citespace5.7 R1 were used to perform a bibliometric analysis in terms of countries, institutions, authors, journals and research areas related to FEN1. A total of 421 publications were included in this analysis. Results Our findings indicated that FEN1 has received more attention and interest from researchers in the past 15 years. Institutes in the United States, specifically the Beckman Research Institute of City of Hope published the most research related to FEN1. Shen BH, Zheng L and Bambara Ra were the most active researchers investigating this endonuclease and most of this research was published in the Journal of Biological Chemistry. The main scientific areas of FEN1 were related to biochemistry, molecular biology, cell biology, genetics and oncology. Research hotspots included biological activities, DNA metabolism mechanisms, protein-protein interactions and gene mutations. Research frontiers included oxidative stress, phosphorylation and tumor progression and treatment. Conclusion This bibliometric study may aid researchers in the understanding of the knowledge base and research frontiers associated with FEN1. In addition, emerging hotspots for research can be used as the subjects of future studies.
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Modeling DNA trapping of anticancer therapeutic targets using missense mutations identifies dominant synthetic lethal interactions. Proc Natl Acad Sci U S A 2021; 118:2100240118. [PMID: 33782138 DOI: 10.1073/pnas.2100240118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Genetic screens can identify synthetic lethal (SL) interactions and uncover potential anticancer therapeutic targets. However, most SL screens have utilized knockout or knockdown approaches that do not accurately mimic chemical inhibition of a target protein. Here, we test whether missense mutations can be utilized as a model for a type of protein inhibition that creates a dominant gain-of-function cytotoxicity. We expressed missense mutations in the FEN1 endonuclease and the replication-associated helicase, CHL1, that inhibited enzymatic activity but retained substrate binding, and found that these mutations elicited a dominant SL phenotype consistent with the generation of cytotoxic protein-DNA or protein-protein intermediates. Genetic screens with nuclease-defective hFEN1 and helicase-deficient yCHL1 captured dominant SL interactions, in which ectopic expression of the mutant form, in the presence of the wild-type form, caused SL in specific mutant backgrounds. Expression of nuclease-defective hFEN1 in yeast elicited DNA binding-dependent dominant SL with homologous recombination mutants. In contrast, dominant SL interactions with helicase-deficient yCHL1 were observed in spindle-associated, Ctf18-alternative replication factor C (Ctf18-RFC) clamp loader complex, and cohesin mutant backgrounds. These results highlight the different mechanisms underlying SL interactions that occur in the presence of an inhibited form of the target protein and point to the utility of modeling trapping mutations in pursuit of more clinically relevant SL interactions.
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Schilling EM, Scherer M, Rothemund F, Stamminger T. Functional regulation of the structure-specific endonuclease FEN1 by the human cytomegalovirus protein IE1 suggests a role for the re-initiation of stalled viral replication forks. PLoS Pathog 2021; 17:e1009460. [PMID: 33770148 PMCID: PMC8026080 DOI: 10.1371/journal.ppat.1009460] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 04/07/2021] [Accepted: 03/08/2021] [Indexed: 11/19/2022] Open
Abstract
Flap endonuclease 1 (FEN1) is a member of the family of structure-specific endonucleases implicated in regulation of DNA damage response and DNA replication. So far, knowledge on the role of FEN1 during viral infections is limited. Previous publications indicated that poxviruses encode a conserved protein that acts in a manner similar to FEN1 to stimulate homologous recombination, double-strand break (DSB) repair and full-size genome formation. Only recently, cellular FEN1 has been identified as a key component for hepatitis B virus cccDNA formation. Here, we report on a novel functional interaction between Flap endonuclease 1 (FEN1) and the human cytomegalovirus (HCMV) immediate early protein 1 (IE1). Our results provide evidence that IE1 manipulates FEN1 in an unprecedented manner: we observed that direct IE1 binding does not only enhance FEN1 protein stability but also phosphorylation at serine 187. This correlates with nucleolar exclusion of FEN1 stimulating its DSB-generating gap endonuclease activity. Depletion of FEN1 and inhibition of its enzymatic activity during HCMV infection significantly reduced nascent viral DNA synthesis demonstrating a supportive role for efficient HCMV DNA replication. Furthermore, our results indicate that FEN1 is required for the formation of DSBs during HCMV infection suggesting that IE1 acts as viral activator of FEN1 in order to re-initiate stalled replication forks. In summary, we propose a novel mechanism of viral FEN1 activation to overcome replication fork barriers at difficult-to-replicate sites in viral genomes.
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Affiliation(s)
| | - Myriam Scherer
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
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Cheng C, Seen D, Zheng C, Zeng R, Li E. Role of Small GTPase RhoA in DNA Damage Response. Biomolecules 2021; 11:212. [PMID: 33546351 PMCID: PMC7913530 DOI: 10.3390/biom11020212] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 01/28/2021] [Accepted: 01/31/2021] [Indexed: 02/06/2023] Open
Abstract
Accumulating evidence has suggested a role of the small GTPase Ras homolog gene family member A (RhoA) in DNA damage response (DDR) in addition to its traditional function of regulating cell morphology. In DDR, 2 key components of DNA repair, ataxia telangiectasia-mutated (ATM) and flap structure-specific endonuclease 1 (FEN1), along with intracellular reactive oxygen species (ROS) have been shown to regulate RhoA activation. In addition, Rho-specific guanine exchange factors (GEFs), neuroepithelial transforming gene 1 (Net1) and epithelial cell transforming sequence 2 (Ect2), have specific functions in DDR, and they also participate in Ras-related C3 botulinum toxin substrate 1 (Rac1)/RhoA interaction, a process which is largely unappreciated yet possibly of significance in DDR. Downstream of RhoA, current evidence has highlighted its role in mediating cell cycle arrest, which is an important step in DNA repair. Unraveling the mechanism by which RhoA modulates DDR may provide more insight into DDR itself and may aid in the future development of cancer therapies.
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Affiliation(s)
| | | | | | | | - Enmin Li
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515031, Guangdong, China; (C.C.); (D.S.); (C.Z.); (R.Z.)
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Wu T, Zhu H, Zhang M, Sun Y, Yang Y, Gu L, Zhang J, Mu D, Wu C, Hu Z, Jiang L, Jia S, Zhang Y, He L, Pan FY, Guo Z. FEN1 inhibitor synergizes with low-dose camptothecin to induce increased cell killing via the mitochondria mediated apoptotic pathway. Gene Ther 2021; 29:407-417. [PMID: 33414522 DOI: 10.1038/s41434-020-00215-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 11/01/2020] [Accepted: 12/04/2020] [Indexed: 12/18/2022]
Abstract
Camptothecin has been used in tumor therapy for a long time but its antitumor effect is rather limited due to the side effect and the drug resistance. FEN1, a major component of DNA repair systems, plays important roles in maintaining genomic stability via DNA replication and repair. Here we found that FEN1 inhibitor greatly sensitizes cancer cells to low-dose camptothecin. The combinative treatment of FEN1 inhibitor and 1 nM camptothecin induced a synthetic lethal effect, which synergistically suppressed cancer cell proliferation and significantly mediated apoptosis both in vitro and in vivo. Our study suggested that targeting FEN1 could be a potent strategy for tumor-targeting cancer therapy.
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Affiliation(s)
- Ting Wu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Hongqiao Zhu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Miaomiao Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Yuling Sun
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Yongjing Yang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Lili Gu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Jing Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Dan Mu
- Affiliated Drum Tower Hospital, Nanjing University School of Medicine, 210008, Nanjing, China
| | - Congye Wu
- Department of Oncology, Nanjing First Hospital, Nanjing Medical University, 210002, Nanjing, China
| | - Zhigang Hu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Longwei Jiang
- Jinlin Hospital of Nanjing University, 210002, Nanjing, China
| | - Shaochang Jia
- Jinlin Hospital of Nanjing University, 210002, Nanjing, China
| | - Ying Zhang
- Jinlin Hospital of Nanjing University, 210002, Nanjing, China
| | - Lingfeng He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China.
| | - Fei-Yan Pan
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China.
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China.
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Zhang H, Ba S, Lee JY, Xie J, Loh TP, Li T. Cancer Biomarker-Triggered Disintegrable DNA Nanogels for Intelligent Drug Delivery. NANO LETTERS 2020; 20:8399-8407. [PMID: 33118827 DOI: 10.1021/acs.nanolett.0c03671] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Even though various techniques have been developed thus far for targeted delivery of therapeutics, design and fabrication of cancer biomarker-triggered disintegrable nanogels, which are exclusively composed of nucleic acid macromolecules, are still challenging nowadays. Here, we describe for the first time our creation of intelligent DNA nanogels whose backbones are sorely disintegrable by flap endonuclease 1 (FEN1), an enzymatic biomarker that is highly overexpressed in most cancer cells but not in their normal counterparts. It is the catalytic actions of intracellular FEN1 on bifurcated DNA structures that lead to the cancer-specific disintegration of our DNA nanogels and controlled release of drugs in target cancer cells. Consequently, the brand-new strategies introduced in the current report could break new ground in designing drug carriers for eliminating unwanted side effects of chemotherapeutic agents and live-cell probes for cancer risk assessment, diagnosis, and prognosis.
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Affiliation(s)
- Hao Zhang
- Institute of Advanced Synthesis (IAS), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
- Yangtze River Delta Research Institute, Northwestern Polytechnical University (NPU), 27 Zigang Road, Taicang, Jiangsu 215400, China
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Sai Ba
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Jasmine Yiqin Lee
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Jianping Xie
- Department of Chemical and Biomolecular and Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Teck-Peng Loh
- Institute of Advanced Synthesis (IAS), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Tianhu Li
- Institute of Advanced Synthesis (IAS), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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Marchetti AL, Guo H. New Insights on Molecular Mechanism of Hepatitis B Virus Covalently Closed Circular DNA Formation. Cells 2020; 9:cells9112430. [PMID: 33172220 PMCID: PMC7694973 DOI: 10.3390/cells9112430] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 12/15/2022] Open
Abstract
The chronic factor of the Hepatitis B Virus (HBV), specifically the covalently closed circular DNA (cccDNA), is a highly stable and active viral episomal genome established in the livers of chronic hepatitis B patients as a constant source of disease. Being able to target and eliminate cccDNA is the end goal for a genuine cure for HBV. Yet how HBV cccDNA is formed from the viral genomic relaxed circular DNA (rcDNA) and by what host factors had been long-standing research questions. It is generally acknowledged that HBV hijacks cellular functions to turn the open circular DNA conformation of rcDNA into cccDNA through DNA repair mechanisms. With great efforts from the HBV research community, there have been several recent leaps in our understanding of cccDNA formation. It is our goal in this review to analyze the recent reports showing evidence of cellular factor's involvement in the molecular pathway of cccDNA biosynthesis.
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Affiliation(s)
- Alexander L. Marchetti
- Department of Microbiology and Immunology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA;
- Cancer Virology Program, Hillman Cancer Center, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Haitao Guo
- Cancer Virology Program, Hillman Cancer Center, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Correspondence:
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van Ravesteyn TW, Arranz Dols M, Pieters W, Dekker M, te Riele H. Extensive trimming of short single-stranded DNA oligonucleotides during replication-coupled gene editing in mammalian cells. PLoS Genet 2020; 16:e1009041. [PMID: 33119594 PMCID: PMC7595315 DOI: 10.1371/journal.pgen.1009041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 08/10/2020] [Indexed: 11/19/2022] Open
Abstract
Through transfection of short single-stranded oligodeoxyribonucleotides (ssODNs) small genomic alterations can be introduced into mammalian cells with high precision. ssODNs integrate into the genome during DNA replication, but the resulting heteroduplex is prone to detection by DNA mismatch repair (MMR), which prevents effective gene modification. We have previously demonstrated that the suppressive action of MMR can be avoided when the mismatching nucleotide in the ssODN is a locked nucleic acid (LNA). Here, we reveal that LNA-modified ssODNs (LMOs) are not integrated as intact entities in mammalian cells, but are severely truncated before and after target hybridization. We found that single additional (non-LNA-modified) mutations in the 5’-arm of LMOs influenced targeting efficiencies negatively and activated the MMR pathway. In contrast, additional mutations in the 3’-arm did not affect targeting efficiencies and were not subject to MMR. Even more strikingly, homology in the 3’-arm was largely dispensable for effective targeting, suggestive for extensive 3’-end trimming. We propose a refined model for LMO-directed gene modification in mammalian cells that includes LMO degradation. The first step of many gene editing approaches in mammalian cells is to generate a targeted DNA lesion. By administering a repair template as second step, endogenous DNA repair mechanisms can be misled to introduce specific gene variants. However, subtle gene modification can also be achieved with high precision through a one-action protocol in the absence of DNA breaks. We have shown before that short single-stranded DNA molecules (LMOs) are very useful to introduce and study genetic variants that may predispose patients to cancer. While LMOs are known to integrate into the genome during DNA replication, the precise mechanism is poorly understood. We targeted mouse embryonic stem cells with differently designed LMOs to examine their effectiveness and editing outcomes. Based on these results we conclude that the two LMO termini are processed at different moments during the gene editing process. While the 3’-arm is degraded prior to LMO binding to the target site, the 5’-arm is degraded afterwards. Counterintuitively we also observe that partial degradation of the 3’-arm increases targeting efficiencies. Taken together our data provides novel mechanistic insight into our understanding of replication-coupled gene editing and may guide future LMO design strategies.
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Affiliation(s)
- Thomas W. van Ravesteyn
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Marcos Arranz Dols
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Wietske Pieters
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Marleen Dekker
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Hein te Riele
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
- * E-mail:
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71
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Xu L, Qu JL, Song N, Zhang LY, Zeng X, Che XF, Hou KZ, Shi S, Feng ZY, Qu XJ, Liu YP, Teng YE. Biological and clinical significance of flap endonuclease‑1 in triple‑negative breast cancer: Support of metastasis and a poor prognosis. Oncol Rep 2020; 44:2443-2454. [PMID: 33125141 PMCID: PMC7610327 DOI: 10.3892/or.2020.7812] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 07/27/2020] [Indexed: 12/17/2022] Open
Abstract
Flap endonuclease‑1 (FEN1), a structure‑specific nuclease participating in DNA replication and repair processes, has been confirmed to promote the proliferation and drug resistance of tumor cells. However, the biological functions of FEN1 in cancer cell migration and invasion have not been defined. In the present study, using online database analysis and immunohistochemistry of the specimens, it was found that FEN1 expression was associated with a highly invasive triple‑negative breast cancer (TNBC) subtype in both breast cancer samples from the Oncomine database and from patients recruited into the study. Furthermore, FEN1 was an important biomarker of lymph node metastasis and poor prognosis in patients with TNBC. FEN1 promoted migration of TNBC cell lines and FEN1 knockdown reduced the number of spontaneous lung metastasis in vivo. Ingenuity Pathway Analysis of FEN1‑related transcripts in 198 patients with TNBC demonstrated that the polo‑like kinase family may be the downstream target of FEN1. PLK4 was further identified as a critical target of FEN1 mediating TNBC cell migration, by regulating actin cytoskeleton rearrangement. The results of the present study validate FEN1 as a therapeutic target in patients with TNBC and revealed a new role for FEN1 in regulating TNBC invasion and metastasis.
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Affiliation(s)
- Lu Xu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Jing-Lei Qu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Na Song
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Ling-Yun Zhang
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Xue Zeng
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Xiao-Fang Che
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Ke-Zuo Hou
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Sha Shi
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Zu-Ying Feng
- Boz Life Science Research and Teaching Institute, San Diego, CA 92109, USA
| | - Xiu-Juan Qu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yun-Peng Liu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yue-E Teng
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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Guilliam TA, Yeeles JTP. An updated perspective on the polymerase division of labor during eukaryotic DNA replication. Crit Rev Biochem Mol Biol 2020; 55:469-481. [PMID: 32883112 DOI: 10.1080/10409238.2020.1811630] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In eukaryotes three DNA polymerases (Pols), α, δ, and ε, are tasked with bulk DNA synthesis of nascent strands during genome duplication. Most evidence supports a model where Pol α initiates DNA synthesis before Pol ε and Pol δ replicate the leading and lagging strands, respectively. However, a number of recent reports, enabled by advances in biochemical and genetic techniques, have highlighted emerging roles for Pol δ in all stages of leading-strand synthesis; initiation, elongation, and termination, as well as fork restart. By focusing on these studies, this review provides an updated perspective on the division of labor between the replicative polymerases during DNA replication.
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Affiliation(s)
- Thomas A Guilliam
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Joseph T P Yeeles
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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73
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Liu SB, Qiu XQ, Guo WQ, Li JL, Su Q, Du JH, Hu HJ, Wang XX, Song YH, Lou X, Xu XB. Transcriptome Analysis of FEN1 Knockdown HEK293T Cell Strain Reveals Alteration in Nucleic Acid Metabolism, Virus Infection, Cell Morphogenesis and Cancer Development. Comb Chem High Throughput Screen 2020; 22:379-386. [PMID: 31272350 DOI: 10.2174/1386207322666190704095602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 12/24/2022]
Abstract
AIM AND OBJECTIVE Flap endonuclease-1 (FEN1) plays a central role in DNA replication and DNA damage repair process. In mammals, FEN1 functional sites variation is related to cancer and chronic inflammation, and supports the role of FEN1 as a tumor suppressor. However, FEN1 is overexpressed in multiple types of cancer cells and is associated with drug resistance, supporting its role as an oncogene. Hence, it is vital to explore the multi-functions of FEN1 in normal cell metabolic process. This study was undertaken to examine how the gene expression profile changes when FEN1 is downregulated in 293T cells. MATERIALS AND METHODS Using the RNA sequencing and real-time PCR approaches, the transcript expression profile of FEN1 knockdown HEK293T cells have been detected for the next step evaluation, analyzation, and validation. RESULTS Our results confirmed that FEN1 is important for cell viability. We showed that when FEN1 downregulation led to the interruption of nucleic acids related metabolisms, cell cycle related metabolisms are significantly interrupted. FEN1 may also participate in non-coding RNA processing, ribosome RNA processing, transfer RNA processing, ribosome biogenesis, virus infection and cell morphogenesis. CONCLUSION These findings provide insight into how FEN1 nuclease might regulate a wide variety of biological processes, and laid the foundation for understanding the role of other RAD2 family nucleases in cell growth and metabolism.
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Affiliation(s)
- Song-Bai Liu
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou 215009, China
| | - Xiu-Qin Qiu
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou 215009, China
| | - Wei-Qiang Guo
- School of Chemistry, Biology and Materials Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jin-Li Li
- Department of Radiation Oncology, The Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Qian Su
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou 215009, China
| | - Jia-Hui Du
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou 215009, China
| | - He-Juan Hu
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou 215009, China
| | - Xiao-Xiao Wang
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou 215009, China
| | - Yao-Hua Song
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, Soochow University, Suzhou 215006, China
| | - Xiao Lou
- 307 Hospital of Chinese People's Liberation Army,The Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China
| | - Xiang-Bin Xu
- College of Food Science and Technology, Hainan University, Haikou 570228, China
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He L, Hu Z, Sun Y, Zhang M, Zhu H, Jiang L, Zhang Q, Mu D, Zhang J, Gu L, Yang Y, Pan FY, Jia S, Guo Z. PRMT1 is critical to FEN1 expression and drug resistance in lung cancer cells. DNA Repair (Amst) 2020; 95:102953. [PMID: 32861926 DOI: 10.1016/j.dnarep.2020.102953] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/30/2020] [Accepted: 08/12/2020] [Indexed: 12/18/2022]
Abstract
The up-regulation of PRMT1 is critical to the cell growth and cancer progression of lung cancer cells. In our research, we found that PRMT1 is important to the DNA repair ability and drug resistance of lung cancer cells. To demonstrate the functions of PRMT1, we identified Flap endonuclease 1 (FEN1) as a post-translationally modified downstream target protein of PRMT1. As a major component of Base Excision Repair pathway, FEN1 plays an important role in DNA replication and DNA damage repair. However, the detailed mechanism of FEN1 up-regulation in lung cancer cells remains unclear. In our study, we identified PRMT1 as a key factor that maintains the high expression levels of FEN1, which is critical to the DNA repair ability and the chemotherapeutic drug resistance of lung cancer cells.
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Affiliation(s)
- Lingfeng He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Zhigang Hu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Yuling Sun
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Miaomiao Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Hongqiao Zhu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Longwei Jiang
- Jinlin Hospital of Nanjing University, Nanjing, 210002, China
| | - Qi Zhang
- Department of Infectious Diseases, Nanjing Liuhe District People's Hospital Affiliated to Yangzhou University, Nanjing, 210012, China
| | - Dan Mu
- Affiliated Drum Tower Hospital, Nanjing University School of Medicine, 210008, Nanjing, China
| | - Jing Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Lili Gu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Yang Yang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China
| | - Fei-Yan Pan
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China.
| | - Shaochang Jia
- Jinlin Hospital of Nanjing University, Nanjing, 210002, China.
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing, 210023, China.
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75
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Ye X, Li Y, Wang L, Fang X, Kong J. All-in-one microfluidic nucleic acid diagnosis system for multiplex detection of sexually transmitted pathogens directly from genitourinary secretions. Talanta 2020; 221:121462. [PMID: 33076082 DOI: 10.1016/j.talanta.2020.121462] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 12/23/2022]
Abstract
Sexually transmitted infections are a serious public health concern worldwide, especially in young people. More than 30 pathogens can cause sexually transmitted diseases and co-infection often occurs. Therefore, the development of fast, low-cost and easy-to-use diagnostic screening methods is urgently needed for disease prevention and control. Herein, we established an all-in-one microfluidic nucleic acid diagnosis system, which could simultaneously detect Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum directly from genitourinary secretions with minimal manual manipulations. This system integrated nucleic acid extraction, amplification, and detection on a single microfluidic chip and could be automatically performed in an integrated detection device. This novel diagnosis tool showed good detection limits, stability (coefficient of variation <6%), specificity (no cross-reaction with 23 other pathogens for each target) and resistance to interference by other substances and the diagnostic efficacy was similar to that of PCR. The turn-around time was reduced to 50 min from sample to answer with automated testing steps. This novel diagnosis tool has the advantages of highly integrated, automated, sample-to-answer detection, and could thus replace the traditional method. This could significantly improve the prevention and control of sexually transmitted diseases.
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Affiliation(s)
- Xin Ye
- Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200433, PR China
| | - Yang Li
- Shanghai Suxin Biotechnology Co. Ltd and Suchuang Diagnostic Products Co., Ltd, Shanghai, 201318, PR China
| | - Lijuan Wang
- Shanghai Suxin Biotechnology Co. Ltd and Suchuang Diagnostic Products Co., Ltd, Shanghai, 201318, PR China
| | - Xueen Fang
- Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200433, PR China.
| | - Jilie Kong
- Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200433, PR China.
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76
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FEN1 endonuclease as a therapeutic target for human cancers with defects in homologous recombination. Proc Natl Acad Sci U S A 2020; 117:19415-19424. [PMID: 32719125 PMCID: PMC7431096 DOI: 10.1073/pnas.2009237117] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Synthetic lethality strategies for cancer therapy exploit cancer-specific genetic defects to identify targets that are uniquely essential to the survival of tumor cells. Here we show RAD27/FEN1, which encodes flap endonuclease 1 (FEN1), a structure-specific nuclease with roles in DNA replication and repair, and has the greatest number of synthetic lethal interactions with Saccharomyces cerevisiae genome instability genes, is a druggable target for an inhibitor-based approach to kill cancers with defects in homologous recombination (HR). The vulnerability of cancers with HR defects to FEN1 loss was validated by studies showing that small-molecule FEN1 inhibitors and FEN1 small interfering RNAs (siRNAs) selectively killed BRCA1- and BRCA2-defective human cell lines. Furthermore, the differential sensitivity to FEN1 inhibition was recapitulated in mice, where a small-molecule FEN1 inhibitor reduced the growth of tumors established from drug-sensitive but not drug-resistant cancer cell lines. FEN1 inhibition induced a DNA damage response in both sensitive and resistant cell lines; however, sensitive cell lines were unable to recover and replicate DNA even when the inhibitor was removed. Although FEN1 inhibition activated caspase to higher levels in sensitive cells, this apoptotic response occurred in p53-defective cells and cell killing was not blocked by a pan-caspase inhibitor. These results suggest that FEN1 inhibitors have the potential for therapeutically targeting HR-defective cancers such as those resulting from BRCA1 and BRCA2 mutations, and other genetic defects.
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77
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Boguszewska K, Szewczuk M, Kaźmierczak-Barańska J, Karwowski BT. The Similarities between Human Mitochondria and Bacteria in the Context of Structure, Genome, and Base Excision Repair System. Molecules 2020; 25:E2857. [PMID: 32575813 PMCID: PMC7356350 DOI: 10.3390/molecules25122857] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 02/06/2023] Open
Abstract
Mitochondria emerged from bacterial ancestors during endosymbiosis and are crucial for cellular processes such as energy production and homeostasis, stress responses, cell survival, and more. They are the site of aerobic respiration and adenosine triphosphate (ATP) production in eukaryotes. However, oxidative phosphorylation (OXPHOS) is also the source of reactive oxygen species (ROS), which are both important and dangerous for the cell. Human mitochondria contain mitochondrial DNA (mtDNA), and its integrity may be endangered by the action of ROS. Fortunately, human mitochondria have repair mechanisms that allow protecting mtDNA and repairing lesions that may contribute to the occurrence of mutations. Mutagenesis of the mitochondrial genome may manifest in the form of pathological states such as mitochondrial, neurodegenerative, and/or cardiovascular diseases, premature aging, and cancer. The review describes the mitochondrial structure, genome, and the main mitochondrial repair mechanism (base excision repair (BER)) of oxidative lesions in the context of common features between human mitochondria and bacteria. The authors present a holistic view of the similarities of mitochondria and bacteria to show that bacteria may be an interesting experimental model for studying mitochondrial diseases, especially those where the mechanism of DNA repair is impaired.
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Affiliation(s)
| | | | | | - Bolesław T. Karwowski
- DNA Damage Laboratory of Food Science Department, Faculty of Pharmacy, Medical University of Lodz, ul. Muszynskiego 1, 90-151 Lodz, Poland; (K.B.); (M.S.); (J.K.-B.)
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78
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Debnath S, Sharma S. RECQ1 Helicase in Genomic Stability and Cancer. Genes (Basel) 2020; 11:E622. [PMID: 32517021 PMCID: PMC7348745 DOI: 10.3390/genes11060622] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/01/2020] [Accepted: 06/03/2020] [Indexed: 12/13/2022] Open
Abstract
RECQ1 (also known as RECQL or RECQL1) belongs to the RecQ family of DNA helicases, members of which are linked with rare genetic diseases of cancer predisposition in humans. RECQ1 is implicated in several cellular processes, including DNA repair, cell cycle and growth, telomere maintenance, and transcription. Earlier studies have demonstrated a unique requirement of RECQ1 in ensuring chromosomal stability and suggested its potential involvement in tumorigenesis. Recent reports have suggested that RECQ1 is a potential breast cancer susceptibility gene, and missense mutations in this gene contribute to familial breast cancer development. Here, we provide a framework for understanding how the genetic or functional loss of RECQ1 might contribute to genomic instability and cancer.
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Affiliation(s)
- Subrata Debnath
- Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street, NW, Washington, DC 20059, USA;
| | - Sudha Sharma
- Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street, NW, Washington, DC 20059, USA;
- National Human Genome Center, College of Medicine, Howard University, 520 W Street, NW, Washington, DC 20059, USA
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79
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A Genome-Wide Screen for Genes Affecting Spontaneous Direct-Repeat Recombination in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2020; 10:1853-1867. [PMID: 32265288 PMCID: PMC7263696 DOI: 10.1534/g3.120.401137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Homologous recombination is an important mechanism for genome integrity maintenance, and several homologous recombination genes are mutated in various cancers and cancer-prone syndromes. However, since in some cases homologous recombination can lead to mutagenic outcomes, this pathway must be tightly regulated, and mitotic hyper-recombination is a hallmark of genomic instability. We performed two screens in Saccharomyces cerevisiae for genes that, when deleted, cause hyper-recombination between direct repeats. One was performed with the classical patch and replica-plating method. The other was performed with a high-throughput replica-pinning technique that was designed to detect low-frequency events. This approach allowed us to validate the high-throughput replica-pinning methodology independently of the replicative aging context in which it was developed. Furthermore, by combining the two approaches, we were able to identify and validate 35 genes whose deletion causes elevated spontaneous direct-repeat recombination. Among these are mismatch repair genes, the Sgs1-Top3-Rmi1 complex, the RNase H2 complex, genes involved in the oxidative stress response, and a number of other DNA replication, repair and recombination genes. Since several of our hits are evolutionarily conserved, and repeated elements constitute a significant fraction of mammalian genomes, our work might be relevant for understanding genome integrity maintenance in humans.
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80
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Ye X, Li Y, Fang X, Kong J. Integrated Microfluidic Sample-to-Answer System for Direct Nucleic Acid-Based Detection of Group B Streptococci in Clinical Vaginal/Anal Swab Samples. ACS Sens 2020; 5:1132-1139. [PMID: 32133842 DOI: 10.1021/acssensors.0c00087] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The group B Streptococcus (GBS) is a type of pathogen that seriously threatens the health of mothers and infants. Prompt and timely diagnosis is crucial for good patient outcomes. However, the traditional bacterial culture and polymerase chain reaction methods are limited by their speed and involve complex operating procedures. Herein, we successfully established an integrated microfluidic sample-to-answer system for nucleic acid-based detection of GBS directly in vaginal/anal swab samples. Meanwhile, we demonstrated a dynamical reaction mechanism of Bst/FEN1-based nucleic acid amplification, which differs from traditional Bst-based isothermal amplification strategies. The system integrates cell lysis and nucleic acid purification, separation, amplification, and detection, enabling rapid (about 45 min to the entire analysis) and highly accurate (98% accuracy) analysis in a clinical setting. Experimental results show that the system offers a good detection limit (500 CFU/mL), perfect specificity (no cross-reactivity with 25 other common pathogens), excellent stability (coefficient of variation less than 3%), and good anti-interference performance. This novel system holds great potential as a nucleic acid-based diagnostic tool in clinical applications for detecting not only GBS but also other types of pathogens.
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Affiliation(s)
- Xin Ye
- Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, P. R. China
| | - Yang Li
- Shanghai Suxin Biotechnology Company Ltd and Suchuang Diagnostic Products Company, Ltd, Shanghai 201318, P. R. China
| | - Xueen Fang
- Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, P. R. China
| | - Jilie Kong
- Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, P. R. China
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81
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Syeda AH, Dimude JU, Skovgaard O, Rudolph CJ. Too Much of a Good Thing: How Ectopic DNA Replication Affects Bacterial Replication Dynamics. Front Microbiol 2020; 11:534. [PMID: 32351461 PMCID: PMC7174701 DOI: 10.3389/fmicb.2020.00534] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 03/12/2020] [Indexed: 12/15/2022] Open
Abstract
Each cell division requires the complete and accurate duplication of the entire genome. In bacteria, the duplication process of the often-circular chromosomes is initiated at a single origin per chromosome, resulting in two replication forks that traverse the chromosome in opposite directions. DNA synthesis is completed once the two forks fuse in a region diametrically opposite the origin. In some bacteria, such as Escherichia coli, the region where forks fuse forms a specialized termination area. Polar replication fork pause sites flanking this area can pause the progression of replication forks, thereby allowing forks to enter but not to leave. Transcription of all required genes has to take place simultaneously with genome duplication. As both of these genome trafficking processes share the same template, conflicts are unavoidable. In this review, we focus on recent attempts to add additional origins into various ectopic chromosomal locations of the E. coli chromosome. As ectopic origins disturb the native replichore arrangements, the problems resulting from such perturbations can give important insights into how genome trafficking processes are coordinated and the problems that arise if this coordination is disturbed. The data from these studies highlight that head-on replication–transcription conflicts are indeed highly problematic and multiple repair pathways are required to restart replication forks arrested at obstacles. In addition, the existing data also demonstrate that the replication fork trap in E. coli imposes significant constraints to genome duplication if ectopic origins are active. We describe the current models of how replication fork fusion events can cause serious problems for genome duplication, as well as models of how such problems might be alleviated both by a number of repair pathways as well as the replication fork trap system. Considering the problems associated both with head-on replication-transcription conflicts as well as head-on replication fork fusion events might provide clues of how these genome trafficking issues have contributed to shape the distinct architecture of bacterial chromosomes.
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Affiliation(s)
- Aisha H Syeda
- Department of Biology, University of York, York, United Kingdom
| | - Juachi U Dimude
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Ole Skovgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Christian J Rudolph
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
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82
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Hamza A, Driessen MRM, Tammpere E, O'Neil NJ, Hieter P. Cross-Species Complementation of Nonessential Yeast Genes Establishes Platforms for Testing Inhibitors of Human Proteins. Genetics 2020; 214:735-747. [PMID: 31937519 PMCID: PMC7054014 DOI: 10.1534/genetics.119.302971] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/13/2020] [Indexed: 01/09/2023] Open
Abstract
Cross-species complementation can be used to generate humanized yeast, which is a valuable resource with which to model and study human biology. Humanized yeast can be used as an in vivo platform to screen for chemical inhibition of human protein drug targets. To this end, we report the systematic complementation of nonessential yeast genes implicated in chromosome instability (CIN) with their human homologs. We identified 20 human-yeast complementation pairs that are replaceable in 44 assays that test rescue of chemical sensitivity and/or CIN defects. We selected a human-yeast pair (hFEN1/yRAD27), which is frequently overexpressed in cancer and is an anticancer therapeutic target, to perform in vivo inhibitor assays using a humanized yeast cell-based platform. In agreement with published in vitro assays, we demonstrate that HU-based PTPD is a species-specific hFEN1 inhibitor. In contrast, another reported hFEN1 inhibitor, the arylstibonic acid derivative NSC-13755, was determined to have off-target effects resulting in a synthetic lethal phenotype with yRAD27-deficient strains. Our study expands the list of human-yeast complementation pairs to nonessential genes by defining novel cell-based assays that can be utilized as a broad resource to study human drug targets.
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Affiliation(s)
- Akil Hamza
- Michael Smith Laboratories, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Maureen R M Driessen
- Michael Smith Laboratories, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Erik Tammpere
- Michael Smith Laboratories, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Nigel J O'Neil
- Michael Smith Laboratories, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Philip Hieter
- Michael Smith Laboratories, University of British Columbia, Vancouver V6T 1Z4, Canada
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83
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Artichoke Polyphenols Sensitize Human Breast Cancer Cells to Chemotherapeutic Drugs via a ROS-Mediated Downregulation of Flap Endonuclease 1. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7965435. [PMID: 31998443 PMCID: PMC6969650 DOI: 10.1155/2020/7965435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/22/2019] [Indexed: 01/20/2023]
Abstract
Combined treatment of several natural polyphenols and chemotherapeutic agents is more effective comparing to the drug alone in inhibiting cancer cell growth. Polyphenolic artichoke extracts (AEs) have been shown to have anticancer properties by triggering apoptosis or reactive oxygen species- (ROS-) mediated senescence when used at high or low doses, respectively. Our aim was to explore the chemosensitizing potential of AEs in order to enhance the efficacy of conventional chemotherapy in breast cancer cells. We employed breast cancer cell lines to assess the potential synergistic effect of a combined treatment of AEs/paclitaxel (PTX) or AEs/adriamycin (ADR) and to determine the underlying mechanisms correlated to this potential therapeutic approach. Our data shows that AEs/PTX reduced cell proliferation by increasing DNA damage response (DDR) mediated by Flap endonuclease 1 (FEN1) downregulation that results into enhanced breast cancer cell sensitivity to chemotherapeutic drugs. We demonstrated that ROS/Nrf2 and p-ERK pathways are two molecular mechanisms involved in the synergistic effect of AEs plus PTX treatment. To highlight the role of ROS herein, we report that the addition of antioxidant N-acetylcysteine (NAC) significantly decreased the antiproliferative effect of the combined treatment. A combined therapy could be able to reduce the dose of chemotherapeutic drugs, minimizing toxicity and side effects. Our results suggest the use of artichoke polyphenols as ROS-mediated sensitizers of chemotherapy paving the way for innovative and promising natural compound-based therapeutic strategies in oncology.
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84
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Williams GM, Petrides AK, Balakrishnan L, Surtees JA. Tracking Expansions of Stable and Threshold Length Trinucleotide Repeat Tracts In Vivo and In Vitro Using Saccharomyces cerevisiae. Methods Mol Biol 2020; 2056:25-68. [PMID: 31586340 DOI: 10.1007/978-1-4939-9784-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Trinucleotide repeat (TNR) tracts are inherently unstable during DNA replication, leading to repeat expansions and/or contractions. Expanded tracts are the cause of over 40 neurodegenerative and neuromuscular diseases. In this chapter, we focus on the (CAG)n and (CTG)n repeat sequences that, when expanded, lead to Huntington's disease (HD) and myotonic dystrophy type 1 (DM1), respectively, as well as a number of other neurodegenerative diseases. TNR tracts in most individuals are relatively small and stable in terms of length. However, TNR tracts become increasingly prone to expansion as tract length increases, eventually leading to very long tracts that disrupt coding (e.g. HD) or noncoding (e.g., DM1) regions of the genome. It is important to understand the early stages in TNR expansions, that is, the transition from small, stable lengths to susceptible threshold lengths. We describe PCR-based in vivo assays, using the model system Saccharomyces cerevisiae, to determine and characterize the dynamic behavior of TNR tracts in the stable and threshold ranges. We also describe a simple in vitro system to assess tract dynamics during 5' single-stranded DNA (ssDNA) flap processing and to assess the role of different DNA metabolism proteins in these dynamics. These assays can ultimately be used to determine factors that influence the early stages of TNR tract expansion.
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Affiliation(s)
- Gregory M Williams
- Centre for Chromosome Biology, National University of Ireland, Galway, Galway, Ireland
- Galway Neuroscience Centre, National Universityof Ireland, Galway, Galway, Ireland
| | | | - Lata Balakrishnan
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Jennifer A Surtees
- Department of Biochemistry, JacobsSchool of Medicine and BiomedicalSciences, State University of New York atBuffalo, Buffalo, NY, USA.
- Genetics, Genomics and Bioinformatics Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA.
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85
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Dong S, Xiao Y, Ma X, He W, Kang J, Peng Z, Wang L, Li Z. miR-193b Increases the Chemosensitivity of Osteosarcoma Cells by Promoting FEN1-Mediated Autophagy. Onco Targets Ther 2019; 12:10089-10098. [PMID: 31819503 PMCID: PMC6878930 DOI: 10.2147/ott.s219977] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/07/2019] [Indexed: 12/24/2022] Open
Abstract
Background Osteosarcoma (OS) is one of the most common malignant bone tumors and specific microRNAs (miRNAs) are closely associated with malignant OS progression. In this study, we examined the role of microRNA-193b-3p (miR-193b) and the involvement of autophagy and apoptosis in the chemosensitivity of OS cells. Methods We employed qRT-PCR, Western blot, and immunohistochemistry to examine the expression levels of miR-193b, flap endonuclease 1 (FEN1), and autophagy-related proteins. Apoptosis was determined by flow cytometry using an Annexin V-FITC/PI apoptosis detection kit. Luciferase reporter assays confirmed the relationship between miR-193b and FEN1. Results miR-193b was downregulated in OS compared to adjacent normal tissues (p < 0.05). miR-193b overexpression in the OS cell lines induced autophagy and apoptosis, as shown by Western blotting and flow cytometry. Knockdown of FEN1, a structure-specific nuclease overexpressed in OS tissues (p < 0.001), induced apoptosis through activation of autophagy. Luciferase reporter assays confirmed that FEN1 is a direct target of miR-193b, FEN1 knockdown reinforced miR-193b induced apoptosis. Moreover, miR-193b expression enhanced epirubicin-induced autophagy and apoptosis. Conclusion Collectively, the results showed that miR-193b/FEN1 may serve as a novel therapeutic target for OS aimed mainly at the induction of autophagy and apoptosis. The miR-193b/FEN1 axis increased the chemosensitivity of OS cells, while activation of autophagy enhanced the anticancer effects of epirubicin.
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Affiliation(s)
- Suwei Dong
- Department of Orthopaedics, The Third Affiliated Hospital of Kunming Medical University (Tumor Hospital of Yunnan Province), Kunming, Yunnan, People's Republic of China
| | - Yanbin Xiao
- Department of Orthopaedics, The Third Affiliated Hospital of Kunming Medical University (Tumor Hospital of Yunnan Province), Kunming, Yunnan, People's Republic of China
| | - Xiang Ma
- Department of Orthopaedics, The Third Affiliated Hospital of Kunming Medical University (Tumor Hospital of Yunnan Province), Kunming, Yunnan, People's Republic of China
| | - Wei He
- Medical Services Section, The First People's Hospital of Yunnan Province, Kunming, Yunnan, People's Republic of China
| | - Jianping Kang
- Department of Orthopaedics, The Third Affiliated Hospital of Kunming Medical University (Tumor Hospital of Yunnan Province), Kunming, Yunnan, People's Republic of China
| | - Zhuohui Peng
- Department of Orthopaedics, The Third Affiliated Hospital of Kunming Medical University (Tumor Hospital of Yunnan Province), Kunming, Yunnan, People's Republic of China
| | - Lei Wang
- Department of Orthopaedics, The Third Affiliated Hospital of Kunming Medical University (Tumor Hospital of Yunnan Province), Kunming, Yunnan, People's Republic of China
| | - Zhen Li
- Department of Cancer Biotherapy Center, The Third Affiliated Hospital of Kunming Medical University (Tumor Hospital of Yunnan Province), Kunming, Yunnan, People's Republic of China
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86
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Li JL, Wang JP, Chang H, Deng SM, Du JH, Wang XX, Hu HJ, Li DY, Xu XB, Guo WQ, Song YH, Guo Z, Sun MX, Wu YW, Liu SB. FEN1 inhibitor increases sensitivity of radiotherapy in cervical cancer cells. Cancer Med 2019; 8:7774-7780. [PMID: 31670906 PMCID: PMC6912068 DOI: 10.1002/cam4.2615] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 09/28/2019] [Accepted: 10/04/2019] [Indexed: 12/12/2022] Open
Abstract
Background Cervical cancer is one of the most common causes of cancer‐associated mortality among affected women in the world. At present, treatment with weekly cisplatin plus ionizing radiation (IR) therapy is the standard regimen for cervical cancer, especially for locally advanced cervical cancer. The purpose of this study is to determine whether FEN1 inhibitors could enhance the therapeutic effect of IR therapy. Methods Western blot was applied to determine the expression of FEN1‐ and apoptosis‐related proteins. Cell growth inhibition assay and colony formation assay were used to determine the effects of FEN1 inhibitor and IR exposure for Hela cells in vitro. CRISPR technology was used to knockdown FEN1 expression level of 293T cells, and tumor xenograft in nude mice was employed to determine the effects of FEN1 inhibitor and IR exposure on tumor growth in vivo. Results Our data revealed that FEN1 is overexpressed in HeLa cell and can be upregulated further by IR. We also demonstrated that FEN1 inhibitor enhances IR sensitivity of cervical cancer in vitro and in vivo. Conclusion FEN1 inhibitor SC13 could sensitize radiotherapy of cervical cancer cell.
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Affiliation(s)
- Jin-Li Li
- Department of Radiation Oncology, The Affiliated Hospital of Soochow University, Suzhou, China
| | - Jian-Ping Wang
- Department of Radiation Oncology, The Affiliated Hospital of Soochow University, Suzhou, China
| | - Hong Chang
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou, China
| | - Sheng-Ming Deng
- Department of Nuclear Medicine, The Affiliated Hospital of Soochow University, Suzhou, China
| | - Jia-Hui Du
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou, China
| | - Xiao-Xiao Wang
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou, China
| | - He-Juan Hu
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou, China
| | - Dong-Yin Li
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou, China
| | - Xiang-Bin Xu
- College of Food Science and Technology, Hainan University, Haikou, China
| | - Wei-Qiang Guo
- School of Chemistry, Biology and Materials Engineering, Suzhou University of Science and Technology, Suzhou, China
| | - Yao-Hua Song
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Min-Xuan Sun
- Jiangsu Key Laboratory of Medical Optics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, China
| | - Yi-Wei Wu
- Department of Nuclear Medicine, The Affiliated Hospital of Soochow University, Suzhou, China
| | - Song-Bai Liu
- Suzhou Key Laboratory for Medical Biotechnology, Suzhou Vocational Health College, Suzhou, China
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87
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Tsegay PS, Lai Y, Liu Y. Replication Stress and Consequential Instability of the Genome and Epigenome. Molecules 2019; 24:molecules24213870. [PMID: 31717862 PMCID: PMC6864812 DOI: 10.3390/molecules24213870] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/25/2019] [Accepted: 10/25/2019] [Indexed: 12/12/2022] Open
Abstract
Cells must faithfully duplicate their DNA in the genome to pass their genetic information to the daughter cells. To maintain genomic stability and integrity, double-strand DNA has to be replicated in a strictly regulated manner, ensuring the accuracy of its copy number, integrity and epigenetic modifications. However, DNA is constantly under the attack of DNA damage, among which oxidative DNA damage is the one that most frequently occurs, and can alter the accuracy of DNA replication, integrity and epigenetic features, resulting in DNA replication stress and subsequent genome and epigenome instability. In this review, we summarize DNA damage-induced replication stress, the formation of DNA secondary structures, peculiar epigenetic modifications and cellular responses to the stress and their impact on the instability of the genome and epigenome mainly in eukaryotic cells.
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Affiliation(s)
- Pawlos S. Tsegay
- Biochemistry Ph.D. Program, Florida International University, Miami, FL 33199, USA;
| | - Yanhao Lai
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA;
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Yuan Liu
- Biochemistry Ph.D. Program, Florida International University, Miami, FL 33199, USA;
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA;
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
- Correspondence:
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88
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Dauber B, Saffran HA, Smiley JR. The herpes simplex virus host shutoff (vhs) RNase limits accumulation of double stranded RNA in infected cells: Evidence for accelerated decay of duplex RNA. PLoS Pathog 2019; 15:e1008111. [PMID: 31626661 PMCID: PMC6821131 DOI: 10.1371/journal.ppat.1008111] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/30/2019] [Accepted: 09/25/2019] [Indexed: 12/12/2022] Open
Abstract
The herpes simplex virus virion host shutoff (vhs) RNase destabilizes cellular and viral mRNAs and blunts host innate antiviral responses. Previous work demonstrated that cells infected with vhs mutants display enhanced activation of the host double-stranded RNA (dsRNA)-activated protein kinase R (PKR), implying that vhs limits dsRNA accumulation in infected cells. Confirming this hypothesis, we show that partially complementary transcripts of the UL23/UL24 and UL30/31 regions of the viral genome increase in abundance when vhs is inactivated, giving rise to greatly increased levels of intracellular dsRNA formed by annealing of the overlapping portions of these RNAs. Thus, vhs limits accumulation of dsRNA at least in part by reducing the levels of complementary viral transcripts. We then asked if vhs also destabilizes dsRNA after its initial formation. Here, we used a reporter system employing two mCherry expression plasmids bearing complementary 3’ UTRs to produce defined dsRNA species in uninfected cells. The dsRNAs are unstable, but are markedly stabilized by co-expressing the HSV dsRNA-binding protein US11. Strikingly, vhs delivered by super-infecting HSV virions accelerates the decay of these pre-formed dsRNAs in both the presence and absence of US11, a novel and unanticipated activity of vhs. Vhs binds the host RNA helicase eIF4A, and we find that vhs-induced dsRNA decay is attenuated by the eIF4A inhibitor hippuristanol, providing evidence that eIF4A participates in the process. Our results show that a herpesvirus host shutoff RNase destabilizes dsRNA in addition to targeting partially complementary viral mRNAs, raising the possibility that the mRNA destabilizing proteins of other viral pathogens dampen the host response to dsRNA through similar mechanisms. Essentially all viruses produce double-stranded RNA (dsRNA) during infection. Host organisms therefore deploy a variety of dsRNA receptors to trigger innate antiviral defenses. Not surprisingly, viruses in turn produce an array of antagonists to block this host response. The best characterized of the viral antagonists function by binding to and masking dsRNA and/or blocking downstream signaling events. Other less studied viral antagonists appear to function by reducing the levels of dsRNA in infected cells, but exactly how they do so remains unknown. Here we show that one such viral antagonist, the herpes simplex virus vhs ribonuclease, reduces dsRNA levels in two distinct ways. First, as previously suggested, it dampens the accumulation of partially complementary viral mRNAs, reducing the potential for generating dsRNA. Second, it helps remove dsRNA after its formation, a novel and surprising activity of a protein best known for its activity on single-stranded mRNA. Many other viral pathogens produce proteins that target mRNAs for rapid destruction, and it will be important to determine if these also limit host dsRNA responses in similar ways.
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Affiliation(s)
- Bianca Dauber
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Holly A. Saffran
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - James R. Smiley
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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89
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Zeng X, Qu X, Zhao C, Xu L, Hou K, Liu Y, Zhang N, Feng J, Shi S, Zhang L, Xiao J, Guo Z, Teng Y, Che X. FEN1 mediates miR-200a methylation and promotes breast cancer cell growth via MET and EGFR signaling. FASEB J 2019; 33:10717-10730. [PMID: 31266372 DOI: 10.1096/fj.201900273r] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Flap endonuclease 1 (FEN1) is recognized as a pivotal factor in DNA replication, long-patch excision repair, and telomere maintenance. Excessive FEN1 expression has been reported to be closely associated with cancer progression, but the specific mechanism has not yet been explored. In the present study, we demonstrated that FEN1 promoted breast cancer cell proliferation via an epigenetic mechanism of FEN1-mediated up-regulation of DNA methyltransferase (DNMT)1 and DNMT3a. FEN1 was proved to interact with DNMT3a through proliferating cell nuclear antigen (PCNA) to suppress microRNA (miR)-200a-5p expression mediated by methylation. Furthermore, miR-200a-5p was identified to repress breast cancer cell proliferation by inhibiting the expression of its target genes, hepatocyte growth factor (MET), and epidermal growth factor receptor (EGFR). Overall, our data surprisingly demonstrate that FEN1 promotes breast cancer cell growth via the formation of FEN1/PCNA/DNMT3a complex to inhibit miR-200a expression by DNMT-mediated methylation and to recover the target genes expression of miR-200a, MET, and EGFR. The novel epigenetic mechanism of FEN1 on proliferation promotion provides a significant clue that FEN1 might serve as a predictive biomarker and therapeutic target for breast cancer.-Zeng, X., Qu, X., Zhao, C., Xu, L., Hou, K., Liu, Y., Zhang, N., Feng, J., Shi, S., Zhang, L., Xiao, J., Guo, Z., Teng, Y., Che, X. FEN1 mediates miR-200a methylation and promotes breast cancer cell growth via MET and EGFR signaling.
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Affiliation(s)
- Xue Zeng
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
- Department of Radiotherapy, Liaoning Cancer Hospital and Institute, Cancer Hospital of China Medical University, Shenyang, China
| | - Xiujuan Qu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Chenyang Zhao
- The Research Center for Medical Genomics, China Medical University, Shenyang, China
| | - Lu Xu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Kezuo Hou
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Yunpeng Liu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Na Zhang
- Department of Radiotherapy, Liaoning Cancer Hospital and Institute, Cancer Hospital of China Medical University, Shenyang, China
| | - Jing Feng
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Sha Shi
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Lingyun Zhang
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Jiawen Xiao
- Department of Medical Oncology, Shenyang Fifth People Hospital, Shenyang, China
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Yuee Teng
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
| | - Xiaofang Che
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
- Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, The First Hospital of China Medical University, Shenyang, China
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90
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Parrilla-Doblas JT, Roldán-Arjona T, Ariza RR, Córdoba-Cañero D. Active DNA Demethylation in Plants. Int J Mol Sci 2019; 20:E4683. [PMID: 31546611 PMCID: PMC6801703 DOI: 10.3390/ijms20194683] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/17/2019] [Accepted: 09/19/2019] [Indexed: 02/06/2023] Open
Abstract
Methylation of cytosine (5-meC) is a critical epigenetic modification in many eukaryotes, and genomic DNA methylation landscapes are dynamically regulated by opposed methylation and demethylation processes. Plants are unique in possessing a mechanism for active DNA demethylation involving DNA glycosylases that excise 5-meC and initiate its replacement with unmodified C through a base excision repair (BER) pathway. Plant BER-mediated DNA demethylation is a complex process involving numerous proteins, as well as additional regulatory factors that avoid accumulation of potentially harmful intermediates and coordinate demethylation and methylation to maintain balanced yet flexible DNA methylation patterns. Active DNA demethylation counteracts excessive methylation at transposable elements (TEs), mainly in euchromatic regions, and one of its major functions is to avoid methylation spreading to nearby genes. It is also involved in transcriptional activation of TEs and TE-derived sequences in companion cells of male and female gametophytes, which reinforces transposon silencing in gametes and also contributes to gene imprinting in the endosperm. Plant 5-meC DNA glycosylases are additionally involved in many other physiological processes, including seed development and germination, fruit ripening, and plant responses to a variety of biotic and abiotic environmental stimuli.
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Affiliation(s)
- Jara Teresa Parrilla-Doblas
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), 14071 Córdoba, Spain.
- Department of Genetics, University of Córdoba, 14071 Córdoba, Spain.
- Reina Sofía University Hospital, 14071 Córdoba, Spain.
| | - Teresa Roldán-Arjona
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), 14071 Córdoba, Spain.
- Department of Genetics, University of Córdoba, 14071 Córdoba, Spain.
- Reina Sofía University Hospital, 14071 Córdoba, Spain.
| | - Rafael R Ariza
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), 14071 Córdoba, Spain.
- Department of Genetics, University of Córdoba, 14071 Córdoba, Spain.
- Reina Sofía University Hospital, 14071 Córdoba, Spain.
| | - Dolores Córdoba-Cañero
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), 14071 Córdoba, Spain.
- Department of Genetics, University of Córdoba, 14071 Córdoba, Spain.
- Reina Sofía University Hospital, 14071 Córdoba, Spain.
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91
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Petri net-based model of the human DNA base excision repair pathway. PLoS One 2019; 14:e0217913. [PMID: 31518347 PMCID: PMC6743755 DOI: 10.1371/journal.pone.0217913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 05/21/2019] [Indexed: 12/14/2022] Open
Abstract
Cellular DNA is daily exposed to several damaging agents causing a plethora of DNA lesions. As a first aid to restore DNA integrity, several enzymes got specialized in damage recognition and lesion removal during the process called base excision repair (BER). A large number of DNA damage types and several different readers of nucleic acids lesions during BER pathway as well as two sub-pathways were considered in the definition of a model using the Petri net framework. The intuitive graphical representation in combination with precise mathematical analysis methods are the strong advantages of the Petri net-based representation of biological processes and make Petri nets a promising approach for modeling and analysis of human BER. The reported results provide new information that will aid efforts to characterize in silico knockouts as well as help to predict the sensitivity of the cell with inactivated repair proteins to different types of DNA damage. The results can also help in identifying the by-passing pathways that may lead to lack of pronounced phenotypes associated with mutations in some of the proteins. This knowledge is very useful when DNA damage-inducing drugs are introduced for cancer therapy, and lack of DNA repair is desirable for tumor cell death.
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92
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MicroRNA-140 impedes DNA repair by targeting FEN1 and enhances chemotherapeutic response in breast cancer. Oncogene 2019; 39:234-247. [PMID: 31471584 DOI: 10.1038/s41388-019-0986-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 05/29/2019] [Accepted: 06/15/2019] [Indexed: 01/18/2023]
Abstract
An increased DNA repair capacity is associated with drug resistance and limits the efficacy of chemotherapy in breast cancers. Flap endonuclease 1 (FEN1) participates in various DNA repair pathways and contributes to cancer progression and drug resistance in chemotherapy. Inhibition of FEN1 serves as a potent strategy for cancer therapy. Here, we demonstrate that microRNA-140 (miR-140) inhibits FEN1 expression via directly binding to its 3' untranslated region, leading to impaired DNA repair and repressed breast cancer progression. Overexpression of miR-140 sensitizes breast cancer cells to chemotherapeutic agents and overcomes drug resistance in breast cancer. Notably, ectopic expression of FEN1 abates the effects of miR-140 on DNA damage and the chemotherapy response in breast cancer cells. Furthermore, the transcription factor/repressor Ying Yang 1 (YY1) directly binds to the miR-140 promoter and activates miR-140 expression, which is attenuated in doxorubicin resistance. Our results demonstrate that miR-140 acts as a tumor suppressor in breast cancer by inhibiting FEN1 to repress DNA damage repair and reveal miR-140 to be a new anti-tumorigenesis factor for adjunctive breast cancer therapy. This novel mechanism will enhance the treatment effect of chemotherapy in breast cancer.
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93
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Thompson MJ, Gotham VJB, Ciani B, Grasby JA. A conserved loop-wedge motif moderates reaction site search and recognition by FEN1. Nucleic Acids Res 2019; 46:7858-7872. [PMID: 29878258 PMCID: PMC6125683 DOI: 10.1093/nar/gky506] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/23/2018] [Indexed: 12/24/2022] Open
Abstract
DNA replication and repair frequently involve intermediate two-way junction structures with overhangs, or flaps, that must be promptly removed; a task performed by the essential enzyme flap endonuclease 1 (FEN1). We demonstrate a functional relationship between two intrinsically disordered regions of the FEN1 protein, which recognize opposing sides of the junction and order in response to the requisite substrate. Our results inform a model in which short-range translocation of FEN1 on DNA facilitates search for the annealed 3'-terminus of a primer strand, which is recognized by breaking the terminal base pair to generate a substrate with a single nucleotide 3'-flap. This recognition event allosterically signals hydrolytic removal of the 5'-flap through reaction in the opposing junction duplex, by controlling access of the scissile phosphate diester to the active site. The recognition process relies on a highly-conserved 'wedge' residue located on a mobile loop that orders to bind the newly-unpaired base. The unanticipated 'loop-wedge' mechanism exerts control over substrate selection, rate of reaction and reaction site precision, and shares features with other enzymes that recognize irregular DNA structures. These new findings reveal how FEN1 precisely couples 3'-flap verification to function.
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Affiliation(s)
- Mark J Thompson
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Victoria J B Gotham
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Barbara Ciani
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Jane A Grasby
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
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94
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Uson ML, Carl A, Goldgur Y, Shuman S. Crystal structure and mutational analysis of Mycobacterium smegmatis FenA highlight active site amino acids and three metal ions essential for flap endonuclease and 5' exonuclease activities. Nucleic Acids Res 2019; 46:4164-4175. [PMID: 29635474 PMCID: PMC5934675 DOI: 10.1093/nar/gky238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/21/2018] [Indexed: 02/02/2023] Open
Abstract
Mycobacterium smegmatis FenA is a nucleic acid phosphodiesterase with flap endonuclease and 5' exonuclease activities. The 1.8 Å crystal structure of FenA reported here highlights as its closest homologs bacterial FEN-family enzymes ExoIX, the Pol1 exonuclease domain and phage T5 Fen. Mycobacterial FenA assimilates three active site manganese ions (M1, M2, M3) that are coordinated, directly and via waters, to a constellation of eight carboxylate side chains. We find via mutagenesis that the carboxylate contacts to all three manganese ions are essential for FenA's activities. Structures of nuclease-dead FenA mutants D125N, D148N and D208N reveal how they fail to bind one of the three active site Mn2+ ions, in a distinctive fashion for each Asn change. The structure of FenA D208N with a phosphate anion engaged by M1 and M2 in a state mimetic of a product complex suggests a mechanism for metal-catalyzed phosphodiester hydrolysis similar to that proposed for human Exo1. A distinctive feature of FenA is that it does not have the helical arch module found in many other FEN/FEN-like enzymes. Instead, this segment of FenA adopts a unique structure comprising a short 310 helix and surface β-loop that coordinates a fourth manganese ion (M4).
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Affiliation(s)
- Maria Loressa Uson
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Ayala Carl
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Yehuda Goldgur
- Structural Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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95
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Bennet IA, Finger LD, Baxter NJ, Ambrose B, Hounslow AM, Thompson MJ, Exell JC, Shahari NNBM, Craggs TD, Waltho JP, Grasby JA. Regional conformational flexibility couples substrate specificity and scissile phosphate diester selectivity in human flap endonuclease 1. Nucleic Acids Res 2019; 46:5618-5633. [PMID: 29718417 PMCID: PMC6009646 DOI: 10.1093/nar/gky293] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 04/09/2018] [Indexed: 02/07/2023] Open
Abstract
Human flap endonuclease-1 (hFEN1) catalyzes the divalent metal ion-dependent removal of single-stranded DNA protrusions known as flaps during DNA replication and repair. Substrate selectivity involves passage of the 5'-terminus/flap through the arch and recognition of a single nucleotide 3'-flap by the α2-α3 loop. Using NMR spectroscopy, we show that the solution conformation of free and DNA-bound hFEN1 are consistent with crystal structures; however, parts of the arch region and α2-α3 loop are disordered without substrate. Disorder within the arch explains how 5'-flaps can pass under it. NMR and single-molecule FRET data show a shift in the conformational ensemble in the arch and loop region upon addition of DNA. Furthermore, the addition of divalent metal ions to the active site of the hFEN1-DNA substrate complex demonstrates that active site changes are propagated via DNA-mediated allostery to regions key to substrate differentiation. The hFEN1-DNA complex also shows evidence of millisecond timescale motions in the arch region that may be required for DNA to enter the active site. Thus, hFEN1 regional conformational flexibility spanning a range of dynamic timescales is crucial to reach the catalytically relevant ensemble.
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Affiliation(s)
- Ian A Bennet
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
| | - L David Finger
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
| | - Nicola J Baxter
- Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S10 2TN, UK.,Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester M1 7DN, UK
| | - Benjamin Ambrose
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
| | - Andrea M Hounslow
- Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S10 2TN, UK
| | - Mark J Thompson
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
| | - Jack C Exell
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
| | - Nur Nazihah B Md Shahari
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
| | - Timothy D Craggs
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
| | - Jonathan P Waltho
- Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S10 2TN, UK.,Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester M1 7DN, UK
| | - Jane A Grasby
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Research, The University of Sheffield, Sheffield S3 7HF, UK
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Xu H, Shi R, Han W, Cheng J, Xu X, Cheng K, Wang L, Tian B, Zheng L, Shen B, Hua Y, Zhao Y. Structural basis of 5' flap recognition and protein-protein interactions of human flap endonuclease 1. Nucleic Acids Res 2019; 46:11315-11325. [PMID: 30295841 PMCID: PMC6265464 DOI: 10.1093/nar/gky911] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/06/2018] [Indexed: 01/30/2023] Open
Abstract
Human flap endonuclease 1 (hFEN1) is a structure-specific nuclease essential for DNA replication and repair processes. hFEN1 has 5′ flap removal activity, as well as gap endonuclease activity that is critical for restarting stalled replication forks. Here, we report the crystal structures of wild-type and mutant hFEN1 proteins in complex with DNA substrates, followed by mutagenesis studies that provide mechanistic insight into the protein–protein interactions of hFEN1. We found that in an α-helix forming the helical gateway of hFEN1 recognizes the 5′ flap prior to its threading into the active site for cleavage. We also found that the β-pin region is rigidified into a short helix in R192F hFEN1–DNA structures, suppressing its gap endonuclease activity and cycle-dependent kinase interactions. Our findings suggest that a single mutation at the primary methylation site can alter the function of hFEN1 and provide insight into the role of the β-pin region in hFEN1 protein interactions that are essential for DNA replication and repair.
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Affiliation(s)
- Hong Xu
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Rongyi Shi
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Wanchun Han
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Jiahui Cheng
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Xiaoli Xu
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Kaiying Cheng
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Liangyan Wang
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Bing Tian
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA 91010, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA 91010, USA
| | - Yuejin Hua
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Ye Zhao
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China
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97
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Abstract
Poly(ADP-ribose) (PAR) polymerase-1 (PARP-1) acts as a DNA damage sensor. It recognizes DNA damage and facilitates DNA repair by recruiting DNA repair machinery to damage sites. Recent studies reported that PARP-1 also plays an important role in DNA replication by recognizing the unligated Okazaki fragments and controlling the speed of fork elongation. On the other hand, emerging evidence reveals that excessive activation of PARP-1 causes chromatin DNA fragmentation and triggers an intrinsic PARP-1-dependent cell death program designated parthanatos, which can be blocked by genetic deletion or pharmacological inhibition of PARP-1. Therefore, PARP-1 plays an essential role in maintaining genomic stability by either facilitating DNA repair/replication or triggering DNA fragmentation to kill cells. A group of structure-specific nucleases is crucial for executing DNA incision and fragmentation following PARP-1 activation. In this review, we will discuss how PARP-1 coordinates with its associated nucleases to maintain genomic integrity and control the decision of cell life and death.
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Affiliation(s)
- Yijie Wang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Weibo Luo
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, 75390, USA; Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Yingfei Wang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, 75390, USA; Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, TX, 75390, USA.
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98
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Liu J, François JM, Capp JP. Gene Expression Noise Produces Cell-to-Cell Heterogeneity in Eukaryotic Homologous Recombination Rate. Front Genet 2019; 10:475. [PMID: 31164905 PMCID: PMC6536703 DOI: 10.3389/fgene.2019.00475] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 05/03/2019] [Indexed: 11/13/2022] Open
Abstract
Variation in gene expression among genetically identical individual cells (called gene expression noise) directly contributes to phenotypic diversity. Whether such variation can impact genome stability and lead to variation in genotype remains poorly explored. We addressed this question by investigating whether noise in the expression of genes affecting homologous recombination (HR) activity either directly (RAD52) or indirectly (RAD27) confers cell-to-cell heterogeneity in HR rate in Saccharomyces cerevisiae. Using cell sorting to isolate subpopulations with various expression levels, we show that spontaneous HR rate is highly heterogeneous from cell-to-cell in clonal populations depending on the cellular amount of proteins affecting HR activity. Phleomycin-induced HR is even more heterogeneous, showing that RAD27 expression variation strongly affects the rate of recombination from cell-to-cell. Strong variations in HR rate between subpopulations are not correlated to strong changes in cell cycle stage. Moreover, this heterogeneity occurs even when simultaneously sorting cells at equal expression level of another gene involved in DNA damage response (BMH1) that is upregulated by DNA damage, showing that the initiating DNA damage is not responsible for the observed heterogeneity in HR rate. Thus gene expression noise seems mainly responsible for this phenomenon. Finally, HR rate non-linearly scales with Rad27 levels showing that total amount of HR cannot be explained solely by the time- or population-averaged Rad27 expression. Altogether, our data reveal interplay between heterogeneity at the gene expression and genetic levels in the production of phenotypic diversity with evolutionary consequences from microbial to cancer cell populations.
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Affiliation(s)
- Jian Liu
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Institut National des Sciences Appliquées de Toulouse, UMR CNRS 5504, UMR INRA 792, Université de Toulouse, Toulouse, France
| | - Jean-Marie François
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Institut National des Sciences Appliquées de Toulouse, UMR CNRS 5504, UMR INRA 792, Université de Toulouse, Toulouse, France
| | - Jean-Pascal Capp
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Institut National des Sciences Appliquées de Toulouse, UMR CNRS 5504, UMR INRA 792, Université de Toulouse, Toulouse, France
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99
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Barnum KJ, Nguyen YT, O'Connell MJ. XPG-related nucleases are hierarchically recruited for double-stranded rDNA break resection. J Biol Chem 2019; 294:7632-7643. [PMID: 30885940 DOI: 10.1074/jbc.ra118.005415] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 03/11/2019] [Indexed: 12/11/2022] Open
Abstract
dsDNA breaks (DSBs) are resected in a 5'→3' direction, generating single-stranded DNA (ssDNA). This promotes DNA repair by homologous recombination and also assembly of signaling complexes that activate the DNA damage checkpoint effector kinase Chk1. In fission yeast (Schizosaccharomyces pombe), genetic screens have previously uncovered a family of three xeroderma pigmentosum G (XPG)-related nucleases (XRNs), known as Ast1, Exo1, and Rad2. Collectively, these XRNs are recruited to a euchromatic DSB and are required for ssDNA production and end resection across the genome. Here, we studied why there are three related but distinct XRN enzymes that are all conserved across a range of species, including humans, whereas all other DSB response proteins are present as single species. Using S. pombe as a model, ChIP and DSB resection analysis assays, and highly efficient I-PpoI-induced DSBs in the 28S rDNA gene, we observed a hierarchy of recruitment for each XRN, with a progressive compensatory recruitment of the other XRNs as the responding enzymes are deleted. Importantly, we found that this hierarchy reflects the requirement for different XRNs to effect efficient DSB resection in the rDNA, demonstrating that the presence of three XRN enzymes is not a simple division of labor. Furthermore, we uncovered a specificity of XRN function with regard to the direction of transcription. We conclude that the DSB-resection machinery is complex, is nonuniform across the genome, and has built-in fail-safe mechanisms, features that are in keeping with the highly pathological nature of DSB lesions.
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Affiliation(s)
- Kevin J Barnum
- From the Department of Oncological Sciences and.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Y Tram Nguyen
- From the Department of Oncological Sciences and.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Matthew J O'Connell
- From the Department of Oncological Sciences and .,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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100
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Mengwasser KE, Adeyemi RO, Leng Y, Choi MY, Clairmont C, D'Andrea AD, Elledge SJ. Genetic Screens Reveal FEN1 and APEX2 as BRCA2 Synthetic Lethal Targets. Mol Cell 2019. [PMID: 30686591 DOI: 10.1016/j.molcel.2018.12.008]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BRCA1 or BRCA2 inactivation drives breast and ovarian cancer but also creates vulnerability to poly(ADP-ribose) polymerase (PARP) inhibitors. To search for additional targets whose inhibition is synthetically lethal in BRCA2-deficient backgrounds, we screened two pairs of BRCA2 isogenic cell lines with DNA-repair-focused small hairpin RNA (shRNA) and CRISPR (clustered regularly interspaced short palindromic repeats)-based libraries. We found that BRCA2-deficient cells are selectively dependent on multiple pathways including base excision repair, ATR signaling, and splicing. We identified APEX2 and FEN1 as synthetic lethal genes with both BRCA1 and BRCA2 loss of function. BRCA2-deficient cells require the apurinic endonuclease activity and the PCNA-binding domain of Ape2 (APEX2), but not Ape1 (APEX1). Furthermore, BRCA2-deficient cells require the 5' flap endonuclease but not the 5'-3' exonuclease activity of Fen1, and chemically inhibiting Fen1 selectively targets BRCA-deficient cells. Finally, we developed a microhomology-mediated end-joining (MMEJ) reporter and showed that Fen1 participates in MMEJ, underscoring the importance of MMEJ as a collateral repair pathway in the context of homologous recombination (HR) deficiency.
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Affiliation(s)
- Kristen E Mengwasser
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Richard O Adeyemi
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Yumei Leng
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Mei Yuk Choi
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Connor Clairmont
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Stephen J Elledge
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA.
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