101
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P53 and Sirt1: routes of metabolism and genome stability. Biochem Pharmacol 2014; 92:149-56. [PMID: 25218422 DOI: 10.1016/j.bcp.2014.08.034] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 12/14/2022]
Abstract
The tumor suppressor p53 is a transcription factor that regulates key processes. But, the outcomes of the p53 response go beyond its role as a nuclear transcription factor. Sirtuin (SIRT1) regulates p53 functions as transcription factor. At the same time, SIRT1 protects the genome under stress conditions. The link between p53 and SIRT1 responses is unique. Both regulate metabolism, stress signaling, cell survival, cell cycle control and genome stability. Recent studies have proposed cancer as a metabolic disease. This is due to the switch from aerobic to anaerobic metabolism during tumor development. Yet, the complex molecular circuits (in and out of the nucleus) of tumor progression remain elusive. In this review, we will focus on the interplay between p53 and SIRT1. We will discuss their roles as nodes for possible therapeutic intervention.
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102
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Maksin-Matveev A, Kanfi Y, Hochhauser E, Isak A, Cohen HY, Shainberg A. Sirtuin 6 protects the heart from hypoxic damage. Exp Cell Res 2014; 330:81-90. [PMID: 25066211 DOI: 10.1016/j.yexcr.2014.07.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/09/2014] [Accepted: 07/11/2014] [Indexed: 12/01/2022]
Abstract
Sirtuin 6 (SIRT6) is a protein associated with prolonged life expectancy. We investigated whether life extension is associated with cardioprotection against hypoxia. The proposed study is to develop approaches to reduce hypoxic damage through the use of the sirtuin pathway and to elucidate the mechanism involved. For that purpose we subjected cardiomyocytes from transgenic mice (TG) with over-expression of SIRT6, to hypoxic stress in cell cultures. We hypothesized that cardiomyocytes from transgenic mice subjected to prolonged hypoxia may release survival factors or fewer damage markers to protect them from hypoxic stress compared with wild type (WT) mice. Lactate dehydrogenase (LDH) and creatine kinase (CK) released to the medium and propidium iodide (PI) binding, were markedly decreased following hypoxia in TG cardiomyocytes. The protective mechanism of SIRT6 over-expression includes the activation of pAMPKα pathway, the increased protein level of B-cell lymphoma 2 (Bcl2), the inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), the decrease of reactive oxygen species (ROS) and the reduction in the protein level of phospho-protein kinase B (pAkt) during hypoxia. Together, all these processes impede the necrosis/apoptosis pathways leading to the improved survival of cardiomyocytes following hypoxia, which might explain life extension.
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Affiliation(s)
- Anna Maksin-Matveev
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Yariv Kanfi
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Edith Hochhauser
- The Laboratory of the Department of Cardiothoracic Surgery, Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva, Israel
| | - Ahuva Isak
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Haim Y Cohen
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Asher Shainberg
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel.
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103
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Guan D, Lim JH, Peng L, Liu Y, Lam M, Seto E, Kao HY. Deacetylation of the tumor suppressor protein PML regulates hydrogen peroxide-induced cell death. Cell Death Dis 2014; 5:e1340. [PMID: 25032863 PMCID: PMC4123062 DOI: 10.1038/cddis.2014.185] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/18/2014] [Accepted: 03/26/2014] [Indexed: 12/29/2022]
Abstract
The promyelocytic leukemia protein (PML) is a tumor suppressor that is expressed at a low level in various cancers. Although post-translational modifications including SUMOylation, phosphorylation, and ubiquitination have been found to regulate the stability or activity of PML, little is known about the role of its acetylation in the control of cell survival. Here we demonstrate that acetylation of lysine 487 (K487) and SUMO1 conjugation of K490 at PML protein are mutually exclusive. We found that hydrogen peroxide (H2O2) promotes PML deacetylation and identified SIRT1 and SIRT5 as PML deacetylases. Both SIRT1 and SIRT5 are required for H2O2-mediated deacetylation of PML and accumulation of nuclear PML protein in HeLa cells. Knockdown of SIRT1 reduces the number of H2O2-induced PML-nuclear bodies (NBs) and increases the survival of HeLa cells. Ectopic expression of wild-type PML but not the K487R mutant rescues H2O2-induced cell death in SIRT1 knockdown cells. Furthermore, ectopic expression of wild-type SIRT5 but not a catalytic defective mutant can also restore H2O2-induced cell death in SIRT1 knockdown cells. Taken together, our findings reveal a novel regulatory mechanism in which SIRT1/SIRT5-mediated PML deacetylation plays a role in the regulation of cancer cell survival.
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Affiliation(s)
- D Guan
- Department of Biochemistry, School of Medicine, Case Western Reserve University, and Comprehensive Cancer Center of Case Western Reserve University, Cleveland, OH, USA
| | - J H Lim
- Department of Biochemistry, School of Medicine, Case Western Reserve University, and Comprehensive Cancer Center of Case Western Reserve University, Cleveland, OH, USA
| | - L Peng
- H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Y Liu
- Department of Biochemistry, School of Medicine, Case Western Reserve University, and Comprehensive Cancer Center of Case Western Reserve University, Cleveland, OH, USA
| | - M Lam
- Department of Dermatology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH, USA
| | - E Seto
- H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - H-Y Kao
- Department of Biochemistry, School of Medicine, Case Western Reserve University, and Comprehensive Cancer Center of Case Western Reserve University, Cleveland, OH, USA
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104
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Abstract
The integrity of our genetic material is under constant attack from numerous endogenous and exogenous agents. The consequences of a defective DNA damage response are well studied in proliferating cells, especially with regards to the development of cancer, yet its precise roles in the nervous system are relatively poorly understood. Here we attempt to provide a comprehensive overview of the consequences of genomic instability in the nervous system. We highlight the neuropathology of congenital syndromes that result from mutations in DNA repair factors and underscore the importance of the DNA damage response in neural development. In addition, we describe the findings of recent studies, which reveal that a robust DNA damage response is also intimately connected to aging and the manifestation of age-related neurodegenerative disorders such as Alzheimer's disease and amyotrophic lateral sclerosis.
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Affiliation(s)
- Ram Madabhushi
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ling Pan
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Li-Huei Tsai
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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105
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Choi JE, Mostoslavsky R. Sirtuins, metabolism, and DNA repair. Curr Opin Genet Dev 2014; 26:24-32. [PMID: 25005742 DOI: 10.1016/j.gde.2014.05.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/11/2014] [Accepted: 05/26/2014] [Indexed: 12/24/2022]
Abstract
Cells evolve to actively coordinate nutrient availability with cellular activity in order to maintain metabolic homeostasis. In addition, active pathways to repair DNA damage are crucial to avoid deleterious genomic instability. In recent years, it has become increasingly clear that availability of intermediate metabolites may play an important role in DNA repair, suggesting that these two seemingly distant cellular activities may be highly coordinated. The sirtuin family of proteins now described as deacylases (they can also remove acyl groups other than acetyl moieties), it appears to have evolved to control both metabolism and DNA repair. In this review, we discuss recent advances that lay the foundation to understanding the role of sirtuins in these two biological processes, and the potential crosstalk to coordinate them.
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Affiliation(s)
- Jee-Eun Choi
- Biological and Biomedical Sciences Graduate Program, Harvard Medical School, Boston, MA 02115, USA; The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Raul Mostoslavsky
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA.
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106
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Li Z, Zhu WG. Targeting histone deacetylases for cancer therapy: from molecular mechanisms to clinical implications. Int J Biol Sci 2014; 10:757-70. [PMID: 25013383 PMCID: PMC4081609 DOI: 10.7150/ijbs.9067] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 04/02/2014] [Indexed: 12/19/2022] Open
Abstract
Genetic abnormalities have been conventionally considered as hallmarks of cancer. However, studies over the past decades have demonstrated that epigenetic regulation also participates in the development of cancer. The fundamental patterns of epigenetic components, such as DNA methylation and histone modifications, are frequently altered in tumor cells. Acetylation is one of the best characterized modifications of histones, which is controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDACs are a group of enzymes which catalyze the removal of the acetyl groups of both histones and non-histone proteins. HDACs are involved in modulating most key cellular processes, including transcriptional regulation, apoptosis, DNA damage repair, cell cycle control, autophagy, metabolism, senescence and chaperone function. Because HDACs have been found to function incorrectly in cancer, various HDAC inhibitors are being investigated to act as cancer chemotherapeutics. The primary purpose of this paper is to summarize recent studies of the links between HDACs and cancer, and further discuss the underlying mechanisms of anti-tumor activities of HDAC inhibitors and clinical implications.
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Affiliation(s)
- Zhiming Li
- 1. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100191, China. ; 2. Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, 100191, China
| | - Wei-Guo Zhu
- 1. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100191, China. ; 2. Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, 100191, China. ; 3. Peking-Tsinghua University Center for Life Sciences, Peking University, Beijing 100871, China
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107
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Ureshino RP, Rocha KK, Lopes GS, Bincoletto C, Smaili SS. Calcium signaling alterations, oxidative stress, and autophagy in aging. Antioxid Redox Signal 2014; 21:123-37. [PMID: 24512092 DOI: 10.1089/ars.2013.5777] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
SIGNIFICANCE Aging is a multi-factorial process that may be associated with several functional and structural deficits which can evolve into degenerative diseases. In this review, we present data that may depict an expanded view of molecular aging theories, beginning with the idea that reactive oxygen species (ROS) are the major effectors in this process. In addition, we have correlated the importance of autophagy as a neuroprotective mechanism and discussed a link between age-related molecules, Ca(2+) signaling, and oxidative stress. RECENT ADVANCES There is evidence suggesting that alterations in Ca(2+) homeostasis, including mitochondrial Ca(2+) overload and alterations in electron transport chain (ETC) complexes, which increase cell vulnerability, are linked to oxidative stress in aging. As much as Ca(2+) signaling is altered in aged cells, excess ROS can be produced due to an ineffective coupling of mitochondrial respiration. Damaged mitochondria might not be removed by the macroautophagic system, which is hampered in aging by lipofuscin accumulation, boosting ROS generation, damaging DNA, and, ultimately, leading to apoptosis. CRITICAL ISSUES This process can lead to altered protein expression (such as p53, Sirt1, and IGF-1) and progress to cell death. This cycle can lead to increased cell vulnerability in aging and contribute to an increased susceptibility to degenerative processes. FUTURE DIRECTIONS A better understanding of Ca(2+) signaling and molecular aging alterations is important for preventing apoptosis in age-related diseases. In addition, caloric restriction, resveratrol and autophagy modulation appear to be predominantly cytoprotective, and further studies of this process are promising in age-related disease therapeutics.
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108
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Hwang BJ, Madabushi A, Jin J, Lin SYS, Lu AL. Histone/protein deacetylase SIRT1 is an anticancer therapeutic target. Am J Cancer Res 2014; 4:211-221. [PMID: 24959376 PMCID: PMC4065402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 04/23/2014] [Indexed: 06/03/2023] Open
Abstract
SIRT1, a member of the NAD(+)-dependent histone/protein deacetylase family, is involved in chromatin remodeling, DNA repair, and stress response and is a potential drug target. 5-fluorouracil (FU) and the SN1-type DNA methylating agent temozolomide (TMZ) are anticancer agents. In this study, we demonstrate that sirt1 knockout mouse embryonic fibroblast cells are more sensitive to FU and DNA methylating agents than normal cells. Based on these findings, the chemotherapy efficacy of SIRT1 inhibitors in combination with FU or TMZ were tested with human breast cancer cells. We found that treatments combining SIRT1 inhibitors with FU or TMZ show synergistic reduction of cell viability and colony formation of breast cancer cells. Thus, inhibition of SIRT1 activity provides a novel anticancer strategy.
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Affiliation(s)
- Bor-Jang Hwang
- Department of Biochemistry and Molecular Biology, University of Maryland School of MedicineBaltimore, MD 21201, USA
| | - Amrita Madabushi
- Department of Biochemistry and Molecular Biology, University of Maryland School of MedicineBaltimore, MD 21201, USA
- Current address: Department of Natural & Physical Sciences, Life Sciences Institute; Baltimore City Community CollegeBaltimore, MD 21201
| | - Jin Jin
- Department of Biochemistry and Molecular Biology, University of Maryland School of MedicineBaltimore, MD 21201, USA
| | - Shiou-Yuh S Lin
- Department of Biochemistry and Molecular Biology, University of Maryland School of MedicineBaltimore, MD 21201, USA
| | - A-Lien Lu
- Department of Biochemistry and Molecular Biology, University of Maryland School of MedicineBaltimore, MD 21201, USA
- University of Maryland Greenebaum Cancer CenterBaltimore, MD 21201, USA
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109
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Abstract
SIRT1 is an important regulator of cellular stress response and genomic integrity. Its role in tumorigenesis is controversial. Whereas sirtuin 1 (SIRT1) can act as a tumor suppressor in some solid tumors, increased expression has been demonstrated in many cancers, including hematologic malignancies. In chronic myeloid leukemia, SIRT1 promoted leukemia development, and targeting SIRT1 sensitized chronic myeloid leukemia progenitors to tyrosine kinase inhibitor treatment. In this study, we investigated the role of SIRT1 in acute myeloid leukemia (AML). We show that SIRT1 protein, but not RNA levels, is overexpressed in AML samples harboring activating mutations in signaling pathways. In FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD)(+)-cells protein, expression of SIRT1 is regulated by FLT3 kinase activity. In addition, SIRT1 function is modulated via the ATM-DBC1-SIRT1 axis in a FLT3-ITD-dependent manner. In murine leukemia models driven by MLL-AF9 or AML1-ETO coexpressing FLT3-ITD, SIRT1 acts as a safeguard to counteract oncogene-induced stress, and leukemic blasts become dependent on SIRT1 activity. Pharmacologic targeting or RNAi-mediated knockdown of SIRT1 inhibited cell growth and sensitized AML cells to tyrosine kinase inhibitor treatment and chemotherapy. This effect was a result of the restoration of p53 activity. Our data suggest that targeting SIRT1 represents an attractive therapeutic strategy to overcome primary resistance in defined subsets of patients with AML.
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110
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Productive replication of human papillomavirus 31 requires DNA repair factor Nbs1. J Virol 2014; 88:8528-44. [PMID: 24850735 DOI: 10.1128/jvi.00517-14] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Activation of the ATM (ataxia telangiectasia-mutated kinase)-dependent DNA damage response (DDR) is necessary for productive replication of human papillomavirus 31 (HPV31). We previously found that DNA repair and homologous recombination (HR) factors localize to sites of HPV replication, suggesting that ATM activity is required to recruit factors to viral genomes that can productively replicate viral DNA in a recombination-dependent manner. The Mre11-Rad50-Nbs1 (MRN) complex is an essential component of the DDR that is necessary for ATM-mediated HR repair and localizes to HPV DNA foci. In this study, we demonstrate that the HPV E7 protein is sufficient to increase levels of the MRN complex and also interacts with MRN components. We have found that Nbs1 depletion blocks productive viral replication and results in decreased localization of Mre11, Rad50, and the principal HR factor Rad51 to HPV DNA foci upon differentiation. Nbs1 contributes to the DDR by acting as an upstream activator of ATM in response to double-strand DNA breaks (DSBs) and as a downstream effector of ATM activity in the intra-S-phase checkpoint. We have found that phosphorylation of ATM and its downstream target Chk2, as well as SMC1 (structural maintenance of chromosome 1), is maintained upon Nbs1 knockdown in differentiating cells. Given that ATM and Chk2 are required for productive replication, our results suggest that Nbs1 contributes to viral replication outside its role as an ATM activator, potentially through ensuring localization of DNA repair factors to viral genomes that are necessary for efficient productive replication. IMPORTANCE The mechanisms that regulate human papillomavirus (HPV) replication during the viral life cycle are not well understood. Our finding that Nbs1 is necessary for productive replication even in the presence of ATM (ataxia telangiectasia-mutated kinase) and Chk2 phosphorylation offers evidence that Nbs1 contributes to viral replication downstream of facilitating ATM activation. Nbs1 is required for the recruitment of Mre11 and Rad50 to viral genomes, suggesting that the MRN complex plays a direct role in facilitating productive viral replication, potentially through the processing of substrates that are recognized by the key homologous recombination (HR) factor Rad51. The discovery that E7 increases levels of MRN components, and MRN complex formation, identifies a novel role for E7 in facilitating productive replication. Our study not only identifies DNA repair factors necessary for HPV replication but also provides a deeper understanding of how HPV utilizes the DNA damage response to regulate viral replication.
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111
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Reversible acetylation of Lin28 mediated by PCAF and SIRT1. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1188-95. [PMID: 24631505 DOI: 10.1016/j.bbamcr.2014.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 02/27/2014] [Accepted: 03/01/2014] [Indexed: 02/06/2023]
Abstract
Lin28 is a small RNA-binding protein that plays an important role in regulating developmental timing, stem cell reprogramming, and oncogenesis. However, the significance of the effect of post-translational modifications on Lin28 activity is not fully understood. In this study, we demonstrated that PCAF directly interacted with and acetylated Lin28. We also showed that the acetylation of Lin28 can be specifically reversed by the deacetylase SIRT1. These findings suggest that the PCAF/SIRT1 balance plays an important role in regulating Lin28 activity. Furthermore, we found that the cold shock domain of Lin28 is the major target of PCAF-mediated acetylation, which leads to a severe reduction in the Lin28 protein levels and an increase in the level of mature let-7a. This study provides the first demonstration that post-translational modification regulates Lin28 activity during let-7a biogenesis and sheds light on the regulation of Lin28 in ES cells and carcinogenesis.
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112
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Histone deacetylase SIRT1 modulates and deacetylates DNA base excision repair enzyme thymine DNA glycosylase. Biochem J 2013; 456:89-98. [PMID: 23952905 DOI: 10.1042/bj20130670] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
TDG (thymine DNA glycosylase) is an essential multifunctional enzyme involved in DNA base excision repair, DNA demethylation and transcription regulation. TDG is the predominant enzyme that removes thymine from T/G mispair, which arises due to deamination of 5-methyl-cytosine at the CpG dinucleotide, thereby preventing C to T mutations. SIRT1 is a member of class III NAD+-dependent histone/protein deacetylases. In the present study, we demonstrate that SIRT1 interacts with residues 67-110 of hTDG (human TDG). In addition, SIRT1 enhances TDG glycosylase activity and deacetylates acetylated TDG. TDG acetylation weakens its interaction with SIRT1. Although acetylated TDG has reduced glycosylase activity towards T/G, 5-formylcytosine/G and 5-carboxylcytosine/G, it has a stronger activity towards a 5-fluorouracil/G substrate as compared with unmodified TDG. SIRT1 weakly stimulates acetylated hTDG activity towards T/G, 5-formylcytosine/G and 5-carboxylcytosine/G as compared with control hTDG. Sirt1-knockout mouse embryonic fibroblast cells have higher levels of TDG expression and acetylation. The physical and functional interactions between SIRT1 and TDG may mediate DNA repair, gene expression and FU (5-fluorouracil)-mediated cytotoxicity.
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113
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Luna A, Aladjem MI, Kohn KW. SIRT1/PARP1 crosstalk: connecting DNA damage and metabolism. Genome Integr 2013; 4:6. [PMID: 24360018 PMCID: PMC3898398 DOI: 10.1186/2041-9414-4-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 12/02/2013] [Indexed: 12/20/2022] Open
Abstract
An intricate network regulates the activities of SIRT1 and PARP1 proteins and continues to be uncovered. Both SIRT1 and PARP1 share a common co-factor nicotinamide adenine dinucleotide (NAD+) and several common substrates, including regulators of DNA damage response and circadian rhythms. We review this complex network using an interactive Molecular Interaction Map (MIM) to explore the interplay between these two proteins. Here we discuss how NAD + competition and post-transcriptional/translational feedback mechanisms create a regulatory network sensitive to environmental cues, such as genotoxic stress and metabolic states, and examine the role of those interactions in DNA repair and ultimately, cell fate decisions.
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Affiliation(s)
- Augustin Luna
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
- Bioinformatics Program, Boston University, Boston, MA 02215, USA
| | - Mirit I Aladjem
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Kurt W Kohn
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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114
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Werner syndrome: association of premature aging and cancer predisposition. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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115
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Woo SR, Byun JG, Kim YH, Park ER, Joo HY, Yun M, Shin HJ, Kim SH, Shen YN, Park JE, Park GH, Lee KH. SIRT1 suppresses cellular accumulation of β-TrCP E3 ligase via protein degradation. Biochem Biophys Res Commun 2013; 441:831-7. [PMID: 24211209 DOI: 10.1016/j.bbrc.2013.10.146] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 10/28/2013] [Indexed: 10/26/2022]
Abstract
β-Transducin repeat-containing protein (β-TrCP), an E3 ligase, promotes the degradation of substrate proteins in response to various stimuli. Even though several β-TrCP substrates have been identified to date, limited information of its upstream regulators is available. Here, we showed that SIRT1 suppresses β-TrCP protein synthesis via post-translational degradation. SIRT1 depletion led to a significant increase in the β-TrCP accumulation without affecting the mRNA level. Consistently, β-TrCP protein accumulation induced by resveratrol was further enhanced upon SIRT1 depletion. Rescue of SIRT1 reversed the effect of resveratrol, leading to reduced β-TrCP protein levels. Proteasomal inhibition led to recovery of β-TrCP in cells with SIRT1 overexpression. Notably, the recovered β-TrCP colocalized mostly with SIRT1. Thus, SIRT1 acts as a negative regulator of β-TrCP synthesis via promoting protein degradation.
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Affiliation(s)
- Seon Rang Woo
- Division of Radiation Cancer Research, Korea Institute of Radiological & Medical Sciences, Seoul 139-706, Republic of Korea
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116
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Chu YL, Wu X, Xu J, Watts JL, Her C. DNA damage induced MutS homologue hMSH4 acetylation. Int J Mol Sci 2013; 14:20966-82. [PMID: 24145748 PMCID: PMC3821653 DOI: 10.3390/ijms141020966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/16/2013] [Accepted: 10/08/2013] [Indexed: 11/24/2022] Open
Abstract
Acetylation of non-histone proteins is increasingly recognized as an important post-translational modification for controlling the actions of various cellular processes including DNA repair and damage response. Here, we report that the human MutS homologue hMSH4 undergoes acetylation following DNA damage induced by ionizing radiation (IR). To determine which acetyltransferases are responsible for hMSH4 acetylation in response to DNA damage, potential interactions of hMSH4 with hTip60, hGCN5, and hMof were analyzed. The results of these experiments indicate that only hMof interacts with hMSH4 in a DNA damage-dependent manner. Intriguingly, the interplay between hMSH4 and hMof manipulates the outcomes of nonhomologous end joining (NHEJ)-mediated DNA double strand break (DSB) repair and thereby controls cell survival in response to IR. This study also shows that hMSH4 interacts with HDAC3, by which HDAC3 negatively regulates the levels of hMSH4 acetylation. Interestingly, elevated levels of HDAC3 correlate with increased NHEJ-mediated DSB repair, suggesting that hMSH4 acetylation per se may not directly affect the role of hMSH4 in DSB repair.
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Affiliation(s)
- Yen-Lin Chu
- School of Molecular Biosciences, Mail Drop 64-7520, Washington State University, Pullman, WA 99164-7520, USA.
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117
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Abstract
The NAD(+)-dependent deacetylase SirT1 regulates gene silencing and genomic stability in response to nutrient deprivation and DNA damage. An important regulator of SirT1 in mammalian cells is DBC1 (deleted in breast cancer 1; KIAA1967 or CCAR2), which binds to SirT1 and inhibits the deacetylation of substrates. Recent studies have revealed that ATM/ATR-mediated phosphorylation of DBC1 promotes binding to SirT1. Here we show that DBC1 is modified by acetylation on two N-terminal lysine residues (K112 and K215). The MYST family histone acetyltransferase hMOF (human MOF) is responsible for DBC1 acetylation. Acetylation of K112 and K215 inhibits DBC1-SirT1 binding and increases SirT1 deacetylase activity. SirT1 also promotes DBC1 deacetylation, suggesting the presence of a negative-feedback mechanism that stabilizes the SirT1-DBC1 complex and limits SirT1 activity. hMOF binding and acetylation of DBC1 are inhibited after DNA damage in an ATM-dependent fashion, contributing to increased SirT1-DBC1 binding after DNA damage. Furthermore, a DBC1 mutant that mimics the acetylated state fails to promote apoptosis after DNA damage. These results suggest that acetylation of DBC1 inhibits binding to SirT1 and serves as a mechanism that connects DNA damage signaling to SirT1 and cell fate determination.
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118
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Yuan H, Su L, Chen WY. The emerging and diverse roles of sirtuins in cancer: a clinical perspective. Onco Targets Ther 2013; 6:1399-416. [PMID: 24133372 PMCID: PMC3797239 DOI: 10.2147/ott.s37750] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Sirtuins are a highly conserved family of nicotinamide adenine dinucleotide (NAD(+))-dependent protein lysine modifying enzymes with deacetylase, adenosine diphosphateribosyltransferase and other deacylase activities. Mammals have seven sirtuins, namely SIRT1-7. They are key regulators for a wide variety of cellular and physiological processes such as cell proliferation, differentiation, DNA damage and stress response, genome stability, cell survival, metabolism, energy homeostasis, organ development, aging, and cancer. Here we present an extensive literature review of the roles of mammalian sirtuins, particularly SIRT1 as that is the most studied sirtuin, in human epithelial, neuronal, hematopoietic, and mesenchymal malignancies, covering breast, prostate, lung, thyroid, liver, colon, gastric, pancreatic, ovarian, and cervical cancers, tumors of the central nervous system, leukemia and lymphoma, and soft tissue sarcomas. Collective evidence suggests sirtuins are involved in both promoting and suppressing tumorigenesis depending on cellular and molecular contexts. We discuss the potential use of sirtuin modulators, especially sirtuin inhibitors, in cancer treatment.
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Affiliation(s)
- Hongfeng Yuan
- Department of Cancer Biology, Beckman Research institute, City of Hope, Duarte, CA, USA
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Abstract
Sirtuins are a conserved family of deacetylases whose activities are dependent on nicotinamide adenine dinucleotide (NAD+). Sirtuins act in different cellular compartments, such as the nucleus where they deacetylate histones and transcriptional factors, in the cytoplasm where they modulate cytoskeletal and signaling molecules, and in the mitochondria where they engage components of the metabolic machinery. Collectively, they tune metabolic processes to energy availability, and modulate stress responses, protein aggregation, inflammatory processes, and genome stability. As such, they have garnered much interest and have been widely studied in aging and age-related neurodegeneration. In this chapter, we review the identification of sirtuins and their biological targets. We focus on their biological mechanisms of action and how they might be regulated, including via NAD metabolism, transcriptional and posttranscriptional control, and as targets of pharmacological agents. Lastly, we highlight the numerous studies suggesting that sirtuins are efficacious therapeutic targets in neurodegenerative disease and injury.
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Affiliation(s)
- Brett Langley
- The Burke Medical Research Institute, 785 Mamaroneck Avenue, White Plains, NY 10605 USA
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10065 USA
| | - Anthony Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10065 USA
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Abstract
Innate resistance to various therapeutic interventions is a hallmark of cancer. In recent years, acquired resistance has emerged as a daunting challenge to targeted cancer therapy, which abolishes the efficacy of otherwise successful targeting drugs. Cancer cells gain the resistance property through a variety of mechanisms in primary and metastatic cancers, involving cellular intrinsic and extrinsic factors. Increasing evidence suggests that the mammalian stress response gene sirtuin 1 (SIRT1) plays a critical role in multiple aspects of cancer drug resistance. SIRT1 decreases drug penetration, confers proliferation and antiapoptotic survival advantages to cancer cells, facilitates acquired resistance through genetic mutations, promotes the survival of cancer stem cells, and changes the tumor microenvironment for resistance in cell-autonomous and -nonautonomous manners. This article provides an overview of research advances in the roles of SIRT1 in cancer drug resistance and highlights the prospect of targeting SIRT1 as a new strategy to overcome cancer drug resistance and improve therapeutic outcomes.
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Affiliation(s)
- Zhiqiang Wang
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, CA, USA
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121
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Raynes R, Brunquell J, Westerheide SD. Stress Inducibility of SIRT1 and Its Role in Cytoprotection and Cancer. Genes Cancer 2013; 4:172-82. [PMID: 24020008 DOI: 10.1177/1947601913484497] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cells must continuously respond to stressful insults via the upregulation of cytoprotective pathways. The longevity factor and deacetylase SIRT1 plays a critical role in coordinating this cellular response to stress. SIRT1 activity and levels are regulated by cellular stressors, including metabolic, genotoxic, oxidative, and proteotoxic stress. As a stress sensor, SIRT1 impacts cell survival by deacetylating substrate proteins to drive the cell towards a cytoprotective pathway. Extreme stress conditions, however, can cause SIRT1 to lead cells down an apoptotic pathway instead. SIRT1 is frequently dysregulated in cancer cells and has been characterized to have a dual role as both an oncogene and a tumor suppressor, likely due to its pivotal function in regulating cytoprotection. Recently, the ability of SIRT1 to regulate HSF1-dependent induction of the heat shock response has highlighted another pathway through which SIRT1 can modulate cytoprotection. Activation of HSF1 results in the production of cytoprotective chaperones that can facilitate the transformed phenotype of cancer cells. In this review, we discuss the stress-dependent regulation of SIRT1. We highlight the role of SIRT1 in stress management and cytoprotection and emphasize SIRT1-dependent activation of HSF1 as a potential mechanism for cancer promotion.
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Affiliation(s)
- Rachel Raynes
- Department of Cell Biology, Microbiology and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, FL, USA
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122
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Abstract
The sirtuin family has emerged as important regulators of diverse physiological and pathological events, including life-span extension, neurodegeneration, age-related disorders, obesity, heart disease, inflammation, and cancer. In mammals, there are 7 members (SIRT1-SIRT7) in the sirtuin family, with the function of SIRT1 being extensively studied in the past decade. SIRT1 can deacetylate histones and a number of nonhistone substrates, which are involved in multiple signaling pathways. Numerous studies have suggested that SIRT1 could act as either a tumor suppressor or tumor promoter depending on its targets in specific signaling pathways or in specific cancers. This review highlights the major pathways regulated by SIRT1 involved in tumorigenesis.
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Affiliation(s)
- Zhenghong Lin
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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123
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Abstract
Sirtuins play an essential role in the cellular response to environmental stress, promoting DNA repair, telomere stability, cell cycle arrest, cellular senescence, and apoptosis. Much attention has been given to the role of sirtuins in aging and cancer development; however, less is known about their role in stem cell regulation. This review focuses in this topic and discusses the possible implications in adult stem cell aging.
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Affiliation(s)
- R M Rodriguez
- Cancer Epigenetics Laboratory, Instituto Universitario de Oncología del Principado de Asturias (IUOPA-HUCA), Universidad de Oviedo, Oviedo, Spain
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124
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McBurney MW, Clark-Knowles KV, Caron AZ, Gray DA. SIRT1 is a Highly Networked Protein That Mediates the Adaptation to Chronic Physiological Stress. Genes Cancer 2013; 4:125-34. [PMID: 24020004 DOI: 10.1177/1947601912474893] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
SIRT1 is a NAD(+)-dependent protein deacetylase that has a very large number of established protein substrates and an equally impressive list of biological functions thought to be regulated by its activity. Perhaps as notable is the remarkable number of points of conflict concerning the role of SIRT1 in biological processes. For example, evidence exists suggesting that SIRT1 is a tumor suppressor, is an oncogene, or has no effect on oncogenesis. Similarly, SIRT1 is variably reported to induce, inhibit, or have no effect on autophagy. We believe that the resolution of many conflicting results is possible by considering recent reports indicating that SIRT1 is an important hub interacting with a complex network of proteins that collectively regulate a wide variety of biological processes including cancer and autophagy. A number of the interacting proteins are themselves hubs that, like SIRT1, utilize intrinsically disordered regions for their promiscuous interactions. Many studies investigating SIRT1 function have been carried out on cell lines carrying undetermined numbers of alterations to the proteins comprising the SIRT1 network or on inbred mouse strains carrying fixed mutations affecting some of these proteins. Thus, the effects of modulating SIRT1 amount and/or activity are importantly determined by the genetic background of the cell (or the inbred strain of mice), and the effects attributed to SIRT1 are synthetic with the background of mutations and epigenetic differences between cells and organisms. Work on mice carrying alterations to the Sirt1 gene suggests that the network in which SIRT1 functions plays an important role in mediating physiological adaptation to various sources of chronic stress such as calorie restriction and calorie overload. Whether the catalytic activity of SIRT1 and the nuclear concentration of the co-factor, NAD(+), are responsible for modulating this activity remains to be determined. However, the effect of modulating SIRT1 activity must be interpreted in the context of the cell or tissue under investigation. Indeed, for SIRT1, we argue that context is everything.
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Affiliation(s)
- Michael W McBurney
- Program in Cancer Therapeutics, Ottawa Hospital Research Institute ; Department of Medicine, University of Ottawa, Ottawa, ON, Canada
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125
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Bosch-Presegué L, Vaquero A. Sirtuins in stress response: guardians of the genome. Oncogene 2013; 33:3764-75. [DOI: 10.1038/onc.2013.344] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/18/2013] [Accepted: 07/19/2013] [Indexed: 12/15/2022]
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126
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Abstract
Lysine acetylation is a common post-translational modification of histone and non-histone proteins. This process has an important function in regulating transcriptional activities and other biological processes. Although several computer programs have been developed to predict protein acetylation sites, deacetylases responsible for known or predicted acetylation sites remain unknown. In this research, Class I histone deacetylases (HDACs) substrates were manually obtained, and sequence features of deacetylation sites were analyzed. We found that three members of Class I HDACs (HDAC1, HDAC2 and HDAC3) shared similar sequence features. Therefore, a method was proposed to identify the substrates of Class I HDACs. We evaluated the efficiency of the prediction based on P-value distribution analysis and leave-one-out test. To validate the result of the prediction, we overexpressed Class I HDACs in cells and detected the acetylation levels of potential substrates. In the experiment, five of the seven predicted proteins were deacetylated by Class I HDACs. These results suggested that our method could effectively predict protein deacetylation sites. The work has been integrated to the website ASEB, which was freely available at http://cmbi.bjmu.edu.cn/huac.
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127
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SIRT2 directs the replication stress response through CDK9 deacetylation. Proc Natl Acad Sci U S A 2013; 110:13546-51. [PMID: 23898190 DOI: 10.1073/pnas.1301463110] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Sirtuin 2 (SIRT2) is a sirtuin family deacetylase that directs acetylome signaling, protects genome integrity, and is a murine tumor suppressor. We show that SIRT2 directs replication stress responses by regulating the activity of cyclin-dependent kinase 9 (CDK9), a protein required for recovery from replication arrest. SIRT2 deficiency results in replication stress sensitivity, impairment in recovery from replication arrest, spontaneous accumulation of replication protein A to foci and chromatin, and a G2/M checkpoint deficit. SIRT2 interacts with and deacetylates CDK9 at lysine 48 in response to replication stress in a manner that is partially dependent on ataxia telangiectasia and Rad3 related (ATR) but not cyclin T or K, thereby stimulating CDK9 kinase activity and promoting recovery from replication arrest. Moreover, wild-type, but not acetylated CDK9, alleviates the replication stress response impairment of SIRT2 deficiency. Collectively, our results define a function for SIRT2 in regulating checkpoint pathways that respond to replication stress through deacetylation of CDK9, providing insight into how SIRT2 maintains genome integrity and a unique mechanism by which SIRT2 may function, at least in part, as a tumor suppressor protein.
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128
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Kong S, Yeung P, Fang D. The class III histone deacetylase sirtuin 1 in immune suppression and its therapeutic potential in rheumatoid arthritis. J Genet Genomics 2013; 40:347-54. [PMID: 23876775 PMCID: PMC4007159 DOI: 10.1016/j.jgg.2013.04.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 02/18/2013] [Accepted: 04/07/2013] [Indexed: 11/27/2022]
Abstract
Rheumatoid arthritis (RA) is a chronic debilitating disease of the joints. Both the innate and adaptive immune responses participate in the development and progression of RA. While several therapeutic reagents, such as TNF-α agonists, have been successfully developed for the clinical use in the treatment of RA, more than half of the patients do not respond to anti-TNF therapy. Therefore, new therapeutic reagents are needed. Recent studies have shown that sirtuin 1 (Sirt1), a nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylase, is a critical negative regulator of both the innate and adaptive immune response in mice, and its altered functions are likely to be involved in autoimmune diseases. Small molecules that modulate Sirt1 functions are potential therapeutic reagents for autoimmune inflammatory diseases. This review highlights the role of Sirt1 in immune regulation and RA.
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Affiliation(s)
- Sinyi Kong
- Department of Pathology, Northwestern University, Feinberg School of Medicine, 303 E Chicago Ave, Chicago, IL 60612, USA
| | - Pricilla Yeung
- Department of Pathology, Northwestern University, Feinberg School of Medicine, 303 E Chicago Ave, Chicago, IL 60612, USA
| | - Deyu Fang
- Department of Pathology, Northwestern University, Feinberg School of Medicine, 303 E Chicago Ave, Chicago, IL 60612, USA
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129
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SIRT1 collaborates with ATM and HDAC1 to maintain genomic stability in neurons. Nat Neurosci 2013; 16:1008-15. [PMID: 23852118 DOI: 10.1038/nn.3460] [Citation(s) in RCA: 175] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 06/11/2013] [Indexed: 12/13/2022]
Abstract
Defects in DNA repair have been linked to cognitive decline with age and neurodegenerative disease, yet the mechanisms that protect neurons from genotoxic stress remain largely obscure. We sought to characterize the roles of the NAD(+)-dependent deacetylase SIRT1 in the neuronal response to DNA double-strand breaks (DSBs). We found that SIRT1 was rapidly recruited to DSBs in postmitotic neurons, where it showed a synergistic relationship with ataxia telangiectasia mutated (ATM). SIRT1 recruitment to breaks was ATM dependent; however, SIRT1 also stimulated ATM autophosphorylation and activity and stabilized ATM at DSB sites. After DSB induction, SIRT1 also bound the neuroprotective class I histone deacetylase HDAC1. We found that SIRT1 deacetylated HDAC1 and stimulated its enzymatic activity, which was necessary for DSB repair through the nonhomologous end-joining pathway. HDAC1 mutations that mimic a constitutively acetylated state rendered neurons more susceptible to DNA damage, whereas pharmacological SIRT1 activators that promoted HDAC1 deacetylation also reduced DNA damage in two mouse models of neurodegeneration. We propose that SIRT1 is an apical transducer of the DSB response and that SIRT1 activation offers an important therapeutic avenue in neurodegeneration.
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130
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Leko V, Park GJ, Lao U, Simon JA, Bedalov A. Enterocyte-specific inactivation of SIRT1 reduces tumor load in the APC(+/min) mouse model. PLoS One 2013; 8:e66283. [PMID: 23799088 PMCID: PMC3682947 DOI: 10.1371/journal.pone.0066283] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 05/08/2013] [Indexed: 01/15/2023] Open
Abstract
SIRT1 is a mammalian NAD(+)-dependent histone deacetylase implicated in metabolism, development, aging and tumorigenesis. Prior studies that examined the effect of enterocyte-specific overexpression and global deletion of SIRT1 on polyp formation in the intestines of APC(+/min) mice, a commonly used model for intestinal tumorigenesis, yielded conflicting results, supporting either tumor-suppressive or tumor-promoting roles for SIRT1, respectively. In order to resolve the controversy emerging from these prior in vivo studies, in the present report we examined the effect of SIRT1 deficiency confined to the intestines, avoiding the systemic perturbations such as growth retardation seen with global SIRT1 deletion. We crossed APC(+/min) mice with mice bearing enterocyte-specific inactivation of SIRT1 and examined polyp development in the progeny. We found that SIRT1-inactivation reduced total polyp surface (9.3 mm(2) vs. 23.3 mm(2), p = 0.01), average polyp size (0.24 mm(2) vs. 0.51 mm(2), p = 0.005) and the number of polyps >0.5 mm in diameter (14 vs. 23, p = 0.04), indicating that SIRT1 affects both the number and size of tumors. Additionally, tumors in SIRT1-deficient mice exhibited markedly increased numbers of cells undergoing apoptosis, suggesting that SIRT1 contributes to tumor growth by enabling survival of tumor cells. Our results indicate that SIRT1 acts as a tumor promoter in the APC(+/min) mouse model of intestinal tumorigenesis.
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Affiliation(s)
- Vid Leko
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Gemma J. Park
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Uyen Lao
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Julian A. Simon
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Antonio Bedalov
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Departments of Medicine and Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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131
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Chaudhuri AD, Yelamanchili SV, Marcondes MCG, Fox HS. Up-regulation of microRNA-142 in simian immunodeficiency virus encephalitis leads to repression of sirtuin1. FASEB J 2013; 27:3720-9. [PMID: 23752207 DOI: 10.1096/fj.13-232678] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
MicroRNA (miR)-142 is up-regulated in the brain in HIV and SIV encephalitis (SIVE). We identified the cell types where miR-142 is up-regulated and its relevant downstream target. Fluorescent in situ hybridization combined with immunofluorescent labeling revealed that miR-142-3p and -5p are expressed within hippocampal neurons and myeloid cells in SIVE. Sirtuin1 (SIRT1) was predicted as a potential miR-142 target by analysis of its 3'-UTR and bioinformatic analysis of factors linked to altered hippocampal gene expression profile in SIVE. Overexpression of pre-miR-142 in HEK293T cells led to a 3.7-fold decrease in SIRT1 protein level. Examination of the individual effects of miR-142-5p and miR-142-3p through overexpression and inhibition studies revealed that significant effects on SIRT1 occurred only with miR-142-5p. Luciferase reporter assays revealed a 2.3-fold inhibition of expression due to interaction of miR-142 with the SIRT1 3'-UTR, mutation analysis revealed that only the miR-142-5p target site was active. MiR-142 expression in primary human neurons led to a small (1.3-fold) but significant decrease in SIRT1 protein level. Furthermore, qRT-PCR revealed up-regulation of miR-142-3p (6.4-fold) and -5p (3.9-fold) and down-regulation of SIRT1 (33-fold) in macrophages/microglia from animals with SIVE. We have therefore elucidated a miR-mediated mechanism of regulation of SIRT1 expression in SIVE.
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Affiliation(s)
- Amrita Datta Chaudhuri
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
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132
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Kim W, Kim JE. Deleted in breast cancer 1 (DBC1) deficiency results in apoptosis of breast cancer cells through impaired responses to UV-induced DNA damage. Cancer Lett 2013; 333:180-6. [DOI: 10.1016/j.canlet.2013.01.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/25/2012] [Accepted: 01/16/2013] [Indexed: 01/18/2023]
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133
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KUO SHOUJEN, LIN HUIYI, CHIEN SUYU, CHEN DARREN. SIRT1 suppresses breast cancer growth through downregulation of the Bcl-2 protein. Oncol Rep 2013; 30:125-30. [DOI: 10.3892/or.2013.2470] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Accepted: 03/06/2013] [Indexed: 11/05/2022] Open
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134
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Abstract
Histone deacetylase inhibitors (HDACis) increase gene expression through induction of histone acetylation. However, it remains unclear whether specific gene expression changes determine the apoptotic response following HDACis administration. Herein, we discuss evidence that HDACis trigger in cancer and leukemia cells not only widespread histone acetylation but also actual increases in reactive oxygen species (ROS) and DNA damage that are further increased following treatment with DNA-damaging chemotherapies. While the origins of ROS production are not completely understood, mechanisms, including inflammation and altered antioxidant signaling, have been reported. While the generation of ROS is an explanation, at least in part, for the source of DNA damage observed with HDACi treatment, DNA damage can also be independently induced by changes in the DNA repair activity and chromatin remodeling factors. Recent development of sirtuin inhibitors (SIRTis) has shown that, similar to HDACis, these drugs induce increases in ROS and DNA damage used singly, or in combination with HDACis and other drugs. Thus, induction of apoptosis by HDACis/SIRTis may result through oxidative stress and DNA damage mechanisms in addition to direct activation of apoptosis-inducing genes. Nevertheless, while DNA damage and stress responses could be of interest as markers for clinical responses, they have yet to be validated as markers for responses to HDACi treatment in clinical trials, alone, and in combination.
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Affiliation(s)
- Carine Robert
- Department of Radiation Oncology and Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
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135
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Fatoba ST, Tognetti S, Berto M, Leo E, Mulvey CM, Godovac-Zimmermann J, Pommier Y, Okorokov AL. Human SIRT1 regulates DNA binding and stability of the Mcm10 DNA replication factor via deacetylation. Nucleic Acids Res 2013; 41:4065-79. [PMID: 23449222 PMCID: PMC3627603 DOI: 10.1093/nar/gkt131] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The eukaryotic DNA replication initiation factor Mcm10 is essential for both replisome assembly and function. Human Mcm10 has two DNA-binding domains, the conserved internal domain (ID) and the C-terminal domain (CTD), which is specific to metazoans. SIRT1 is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase that belongs to the sirtuin family. It is conserved from yeast to human and participates in cellular controls of metabolism, longevity, gene expression and genomic stability. Here we report that human Mcm10 is an acetylated protein regulated by SIRT1, which binds and deacetylates Mcm10 both in vivo and in vitro, and modulates Mcm10 stability and ability to bind DNA. Mcm10 and SIRT1 appear to act synergistically for DNA replication fork initiation. Furthermore, we show that the two DNA-binding domains of Mcm10 are modulated in distinct fashion by acetylation/deacetylation, suggesting an integrated regulation mechanism. Overall, our study highlights the importance of protein acetylation for DNA replication initiation and progression, and suggests that SIRT1 may mediate a crosstalk between cellular circuits controlling metabolism and DNA synthesis.
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Affiliation(s)
- Samuel T Fatoba
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
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136
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Serravallo M, Jagdeo J, Glick SA, Siegel DM, Brody NI. Sirtuins in dermatology: applications for future research and therapeutics. Arch Dermatol Res 2013; 305:269-82. [PMID: 23377138 DOI: 10.1007/s00403-013-1320-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 01/13/2013] [Accepted: 01/21/2013] [Indexed: 12/31/2022]
Abstract
Sirtuins are a family of seven proteins in humans (SIRT1-SIRT7) that are involved in multiple cellular processes relevant to dermatology. The role of sirtuins in other organ systems is established. However, the importance of these proteins in dermatology is less defined. Recently, sirtuins gained international attention because of their role as "longevity proteins" that may extend and enhance human life. Sirtuins function in the cell via histone deacetylase and/or adenosine diphosphate ribosyltransferase enzymatic activity that target histone and non-histone substrates, including transcription regulators, tumor suppressors, structural proteins, DNA repair proteins, cell signaling proteins, transport proteins, and enzymes. Sirtuins are involved in cellular pathways related to skin structure and function, including aging, ultraviolet-induced photoaging, inflammation, epigenetics, cancer, and a variety of cellular functions including cell cycle, DNA repair and proliferation. This review highlights sirtuin-related cellular pathways, therapeutics and pharmacological targets in atopic dermatitis, bullous dermatoses, collagen vascular disorders, psoriasis, systemic lupus erythematosus, hypertrophic and keloid scars, cutaneous infections, and non-melanoma and melanoma skin cancer. Also discussed is the role of sirtuins in the following genodermatoses: ataxia telangiectasia, Cowden's syndrome, dyskeratosis congenita, Rubenstein-Taybi, Werner syndrome, and xeroderma pigmentosum. The pathophysiology of these inherited diseases is not well understood, and sirtuin-related processes represent potential therapeutic targets for diseases lacking suitable alternative treatments. The goal of this review is to bring attention to the dermatology community, physicians, and scientists, the importance of sirtuins in dermatology and provide a foundation and impetus for future discussion, research and pharmacologic discovery.
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Affiliation(s)
- Melissa Serravallo
- Department of Dermatology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
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137
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Integration of the metabolic/redox state, histone gene switching, DNA replication and S-phase progression by moonlighting metabolic enzymes. Biosci Rep 2013; 33:e00018. [PMID: 23134369 PMCID: PMC3561917 DOI: 10.1042/bsr20120059] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The concept of one-protein–multiple-function, i.e. moonlighting proteins, is an ever-expanding paradigm. We obtained compelling evidence that an array of ‘cytoplasmic’ metabolic enzymes can enter the nuclei to carry out moonlighting transcription functions; this phenomenon is conserved from Drosophila to humans. Of particular interest are the classical glycolytic enzymes GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and LDH (lactate dehydrogenase), which utilize NAD(H) as coenzymes and not only moonlight (in their nuclear forms) to regulate the transcription of S-phase-specific histone genes, but also act as metabolic/redox sensors that link histone gene switching to DNA replication and S-phase progression.
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138
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Leng S, Picchi MA, Liu Y, Thomas CL, Willis DG, Bernauer AM, Carr TG, Mabel PT, Han Y, Amos CI, Lin Y, Stidley CA, Gilliland FD, Jacobson MR, Belinsky SA. Genetic variation in SIRT1 affects susceptibility of lung squamous cell carcinomas in former uranium miners from the Colorado plateau. Carcinogenesis 2013; 34:1044-50. [PMID: 23354305 DOI: 10.1093/carcin/bgt024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Epidemiological studies of underground miners suggested that occupational exposure to radon causes lung cancer with squamous cell carcinoma (SCC) as the predominant histological type. However, the genetic determinants for susceptibility of radon-induced SCC in miners are unclear. Double-strand breaks induced by radioactive radon daughters are repaired primarily by non-homologous end joining (NHEJ) that is accompanied by the dynamic changes in surrounding chromatin, including nucleosome repositioning and histone modifications. Thus, a molecular epidemiological study was conducted to assess whether genetic variation in 16 genes involved in NHEJ and related histone modification affected susceptibility for SCC in radon-exposed former miners (267 SCC cases and 383 controls) from the Colorado plateau. A global association between genetic variation in the haplotype block where SIRT1 resides and the risk for SCC in miners (P = 0.003) was identified. Haplotype alleles tagged by the A allele of SIRT1 rs7097008 were associated with increased risk for SCC (odds ratio = 1.69, P = 8.2 × 10(-5)) and greater survival in SCC cases (hazard ratio = 0.79, P = 0.03) in miners. Functional validation of rs7097008 demonstrated that the A allele was associated with reduced gene expression in bronchial epithelial cells and compromised DNA repair capacity in peripheral lymphocytes. Together, these findings substantiate genetic variation in SIRT1 as a risk modifier for developing SCC in miners and suggest that SIRT1 may also play a tumor suppressor role in radon-induced cancer in miners.
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Affiliation(s)
- Shuguang Leng
- Lung Cancer Program, Lovelace Respiratory Research Institute, Albuquerque, NM 87108, USA
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139
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Hsiao KY, Mizzen CA. Histone H4 deacetylation facilitates 53BP1 DNA damage signaling and double-strand break repair. J Mol Cell Biol 2013; 5:157-65. [PMID: 23329852 DOI: 10.1093/jmcb/mjs066] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
53BP1 and other DNA damage response (DDR) proteins form foci at double-strand breaks (DSBs) which promote their repair by nonhomologous end joining (NHEJ). Focal accumulation of 53BP1 depends on the specific interaction of its tandem Tudor domain with dimethylated lysine 20 in histone H4 (H4K20me2). How 53BP1 foci dynamics are regulated is unclear since H4K20me2 is highly abundant, established largely in the absence of DNA damage, and uncertainty exists about the roles of candidate H4K20 methyltransferases in 53BP1 foci formation. Here, we show that 53BP1 foci assemble primarily on H4K20me2 established prior to DNA damage by the SETD8 and SUV420 methyltransferases rather than de novo H4K20 methylation mediated by MMSET/WHSC1. Moreover, we define a novel role for H4K16 acetylation in regulating 53BP1 foci dynamics. Concurrent acetylation at H4K16 antagonizes 53BP1 binding to extant H4K20me2 until DSBs elicit transient, localized H4 deacetylation that facilitates 53BP1 foci formation and NHEJ, and is associated with global repression of gene transcription. Our findings demonstrate that rapid induction of H4 deacetylation by DSBs affects multiple aspects of the DDR, and also suggest that antagonism of 53BP1 binding to H4K20me2 by H4K16 hyperacetylation may contribute to the efficacy of histone deacetylase inhibitors for cancer therapy.
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Affiliation(s)
- Kuei-Yang Hsiao
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL 61801, USA
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140
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DNA damage due to oxidative stress in Chronic Obstructive Pulmonary Disease (COPD). Int J Mol Sci 2012; 13:16853-64. [PMID: 23222732 PMCID: PMC3546726 DOI: 10.3390/ijms131216853] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 10/31/2012] [Accepted: 11/19/2012] [Indexed: 12/22/2022] Open
Abstract
According to the American Thorasic Society (ATS)/European Respiratory Society (ERS) Statement, chronic obstructive pulmonary disease (COPD) is defined as a preventable and treatable disease with a strong genetic component, characterized by airflow limitation that is not fully reversible, but is usually progressive and associated with an enhanced inflammatory response of the lung to noxious particles or gases. The main features of COPD are chronic inflammation of the airways and progressive destruction of lung parenchyma and alveolar structure. The pathogenesis of COPD is complex due to the interactions of several mechanisms, such as inflammation, proteolytic/antiproteolytic imbalance, oxidative stress, DNA damage, apoptosis, enhanced senescence of the structural cells and defective repair processes. This review focuses on the effects of oxidative DNA damage and the consequent immune responses in COPD. In susceptible individuals, cigarette smoke injures the airway epithelium generating the release of endogenous intracellular molecules or danger-associated molecular patterns from stressed or dying cells. These signals are captured by antigen presenting cells and are transferred to the lymphoid tissue, generating an adaptive immune response and enhancing chronic inflammation.
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141
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Gorenne I, Kumar S, Gray K, Figg N, Yu H, Mercer J, Bennett M. Vascular smooth muscle cell sirtuin 1 protects against DNA damage and inhibits atherosclerosis. Circulation 2012; 127:386-96. [PMID: 23224247 DOI: 10.1161/circulationaha.112.124404] [Citation(s) in RCA: 205] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Vascular smooth muscle cells (VSMCs) in human atherosclerosis manifest extensive DNA damage and activation of the DNA damage response, a pathway that coordinates cell cycle arrest and DNA repair, or can trigger apoptosis or cell senescence. Sirtuin 1 deacetylase (SIRT1) regulates cell ageing and energy metabolism and regulates the DNA damage response through multiple targets. However, the direct role of SIRT1 in atherosclerosis and how SIRT1 in VSMCs might regulate atherosclerosis are unknown. METHODS AND RESULTS SIRT1 expression was reduced in human atherosclerotic plaques and VSMCs both derived from plaques and undergoing replicative senescence. SIRT1 inhibition reduced DNA repair and induced apoptosis, in part, through reduced activation of the repair protein Nijmegen Breakage Syndrome-1 but not p53. Fat feeding reduced SIRT1 and induced DNA damage in VSMCs. VSMCs from mice expressing inactive truncated SIRT1 (Δex4) showed increased oxidized low-density lipoprotein-induced DNA damage and senescence. ApoE(-/-) mice expressing SIRT1(Δex4) only in smooth muscle cells demonstrated increased DNA damage response activation and apoptosis, increased atherosclerosis, reduced relative fibrous cap thickness, and medial degeneration. CONCLUSIONS SIRT1 is reduced in human atherosclerosis and is a critical regulator of the DNA damage response and survival in VSMCs. VSMC SIRT1 protects against DNA damage, medial degeneration, and atherosclerosis.
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142
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Nowsheen S, Yang E. The intersection between DNA damage response and cell death pathways. Exp Oncol 2012; 34:243-254. [PMID: 23070009 PMCID: PMC3754840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Apoptosis is a finely regulated process that serves to determine the fate of cells in response to various stresses. One such stress is DNA damage, which not only can signal repair processes but is also intimately involved in regulating cell fate. In this review we examine the relationship between the DNA damage/repair response in cell survival and apoptosis following insults to the DNA. Elucidating these pathways and the crosstalk between them is of great importance, as they eventually contribute to the etiology of human disease such as cancer and may play key roles in determining therapeutic response. This article is part of a Special Issue entitled "Apoptosis: Four Decades Later".
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Affiliation(s)
- S. Nowsheen
- Departments of Radiation Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Alabama, USA
| | - E.S. Yang
- Departments of Radiation Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Alabama, USA
- Departments of Cell, Developmental, and Integrative Biology, Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Alabama, USA
- Departments of Pharmacology and Toxicology, Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Alabama, USA
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143
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Nogueiras R, Habegger KM, Chaudhary N, Finan B, Banks AS, Dietrich MO, Horvath TL, Sinclair DA, Pfluger PT, Tschöp MH. Sirtuin 1 and sirtuin 3: physiological modulators of metabolism. Physiol Rev 2012; 92:1479-514. [PMID: 22811431 DOI: 10.1152/physrev.00022.2011] [Citation(s) in RCA: 496] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The sirtuins are a family of highly conserved NAD(+)-dependent deacetylases that act as cellular sensors to detect energy availability and modulate metabolic processes. Two sirtuins that are central to the control of metabolic processes are mammalian sirtuin 1 (SIRT1) and sirtuin 3 (SIRT3), which are localized to the nucleus and mitochondria, respectively. Both are activated by high NAD(+) levels, a condition caused by low cellular energy status. By deacetylating a variety of proteins that induce catabolic processes while inhibiting anabolic processes, SIRT1 and SIRT3 coordinately increase cellular energy stores and ultimately maintain cellular energy homeostasis. Defects in the pathways controlled by SIRT1 and SIRT3 are known to result in various metabolic disorders. Consequently, activation of sirtuins by genetic or pharmacological means can elicit multiple metabolic benefits that protect mice from diet-induced obesity, type 2 diabetes, and nonalcoholic fatty liver disease.
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Affiliation(s)
- Ruben Nogueiras
- Department of Physiology, School of Medicine-Instituto de Investigaciones Sanitarias, University of Santiago de Compostela, Santiago de Compostela, Spain
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144
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Abstract
Sirt1, the closest mammalian homolog of the Sir2 yeast longevity protein, has been extensively investigated in the last few years as an avenue to understand the connection linking nutrients and energy metabolism with aging and related diseases. From this research effort the picture has emerged of an enzyme at the hub of a complex array of molecular interactions whereby nutrient-triggered signals are translated into several levels of adaptive cell responses, the failure of which underlies diseases as diverse as diabetes, neurodegeneration and cancer. Sirt1 thus connects moderate calorie intake to “healthspan,” and a decline of Sirt-centered protective circuits over time may explain the “catastrophic” nature of aging.
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Affiliation(s)
- Salvatore Fusco
- Institute of General Pathology, Catholic University Medical School, Rome, Italy
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145
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O'Sullivan RJ, Karlseder J. The great unravelling: chromatin as a modulator of the aging process. Trends Biochem Sci 2012; 37:466-76. [PMID: 22959736 DOI: 10.1016/j.tibs.2012.08.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 08/01/2012] [Accepted: 08/07/2012] [Indexed: 02/01/2023]
Abstract
During embryogenesis, the establishment of chromatin states permits the implementation of genetic programs that allow the faithful development of the organism. However, these states are not fixed and there is much evidence that stochastic or chronic deterioration of chromatin organization, as correlated by transcriptional alterations and the accumulation of DNA damage in cells, occurs during the lifespan of the individual. Whether causal or simply a byproduct of macromolecular decay, these changes in chromatin states have emerged as potentially central conduits of mammalian aging. This review explores the current state of our understanding of the links between chromatin organization and aging.
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Affiliation(s)
- Roderick J O'Sullivan
- The Salk Institute for Biological Studies, Molecular and Cellular Biology Department, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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146
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Bouwman P, Jonkers J. The effects of deregulated DNA damage signalling on cancer chemotherapy response and resistance. Nat Rev Cancer 2012; 12:587-98. [PMID: 22918414 DOI: 10.1038/nrc3342] [Citation(s) in RCA: 457] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tumours with specific DNA repair defects can be completely dependent on back-up DNA repair pathways for their survival. This dependence can be exploited therapeutically to induce synthetic lethality in tumour cells. For instance, homologous recombination (HR)-deficient tumours can be effectively targeted by DNA double-strand break-inducing agents. However, not all HR-defective tumours respond equally well to this type of therapy. Tumour cells may acquire resistance by invoking biochemical mechanisms that reduce drug action or by acquiring additional alterations in DNA damage response pathways. A thorough understanding of these processes is important for predicting treatment response and for the development of novel treatment strategies that prevent the emergence of therapy-resistant tumours.
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Affiliation(s)
- Peter Bouwman
- Division of Molecular Pathology and Cancer Systems Biology Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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147
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Xiao Y, Karnati S, Qian G, Nenicu A, Fan W, Tchatalbachev S, Höland A, Hossain H, Guillou F, Lüers GH, Baumgart-Vogt E. Cre-mediated stress affects sirtuin expression levels, peroxisome biogenesis and metabolism, antioxidant and proinflammatory signaling pathways. PLoS One 2012; 7:e41097. [PMID: 22829911 PMCID: PMC3400606 DOI: 10.1371/journal.pone.0041097] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 06/21/2012] [Indexed: 11/28/2022] Open
Abstract
Cre-mediated excision of loxP sites is widely used in mice to manipulate gene function in a tissue-specific manner. To analyze phenotypic alterations related to Cre-expression, we have used AMH-Cre-transgenic mice as a model system. Different Cre expression levels were obtained by investigation of C57BL/6J wild type as well as heterozygous and homozygous AMH-Cre-mice. Our results indicate that Cre-expression itself in Sertoli cells already has led to oxidative stress and lipid peroxidation (4-HNE lysine adducts), inducing PPARα/γ, peroxisome proliferation and alterations of peroxisome biogenesis (PEX5, PEX13 and PEX14) as well as metabolic proteins (ABCD1, ABCD3, MFP1, thiolase B, catalase). In addition to the strong catalase increase, a NRF2- and FOXO3-mediated antioxidative response (HMOX1 of the endoplasmic reticulum and mitochondrial SOD2) and a NF-κB activation were noted. TGFβ1 and proinflammatory cytokines like IL1, IL6 and TNFα were upregulated and stress-related signaling pathways were induced. Sertoli cell mRNA-microarray analysis revealed an increase of TNFR2-signaling components. 53BP1 recruitment and expression levels for DNA repair genes as well as for p53 were elevated and the ones for related sirtuin deacetylases affected (SIRT 1, 3-7) in Sertoli cells. Under chronic Cre-mediated DNA damage conditions a strong downregulation of Sirt1 was observed, suggesting that the decrease of this important coordinator between DNA repair and metabolic signaling might induce the repression release of major transcription factors regulating metabolic and cytokine-mediated stress pathways. Indeed, caspase-3 was activated and increased germ cell apoptosis was observed, suggesting paracrine effects. In conclusion, the observed wide stress-induced effects and metabolic alterations suggest that it is essential to use the correct control animals (Cre/Wt) with matched Cre expression levels to differentiate between Cre-mediated and specific gene-knock out-mediated effects.
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Affiliation(s)
- Yu Xiao
- Institute for Anatomy and Cell Biology II, Justus Liebig University Giessen, Giessen, Germany
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148
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Perspectives on translational and therapeutic aspects of SIRT1 in inflammaging and senescence. Biochem Pharmacol 2012; 84:1332-9. [PMID: 22796566 DOI: 10.1016/j.bcp.2012.06.031] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 06/28/2012] [Accepted: 06/29/2012] [Indexed: 02/08/2023]
Abstract
Sirtuin1 (SIRT1), a type III protein deacetylase, is considered as a novel anti-aging protein involved in regulation of cellular senescence/aging and inflammation. SIRT1 level and activity are decreased during lung inflammaging caused by oxidative stress. The mechanism of SIRT1-mediated protection against inflammaging is associated with the regulation of inflammation, premature senescence, telomere attrition, senescence associated secretory phenotype, and DNA damage response. A variety of dietary polyphenols and pharmacological activators are shown to regulate SIRT1 so as to intervene the progression of type 2 diabetes, cancer, cardiovascular diseases, and chronic obstructive pulmonary disease associated with inflammaging. However, recent studies have shown the non-specific regulation of SIRT1 by the aforementioned pharmacological activators and polyphenols. In this perspective, we have briefly discussed the role of SIRT1 in regulation of cellular senescence and its associated secretory phenotype, DNA damage response, particularly in lung inflammaging and during the development of chronic obstructive pulmonary diseases. We have also discussed the potential directions for future translational therapeutic avenues for SIRT1 in modulating lung inflammaging associated with senescence in chronic lung diseases associated with increased oxidative stress.
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149
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Xie J, Peng M, Guillemette S, Quan S, Maniatis S, Wu Y, Venkatesh A, Shaffer SA, Brosh RM, Cantor SB. FANCJ/BACH1 acetylation at lysine 1249 regulates the DNA damage response. PLoS Genet 2012; 8:e1002786. [PMID: 22792074 PMCID: PMC3390368 DOI: 10.1371/journal.pgen.1002786] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 05/10/2012] [Indexed: 01/08/2023] Open
Abstract
BRCA1 promotes DNA repair through interactions with multiple proteins, including CtIP and FANCJ (also known as BRIP1/BACH1). While CtIP facilitates DNA end resection when de-acetylated, the function of FANCJ in repair processing is less well defined. Here, we report that FANCJ is also acetylated. Preventing FANCJ acetylation at lysine 1249 does not interfere with the ability of cells to survive DNA interstrand crosslinks (ICLs). However, resistance is achieved with reduced reliance on recombination. Mechanistically, FANCJ acetylation facilitates DNA end processing required for repair and checkpoint signaling. This conclusion was based on the finding that FANCJ and its acetylation were required for robust RPA foci formation, RPA phosphorylation, and Rad51 foci formation in response to camptothecin (CPT). Furthermore, both preventing and mimicking FANCJ acetylation at lysine 1249 disrupts FANCJ function in checkpoint maintenance. Thus, we propose that the dynamic regulation of FANCJ acetylation is critical for robust DNA damage response, recombination-based processing, and ultimately checkpoint maintenance. The BRCA1–Fanconi anemia (FA) pathway is required for both tumor suppression and cell survival, particularly following treatment with DNA damaging agents that induce DNA interstrand crosslinks (ICLs). ICL processing by the BRCA–FA pathway includes promotion of homologous recombination (HR) and DNA damage tolerance through translesion synthesis. However, little is known about how the BRCA–FA pathway or these ICL processing mechanisms are regulated. Here, we identify acetylation as a DNA damage–dependent regulator of the BRCA–FA protein, FANCJ. FANCJ acetylation at lysine 1249 is enhanced by expression of the histone acetyltransferase CBP and reduced by expression of histone deacetylases HDAC3 or SIRT1. Furthermore, acetylation on endogenous FANCJ is induced upon treatment of cells with agents that generate DNA lesions. Consistent with this post-translation event regulating FANCJ function during cellular DNA repair, preventing FANCJ acetylation skews ICL processing. Cells have reduced reliance on HR factor Rad54 and greater reliance on translesion synthesis polymerase polη. Our data indicate that FANCJ acetylation contributes to DNA end processing that is required for HR. Furthermore, resection-dependent checkpoint maintenance relies on the dynamic regulation of FANCJ acetylation. The implication of these findings is that FANCJ acetylation contributes to DNA repair choice within the BRCA–FA pathway.
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Affiliation(s)
- Jenny Xie
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Min Peng
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Shawna Guillemette
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Steven Quan
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Stephanie Maniatis
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Yuliang Wu
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH Biomedical Research Center, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Aditya Venkatesh
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Scott A. Shaffer
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Robert M. Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH Biomedical Research Center, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Sharon B. Cantor
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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150
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Thompson LH. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography. Mutat Res 2012; 751:158-246. [PMID: 22743550 DOI: 10.1016/j.mrrev.2012.06.002] [Citation(s) in RCA: 261] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 06/09/2012] [Accepted: 06/16/2012] [Indexed: 12/15/2022]
Abstract
The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships.
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Affiliation(s)
- Larry H Thompson
- Biology & Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, United States.
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