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Noto A, Valenzisi P, Fratini F, Kulikowicz T, Sommers JA, Di Feo F, Palermo V, Semproni M, Crescenzi M, Brosh RM, Franchitto A, Pichierri P. PHOSPHORYLATION-DEPENDENT ASSOCIATION OF WRN WITH RPA IS REQUIRED FOR RECOVERY OF REPLICATION FORKS STALLED AT SECONDARY DNA STRUCTURES. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552428. [PMID: 37609214 PMCID: PMC10441285 DOI: 10.1101/2023.08.08.552428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The WRN protein mutated in the hereditary premature aging disorder Werner syndrome plays a vital role in handling, processing, and restoring perturbed replication forks. One of its most abundant partners, Replication Protein A (RPA), has been shown to robustly enhance WRN helicase activity in specific cases when tested in vitro. However, the significance of RPA-binding to WRN at replication forks in vivo has remained largely unexplored. In this study, we have identified several conserved phosphorylation sites in the acidic domain of WRN that are targeted by Casein Kinase 2 (CK2). Surprisingly, these phosphorylation sites are essential for the interaction between WRN and RPA, both in vitro and in human cells. By characterizing a CK2-unphosphorylatable WRN mutant that lacks the ability to bind RPA, we have determined that the WRN-RPA complex plays a critical role in fork recovery after replication stress whereas the WRN-RPA interaction is not necessary for the processing of replication forks or preventing DNA damage when forks stall or collapse. When WRN fails to bind RPA, fork recovery is impaired, leading to the accumulation of single-stranded DNA gaps in the parental strands, which are further enlarged by the structure-specific nuclease MRE11. Notably, RPA-binding by WRN and its helicase activity are crucial for countering the persistence of G4 structures after fork stalling. Therefore, our findings reveal for the first time a novel role for the WRN-RPA interaction to facilitate fork restart, thereby minimizing G4 accumulation at single-stranded DNA gaps and suppressing accumulation of unreplicated regions that may lead to MUS81-dependent double-strand breaks requiring efficient repair by RAD51 to prevent excessive DNA damage.
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Affiliation(s)
- Alessandro Noto
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Pasquale Valenzisi
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Federica Fratini
- Core Facilities Technical-Scientific Service, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Tomasz Kulikowicz
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Joshua A. Sommers
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Flavia Di Feo
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Valentina Palermo
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Maurizio Semproni
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Marco Crescenzi
- Core Facilities Technical-Scientific Service, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Robert M. Brosh
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Annapaola Franchitto
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Pietro Pichierri
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
- Istituto Nazionale di Biostrutture e Biosistemi, Viale delle Medaglie d’Oro 305 – 00134 Rome (Italy)
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Lu H, Davis AJ. Human RecQ Helicases in DNA Double-Strand Break Repair. Front Cell Dev Biol 2021. [DOI: 10.3389/fcell.2021.640755 order by 1-- znbp] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Lu H, Davis AJ. Human RecQ Helicases in DNA Double-Strand Break Repair. Front Cell Dev Biol 2021. [DOI: 10.3389/fcell.2021.640755 order by 1-- azli] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Lu H, Davis AJ. Human RecQ Helicases in DNA Double-Strand Break Repair. Front Cell Dev Biol 2021; 9:640755. [PMID: 33718381 PMCID: PMC7947261 DOI: 10.3389/fcell.2021.640755] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund-Thomson syndrome (RTS), Baller-Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Affiliation(s)
- Huiming Lu
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Anthony J. Davis
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, United States
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Human Exonuclease 1 (EXO1) Regulatory Functions in DNA Replication with Putative Roles in Cancer. Int J Mol Sci 2018; 20:ijms20010074. [PMID: 30585186 PMCID: PMC6337416 DOI: 10.3390/ijms20010074] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/12/2018] [Accepted: 12/19/2018] [Indexed: 12/11/2022] Open
Abstract
Human exonuclease 1 (EXO1), a 5'→3' exonuclease, contributes to the regulation of the cell cycle checkpoints, replication fork maintenance, and post replicative DNA repair pathways. These processes are required for the resolution of stalled or blocked DNA replication that can lead to replication stress and potential collapse of the replication fork. Failure to restart the DNA replication process can result in double-strand breaks, cell-cycle arrest, cell death, or cellular transformation. In this review, we summarize the involvement of EXO1 in the replication, DNA repair pathways, cell cycle checkpoints, and the link between EXO1 and cancer.
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Ammar UM, Abdel-Maksoud MS, Oh CH. Recent advances of RAF (rapidly accelerated fibrosarcoma) inhibitors as anti-cancer agents. Eur J Med Chem 2018; 158:144-166. [PMID: 30216849 DOI: 10.1016/j.ejmech.2018.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 09/01/2018] [Accepted: 09/03/2018] [Indexed: 12/19/2022]
Abstract
Frequent oncogenic mutations have been identified in MAPK (mitogen-activated protein kinase) signaling pathway components. As a result, MAPK pathway is associated with human cancer initiation, in particular RAF (rapidly accelerated fibrosarcoma) component. The mutation in RAF component leads to auto-activation of MAPK signaling pathway, stimulating the uncontrolled cell growth and proliferation. In last few years, diverse chemical scaffolds have been identified as RAF inhibitors. Most of these scaffolds show potent anti-cancer activity. The present review highlights the recent investigations of RAF inhibitors during the last five years.
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Affiliation(s)
- Usama M Ammar
- Center for Biomaterials, Korea Institute of Science & Technology (KIST), Seoul, Seongbuk-gu, 02792, Republic of Korea; Department of Biomolecular Science, University of Science & Technology (UST), Daejeon, Yuseong-gu, 34113, Republic of Korea; Pharmaceutical Chemistry Department, Faculty of Pharmacy, Ahram Canadian University, Giza, 12566, Egypt
| | - Mohammed S Abdel-Maksoud
- Medicinal & Pharmaceutical Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Centre (NRC), Dokki, Giza, 12622, Egypt
| | - Chang-Hyun Oh
- Center for Biomaterials, Korea Institute of Science & Technology (KIST), Seoul, Seongbuk-gu, 02792, Republic of Korea; Department of Biomolecular Science, University of Science & Technology (UST), Daejeon, Yuseong-gu, 34113, Republic of Korea.
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Yu MC, Lee CW, Lee YS, Lian JH, Tsai CL, Liu YP, Wu CH, Tsai CN. Prediction of early-stage hepatocellular carcinoma using OncoScan chromosomal copy number aberration data. World J Gastroenterol 2017; 23:7818-7829. [PMID: 29209123 PMCID: PMC5703911 DOI: 10.3748/wjg.v23.i44.7818] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/26/2017] [Accepted: 11/07/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To identify chromosomal copy number aberrations (CNAs) in early-stage hepatocellular carcinoma (HCC) and analyze whether they are correlated with patient prognosis.
METHODS One hundred and twenty patients with early-stage HCC were enrolled in our study, with the collection of formalin fixed, paraffin-embedded (FFPE) specimens and clinicopathological data. Tumor areas were marked by certified pathologists on a hematoxylin and eosin-stained slide, and cancer and adjacent non-cancerous tissues underwent extraction of DNA, which was analyzed with the Affymetrix OncoScan platform to assess CNAs and loss of heterozygosity (LOH). Ten individuals with nonmalignant disease were used as the control group. Another cohort consisting of 40 patients with stage I/II HCC were enrolled to analyze gene expression and to correlate findings with the OncoScan data.
RESULTS Copy number amplifications occurred at chromosomes 1q21.1-q44 and 8q12.3-24.3 and deletions were found at 4q13.1-q35.2, 8p 23.2-21.1, 16q23.3-24.3, and 17p13.3-12, while LOH commonly occurred at 1p32.3, 3p21.31, 8p23.2-21.1, 16q22.1-24.3, and 17p 13.3-11 in early-stage HCC. Using Cox regression analysis, we also found that a higher percentage of genome change (≥ 60%) was an independent factor for worse prognosis in early-stage HCC (P = 0.031). Among the 875 genes in the OncoScan GeneChip, six were independent predictors of worse disease-free survival, of which three were amplified (MYC, ELAC2, and SYK) and three were deleted (GAK, MECOM, and WRN). Further, patients with HCC who exhibited ≥ 3 CNAs involving these six genes have worse outcomes compared to those who had < 3 CNAs (P < 0.001). Similarly, Asian patients with stage I HCC from The Cancer Genome Atlas harboring CNAs with these genes were also predicted to have poorer outcomes.
CONCLUSION Patients with early-stage HCC and increased genome change or CNAs involving MYC, ELAC2, SYK, GAK, MECOM, or WRN are at risk for poorer outcome after resection.
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Affiliation(s)
- Ming-Chin Yu
- Department of Surgery, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
- Department of Surgery, Xiamen Chang Gung Hospital, Xiamen 361028, China
| | - Chao-Wei Lee
- Department of Surgery, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan 33302, Taiwan
| | - Yun-Shien Lee
- Genomic Medicine Core Laboratory, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
- Department of Biotechnology, Ming-Chuan University, Taoyuan 33348, Taiwan
| | - Jang-Hau Lian
- Genomic Medicine Core Laboratory, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
| | - Chia-Lung Tsai
- Genomic Medicine Core Laboratory, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
| | - Yi-Ping Liu
- Department of Surgery, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
| | - Chun-Hsing Wu
- Department of Surgery, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
| | - Chi-Neu Tsai
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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Interactive Roles of DNA Helicases and Translocases with the Single-Stranded DNA Binding Protein RPA in Nucleic Acid Metabolism. Int J Mol Sci 2017; 18:ijms18061233. [PMID: 28594346 PMCID: PMC5486056 DOI: 10.3390/ijms18061233] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/30/2017] [Accepted: 06/01/2017] [Indexed: 01/05/2023] Open
Abstract
Helicases and translocases use the energy of nucleoside triphosphate binding and hydrolysis to unwind/resolve structured nucleic acids or move along a single-stranded or double-stranded polynucleotide chain, respectively. These molecular motors facilitate a variety of transactions including replication, DNA repair, recombination, and transcription. A key partner of eukaryotic DNA helicases/translocases is the single-stranded DNA binding protein Replication Protein A (RPA). Biochemical, genetic, and cell biological assays have demonstrated that RPA interacts with these human molecular motors physically and functionally, and their association is enriched in cells undergoing replication stress. The roles of DNA helicases/translocases are orchestrated with RPA in pathways of nucleic acid metabolism. RPA stimulates helicase-catalyzed DNA unwinding, enlists translocases to sites of action, and modulates their activities in DNA repair, fork remodeling, checkpoint activation, and telomere maintenance. The dynamic interplay between DNA helicases/translocases and RPA is just beginning to be understood at the molecular and cellular levels, and there is still much to be learned, which may inform potential therapeutic strategies.
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DNA damage tolerance pathway involving DNA polymerase ι and the tumor suppressor p53 regulates DNA replication fork progression. Proc Natl Acad Sci U S A 2016; 113:E4311-9. [PMID: 27407148 DOI: 10.1073/pnas.1605828113] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
DNA damage tolerance facilitates the progression of replication forks that have encountered obstacles on the template strands. It involves either translesion DNA synthesis initiated by proliferating cell nuclear antigen monoubiquitination or less well-characterized fork reversal and template switch mechanisms. Herein, we characterize a novel tolerance pathway requiring the tumor suppressor p53, the translesion polymerase ι (POLι), the ubiquitin ligase Rad5-related helicase-like transcription factor (HLTF), and the SWI/SNF catalytic subunit (SNF2) translocase zinc finger ran-binding domain containing 3 (ZRANB3). This novel p53 activity is lost in the exonuclease-deficient but transcriptionally active p53(H115N) mutant. Wild-type p53, but not p53(H115N), associates with POLι in vivo. Strikingly, the concerted action of p53 and POLι decelerates nascent DNA elongation and promotes HLTF/ZRANB3-dependent recombination during unperturbed DNA replication. Particularly after cross-linker-induced replication stress, p53 and POLι also act together to promote meiotic recombination enzyme 11 (MRE11)-dependent accumulation of (phospho-)replication protein A (RPA)-coated ssDNA. These results implicate a direct role of p53 in the processing of replication forks encountering obstacles on the template strand. Our findings define an unprecedented function of p53 and POLι in the DNA damage response to endogenous or exogenous replication stress.
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Design, biological evaluation and 3D QSAR studies of novel dioxin-containing triaryl pyrazoline derivatives as potential B-Raf inhibitors. Bioorg Med Chem 2016; 24:3052-3061. [DOI: 10.1016/j.bmc.2016.05.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 05/10/2016] [Accepted: 05/11/2016] [Indexed: 01/14/2023]
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19
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Micewicz ED, Sharma S, Waring AJ, Luong HT, McBride WH, Ruchala P. Bridged Analogues for p53-Dependent Cancer Therapy Obtained by S-Alkylation. Int J Pept Res Ther 2015; 22:67-81. [PMID: 26957954 DOI: 10.1007/s10989-015-9487-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A small library of anticancer, cell-permeating, stapled peptides based on potent dual-specific antagonist of p53-MDM2/MDMX interactions, PMI-N8A, was synthesized, characterized and screened for anticancer activity against human colorectal cancer cell line, HCT-116. Employed synthetic modifications included: S-alkylation-based stapling, point mutations increasing hydrophobicity in key residues as well as improvement of cell-permeability by introduction of polycationic sequence(s) that were woven into the sequence of parental peptide. Selected analogue, ArB14Co, was also tested in vivo and exhibited potent anticancer bioactivity at the low dose (3.0 mg/kg). Collectively, our findings suggest that application of stapling in combination with rational design of polycationic short analogues may be a suitable approach in the development of physiologically active p53-MDM2/MDMX peptide inhibitors.
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Affiliation(s)
- Ewa D Micewicz
- Department of Radiation Oncology, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Shantanu Sharma
- Materials and Process Simulation Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Alan J Waring
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA, Medical Center, 1000 West Carson Street, Torrance, CA 90502, USA
| | - Hai T Luong
- Department of Analytical Operations, Gilead Sciences, Inc., 4049 Avenida de la Plata, Oceanside CA, 92056, USA
| | - William H McBride
- Department of Radiation Oncology, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Piotr Ruchala
- Department of Psychiatry and Biobehavioral Sciences, University of California at Los Angeles, 760 Westwood Plaza, Los Angeles, CA 90024, USA
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20
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Seco-Cervera M, Spis M, García-Giménez JL, Ibañez-Cabellos JS, Velázquez-Ledesma A, Esmorís I, Bañuls S, Pérez-Machado G, Pallardó FV. Oxidative stress and antioxidant response in fibroblasts from Werner and atypical Werner syndromes. Aging (Albany NY) 2015; 6:231-45. [PMID: 24799429 PMCID: PMC4012939 DOI: 10.18632/aging.100649] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Werner Syndrome (WS, ICD-10 E34.8, ORPHA902) and Atypical Werner Syndrome (AWS, ICD-10 E34.8, ORPHA79474) are very rare inherited syndromes characterized by premature aging. While approximately 90% of WS individuals have any of a range of mutations in the WRN gene, there exists a clinical subgroup in which the mutation occurs in the LMNA/C gene in heterozygosity. Although both syndromes exhibit an age-related pleiotropic phenotype, AWS manifests the onset of the disease during childhood, while major symptoms in WS appear between the ages of 20 and 30. To study the molecular mechanisms of progeroid diseases provides a useful insight into the normal aging process. Main changes found were the decrease in Cu/Zn and Mn SOD activities in the three cell lines. In AWS, both mRNA SOD and protein levels were also decreased. Catalase and glutathione peroxidases decrease, mainly in AWS. Glutaredoxin (Grx) and thioredoxin (Trx) protein expression was lower in the three progeroid cell lines. Grx and Trx were subjected to post-transcriptional regulation, because protein expression was reduced although mRNA levels were not greatly affected in WS.
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Affiliation(s)
- Marta Seco-Cervera
- CIBERER. Centro de Investigación Biomédica en Red de Enfermedades Raras, Valencia, Spain
| | | | | | | | | | | | | | | | - Federico V Pallardó
- Department of Physiology, Medicine School, University of Valencia, Valencia. Spain
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21
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Sommers JA, Suhasini AN, Brosh RM. Protein degradation pathways regulate the functions of helicases in the DNA damage response and maintenance of genomic stability. Biomolecules 2015; 5:590-616. [PMID: 25906194 PMCID: PMC4496686 DOI: 10.3390/biom5020590] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/09/2015] [Accepted: 04/13/2015] [Indexed: 12/18/2022] Open
Abstract
Degradation of helicases or helicase-like proteins, often mediated by ubiquitin-proteasomal pathways, plays important regulatory roles in cellular mechanisms that respond to DNA damage or replication stress. The Bloom’s syndrome helicase (BLM) provides an example of how helicase degradation pathways, regulated by post-translational modifications and protein interactions with components of the Fanconi Anemia (FA) interstrand cross-link (ICL) repair pathway, influence cell cycle checkpoints, DNA repair, and replication restart. The FANCM DNA translocase can be targeted by checkpoint kinases that exert dramatic effects on FANCM stability and chromosomal integrity. Other work provides evidence that degradation of the F-box DNA helicase (FBH1) helps to balance translesion synthesis (TLS) and homologous recombination (HR) repair at blocked replication forks. Degradation of the helicase-like transcription factor (HLTF), a DNA translocase and ubiquitylating enzyme, influences the choice of post replication repair (PRR) pathway. Stability of the Werner syndrome helicase-nuclease (WRN) involved in the replication stress response is regulated by its acetylation. Turning to transcription, stability of the Cockayne Syndrome Group B DNA translocase (CSB) implicated in transcription-coupled repair (TCR) is regulated by a CSA ubiquitin ligase complex enabling recovery of RNA synthesis. Collectively, these studies demonstrate that helicases can be targeted for degradation to maintain genome homeostasis.
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Affiliation(s)
- Joshua A Sommers
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, NIH Biomedical Research Center, 251 Bayview Blvd, Baltimore, MD 21224, USA.
| | - Avvaru N Suhasini
- Department of Medicine, Division of Hematology & Medical Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
| | - Robert M Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, NIH Biomedical Research Center, 251 Bayview Blvd, Baltimore, MD 21224, USA.
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22
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Ireno IC, Wiehe RS, Stahl AI, Hampp S, Aydin S, Troester MA, Selivanova G, Wiesmüller L. Modulation of the poly (ADP-ribose) polymerase inhibitor response and DNA recombination in breast cancer cells by drugs affecting endogenous wild-type p53. Carcinogenesis 2014; 35:2273-82. [PMID: 25085902 DOI: 10.1093/carcin/bgu160] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Synthetic lethal interactions between poly (ADP-ribose) polymerase (PARP) and homologous recombination (HR) repair pathways have been exploited for the development of novel mono- and combination cancer therapies. The tumor suppressor p53 was demonstrated to exhibit indirect and direct regulatory activities in DNA repair, particularly in DNA double-strand break (DSB)-induced and replication-associated HR. In this study, we tested a potential influence of the p53 status on the response to PARP inhibition, which is known to cause replication stress. Silencing endogenous or inducibly expressing p53 we found a protective effect of p53 on PARP inhibitor (PARPi)-mediated cytotoxicities. This effect was specific for wild-type versus mutant p53 and observed in cancer but not in non-transformed cell lines. Enhanced cytotoxicities after treatment with the p53-inhibitory drug Pifithrinα further supported p53-mediated resistance to PARP inhibition. Surprisingly, we equally observed increased PARPi sensitivity in the presence of the p53-activating compound Nutlin-3. As a common denominator, both drug responses correlated with decreased HR activities: Pifithrinα downregulated spontaneous HR resulting in damage accumulation. Nutlin-3 induced a decrease of DSB-induced HR, which was accompanied by a severe drop in RAD51 protein levels. Thus, we revealed a novel link between PARPi responsiveness and p53-controlled HR activities. These data expand the concept of cell and stress type-dependent healer and killer functions of wild-type p53 in response to cancer therapeutic treatment. Our findings have implications for the individualized design of cancer therapies using PARPi and the potentially combined use of p53-modulatory drugs.
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Affiliation(s)
| | - Rahel Stephanie Wiehe
- Department of Obstetrics and Gynecology, Ulm University, Prittwitzstrasse 43, D-89075 Ulm, Germany,
| | - Andreea Iulia Stahl
- Department of Obstetrics and Gynecology, Ulm University, Prittwitzstrasse 43, D-89075 Ulm, Germany
| | - Stephanie Hampp
- Department of Obstetrics and Gynecology, Ulm University, Prittwitzstrasse 43, D-89075 Ulm, Germany
| | - Sevtap Aydin
- Department of Obstetrics and Gynecology, Ulm University, Prittwitzstrasse 43, D-89075 Ulm, Germany, Department of Toxicology, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey
| | | | - Galina Selivanova
- Department of Microbiology Tumor and Cell Biology, Karolinska Institutet, Stockholm 17177, Sweden
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Prittwitzstrasse 43, D-89075 Ulm, Germany,
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23
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Yang YS, Zhang F, Tang DJ, Yang YH, Zhu HL. Modification, biological evaluation and 3D QSAR studies of novel 2-(1,3-diaryl- 4,5-dihydro-1H-pyrazol-5-yl)phenol derivatives as inhibitors of B-Raf kinase. PLoS One 2014; 9:e95702. [PMID: 24827980 PMCID: PMC4020744 DOI: 10.1371/journal.pone.0095702] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/28/2014] [Indexed: 11/25/2022] Open
Abstract
A series of novel 2-(1,3-diaryl- 4,5-dihydro-1H-pyrazol-5-yl)phenol derivatives (C1-C24) have been synthesized. The B-Raf inhibitory activity and anti-proliferation activity of these compounds have been tested. Compound C6 displayed the most potent biological activity against B-RafV600E (IC50 = 0.15 µM) and WM266.4 human melanoma cell line (GI50 = 1.75 µM), being comparable with the positive control (Vemurafenib and Erlotinib) and more potent than our previous best compounds. The docking simulation was performed to analyze the probable binding models and poses while the QSAR model was built to check the previous work as well as to introduce new directions. This work aimed at seeking more potent inhibitors as well as discussing some previous findings. As a result, the introduction of ortho-hydroxyl group on 4,5-dihydro-1H-pyrazole skeleton did reinforce the anti-tumor activity while enlarging the group on N-1 of pyrazoline was also helpful.
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Affiliation(s)
- Yu-Shun Yang
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, P. R. China
- Institute of Chemical and Biomedical Science, Nanjing University, Nanjing, P. R. China
| | - Fei Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, P. R. China
| | - Dan-Jie Tang
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, P. R. China
| | - Yong-Hua Yang
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, P. R. China
| | - Hai-Liang Zhu
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, P. R. China
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24
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Wang HC, Ho CH, Hsu KC, Yang JM, Wang AHJ. DNA mimic proteins: functions, structures, and bioinformatic analysis. Biochemistry 2014; 53:2865-74. [PMID: 24766129 DOI: 10.1021/bi5002689] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
DNA mimic proteins have DNA-like negative surface charge distributions, and they function by occupying the DNA binding sites of DNA binding proteins to prevent these sites from being accessed by DNA. DNA mimic proteins control the activities of a variety of DNA binding proteins and are involved in a wide range of cellular mechanisms such as chromatin assembly, DNA repair, transcription regulation, and gene recombination. However, the sequences and structures of DNA mimic proteins are diverse, making them difficult to predict by bioinformatic search. To date, only a few DNA mimic proteins have been reported. These DNA mimics were not found by searching for functional motifs in their sequences but were revealed only by structural analysis of their charge distribution. This review highlights the biological roles and structures of 16 reported DNA mimic proteins. We also discuss approaches that might be used to discover new DNA mimic proteins.
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Affiliation(s)
- Hao-Ching Wang
- Graduate Institute of Translational Medicine, College of Medical Science and Technology, Taipei Medical University , Taipei 110, Taiwan
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25
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El-Nassan HB. Recent progress in the identification of BRAF inhibitors as anti-cancer agents. Eur J Med Chem 2014; 72:170-205. [DOI: 10.1016/j.ejmech.2013.11.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/05/2013] [Accepted: 11/18/2013] [Indexed: 12/26/2022]
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26
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Synthesis, biological evaluation of novel 4,5-dihydro-2H-pyrazole 2-hydroxyphenyl derivatives as BRAF inhibitors. Bioorg Med Chem 2012; 20:6089-96. [DOI: 10.1016/j.bmc.2012.08.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/14/2012] [Accepted: 08/16/2012] [Indexed: 11/22/2022]
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27
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Serrano MA, Li Z, Dangeti M, Musich PR, Patrick S, Roginskaya M, Cartwright B, Zou Y. DNA-PK, ATM and ATR collaboratively regulate p53-RPA interaction to facilitate homologous recombination DNA repair. Oncogene 2012; 32:2452-62. [PMID: 22797063 PMCID: PMC3651755 DOI: 10.1038/onc.2012.257] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Homologous recombination (HR) and nonhomologous end-joining (NHEJ) are two distinct DNA double-strand break (DSB) repair pathways. Here we report that DNA-dependent protein kinase (DNA-PK), the core component of NHEJ, partnering with DNA-damage checkpoint kinases ataxia telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR), regulates HR repair of DSBs. The regulation was accomplished through modulation of the p53 and replication protein A (RPA) interaction. We show that upon DNA damage, p53 and RPA were freed from a p53-RPA complex by simultaneous phosphorylations of RPA at the N-terminus of RPA32 subunit by DNA-PK and of p53 at Ser37 and Ser46 in a Chk1/Chk2-independent manner by ATR and ATM, respectively. Neither the phosphorylation of RPA nor of p53 alone could dissociate p53 and RPA. Furthermore, disruption of the release significantly compromised HR repair of DSBs. Our results reveal a mechanism for the crosstalk between HR repair and NHEJ through the co-regulation of p53-RPA interaction by DNA-PK, ATM and ATR.
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Affiliation(s)
- M A Serrano
- Department of Biochemistry and Molecular Biology, JH Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA
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28
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Mangerich A, Veith S, Popp O, Fahrer J, Martello R, Bohr VA, Bürkle A. Quantitative analysis of WRN exonuclease activity by isotope dilution mass spectrometry. Mech Ageing Dev 2012; 133:575-9. [PMID: 22766507 DOI: 10.1016/j.mad.2012.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 05/11/2012] [Accepted: 06/19/2012] [Indexed: 12/31/2022]
Abstract
Werner syndrome is a disorder characterized by a premature aging phenotype. The disease is caused by mutations in the WRN gene which encodes a DNA helicase/exonuclease which is involved in multiple aspects of DNA metabolism. Current methods mostly rely on radiometric techniques to assess WRN exonuclease activity. Here we present an alternative, quantitative approach based on non-radioactive isotope dilution mass spectrometry (LC-MS/MS). A oligoduplex substrate mimicking the telomeric sequence was used for method development. Released nucleotides, which correlate with the degree of oligoduplex degradation, were dephosphorylated, purified, and quantified by LC-MS/MS. Heavy-isotope-labeled internal standards were used to account for technical variability. The method was validated in terms of reproducibility, time-course and concentration-dependency of the reaction. As shown in this study, the LC-MS/MS method can assess exonuclease activity of WRN mutants, WRN's substrate and strand specificity, and modulatory effects of WRN interaction partners and posttranslational modifications. Moreover, it can be used to analyze the selectivity and processivity of WRN exonuclease and allows the screening of small molecules for WRN exonuclease inhibitors. Importantly, this approach can easily be adapted to study nucleases other than WRN. This is of general interest, because exonucleases are key players in DNA metabolism and aging mechanisms.
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Affiliation(s)
- Aswin Mangerich
- Molecular Toxicology Group, Department of Biology, University of Konstanz, 78457 Konstanz, Germany.
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29
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p53 Ser15 phosphorylation disrupts the p53-RPA70 complex and induces RPA70-mediated DNA repair in hypoxia. Biochem J 2012; 443:811-20. [PMID: 22288499 DOI: 10.1042/bj20111627] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cellular stressors are known to inhibit the p53-RPA70 (replication protein A, 70 kDa subunit) complex, and RPA70 increases cellular DNA repair in cancer cells. We hypothesized that regulation of RPA70-mediated DNA repair might be responsible for the inhibition of apoptosis in hypoxic tumours. We have shown that, in cancer cells, hypoxia disrupts the p53-RPA70 complex, thereby enhancing RPA70-mediated NER (nucleotide excision repair)/NHEJ (non-homologous end-joining) repair. In normal cells, RPA70 binds to the p53-NTD (N-terminal domain), whereas this binding is disrupted in hypoxia. Phosphorylation of p53-NTD is a crucial event in dissociating both NTD-RPA70 and p53-RPA70 complexes. Serial mutations at serine and threonine residues in the NTD confirm that p53(Ser15) phosphorylation induces dissociation of the p53-RPA70 complex in hypoxia. DNA-PK (DNA-dependent protein kinase) is shown to induce p53(Ser15) phosphorylation, thus enhancing RPA70-mediated NER/NHEJ repair. Furthermore, RPA70 gene silencing induces significant increases in cellular apoptosis in the resistant hypoxic cancer cells. We have thus elucidated a novel pathway showing how DNA-PK-mediated p53(Ser15) phosphorylation dissociates the p53-RPA70 complex, thus enhancing NER/NHEJ repair, which causes resistance to apoptosis in hypoxic cancer cells. This novel finding may open new strategies in developing cancer therapeutics on the basis of the regulation of RPA70-mediated NER/NHEJ repair.
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30
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Li CY, Li QS, Yan L, Sun XG, Wei R, Gong HB, Zhu HL. Synthesis, biological evaluation and 3D-QSAR studies of novel 4,5-dihydro-1H-pyrazole niacinamide derivatives as BRAF inhibitors. Bioorg Med Chem 2012; 20:3746-55. [DOI: 10.1016/j.bmc.2012.04.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 04/21/2012] [Accepted: 04/23/2012] [Indexed: 11/26/2022]
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31
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De S, Kumari J, Mudgal R, Modi P, Gupta S, Futami K, Goto H, Lindor NM, Furuichi Y, Mohanty D, Sengupta S. RECQL4 is essential for the transport of p53 to mitochondria in normal human cells in the absence of exogenous stress. J Cell Sci 2012; 125:2509-22. [PMID: 22357944 DOI: 10.1242/jcs.101501] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mutations in RECQL4 helicase are associated with Rothmund-Thomson syndrome (RTS). A subset of RTS patients is predisposed to cancer and is sensitive to DNA damaging agents. The enhanced sensitivity of cells from RTS patients correlates with the accumulation of transcriptionally active nuclear p53. We found that in untreated normal human cells these two nuclear proteins, p53 and RECQL4, instead colocalize in the mitochondrial nucleoids. RECQL4 accumulates in mitochondria in all phases of the cell cycle except S phase and physically interacts with p53 only in the absence of DNA damage. p53-RECQL4 binding leads to the masking of the nuclear localization signal of p53. The N-terminal 84 amino acids of RECQL4 contain a mitochondrial localization signal, which causes the localization of RECQL4-p53 complex to the mitochondria. RECQL4-p53 interaction is disrupted after stress, allowing p53 translocation to the nucleus. In untreated normal cells RECQL4 optimizes de novo replication of mtDNA, which is consequently decreased in fibroblasts from RTS patients. Wild-type RECQL4-complemented RTS cells show relocalization of both RECQL4 and p53 to the mitochondria, loss of p53 activation, restoration of de novo mtDNA replication and resistance to different types of DNA damage. In cells expressing Δ84 RECQL4, which cannot translocate to mitochondria, all the above functions are compromised. The recruitment of p53 to the sites of de novo mtDNA replication is also regulated by RECQL4. Thus these findings elucidate the mechanism by which p53 is regulated by RECQL4 in unstressed normal cells and also delineates the mitochondrial functions of the helicase.
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Affiliation(s)
- Siddharth De
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
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32
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Hathaway JD, Haque A. Insights into the Role of PAX-3 in the Development of Melanocytes and Melanoma. ACTA ACUST UNITED AC 2011; 4:1-6. [PMID: 24790680 DOI: 10.2174/1874079001104010001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Melanoma is the deadliest form of skin cancer in the United States with an increasing prevalence. However, the development of melanoma from a melanocyte precursor is still poorly defined. Understanding the molecules responsible for melanoma progression may lead to improved targeted therapy. One potential molecule is the paired box-3 (PAX-3) protein, which has been implicated in the development of melanocytes and malignant melanoma. In melanoma, the expression of PAX-3 is believed to be differentially regulated, and has been linked with malignancies and staging of the disease. The loss of PAX-3 regulation has also been associated with the loss of transforming growth factor-beta (TGF-β) activity, but its effect on PAX-3 in differentiated melanocytes as well as metastatic melanoma remains unclear. Understanding PAX-3 regulation could potentially shift melanoma to a less aggressive and less metastatic disease. This review summarizes our current knowledge on PAX-3 during melanocyte development, its regulation, and its implications in the development of novel chemo-immunotherapeutics against metastatic melanoma.
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Affiliation(s)
- Jessica Diann Hathaway
- Department of Microbiology and Immunology, Charles Darby Children's Research Institute, and Hollings Cancer Center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425
| | - Azizul Haque
- Department of Microbiology and Immunology, Charles Darby Children's Research Institute, and Hollings Cancer Center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425
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33
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Comparison of proliferation and genomic instability responses to WRN silencing in hematopoietic HL60 and TK6 cells. PLoS One 2011; 6:e14546. [PMID: 21267443 PMCID: PMC3022623 DOI: 10.1371/journal.pone.0014546] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 12/11/2010] [Indexed: 02/05/2023] Open
Abstract
Background Werner syndrome (WS) results from defects in the RecQ helicase (WRN) and is characterized by premature aging and accelerated tumorigenesis. Contradictorily, WRN deficient human fibroblasts derived from WS patients show a characteristically slower cell proliferation rate, as do primary fibroblasts and human cancer cell lines with WRN depletion. Previous studies reported that WRN silencing in combination with deficiency in other genes led to significantly accelerated cellular proliferation and tumorigenesis. The aim of the present study was to examine the effects of silencing WRN in p53 deficient HL60 and p53 wild-type TK6 hematopoietic cells, in order to further the understanding of WRN-associated tumorigenesis. Methodology/Principal Findings We found that silencing WRN accelerated the proliferation of HL60 cells and decreased the cell growth rate of TK6 cells. Loss of WRN increased DNA damage in both cell types as measured by COMET assay, but elicited different responses in each cell line. In HL60 cells, but not in TK6 cells, the loss of WRN led to significant increases in levels of phosphorylated RB and numbers of cells progressing from G1 phase to S phase as shown by cell cycle analysis. Moreover, WRN depletion in HL60 cells led to the hyper-activation of homologous recombination repair via up-regulation of RAD51 and BLM protein levels. This resulted in DNA damage disrepair, apparent by the increased frequencies of both spontaneous and chemically induced structural chromosomal aberrations and sister chromatid exchanges. Conclusions/Significance Together, our data suggest that the effects of WRN silencing on cell proliferation and genomic instability are modulated probably by other genetic factors, including p53, which might play a role in the carcinogenesis induced by WRN deficiency.
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34
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Fernandez-Fernandez MR, Sot B. The relevance of protein-protein interactions for p53 function: the CPE contribution. Protein Eng Des Sel 2010; 24:41-51. [PMID: 20952436 DOI: 10.1093/protein/gzq074] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The relevance of p53 as a tumour suppressor is evident from the fact that more than 50% of the human cancers hold mutations in the gene coding for p53, and of the remaining cancers a considerable number have alterations in the p53 pathway. From its discovery 30 years ago, the importance of p53 as an essential transcription factor for tumour suppression has become clear. More recently, new and seemingly diverse roles of p53 have been discovered. It soon became clear that protein-protein interactions play an important role in the regulation of the p53 function at different levels. Here we review the contribution by Prof. Fersht and his group towards understanding the basis and functional relevance of p53 protein-protein interactions, and the important role that protein science, biophysics and structural biology have played in the science produced in the Centre for Protein Engineering over the years.
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35
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Niculescu-Duvaz D, Niculescu-Duvaz I, Suijkerbuijk BM, Ménard D, Zambon A, Nourry A, Davies L, Manne HA, Friedlos F, Ogilvie L, Hedley D, Takle AK, Wilson DM, Pons JF, Coulter T, Kirk R, Cantarino N, Whittaker S, Marais R, Springer CJ. Novel tricyclic pyrazole BRAF inhibitors with imidazole or furan central scaffolds. Bioorg Med Chem 2010; 18:6934-52. [PMID: 20667740 PMCID: PMC2956513 DOI: 10.1016/j.bmc.2010.06.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 06/08/2010] [Accepted: 06/10/2010] [Indexed: 12/17/2022]
Abstract
V-RAF murine sarcoma viral oncogene homolog B1 (BRAF) is a serine/threonine-specific protein kinase that is mutated with high frequency in cutaneous melanoma, and many other cancers. Inhibition of mutant BRAF is an attractive therapeutic approach for the treatment of melanoma. A triarylimidazole BRAF inhibitor bearing a phenylpyrazole group (dimethyl-[2-(4-{5-[4-(1H-pyrazol-3-yl)-phenyl]-4-pyridin-4-yl-1H-imidazol-2-yl}-phenoxy)-ethyl]-amine, 1a) was identified as an active BRAF inhibitor. Based on this starting point, we synthesized a series of analogues leading to the discovery of 6-{2-[4-(4-methyl-piperazin-1-yl)-phenyl]-5-pyridin-4-yl-3H-imidazol-4-yl}-2,4-dihydro-indeno[1,2-c]pyrazole (1j), with nanomolar activity in three assays: inhibition of purified mutant BRAF activity in vitro; inhibition of oncogenic BRAF-driven extracellular regulated kinase (ERK) activation in BRAF mutant melanoma cell lines; and inhibition of proliferation in these cells.
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Key Words
- boc, tert-butoxycarbonyl
- braf, v-raf murine sarcoma viral oncogene homolog b1
- dcm, dichloromethane
- dmf, dimethylformamide
- erk, extracellular regulated kinase
- mapk, mitogen-activated protein kinase
- mek, mapk/erk kinase
- mom, methoxymethyl
- pk, pharmacokinetics
- raf, rapidly growing fibrosarcoma
- sar, structure–activity relationship
- tfa, trifluoroacetic acid
- thf, tetrahydrofuran
- braf
- kinase inhibitors
- anticancer
- melanoma
- triarylimidazole
- dihydroindenopyrazole
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Affiliation(s)
- Dan Niculescu-Duvaz
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Ion Niculescu-Duvaz
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Bart M.J.M. Suijkerbuijk
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Delphine Ménard
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Alfonso Zambon
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Arnaud Nourry
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Lawrence Davies
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Helen A. Manne
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Frank Friedlos
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Lesley Ogilvie
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Douglas Hedley
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Andrew K. Takle
- Department of Medicinal Chemistry, Neurology and GI Centre of Excellence for Drug Discovery, GlaxoSmithKline Pharmaceuticals, New Frontiers Science Park, Third Avenue, Harlow, Essex CM19 5AW, United Kingdom
| | - David M. Wilson
- Department of Medicinal Chemistry, Neurology and GI Centre of Excellence for Drug Discovery, GlaxoSmithKline Pharmaceuticals, New Frontiers Science Park, Third Avenue, Harlow, Essex CM19 5AW, United Kingdom
| | - Jean-Francois Pons
- Evotec (UK) Ltd, 114 Milton Park, Abingdon, Oxfordshire OX14 4SA, United Kingdom
| | - Tom Coulter
- Evotec (UK) Ltd, 114 Milton Park, Abingdon, Oxfordshire OX14 4SA, United Kingdom
| | - Ruth Kirk
- The Institute of Cancer Research, Cancer Research UK Centre for Cell and Molecular Biology, 237 Fulham Road, London SW3 6JB, United Kingdom
| | - Neus Cantarino
- The Institute of Cancer Research, Cancer Research UK Centre for Cell and Molecular Biology, 237 Fulham Road, London SW3 6JB, United Kingdom
| | - Steven Whittaker
- The Institute of Cancer Research, Cancer Research UK Centre for Cell and Molecular Biology, 237 Fulham Road, London SW3 6JB, United Kingdom
| | - Richard Marais
- The Institute of Cancer Research, Cancer Research UK Centre for Cell and Molecular Biology, 237 Fulham Road, London SW3 6JB, United Kingdom
| | - Caroline J. Springer
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
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Rossi ML, Ghosh AK, Bohr VA. Roles of Werner syndrome protein in protection of genome integrity. DNA Repair (Amst) 2010; 9:331-44. [PMID: 20075015 DOI: 10.1016/j.dnarep.2009.12.011] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Werner syndrome protein (WRN) is one of a family of five human RecQ helicases implicated in the maintenance of genome stability. The conserved RecQ family also includes RecQ1, Bloom syndrome protein (BLM), RecQ4, and RecQ5 in humans, as well as Sgs1 in Saccharomyces cerevisiae, Rqh1 in Schizosaccharomyces pombe, and homologs in Caenorhabditis elegans, Xenopus laevis, and Drosophila melanogaster. Defects in three of the RecQ helicases, RecQ4, BLM, and WRN, cause human pathologies linked with cancer predisposition and premature aging. Mutations in the WRN gene are the causative factor of Werner syndrome (WS). WRN is one of the best characterized of the RecQ helicases and is known to have roles in DNA replication and repair, transcription, and telomere maintenance. Studies both in vitro and in vivo indicate that the roles of WRN in a variety of DNA processes are mediated by post-translational modifications, as well as several important protein-protein interactions. In this work, we will summarize some of the early studies on the cellular roles of WRN and highlight the recent findings that shed some light on the link between the protein with its cellular functions and the disease pathology.
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Affiliation(s)
- Marie L Rossi
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD 21224, USA
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37
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Abstract
Currently, around 11 million people are living with a tumour that contains an inactivating mutation of TP53 (the human gene that encodes p53) and another 11 million have tumours in which the p53 pathway is partially abrogated through the inactivation of other signalling or effector components. The p53 pathway is therefore a prime target for new cancer drug development, and several original approaches to drug discovery that could have wide applications to drug development are being used. In one approach, molecules that activate p53 by blocking protein-protein interactions with MDM2 are in early clinical development. Remarkable progress has also been made in the development of p53-binding molecules that can rescue the function of certain p53 mutants. Finally, cell-based assays are being used to discover compounds that exploit the p53 pathway by either seeking targets and compounds that show synthetic lethality with TP53 mutations or by looking for non-genotoxic activators of the p53 response.
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Ding SL, Shen CY. Model of human aging: recent findings on Werner's and Hutchinson-Gilford progeria syndromes. Clin Interv Aging 2008; 3:431-44. [PMID: 18982914 PMCID: PMC2682376 DOI: 10.2147/cia.s1957] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The molecular mechanisms involved in human aging are complicated. Two progeria syndromes, Werner's syndrome (WS) and Hutchinson-Gilford progeria syndrome (HGPS), characterized by clinical features mimicking physiological aging at an early age, provide insights into the mechanisms of natural aging. Based on recent findings on WS and HGPS, we suggest a model of human aging. Human aging can be triggered by two main mechanisms, telomere shortening and DNA damage. In telomere-dependent aging, telomere shortening and dysfunction may lead to DNA damage responses which induce cellular senescence. In DNA damage-initiated aging, DNA damage accumulates, along with DNA repair deficiencies, resulting in genomic instability and accelerated cellular senescence. In addition, aging due to both mechanisms (DNA damage and telomere shortening) is strongly dependent on p53 status. These two mechanisms can also act cooperatively to increase the overall level ofgenomic instability, triggering the onset of human aging phenotypes.
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Affiliation(s)
- Shian-Ling Ding
- Department of Nursing, Kang-Ning Junior College of Medical Care and Management,Taipei,Taiwan.
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Christmann M, Tomicic MT, Gestrich C, Roos WP, Bohr VA, Kaina B. WRN protects against topo I but not topo II inhibitors by preventing DNA break formation. DNA Repair (Amst) 2008; 7:1999-2009. [PMID: 18805512 DOI: 10.1016/j.dnarep.2008.08.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/15/2008] [Accepted: 08/25/2008] [Indexed: 12/24/2022]
Abstract
The Werner syndrome helicase/3'-exonuclease (WRN) is a major component of the DNA repair and replication machinery. To analyze whether WRN is involved in the repair of topoisomerase-induced DNA damage we utilized U2-OS cells, in which WRN is stably down-regulated (wrn-kd), and the corresponding wild-type cells (wrn-wt). We show that cells not expressing WRN are hypersensitive to the toxic effect of the topoisomerase I inhibitor topotecan, but not to the topoisomerase II inhibitor etoposide. This was shown by mass survival assays, colony formation and induction of apoptosis. Upon topotecan treatment WRN deficient cells showed enhanced DNA replication inhibition and S-phase arrest, whereas after treatment with etoposide they showed the same cell cycle response as the wild-type. A considerable difference between WRN and wild-type cells was observed for DNA single- and double-strand break formation in response to topotecan. Topotecan induced DNA single-strand breaks 6h after treatment. In both wrn-wt and wrn-kd cells these breaks were repaired at similar kinetics. However, in wrn-kd but not wrn-wt cells they were converted into DNA double-strand breaks (DSBs) at high frequency, as shown by neutral comet assay and phosphorylation of H2AX. Our data provide evidence that WRN is involved in the repair of topoisomerase I, but not topoisomerase II-induced DNA damage, most likely via preventing the conversion of DNA single-strand breaks into DSBs during the resolution of stalled replication forks at topo I-DNA complexes. We suggest that the WRN status of tumor cells impacts anticancer therapy with topoisomerase I, but not topoisomerase II inhibitors.
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Affiliation(s)
- Markus Christmann
- Department of Toxicology, University of Mainz, Obere Zahlbacher Strasse 67, D-55131 Mainz, Germany
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40
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Gupta R, Brosh RM. Helicases as prospective targets for anti-cancer therapy. Anticancer Agents Med Chem 2008; 8:390-401. [PMID: 18473724 DOI: 10.2174/187152008784220339] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
It has been proposed that selective inactivation of a DNA repair pathway may enhance anti-cancer therapies that eliminate cancerous cells through the cytotoxic effects of DNA damaging agents or radiation. Given the unique and critically important roles of DNA helicases in the DNA damage response, DNA repair, and maintenance of genomic stability, a number of strategies currently being explored or in use to combat cancer may be either mediated or enhanced through the modulation of helicase function. The focus of this review will be to examine the roles of helicases in DNA repair that might be suitably targeted by cancer therapeutic approaches. Treatment of cancers with anti-cancer drugs such as small molecule compounds that modulate helicase expression or function is a viable approach to selectively kill cancer cells through the inactivation of helicase-dependent DNA repair pathways, particularly those associated with DNA recombination, replication restart, and cell cycle checkpoint.
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Affiliation(s)
- Rigu Gupta
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
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41
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Li K, Casta A, Wang R, Lozada E, Fan W, Kane S, Ge Q, Gu W, Orren D, Luo J. Regulation of WRN Protein Cellular Localization and Enzymatic Activities by SIRT1-mediated Deacetylation. J Biol Chem 2008; 283:7590-8. [DOI: 10.1074/jbc.m709707200] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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42
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WRN promoter methylation possibly connects mucinous differentiation, microsatellite instability and CpG island methylator phenotype in colorectal cancer. Mod Pathol 2008; 21:150-8. [PMID: 18084250 DOI: 10.1038/modpathol.3800996] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Werner syndrome is a premature aging syndrome characterized by early onset of cancer and abnormal cellular metabolism of glycosaminoglycan. The WRN helicase plays an important role in the maintenance of telomere function. WRN promoter methylation and gene silencing are common in colorectal cancer with the CpG island methylator phenotype (CIMP), which is associated with microsatellite instability (MSI) and mucinous tumors. However, no study has examined the relationship between mucinous differentiation, WRN methylation, CIMP and MSI in colorectal cancer. Utilizing 903 population-based colorectal cancers and real-time PCR (MethyLight), we quantified DNA methylation in WRN and eight other promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1) known to be specific for CIMP. Supporting WRN as a good CIMP marker, WRN methylation was correlated well with CIMP-high diagnosis (> or =6/8 methylated promoters), demonstrating 89% sensitivity and 81% specificity. WRN methylation was associated with the presence of any mucinous component and > or =50% mucinous component (P<0.0001). Because both MSI and CIMP were associated with mucinous tumors and WRN methylation, we stratified tumors into 9 MSI/CIMP subtypes, to examine whether the relationship between WRN methylation and mucin still persisted. In each MSI/CIMP subtype, tumors with mucinous component were persistently more common in WRN-methylated tumors than WRN-unmethylated tumors (P=0.004). No relations of WRN methylation with other variables (age, sex, tumor location, poor differentiation, signet ring cells, lymphocytic reactions, KRAS, BRAF, p53, p21 or 18q loss of heterozygosity) persisted after tumors were stratified by CIMP status. In conclusion, WRN methylation is associated with mucinous differentiation independent of CIMP and MSI status. Our data suggest a possible role of WRN methylation in mucinous differentiation, and may provide explanation to the enigmatic association between mucin and MSI/CIMP.
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43
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Abstract
Genomic instability leads to mutations, cellular dysfunction and aberrant phenotypes at the tissue and organism levels. A number of mechanisms have evolved to cope with endogenous or exogenous stress to prevent chromosomal instability and maintain cellular homeostasis. DNA helicases play important roles in the DNA damage response. The RecQ family of DNA helicases is of particular interest since several human RecQ helicases are defective in diseases associated with premature aging and cancer. In this review, we will provide an update on our understanding of the specific roles of human RecQ helicases in the maintenance of genomic stability through their catalytic activities and protein interactions in various pathways of cellular nucleic acid metabolism with an emphasis on DNA replication and repair. We will also discuss the clinical features of the premature aging disorders associated with RecQ helicase deficiencies and how they relate to the molecular defects.
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Affiliation(s)
- Robert M Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
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Abstract
In the past several years, remarkable progress has been made in the understanding of the mechanisms of premature aging. These rare, genetic conditions offer valuable insights into the normal aging process and the complex biology of cardiovascular disease. Many of these advances have been made in the most dramatic of these disorders, Hutchinson–Gilford progeria syndrome. Although characterized by features of normal aging such as alopecia, skin wrinkling, and osteoporosis, patients with Hutchinson–Gilford progeria syndrome are affected by accelerated, premature arteriosclerotic disease that leads to heart attacks and strokes at a mean age of 13 years. In this review, we highlight recent advances in the biology of premature aging uncovered in Hutchinson–Gilford progeria syndrome and other accelerated aging syndromes, advances that provide insight into the mechanisms of cardiovascular diseases ranging from atherosclerosis to arrhythmias.
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Affiliation(s)
- Brian C Capell
- Genome Technology Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892-2486, USA
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45
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Abstract
Convergent studies demonstrated that p53 regulates homologous recombination (HR) independently of its classic tumour-suppressor functions in transcriptionally transactivating cellular target genes that are implicated in growth control and apoptosis. In this review, we summarise the analyses of the involvement of p53 in spontaneous and double-strand break (DSB)-triggered HR and in alternative DSB repair routes. Molecular characterisation indicated that p53 controls the fidelity of Rad51-dependent HR and represses aberrant processing of replication forks after stalling at unrepaired DNA lesions. These findings established a genome stabilising role of p53 in counteracting error-prone DSB repair. However, recent work has also unveiled a stimulatory role for p53 in topoisomerase I-induced recombinative repair events that may have implications for a gain-of-function phenotype of cancer-related p53 mutants. Additional evidence will be discussed which suggests that p53 and/or p53-regulated gene products also contribute to nucleotide excision, base excision, and mismatch repair.
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Affiliation(s)
- S A Gatz
- Universitätsklinik für Kinder- und Jugendmedizin, Eythstr. 24, 89075 Ulm, Germany
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46
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Gupta R, Sharma S, Sommers JA, Kenny MK, Cantor SB, Brosh RM. FANCJ (BACH1) helicase forms DNA damage inducible foci with replication protein A and interacts physically and functionally with the single-stranded DNA-binding protein. Blood 2007; 110:2390-8. [PMID: 17596542 PMCID: PMC1988918 DOI: 10.1182/blood-2006-11-057273] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The BRCA1 associated C-terminal helicase (BACH1, designated FANCJ) is implicated in the chromosomal instability genetic disorder Fanconi anemia (FA) and hereditary breast cancer. A critical role of FANCJ helicase may be to restart replication as a component of downstream events that occur during the repair of DNA cross-links or double-strand breaks. We investigated the potential interaction of FANCJ with replication protein A (RPA), a single-stranded DNA-binding protein implicated in both DNA replication and repair. FANCJ and RPA were shown to coimmunoprecipitate most likely through a direct interaction of FANCJ and the RPA70 subunit. Moreover, dependent on the presence of BRCA1, FANCJ colocalizes with RPA in nuclear foci after DNA damage. Our data are consistent with a model in which FANCJ associates with RPA in a DNA damage-inducible manner and through the protein interaction RPA stimulates FANCJ helicase to better unwind duplex DNA substrates. These findings identify RPA as the first regulatory partner of FANCJ. The FANCJ-RPA interaction is likely to be important for the role of the helicase to more efficiently unwind DNA repair intermediates to maintain genomic stability.
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Affiliation(s)
- Rigu Gupta
- Laboratory of Molecular Gerontology, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD 21224, USA
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47
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Sharma S, Doherty K, Brosh R. Mechanisms of RecQ helicases in pathways of DNA metabolism and maintenance of genomic stability. Biochem J 2006; 398:319-37. [PMID: 16925525 PMCID: PMC1559444 DOI: 10.1042/bj20060450] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Helicases are molecular motor proteins that couple the hydrolysis of NTP to nucleic acid unwinding. The growing number of DNA helicases implicated in human disease suggests that their vital specialized roles in cellular pathways are important for the maintenance of genome stability. In particular, mutations in genes of the RecQ family of DNA helicases result in chromosomal instability diseases of premature aging and/or cancer predisposition. We will discuss the mechanisms of RecQ helicases in pathways of DNA metabolism. A review of RecQ helicases from bacteria to human reveals their importance in genomic stability by their participation with other proteins to resolve DNA replication and recombination intermediates. In the light of their known catalytic activities and protein interactions, proposed models for RecQ function will be summarized with an emphasis on how this distinct class of enzymes functions in chromosomal stability maintenance and prevention of human disease and cancer.
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Affiliation(s)
- Sudha Sharma
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, U.S.A
| | - Kevin M. Doherty
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, U.S.A
| | - Robert M. Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, U.S.A
- To whom correspondence should be addressed (email )
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Abstract
Werner syndrome (WS) is a segmental progeroid syndrome in which patients display pleiotropic features of aging seen in the normal population. The advent of positional cloning in the 1990s markedly accelerated the identification of human disease-causing genes. In 1996, mutations in WRN, which was shown to encode a new, putative member of the family of RecQ DNA helicases, were identified in four patients as the cause of WS. Ten years after the identification of WRN, what have we learned about its role in WS, and its contribution to normal aging?
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Affiliation(s)
- Fuki M Hisama
- Department of Neurology, Yale University, New Haven, CT 06520, USA.
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49
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Huang S, Lee L, Hanson NB, Lenaerts C, Hoehn H, Poot M, Rubin CD, Chen DF, Yang CC, Juch H, Dorn T, Spiegel R, Oral EA, Abid M, Battisti C, Lucci-Cordisco E, Neri G, Steed EH, Kidd A, Isley W, Showalter D, Vittone JL, Konstantinow A, Ring J, Meyer P, Wenger SL, von Herbay A, Wollina U, Schuelke M, Huizenga CR, Leistritz DF, Martin GM, Mian IS, Oshima J. The spectrum of WRN mutations in Werner syndrome patients. Hum Mutat 2006; 27:558-67. [PMID: 16673358 PMCID: PMC1868417 DOI: 10.1002/humu.20337] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The International Registry of Werner syndrome (www.wernersyndrome.org) has been providing molecular diagnosis of the Werner syndrome (WS) for the past decade. The present communication summarizes, from among 99 WS subjects, the spectrum of 50 distinct mutations discovered by our group and by others since the WRN gene (also called RECQL2 or REQ3) was first cloned in 1996; 25 of these have not previously been published. All WRN mutations reported thus far have resulted in the elimination of the nuclear localization signal at the C-terminus of the protein, precluding functional interactions in the nucleus; thus, all could be classified as null mutations. We now report two new mutations in the N-terminus that result in instability of the WRN protein. Clinical data confirm that the most penetrant phenotype is bilateral ocular cataracts. Other cardinal signs were seen in more than 95% of the cases. The median age of death, previously reported to be in the range of 46-48 years, is 54 years. Lymphoblastoid cell lines (LCLs) have been cryopreserved from the majority of our index cases, including material from nuclear pedigrees. These, as well as inducible and complemented hTERT (catalytic subunit of human telomerase) immortalized skin fibroblast cell lines are available to qualified investigators.
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Affiliation(s)
- Shurong Huang
- Department of Pathology, University of Washington, Seattle, Washington 98195-7470, USA
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50
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Guay D, Gaudreault I, Massip L, Lebel M. Formation of a nuclear complex containing the p53 tumor suppressor, YB-1, and the Werner syndrome gene product in cells treated with UV light. Int J Biochem Cell Biol 2006; 38:1300-13. [PMID: 16584908 DOI: 10.1016/j.biocel.2006.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 12/23/2005] [Accepted: 01/16/2006] [Indexed: 12/27/2022]
Abstract
YB-1 is a multifunctional protein involved in the regulation of transcription, translation, and mRNA splicing. In recent years, several laboratories have demonstrated that YB-1 is also directly involved in the cellular response to genotoxic stress. Accordingly, one report has indicated that the Werner syndrome gene product (WRN) is eluted from an YB-1 affinity chromatography column. Werner syndrome is a rare disorder characterized by the premature onset of a number of age-related diseases, including cancer. The gene responsible for Werner syndrome encodes a DNA helicase/exonuclease protein believed to be involved in some aspect of DNA repair with p53. In this study, we demonstrate that the tumor suppressor, p53, bridges the WRN and YB-1 proteins in vitro. Microscopic analyses of fluorescent-tagged proteins and co-immunoprecipitation experiments confirmed the formation of an YB-1/p53/WRN complex in human cells, but only after treatment with UV light. We also confirmed that p53 is a major player in the translocation of GFP-YB-1 fusion proteins from the cytoplasm to several nuclear foci containing WRN proteins upon UV irradiation. Such translocation did not occur in cells treated with the topoisomerase inhibitor, etoposide, or the radiomimetic drug, bleomycin. Such results suggest that an YB-1/p53/WRN complex is formed in response to the emergence of specific DNA lesions in cells.
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Affiliation(s)
- David Guay
- Centre de Recherche en Cancérologie de l'Université Laval, Hôpital Hôtel-Dieu de Québec, Centre Hospitalier Universitaire de Québec, 9 McMahon St, Que., Canada G1R 2J6
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