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Chen YF, Dugas TR. Endothelial mitochondrial senescence accelerates cardiovascular disease in antiretroviral-receiving HIV patients. Toxicol Lett 2019; 317:13-23. [PMID: 31562912 DOI: 10.1016/j.toxlet.2019.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/12/2019] [Accepted: 09/21/2019] [Indexed: 02/06/2023]
Abstract
Combination antiretroviral therapy (cART) has been hugely successful in reducing the mortality associated with human immunodeficiency virus (HIV) infection, resulting in a growing population of people living with HIV (PLWH). Since PLWH now have a longer life expectancy, chronic comorbidities have become the focus of the clinical management of HIV. For example, cardiovascular complications are now one of the most prevalent causes of death in PLWH. Numerous epidemiological studies show that antiretroviral treatment increases cardiovascular disease (CVD) risk and early onset of CVD in PLWH. Nucleoside reverse transcriptase inhibitors (NRTIs) are the backbone of cART, and two NRTIs are typically used in combination with one drug from another drug class, e.g., a fusion inhibitor. NRTIs are known to induce mitochondrial dysfunction, contributing to toxicity in numerous tissues, such as myopathy, lipoatrophy, neuropathy, and nephropathy. In in vitro studies, short-term NRTI treatment induces an endothelial dysfunction with an increased reactive oxygen species (ROS) production; long-term NRTI treatment decreases cell replication capacity, while increasing mtROS production and senescent cell accumulation. These findings suggest that a mitochondrial oxidative stress is involved in the pathogenesis of NRTI-induced endothelial dysfunction and premature senescence. Mitochondrial dysfunction, defined by a compromised mitochondrial quality control via biogenesis and mitophagy, has a causal role in premature endothelial senescence and can potentially initiate early cardiovascular disease (CVD) development in PLWH. In this review, we explore the hypothesis and present literature supporting that long-term NRTI treatment induces vascular dysfunction by interfering with endothelial mitochondrial homeostasis and provoking mitochondrial genomic instability, resulting in premature endothelial senescence.
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Affiliation(s)
- Yi-Fan Chen
- Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, LA, 70808, United States
| | - Tammy R Dugas
- Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, LA, 70808, United States.
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2
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Rice A, Del Rio Hernandez A. The Mutational Landscape of Pancreatic and Liver Cancers, as Represented by Circulating Tumor DNA. Front Oncol 2019; 9:952. [PMID: 31608239 PMCID: PMC6769086 DOI: 10.3389/fonc.2019.00952] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 09/09/2019] [Indexed: 02/06/2023] Open
Abstract
The mutational landscapes of pancreatic and liver cancers share many common genetic alterations which drive cancer progression. However, these mutations do not occur in all cases of these diseases, and this tumoral heterogeneity impedes diagnosis, prognosis, and therapeutic development. One minimally invasive method for the evaluation of tumor mutations is the analysis of circulating tumor DNA (ctDNA), released through apoptosis, necrosis, and active secretion by tumor cells into various body fluids. By observing mutations in those genes which promote transformation by controlling the cell cycle and oncogenic signaling pathways, a representation of the mutational profile of the tumor is revealed. The analysis of ctDNA is a promising technique for investigating these two gastrointestinal cancers, as many studies have reported on the accuracy of ctDNA assessment for diagnosis and prognosis using a variety of techniques.
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Affiliation(s)
- Alistair Rice
- Cellular and Molecular Biomechanics Laboratory, Department of Bioengineering, Faculty of Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Armando Del Rio Hernandez
- Cellular and Molecular Biomechanics Laboratory, Department of Bioengineering, Faculty of Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
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3
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Toupchian O, Sotoudeh G, Mansoori A, Abdollahi S, Ali Keshavarz S, Djalali M, Nasli-Esfahani E, Alvandi E, Chahardoli R, Koohdani F. DHA-enriched fish oil upregulates cyclin-dependent kinase inhibitor 2A (P16INK) expression and downregulates telomerase activity without modulating effects of PPARγ Pro12Ala polymorphism in type 2 diabetic patients: A randomized, double-blind, placebo-controlled clinical trial. Clin Nutr 2018; 37:91-98. [DOI: 10.1016/j.clnu.2016.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 12/08/2016] [Accepted: 12/08/2016] [Indexed: 01/09/2023]
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4
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Behrens YL, Thomay K, Hagedorn M, Ebersold J, Henrich L, Nustede R, Schlegelberger B, Göhring G. Comparison of different methods for telomere length measurement in whole blood and blood cell subsets: Recommendations for telomere length measurement in hematological diseases. Genes Chromosomes Cancer 2017; 56:700-708. [DOI: 10.1002/gcc.22475] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 12/12/2022] Open
Affiliation(s)
- Yvonne Lisa Behrens
- Department of Human Genetics; Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
| | - Kathrin Thomay
- Department of Human Genetics; Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
| | - Maike Hagedorn
- Department of Human Genetics; Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
| | - Juliane Ebersold
- Department of Human Genetics; Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
| | - Lea Henrich
- Department of Human Genetics; Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
| | - Rainer Nustede
- Pediatric surgery, Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
| | - Brigitte Schlegelberger
- Department of Human Genetics; Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
| | - Gudrun Göhring
- Department of Human Genetics; Hannover Medical School; Carl-Neuberg-Str.1 Hannover 30625 Germany
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5
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Adámik M, Kejnovská I, Bažantová P, Petr M, Renčiuk D, Vorlíčková M, Brázdová M. p53 binds human telomeric G-quadruplex in vitro. Biochimie 2016; 128-129:83-91. [PMID: 27422117 DOI: 10.1016/j.biochi.2016.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/11/2016] [Indexed: 01/08/2023]
Abstract
The tumor suppressor protein p53 is a key factor in genome stability and one of the most studied of DNA binding proteins. This is the first study on the interaction of wild-type p53 with guanine quadruplexes formed by the human telomere sequence. Using electromobility shift assay and ELISA, we show that p53 binding to telomeric G-quadruplexes increases with the number of telomeric repeats. Further, p53 strongly favors G-quadruplexes folded in potassium over those formed in sodium, thus indicating the telomeric G-quadruplex conformational selectivity of p53. The presence of the quadruplex-stabilizing ligand, N-methyl mesoporphyrin IX (NMM), increases p53 recognition of G-quadruplexes in potassium. Using deletion mutants and selective p53 core domain oxidation, both p53 DNA binding domains are shown to be crucial for telomeric G-quadruplex recognition.
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Affiliation(s)
- Matej Adámik
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-612 65 Brno, Czech Republic
| | - Iva Kejnovská
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-612 65 Brno, Czech Republic
| | - Pavla Bažantová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-612 65 Brno, Czech Republic
| | - Marek Petr
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-612 65 Brno, Czech Republic
| | - Daniel Renčiuk
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-612 65 Brno, Czech Republic
| | - Michaela Vorlíčková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-612 65 Brno, Czech Republic
| | - Marie Brázdová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-612 65 Brno, Czech Republic.
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6
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Friis-Ottessen M, Burum-Auensen E, Schjølberg AR, Ekstrøm PO, Andersen SN, Clausen OP, De Angelis PM. TP53/p53 alterations and Aurora A expression in progressor and non-progressor colectomies from patients with longstanding ulcerative colitis. Int J Mol Med 2014; 35:24-30. [PMID: 25333414 PMCID: PMC4249752 DOI: 10.3892/ijmm.2014.1974] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 09/16/2014] [Indexed: 12/12/2022] Open
Abstract
Aneuploidy is a common feature in the colonic mucosa of patients suffering from the inflammatory bowel disease ulcerative colitis (UC) and often precedes the development of dysplasia and cancer. Aneuploidy is assumed to be caused by missegregation of chromosomes during mitosis, often due to a faulty spindle assembly checkpoint. p53 is a tumour suppressor protein known to regulate the spindle assembly checkpoint and is frequently mutated in aneuploid cells. Aurora A is a presumed oncoprotein, also involved in regulation of the spindle assembly checkpoint. In the present study, we examined the mutational frequency of TP53 and the protein levels of p53 in a set of 20 progressor and 10 non-progressor colectomies from patients suffering from longstanding UC. In addition, we re-examined previously published immunohistochemical data on Aurora A expression using the same material. Levels of Aurora A were re-examined with regard to DNA ploidy status and dysplasia within the progressors, as well as in relation to p53 accumulation and TP53 mutational status. We detected p53 accumulation only within the progressor colectomies, where it could be followed back 14 years prior to the colectomies, in pre-colectomy biopsies. TP53 mutations were detected in both progressors and non-progressors. Expression levels of Aurora A were similar in the progressors and non-progressors. Within the group of progressors however, low levels of Aurora A were associated with areas of DNA aneuploidy, as well as with increasing degrees of dysplasia. Our results indicate that alterations in p53 may be an early biomarker of a progressor colon, and that p53 is accumulated early in UC-related carcinogenesis. Furthermore, a decreased Aurora A expression is associated with the development of DNA aneuploidy, as well as with dysplasia in UC progressors.
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Affiliation(s)
- Mariann Friis-Ottessen
- Division of Diagnostics and Intervention, Department of Pathology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | | | | | - Per Olaf Ekstrøm
- Division of Surgery and Cancer Medicine, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Solveig N Andersen
- Department of Pathology, Akershus University Hospital, Division of Medicine and Laboratory Sciences, University of Oslo, Oslo, Norway
| | | | - Paula M De Angelis
- Division of Diagnostics and Intervention, Department of Pathology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
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Menon R, Boldogh I, Hawkins HK, Woodson M, Polettini J, Syed TA, Fortunato SJ, Saade GR, Papaconstantinou J, Taylor RN. Histological evidence of oxidative stress and premature senescence in preterm premature rupture of the human fetal membranes recapitulated in vitro. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1740-51. [PMID: 24832021 DOI: 10.1016/j.ajpath.2014.02.011] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/09/2014] [Accepted: 02/04/2014] [Indexed: 12/15/2022]
Abstract
Preterm prelabor rupture of the membranes (pPROM) may lead to preterm births (PTBs). We investigated premature senescence of fetal membranes in women with pPROM and spontaneous PTB with intact membranes (<34 weeks) and the inducibility fetal membrane senescence phenotype by oxidative stress in vitro. IHC was performed for p53, p21, and phospho (p)-p38 mitogen-activated protein kinase (MAPK) as markers of senescence phenotype in pPROM, PTBs, and term births. Term fetal membranes were exposed to cigarette smoke extract to induce oxidative stress. Western blots documented p-p53 and p-p38 MAPK. Transmission electron microscopy assessed cellular morphologic features in clinical and cigarette smoke extract-treated membranes. A total of 80% of pPROM cells and >60% of term cells were positive for all three senescence phenotype markers, and concentrations were higher than in PTBs (P < 0.05). p53 staining was comparable in membranes from PTB and term birth pregnancies, whereas only <30% and <45% of cells were positive for p21 and p38 MAPK, respectively. In vitro cigarette smoke extract exposure increased p-p38 MAPK without any detectable change in p-p53 MAPK. Enlargement of organelles consistent with senescence phenotype was evident in pPROM and term membranes in vivo and after cigarette smoke extract treatment in vitro but was less apparent in PTBs. Histologic and biochemical resemblance of pPROM and term membranes suggests premature senescence of the membranes is a mechanistic feature in pPROM, and this can be phenocopied in an in vitro model.
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Affiliation(s)
- Ramkumar Menon
- Division of Maternal-Fetal Medicine Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas.
| | - Istvan Boldogh
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Hal K Hawkins
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Michael Woodson
- Electron Microscopy Core Laboratory, The University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Jossimara Polettini
- Division of Maternal-Fetal Medicine Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Tariq Ali Syed
- Division of Maternal-Fetal Medicine Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
| | | | - George R Saade
- Division of Maternal-Fetal Medicine Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas
| | - John Papaconstantinou
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Robert N Taylor
- Department of Obstetrics and Gynecology, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Cheung HH, Liu X, Canterel-Thouennon L, Li L, Edmonson C, Rennert OM. Telomerase protects werner syndrome lineage-specific stem cells from premature aging. Stem Cell Reports 2014; 2:534-46. [PMID: 24749076 PMCID: PMC3986587 DOI: 10.1016/j.stemcr.2014.02.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 02/20/2014] [Accepted: 02/20/2014] [Indexed: 12/12/2022] Open
Abstract
Werner syndrome (WS) patients exhibit premature aging predominantly in mesenchyme-derived tissues, but not in neural lineages, a consequence of telomere dysfunction and accelerated senescence. The cause of this lineage-specific aging remains unknown. Here, we document that reprogramming of WS fibroblasts to pluripotency elongated telomere length and prevented telomere dysfunction. To obtain mechanistic insight into the origin of tissue-specific aging, we differentiated iPSCs to mesenchymal stem cells (MSCs) and neural stem/progenitor cells (NPCs). We observed recurrence of premature senescence associated with accelerated telomere attrition and defective synthesis of the lagging strand telomeres in MSCs, but not in NPCs. We postulate this “aging” discrepancy is regulated by telomerase. Expression of hTERT or p53 knockdown ameliorated the accelerated aging phenotypein MSC, whereas inhibition of telomerase sensitized NPCs to DNA damage. Our findings unveil a role for telomerase in the protection of accelerated aging in a specific lineage of stem cells. Prevention of premature senescence with corrected telomeres in reprogrammed WS iPSCs Recurrence of premature senescence and telomere dysfunction in WS iPSC-derived MSCs Rescue of premature senescence in WS MSCs by hTERT overexpression or p53 depletion Telomerase protects and prevents NPCs from DNA damage
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Affiliation(s)
- Hoi-Hung Cheung
- Laboratory of Clinical and Developmental Genomics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA ; School of Biomedical Sciences, Faculty of Medicine, the Chinese University of Hong Kong, Shatin, N.T., 852 Hong Kong S.A.R
| | - Xiaozhuo Liu
- Laboratory of Clinical and Developmental Genomics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA ; School of Biomedical Sciences, Faculty of Medicine, the Chinese University of Hong Kong, Shatin, N.T., 852 Hong Kong S.A.R
| | - Lucile Canterel-Thouennon
- Laboratory of Clinical and Developmental Genomics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lu Li
- School of Biomedical Sciences, Faculty of Medicine, the Chinese University of Hong Kong, Shatin, N.T., 852 Hong Kong S.A.R
| | - Catherine Edmonson
- Laboratory of Clinical and Developmental Genomics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Owen M Rennert
- Laboratory of Clinical and Developmental Genomics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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9
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Menon R, Boldogh I, Urrabaz-Garza R, Polettini J, Syed TA, Saade GR, Papaconstantinou J, Taylor RN. Senescence of primary amniotic cells via oxidative DNA damage. PLoS One 2013; 8:e83416. [PMID: 24386195 PMCID: PMC3873937 DOI: 10.1371/journal.pone.0083416] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/12/2013] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Oxidative stress is a postulated etiology of spontaneous preterm birth (PTB) and preterm prelabor rupture of the membranes (pPROM); however, the precise mechanistic role of reactive oxygen species (ROS) in these complications is unclear. The objective of this study is to examine impact of a water soluble cigarette smoke extract (wsCSE), a predicted cause of pregnancy complications, on human amnion epithelial cells. METHODS Amnion cells isolated from fetal membranes were exposed to wsCSE prepared in cell culture medium and changes in ROS levels, DNA base and strand damage was determined by using 2'7'-dichlorodihydro-fluorescein and comet assays as well as Fragment Length Analysis using Repair Enzymes (FLARE) assays, respectively. Western blot analyses were used to determine the changes in mass and post-translational modification of apoptosis signal-regulating kinase (ASK1), phospho-p38 (P-p38 MAPK), and p19(arf). Expression of senescence-associated β-galectosidase (SAβ-gal) was used to confirm cell ageing in situ. RESULTS ROS levels in wsCSE-exposed amnion cells increased rapidly (within 2 min) and significantly (p<0.01) at all-time points, and DNA strand and base damage was evidenced by comet and FLARE assays. Activation of ASK1, P-p38 MAPK and p19(Arf) correlated with percentage of SAβ-gal expressing cells after wsCSE treatment. The antioxidant N-acetyl-L-cysteine (NAC) prevented ROS-induced DNA damage and phosphorylation of p38 MAPK, whereas activation of ASK1 and increased expression of p19(Arf) were not significantly affected by NAC. CONCLUSIONS The findings support the hypothesis that compounds in wsCSE induces amnion cell senescence via a mechanism involving ROS and DNA damage. Both pathways may contribute to PTB and pPROM. Our results imply that antioxidant interventions that control ROS may interrupt pathways leading to pPROM and other causes of PTB.
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Affiliation(s)
- Ramkumar Menon
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine Perinatal Research, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Istvan Boldogh
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Rheanna Urrabaz-Garza
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine Perinatal Research, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Jossimara Polettini
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine Perinatal Research, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Tariq Ali Syed
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine Perinatal Research, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - George R. Saade
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine Perinatal Research, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - John Papaconstantinou
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Robert N. Taylor
- Department of Obstetrics and Gynecology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
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Sequence-specific and DNA structure-dependent interactions of Escherichia coli MutS and human p53 with DNA. Anal Biochem 2013; 442:51-61. [PMID: 23928048 DOI: 10.1016/j.ab.2013.07.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 07/19/2013] [Accepted: 07/23/2013] [Indexed: 11/20/2022]
Abstract
Many proteins involved in DNA repair systems interact with DNA that has structure altered from the typical B-form helix. Using magnetic beads to immobilize DNAs containing various types of structures, we evaluated the in vitro binding activities of two well-characterized DNA repair proteins, Escherichia coli MutS and human p53. E. coli MutS bound to double-stranded DNAs, with higher affinity for a G/T mismatch compared to a G/A mismatch and highest affinity for larger non-B-DNA structures. E. coli MutS bound best to DNA between pH 6 and 9. Experiments discriminated between modes of p53-DNA binding, and increasing ionic strength reduced p53 binding to nonspecific double-stranded DNA, but had minor effects on binding to consensus response sequences or single-stranded DNA. Compared to nonspecific DNA sequences, p53 bound with a higher affinity to mismatches and base insertions, while binding to various hairpin structures was similar to that observed to its consensus DNA sequence. For hairpins containing CTG repeats, the extent of p53 binding was proportional to the size of the repeat. In summary, using the flexibility of the magnetic bead separation assay we demonstrate that pH and ionic strength influence the binding of two DNA repair proteins to a variety of DNA structures.
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11
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Arora R, Brun CMC, Azzalin CM. TERRA: Long Noncoding RNA at Eukaryotic Telomeres. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2011; 51:65-94. [PMID: 21287134 DOI: 10.1007/978-3-642-16502-3_4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Telomeres protect the ends of linear eukaryotic chromosomes from being recognized as DNA double-stranded breaks, thereby maintaining the stability of our genome. The highly heterochromatic nature of telomeres had, for a long time, reinforced the idea that telomeres were transcriptionally silent. Since a few years, however, we know that DNA-dependent RNA polymerase II transcribes telomeric DNA into TElomeric Repeat-containing RNA (TERRA) molecules in a large variety of eukaryotes. In this chapter, we summarize the current knowledge of telomere structure and function and extensively review data accumulated on TERRA biogenesis and regulation. We also discuss putative functions of TERRA in preserving telomere stability and propose future directions for research encompassing this novel and exciting aspect of telomere biology.
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Affiliation(s)
- Rajika Arora
- Institute of Biochemistry, ETHZ-Eidgenössische Technische Hochschule Zürich, CH-8093, Zürich, Switzerland
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12
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Guo XF, Cao EH. Telomeric plasmid induces human cancer cell dysfunction depending on ATM activity. Cell Biochem Funct 2010; 28:381-6. [PMID: 20535839 DOI: 10.1002/cbf.1664] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Telomeres are essential for chromosome stability and the regulation of the replicative life-span of somatic cells. Many studies showed that exogenous telomeric repeats could activate p53 protein. It is not known how cell dysfunction is induced by telomeric plasmids. A covalent closed circular (ccc) double-stranded plasmid containing (TTAGGG)(96) repeats (pRST5) was transiently transfected into the human gastric cancer MGC-803 cells. We first confirmed that the cell viabilities decreased by 27%, cell senescence increased by 62% and G2/M cycle arrested in pRST5 plasmid transfected cells. Compared to control groups, cells transfected with telomeric plasmids showed an ATM-dependent increasing of p53, TRF1, and TRF2 expression. Furthermore, telomere dysfunction-induced foci (TIF) were observed. In conclusion, telomeric plasmids can elicit endogenous telomere dysfunction and induce cell senescence by activating ATM-p53 pathway.
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Affiliation(s)
- Xiao-Fei Guo
- Institute of Biophysics, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Chaoyang District, Beijing, PR China
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13
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14
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Abstract
A number of proteins are activated by stress stimuli but none so spectacularly or with the degree of complexity as the tumour suppressor p53 (human p53 gene or protein). Once stabilized, p53 is responsible for the transcriptional activation of a series of proteins involved in cell cycle control, apoptosis and senescence. This protein is present at low levels in resting cells but after exposure to DNA-damaging agents and other stress stimuli it is stabilized and activated by a series of post-translational modifications that free it from MDM2 (mouse double minute 2 but used interchangeably to denote human also), a ubiquination ligase that ubiquitinates it prior to proteasome degradation. The stability of p53 is also influenced by a series of other interacting proteins. In this review, we discuss the post-translational modifications to p53 in response to different stresses and the consequences of these changes.
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Affiliation(s)
- M F Lavin
- The Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
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15
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Walter K, Warnecke G, Bowater R, Deppert W, Kim E. tumor suppressor p53 binds with high affinity to CTG.CAG trinucleotide repeats and induces topological alterations in mismatched duplexes. J Biol Chem 2005; 280:42497-507. [PMID: 16230356 DOI: 10.1074/jbc.m507038200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
DNA binding is central to the ability of p53 to function as a tumor suppressor. In line with the remarkable functional versatility of p53, which can act on DNA as a transcription, repair, recombination, replication, and chromatin accessibility factor, the modes of p53 interaction with DNA are also versatile. One feature common to all modes of p53-DNA interaction is the extraordinary sensitivity of p53 to the topology of its target DNA. Whereas the strong impact of DNA topology has been demonstrated for p53 binding to sequence-specific sites or to DNA lesions, the possibility that DNA structure-dependent recognition may underlie p53 interaction with other types of DNA has not been addressed until now. We demonstrate for the first time that conformationally flexible CTG.CAG trinucleotide repeats comprise a novel class of p53-binding sites targeted by p53 in a DNA structure-dependent mode in vitro and in vivo. Our major finding is that p53 binds to CTG.CAG tracts by different modes depending on the conformation of DNA. Although p53 binds preferentially to hairpins formed by either CTG or CAG strands, it can also bind to linear forms of CTG.CAG tracts such as canonic B DNA or mismatched duplex. Intriguingly, by binding to a mismatched duplex p53 can induce further topological alterations in DNA, indicating that p53 may act as a DNA topology-modulating factor.
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Affiliation(s)
- Korden Walter
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie, Martinistrasse 52, D-20251, Hamburg, Germany
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Zhang Y, Cao EH, Qin JF. Up-regulation of telomere-binding TRF1, TRF2 related to reactive oxygen species induced by As(2)O(3) in MGC-803 cells. Eur J Pharmacol 2005; 516:1-9. [PMID: 15904916 DOI: 10.1016/j.ejphar.2005.04.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2005] [Revised: 04/12/2005] [Accepted: 04/14/2005] [Indexed: 12/22/2022]
Abstract
In this work, our study focused on As(2)O(3) action in view point of telomere. Results showed that treatment of human gastric cancer MGC-803 cells with arsenic trioxide could cause up-regulation of telomeric repeat binding factor TRF1 and TRF2 mRNA and protein levels, and induced G2/M phase arrest and cell apoptosis. At the same time, telomere length shortening and telomerase inhibitory were not obvious. Flow cytometry measurements indicated that the increase of TRF1 and TRF2 proteins is related to oxidative stress by arsenic trioxide. Results also indicate that after arsenic trioxide treatment, p53 protein levels increased significantly and also could bind directly at the telomere t-loop junction. These findings demonstrate arsenic trioxide-induced cell cycle arrest and apoptosis might involve a novel pathway related to TRF1, TRF2 protein.
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Affiliation(s)
- Yan Zhang
- Institute of Biophysics, Academia Sinica, Graduate School of the Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, P.R. China
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Kim E, Deppert W. The complex interactions of p53 with target DNA: we learn as we go. Biochem Cell Biol 2003; 81:141-50. [PMID: 12897847 DOI: 10.1139/o03-046] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The most import biological function of the tumor suppressor p53 is that of a sequence-specific transactivator. In response to a variety of cellular stress stimuli, p53 induces the transcription of an ever-increasing number of target genes, leading to growth arrest and repair, or to apoptosis. Long considered as a "latent" DNA binder that requires prior activation by C-terminal modification, recent data provide strong evidence that the DNA binding activity of p53 is strongly dependent on structural features within the target DNA and is latent only if the target DNA lacks a certain structural signal code. In this review we discuss evidence for complex interactions of p53 with DNA, which are strongly dependent on the dynamics of DNA structure, especially in the context of chromatin. We provide a model of how this complexity may serve to achieve selectivity of target gene regulation by p53 and how DNA structure in the context of chromatin may serve to modulate p53 functions.
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Affiliation(s)
- Ella Kim
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie, Universität Hamburg, Germany
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18
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Nur-E-Kamal A, Li TK, Zhang A, Qi H, Hars ES, Liu LF. Single-stranded DNA induces ataxia telangiectasia mutant (ATM)/p53-dependent DNA damage and apoptotic signals. J Biol Chem 2003; 278:12475-81. [PMID: 12540848 DOI: 10.1074/jbc.m212915200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Single-stranded DNA has been speculated to be the initial signal in the DNA damage signaling pathway. We showed that introduction of single-stranded DNA with diverse sequences into mammalian cells induced DNA damage as well as apoptosis signals. Like DNA damaging agents, single-stranded DNA up-regulated p53 and activated the nuclear kinase ataxia telangiectasia mutant (ATM) as evidenced by phosphorylation of histone 2AX, an endogenous ATM substrate. Single-stranded DNA also triggered apoptosis as evidenced by the formation of caspase-dependent chromosomal DNA strand breaks, cytochrome c release, and increase in reactive oxygen species production. Moreover, single-stranded DNA-induced apoptosis was reduced significantly in p53 null cells and in cells treated with ATM small interfering RNA. These results suggest that single-stranded DNA may act upstream of ATM/p53 in DNA damage signaling.
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Affiliation(s)
- Alam Nur-E-Kamal
- Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA.
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19
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Eller MS, Li GZ, Firoozabadi R, Puri N, Gilchrest BA. Induction of a p95/Nbs1-mediated S phase checkpoint by telomere 3' overhang specific DNA. FASEB J 2003; 17:152-62. [PMID: 12554694 DOI: 10.1096/fj.02-0197com] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Telomere shortening induces a nonproliferative senescent phenotype, believed to reduce cancer risk, and telomeres are involved in a poorly understood manner in responses to DNA damage. Although telomere disruption induces p53 and triggers apoptosis or cell cycle arrest, the features of the disrupted telomere that trigger this response and the precise mechanism involved are poorly understood. Using human cells, we show that DNA oligonucleotides homologous to the telomere 3' overhang sequence specifically induce and activate p53 and activate an S phase checkpoint by modifying the Nijmegen breakage syndrome protein, known to mediate the S phase checkpoint after DNA damage. These responses are mediated, at least in part, by the ATM kinase and are not attributable to disruption of cellular telomeres. Based on these and earlier data, we propose that these oligonucleotides mimic a physiological signal, exposure of the telomere 3' overhang due to opening of the normal telomere loop structure, and hence evoke these protective antiproliferative responses in the absence of DNA damage or telomere disruption.
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Affiliation(s)
- Mark S Eller
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118-2394, USA
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20
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Eller MS, Puri N, Hadshiew IM, Venna SS, Gilchrest BA. Induction of apoptosis by telomere 3' overhang-specific DNA. Exp Cell Res 2002; 276:185-93. [PMID: 12027448 DOI: 10.1006/excr.2002.5531] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Telomeres are tandem repeats of a specific TTAGGG nucleotide sequence at the ends of chromosomes. Telomere shortening is proposed to act as a biological clock and cancer prevention mechanism by inducing a nonproliferative, senescent phenotype after a limited number of cellular divisions. Recent evidence also suggests that telomere disruption can trigger apoptosis in certain cell types, mimicking a major cellular response to DNA damage. Here, we show that addition of DNA oligonucleotides homologous to the telomere 3' overhang sequence causes lymphocytic (Jurkat) cells to undergo apoptosis, as described for lymphocytes following telomere loop disruption. We further implicate the p53 tumor suppressor and transcription factor, as well as the p53 homolog p73 and the E2F1 transcription factor, in mediating the apoptotic response. We propose that exposure of the telomere 3' overhang due to opening of the normal telomere loop structure is a physiologic signal for these DNA damage-like responses in vivo and that oligonucleotides partially or completely homologous to the telomere overhang mimic this signal in the absence of DNA damage or telomere disruption.
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Affiliation(s)
- Mark S Eller
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118-2394, USA
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