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Krupina K, Goginashvili A, Cleveland DW. Scrambling the genome in cancer: causes and consequences of complex chromosome rearrangements. Nat Rev Genet 2024; 25:196-210. [PMID: 37938738 PMCID: PMC10922386 DOI: 10.1038/s41576-023-00663-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2023] [Indexed: 11/09/2023]
Abstract
Complex chromosome rearrangements, known as chromoanagenesis, are widespread in cancer. Based on large-scale DNA sequencing of human tumours, the most frequent type of complex chromosome rearrangement is chromothripsis, a massive, localized and clustered rearrangement of one (or a few) chromosomes seemingly acquired in a single event. Chromothripsis can be initiated by mitotic errors that produce a micronucleus encapsulating a single chromosome or chromosomal fragment. Rupture of the unstable micronuclear envelope exposes its chromatin to cytosolic nucleases and induces chromothriptic shattering. Found in up to half of tumours included in pan-cancer genomic analyses, chromothriptic rearrangements can contribute to tumorigenesis through inactivation of tumour suppressor genes, activation of proto-oncogenes, or gene amplification through the production of self-propagating extrachromosomal circular DNAs encoding oncogenes or genes conferring anticancer drug resistance. Here, we discuss what has been learned about the mechanisms that enable these complex genomic rearrangements and their consequences in cancer.
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Affiliation(s)
- Ksenia Krupina
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Alexander Goginashvili
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Don W Cleveland
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA.
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Borghini A, Ndreu R, Canale P, Campolo J, Marinaro I, Mercuri A, Turchi S, Andreassi MG. Telomere Length, Mitochondrial DNA, and Micronucleus Yield in Response to Oxidative Stress in Peripheral Blood Mononuclear Cells. Int J Mol Sci 2024; 25:1428. [PMID: 38338706 PMCID: PMC10855977 DOI: 10.3390/ijms25031428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Telomere shortening, chromosomal damage, and mitochondrial dysfunction are major initiators of cell aging and biomarkers of many diseases. However, the underlying correlations between nuclear and mitochondrial DNA alterations remain unclear. We investigated the relationship between telomere length (TL) and micronucleus (MN) and their association with mitochondrial DNA copy number (mtDNAcn) in peripheral blood mononuclear cells (PBMCs) in response to 100 μM and 200 μM of hydrogen peroxide (H2O2) at 44, 72, and 96 h. Significant TL shortening was observed after both doses of H2O2 and at all times (all p < 0.05). A concomitant increase in MN was found at 72 h (p < 0.01) and persisted at 96 h (p < 0.01). An increase in mtDNAcn (p = 0.04) at 200 µM of H2O2 was also found. In PBMCs treated with 200 µM H2O2, a significant inverse correlation was found between TL and MN (r = -0.76, p = 0.03), and mtDNA content was directly correlated with TL (r = 0.6, p = 0.04) and inversely related to MN (r = -0.78, p = 0.02). Telomere shortening is the main triggering mechanism of chromosomal damage in stimulated T lymphocytes under oxidative stress. The significant correlations between nuclear DNA damage and mtDNAcn support the notion of a telomere-mitochondria axis that might influence age-associated pathologies and be a target for the development of relevant anti-aging drugs.
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Affiliation(s)
- Andrea Borghini
- CNR Institute of Clinical Physiology, 56124 Pisa, Italy; (R.N.); (P.C.); (I.M.); (A.M.); (S.T.); (M.G.A.)
| | - Rudina Ndreu
- CNR Institute of Clinical Physiology, 56124 Pisa, Italy; (R.N.); (P.C.); (I.M.); (A.M.); (S.T.); (M.G.A.)
| | - Paola Canale
- CNR Institute of Clinical Physiology, 56124 Pisa, Italy; (R.N.); (P.C.); (I.M.); (A.M.); (S.T.); (M.G.A.)
- Health Science Interdisciplinary Center, Sant’Anna School of Advanced Studies, 56124 Pisa, Italy
| | - Jonica Campolo
- CNR Institute of Clinical Physiology, ASST Grande Ospedale Metropolitano Niguarda, 20142 Milan, Italy;
| | - Irene Marinaro
- CNR Institute of Clinical Physiology, 56124 Pisa, Italy; (R.N.); (P.C.); (I.M.); (A.M.); (S.T.); (M.G.A.)
| | - Antonella Mercuri
- CNR Institute of Clinical Physiology, 56124 Pisa, Italy; (R.N.); (P.C.); (I.M.); (A.M.); (S.T.); (M.G.A.)
| | - Stefano Turchi
- CNR Institute of Clinical Physiology, 56124 Pisa, Italy; (R.N.); (P.C.); (I.M.); (A.M.); (S.T.); (M.G.A.)
| | - Maria Grazia Andreassi
- CNR Institute of Clinical Physiology, 56124 Pisa, Italy; (R.N.); (P.C.); (I.M.); (A.M.); (S.T.); (M.G.A.)
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Nassour J, Przetocka S, Karlseder J. Telomeres as hotspots for innate immunity and inflammation. DNA Repair (Amst) 2024; 133:103591. [PMID: 37951043 PMCID: PMC10842095 DOI: 10.1016/j.dnarep.2023.103591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/05/2023] [Accepted: 10/24/2023] [Indexed: 11/13/2023]
Abstract
Aging is marked by the gradual accumulation of deleterious changes that disrupt organ function, creating an altered physiological state that is permissive for the onset of prevalent human diseases. While the exact mechanisms governing aging remain a subject of ongoing research, there are several cellular and molecular hallmarks that contribute to this biological process. This review focuses on two factors, namely telomere dysfunction and inflammation, which have emerged as crucial contributors to the aging process. We aim to discuss the mechanistic connections between these two distinct hallmarks and provide compelling evidence highlighting the loss of telomere protection as a driver of pro-inflammatory states associated with aging. By reevaluating the interplay between telomeres, innate immunity, and inflammation, we present novel perspectives on the etiology of aging and its associated diseases.
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Affiliation(s)
- Joe Nassour
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, 12801 E. 17th Ave, Aurora, CO 80045, USA; The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Sara Przetocka
- The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Jan Karlseder
- The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA 92037, USA.
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Yue K, Yao X. Prognostic model based on telomere-related genes predicts the risk of oral squamous cell carcinoma. BMC Oral Health 2023; 23:484. [PMID: 37452322 PMCID: PMC10347773 DOI: 10.1186/s12903-023-03157-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 06/21/2023] [Indexed: 07/18/2023] Open
Abstract
BACKGROUND This study investigated a potential prognostic model based on telomere-related genes (TRGs) for the clinical prediction of oral squamous cell carcinoma (OSCC). METHODS Gene expression data and associated clinical phenotypes were obtained from online databases. Differentially expressed (DE)-TRGs were identified between OSCC and normal samples, followed by protein-protein interaction and enrichment analyses. Subsequently, the prognostic genes explored based on the DE-TRGs and survival data were applied in the establishment of the current prognostic model, and an integrated analysis was performed between high- and low-risk groups using a prognostic model. The expression of certain prognostic genes identified in the present study was validated using qPCR analysis and/or western blot in OSCC cell lines and clinical samples. RESULTS 169 DE-TRGs were identified between the OSCC samples and controls. DE-TRGs are mainly involved in functions such as hypoxia response and pathways such as the cell cycle. Eight TRGs (CCNB1, PDK4, PLOD2, RACGAP1, MET, PLK1, KPNA2, and CCNA2) associated with OSCC survival and prognosis were used to construct a prognostic model. qPCR analysis and western blot showed that most of the eight prognostic genes were consistent with the current bioinformatics results. Analysis of the high- and low-risk groups for OSCC determined by the prognostic model showed that the current prognostic model was reliable. CONCLUSIONS A novel prognostic model for OSCC was constructed by TRGs. PLOD2 and APLK1 may participate in the progression of OSCC via responses to hypoxia and cell cycle pathways, respectively. TRGs, including KPNA2 and CCNA2, may serve as novel prognostic biomarkers for OSCC.
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Affiliation(s)
- Kun Yue
- Department of Stomatology, Weifang Hospital of Traditional Chinese Medicine, Weifang, 261000, Shandong, China
| | - Xue Yao
- Department of Stomatology, Sunshine Union Hospital, 9000 Yingqian Road, High-tech Zone, Weifang, 261000, Shandong, China.
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Dhillon VS, Deo P, Fenech M. The Relationship between Telomere Length and Nucleoplasmic Bridges and Severity of Disease in Prostate Cancer Patients. Cancers (Basel) 2023; 15:3351. [PMID: 37444460 DOI: 10.3390/cancers15133351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Telomeres are repetitive nucleotide (TTAGGG) sequences that stabilize the chromosome ends and play an important role in the prevention of cancer initiation and progression. Nucleoplasmic bridges (NPBs) are formed when chromatids remain joined together during mitotic anaphase either due to mis-repair of DNA breaks or due to chromatid end fusion as a result of telomere loss or telomere dysfunction. We tested the hypotheses that (i) telomere length (TL) is shorter in prostate cancer (PC) patients relative to healthy age-matched individuals, (ii) TL differs in different stages of PC and (iii) shorter TL is significantly correlated with NPBs formation in PC cases. TL was measured in whole blood by well-established quantitative PCR method and the frequency of NPBs was measured in lymphocytes using cytokinesis-block micronucleus cytome (CBMNcyt) assay. Our results indicate that TL is shorter and NPBs are increased in PC patients relative to age-matched healthy controls. Furthermore, TL was significantly shorter (p = 0.03) in patients with a Gleason score more than 7 and there was also a significant trend of decreasing TL across all three stages (p trend = 0.01; Gleason score <7, 7 and >7). Furthermore, TL was significantly inversely correlated with NPB frequency in PC patients (r = -0.316; p = 0.001) but not in controls (r = 0.163; p = 0.06) and their relationships became stronger with higher Gleason scores. More studies are required that can confirm our observations and explore mechanistic differences in the role of telomeres in NPB formation in PC cases relative to non-cancer cases.
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Affiliation(s)
- Varinderpal S Dhillon
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide 5000, Australia
| | - Permal Deo
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide 5000, Australia
| | - Michael Fenech
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide 5000, Australia
- Genome Health Foundation, North Brighton 5048, Australia
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Sanpedro-Luna JA, Jacinto-Vázquez JJ, Anastacio-Marcelino E, Posadas-Gutiérrez CM, Olmos-Pineda I, González-Bernal JA, Carcaño-Montiel M, Vega-Alvarado L, Vázquez-Cruz C, Sánchez-Alonso P. Telomerase RNA plays a major role in the completion of the life cycle in Ustilago maydis and shares conserved domains with other Ustilaginales. PLoS One 2023; 18:e0281251. [PMID: 36952474 PMCID: PMC10035886 DOI: 10.1371/journal.pone.0281251] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/18/2023] [Indexed: 03/25/2023] Open
Abstract
The RNA subunit of telomerase is an essential component whose primary sequence and length are poorly conserved among eukaryotic organisms. The phytopathogen Ustilago maydis is a dimorphic fungus of the order Ustilaginales. We analyzed several species of Ustilaginales to computationally identify the TElomere RNA (TER) gene ter1. To confirm the identity of the TER gene, we disrupted the gene and characterized telomerase-negative mutants. Similar to catalytic TERT mutants, ter1Δ mutants exhibit phenotypes of growth delay, telomere shortening and low replicative potential. ter1-disrupted mutants were unable to infect maize seedlings in heterozygous crosses and showed defects such as cell cycle arrest and segregation failure. We concluded that ter1, which encodes the TER subunit of the telomerase of U. maydis, have similar and perhaps more extensive functions than trt1.
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Affiliation(s)
- Juan Antonio Sanpedro-Luna
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - José Juan Jacinto-Vázquez
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Estela Anastacio-Marcelino
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | | | - Iván Olmos-Pineda
- Facultad de Ciencias de la Computación, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Jesús Antonio González-Bernal
- Department of Computer Science and Engineering, The University of Texas Arlington, Arlington, Texas, United States of America
| | - Moisés Carcaño-Montiel
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Leticia Vega-Alvarado
- Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, México, México
| | - Candelario Vázquez-Cruz
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Patricia Sánchez-Alonso
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
- * E-mail:
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de Oliveira FM, Jamur VR, Merfort LW, Pozzo AR, Mai S. Three-dimensional nuclear telomere architecture and differential expression of aurora kinase genes in chronic myeloid leukemia to measure cell transformation. BMC Cancer 2022; 22:1024. [PMID: 36175852 PMCID: PMC9520804 DOI: 10.1186/s12885-022-10094-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 09/14/2022] [Indexed: 11/10/2022] Open
Abstract
Background Telomere dysfunction results in aneuploidy, and ongoing chromosomal abnormalities. The three-dimensional (3D) nuclear organization of telomeres allows for a distinction between normal and tumor cells. On the other hand, aurora kinase genes (AURKA and AURKB) play an important role regulating the cell cycle. A correlation between overexpression of aurora kinase genes and clinical aggressiveness has been demonstrated in different types of neoplasias. To better understand cellular and molecular mechanisms of CML evolution, it was examined telomere dysfunction (alterations in the 3D nuclear telomere architecture), and the expression levels of AURKA and AURKB genes in two clinical distinct subgroups of CML samples, from the same patient. Methods Eighteen CML patients, in total, 36 bone marrow samples (18 patients, chronic vs. accelerated/blast phase) were eligible for 3D telomeric investigations. Quantitative 3D imaging, cytologic diagnosis and cytogenetic determination of additional chromosomal abnormalities were assessed according to standard protocols. Results Using TeloView software, two CML subgroups were defined based on their 3D telomeric profiles, reflecting the different stages of the disease (chronic vs. accelerated/blast phase). Statistical analyses showed significant differences between the CML subgroups (p < 0.001). We also found that AURKA and AURKB mRNA were expressed at significantly higher levels in both CML subgroups, when compared with healthy donors. Our findings suggest that the evolution of CML progresses from a low to a high level of telomere dysfunction, that is, from an early stage to a more aggressive stage, followed by disease transformation, as demonstrated by telomere, additional chromosomal abnormalities, and gene expression profile dynamics. Conclusions Thus, we demonstrated that 3D telomere organization, in accordance with the genomic instability observed in CML samples were able to distinguish subgroup CML patients. Classifying CML patients based on these characteristics might represent an important strategy to define better therapeutic strategies.
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Affiliation(s)
- Fábio Morato de Oliveira
- Laboratory of Medical Genetics, Câmpus Jatobá - Cidade Universitária, Federal University of Jataí, BR 364, km 195, n° 3800, Jataí, CEP 75801-615, Brazil.
| | - Valderez Ravaglio Jamur
- Complexo Hospital das Clínicas, Universidade Federal do Paraná, Curitiba, Paraná, 80060-240, Brazil
| | - Lismeri Wuicik Merfort
- Complexo Hospital das Clínicas, Universidade Federal do Paraná, Curitiba, Paraná, 80060-240, Brazil
| | - Aline Rangel Pozzo
- Research Institute in Oncology and Hematology CancerCare Manitoba, The Genomic Centre for Cancer Research and Diagnosis, The University of Manitoba, Winnipeg, MB, R3E 0V9, Canada
| | - Sabine Mai
- Research Institute in Oncology and Hematology CancerCare Manitoba, The Genomic Centre for Cancer Research and Diagnosis, The University of Manitoba, Winnipeg, MB, R3E 0V9, Canada.
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Sharma R, Jindal R. In vivo genotoxic effects of commercial grade cypermethrin on fish peripheral erythrocytes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2022; 63:204-214. [PMID: 35527348 DOI: 10.1002/em.22484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/14/2022] [Accepted: 04/29/2022] [Indexed: 06/14/2023]
Abstract
The study explicates the genotoxic effects of commercial grade cypermethrin on peripheral erythrocytes of Catla catla, chronically exposed to two environmentally relevant concentrations. The fish was treated with sub-lethal concentrations 0.12 μg/L and 0.41 μg/L (1/10th and /1/3rd of 96 h LC50 ) of cypermethrin for 45 days. DNA damage in the exposed fish was assessed using alkaline comet assay, presence of micronuclei (MN), erythrocyte nuclear and cytoplasmic abnormalities. Exposure to cypermethrin induced a dose-dependent increase in percent DNA damage, micronucleus frequency and erythrocyte abnormalities. Nuclear anomalies such as notched nuclei, lobed nuclei, bridged nuclei, and deformed nuclei; and cytoplasmic anomalies like anisochromasia, vacuolated cytoplasm, lobed cells, and echinocytes were observed. The findings revealed the genotoxic potential of commercial formulations pyrethroid cypermethrin at concentrations found in the environment and their potential deleterious effects on nontarget aquatic organisms.
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Affiliation(s)
- Ritu Sharma
- Aquatic Biology Laboratory, Department of Zoology, Panjab University, Chandigarh, India
| | - Rajinder Jindal
- Aquatic Biology Laboratory, Department of Zoology, Panjab University, Chandigarh, India
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Obesity, oxidative DNA damage and vitamin D as predictors of genomic instability in children and adolescents. Int J Obes (Lond) 2021; 45:2095-2107. [PMID: 34158611 PMCID: PMC8380542 DOI: 10.1038/s41366-021-00879-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 05/18/2021] [Accepted: 05/27/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND/OBJECTIVES Epidemiological evidence indicates obesity in childhood and adolescence to be an independent risk factor for cancer and premature mortality in adulthood. Pathological implications from excess adiposity may begin early in life. Obesity is concurrent with a state of chronic inflammation, a well-known aetiological factor for DNA damage. In addition, obesity has been associated with micro-nutritional deficiencies. Vitamin D has attracted attention for its anti-inflammatory properties and role in genomic integrity and stability. The aim of this study was to determine a novel approach for predicting genomic instability via the combined assessment of adiposity, DNA damage, systemic inflammation, and vitamin D status. SUBJECTS/METHODS We carried out a cross-sectional study with 132 participants, aged 10-18, recruited from schools and paediatric obesity clinics in London. Anthropometric assessments included BMI Z-score, waist and hip circumference, and body fat percentage via bioelectrical impedance. Inflammation and vitamin D levels in saliva were assessed by enzyme-linked immunosorbent assay. Oxidative DNA damage was determined via quantification of 8-hydroxy-2'-deoxyguanosine in urine. Exfoliated cells from the oral cavity were scored for genomic instability via the buccal cytome assay. RESULTS As expected, comparisons between participants with obesity and normal range BMI showed significant differences in anthropometric measures (p < 0.001). Significant differences were also observed in some measures of genomic instability (p < 0.001). When examining relationships between variables for all participants, markers of adiposity positively correlated with acquired oxidative DNA damage (p < 0.01) and genomic instability (p < 0.001), and negatively correlated with vitamin D (p < 0.01). Multiple regression analyses identified obesity (p < 0.001), vitamin D (p < 0.001), and oxidative DNA damage (p < 0.05) as the three significant predictors of genomic instability. CONCLUSIONS Obesity, oxidative DNA damage, and vitamin D deficiency are significant predictors of genomic instability. Non-invasive biomonitoring and predictive modelling of genomic instability in young patients with obesity may contribute to the prioritisation and severity of clinical intervention measures.
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da Costa Araújo AP, de Andrade Vieira JE, Malafaia G. Toxicity and trophic transfer of polyethylene microplastics from Poecilia reticulata to Danio rerio. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140217. [PMID: 32623154 DOI: 10.1016/j.scitotenv.2020.140217] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
The potential transfer of microplastics (MPs) between vertebrates belonging to the same taxonomic group, and the impact of such a transfer on higher trophic levels remains little explored. An experimental food chain with two fish species was installed to test the hypothesis that polyethylene MPs (PE MPs) can accumulate in animals and cause behavioral, mutagenic and cytotoxic changes at upper trophic levels. Poecilia reticulata fry were exposed to MPs for 48 h and, subsequently, offered (as food) to Danio rerio adults for 10 days to simulate an upper level food chain. PE MPs quantification in fry and in different Danio rerio tissues evidenced their accumulation at the two assessed trophic levels. This finding suggested their absorption, adherence and translocation from one organism to another. The accumulation seen in D. rerio directly exposed to MPs was associated with behavioral disorders at upper trophic level. These animals presented behavior suggestive of anti-predatory response deficit when they were confronted with a potential aquatic predator (Geophagus brasiliensis). This finding was inferred through lower school cohesion, shallower school depth and shorter distance from the potential predator. In addition, animals exposed to MPs recorded higher nuclear abnormality rates and changes in the size and shape of erythrocytes and in their nuclei; this outcome has suggested mutagenic and cytotoxic effects, respectively. Based on the current results, MPs are transferred through a food chain that only involves two vertebrates. MPs enter the vertebrates' organs, change their behavior and induce mutagenic and cytotoxic processes in animals, which can cause significant ecological consequences in freshwater ecosystems.
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Affiliation(s)
- Amanda Pereira da Costa Araújo
- Biological Research Laboratory, Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus, Urutaí, GO, Brazil
| | - Julya Emmanuela de Andrade Vieira
- Biological Research Laboratory, Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus, Urutaí, GO, Brazil
| | - Guilherme Malafaia
- Biological Research Laboratory, Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus, Urutaí, GO, Brazil.
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Putative Origins of Cell-Free DNA in Humans: A Review of Active and Passive Nucleic Acid Release Mechanisms. Int J Mol Sci 2020; 21:ijms21218062. [PMID: 33137955 PMCID: PMC7662960 DOI: 10.3390/ijms21218062] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 12/14/2022] Open
Abstract
Through various pathways of cell death, degradation, and regulated extrusion, partial or complete genomes of various origins (e.g., host cells, fetal cells, and infiltrating viruses and microbes) are continuously shed into human body fluids in the form of segmented cell-free DNA (cfDNA) molecules. While the genetic complexity of total cfDNA is vast, the development of progressively efficient extraction, high-throughput sequencing, characterization via bioinformatics procedures, and detection have resulted in increasingly accurate partitioning and profiling of cfDNA subtypes. Not surprisingly, cfDNA analysis is emerging as a powerful clinical tool in many branches of medicine. In addition, the low invasiveness of longitudinal cfDNA sampling provides unprecedented access to study temporal genomic changes in a variety of contexts. However, the genetic diversity of cfDNA is also a great source of ambiguity and poses significant experimental and analytical challenges. For example, the cfDNA population in the bloodstream is heterogeneous and also fluctuates dynamically, differs between individuals, and exhibits numerous overlapping features despite often originating from different sources and processes. Therefore, a deeper understanding of the determining variables that impact the properties of cfDNA is crucial, however, thus far, is largely lacking. In this work we review recent and historical research on active vs. passive release mechanisms and estimate the significance and extent of their contribution to the composition of cfDNA.
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High homocysteine promotes telomere dysfunction and chromosomal instability in human neuroblastoma SH-SY5Y cells. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2020; 854-855:503197. [PMID: 32660821 DOI: 10.1016/j.mrgentox.2020.503197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/29/2022]
Abstract
Telomeres, specialized structures at the ends of linear chromosomes, protect chromosome ends from degradation, recombination, and mis-repair. Critically short telomere length (TL) may result in chromosome instability (CIN), causing tumor promotion and, at higher levels, cell death and tumor suppression. Homocysteine (Hcy) is a sulfur-containing amino acid involved in one-carbon metabolism. Elevated plasma Hcy is a cancer risk factor. Human SH-SY5Y neuroblastoma cells were treated with pathophysiological concentrations of Hcy (15-120 μM) for 14 and 28 days. The cytokinesis-block micronucleus cytome assay was used to determine cytostasis (nuclear division index, NDI), cell death (apoptosis and necrosis), and CIN (micronuclei, nucleoplasmic bridges, and nuclear buds in binucleated cells). Quantitative PCR was used to measure TL and the expression of hTERT, the gene encoding the catalytic subunit of telomerase for TL elongation. The results showed that Hcy induced elongation of TL and fluctuating changes in expression of hTERT. TL elongation was associated with increased CIN. Hcy decreased the NDI and increased cell death. This study shows that there is cross-talk between Hcy and TL in tumor cells and supports the concept that high Hcy inhibits cell division and promotes the death of tumor cells by abnormal elongation of TL and elevation of CIN.
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Handa K, Jindal R. Genotoxicity induced by hexavalent chromium leading to eryptosis in Ctenopharyngodon idellus. CHEMOSPHERE 2020; 247:125967. [PMID: 32069732 DOI: 10.1016/j.chemosphere.2020.125967] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/02/2020] [Accepted: 01/18/2020] [Indexed: 06/10/2023]
Abstract
The initiation of eryptosis as a result of genotoxic action of Cr(VI), seen through micronucleus and comet assay in the peripheral erythrocytes of Ctenopharyngodon idellus was evaluated through RT-qPCR. For this, fish was exposed to sublethal concentration of hexavalent chromium (5.30 and 10.63 mg/L), and the blood was sampled on different endpoints (15, 30 and 45 days). Accumulation of chromium in the erythrocytes was also studied, which depicted a significant increase in toxicant concentration and time dependent manner. Both concentrations of hexavalent chromium induced DNA damage, visible in the form of comet tails. The presence of micronuclei in the erythrocytes was accompanied with occurrence of nuclear bud (NBu), lobed nucleus (Lb), notched nucleus (Nt), vacuolated nucleus (Vn), binucleated cell (Bn) as nuclear abnormalities; and acanthocytes (Ac), echinocytes (Ec), notched cells (Nc), microcytes (Mc) and vacuolated cytoplasm (Vc) as cytoplasmic abnormalities. The expression of genes related to intrinsic apoptotic pathway induced by Cr(VI) presented significant (p < 0.05) upregulation in the expression of p53, Bax, Apaf-1, caspase9 and caspase3, and downregulation of Bcl2; inferring the initiation of apoptotic pathway. The ration of Bax and Bcl2 also appended the apoptotic state of the erythrocytes. From the present investigation, it can be concluded that genotoxicity induced by hexavalent chromium lead to eryptosis in C. idellus.
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Affiliation(s)
- Kriti Handa
- Aquatic Biology Laboratory, Department of Zoology, Panjab University, Chandigarh, 160014, India.
| | - Rajinder Jindal
- Aquatic Biology Laboratory, Department of Zoology, Panjab University, Chandigarh, 160014, India.
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da Costa Araújo AP, de Melo NFS, de Oliveira Junior AG, Rodrigues FP, Fernandes T, de Andrade Vieira JE, Rocha TL, Malafaia G. How much are microplastics harmful to the health of amphibians? A study with pristine polyethylene microplastics and Physalaemus cuvieri. JOURNAL OF HAZARDOUS MATERIALS 2020; 382:121066. [PMID: 31473515 DOI: 10.1016/j.jhazmat.2019.121066] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 08/20/2019] [Accepted: 08/20/2019] [Indexed: 05/20/2023]
Abstract
Microplastics (MPs) are critical emerging pollutants found in the environment worldwide; however, its toxicity in aquatic in amphibians, is poorly known. Thus, the aim of the present study is to assess the toxicological potential of polyethylene microplastics (PE MPs) in Physalaemus cuvieri tadpoles. According to the results, tadpoles' exposure to MP PE at concentration 60 mg/L for 7 days led to mutagenic effects, which were evidenced by the increased number of abnormalities observed in nuclear erythrocytes. The small size of erythrocytes and their nuclei area, perimeter, width, length, and radius, as well as the lower nucleus/cytoplasm ratio observed in tadpoles exposed to PE MPs confirmed its cytotoxicity. External morphological changes observed in the animal models included reduced ratio between total length and mouth-cloaca distance, caudal length, ocular area, mouth area, among others. PE MPs increased the number of melanophores in the skin and pigmentation rate in the assessed areas. Finally, PE MPs were found in gills, gastrointestinal tract, liver, muscle tissues of the tail and in the blood, a fact that confirmed MP accumulation by tadpoles. Therefore, the present study pioneering evidenced how MPs can affect the health of amphibians.
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Affiliation(s)
- Amanda Pereira da Costa Araújo
- Biological Research Laboratory, Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus, Urutaí, GO, Brazil
| | | | | | - Fernando Postalli Rodrigues
- Biological Research Laboratory, Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus, Urutaí, GO, Brazil
| | - Thiago Fernandes
- Laboratory of Electron Microscopy and Microanalysis, State University of Londrina, Londrina, PR, Brazil
| | - Julya Emmanuela de Andrade Vieira
- Biological Research Laboratory, Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus, Urutaí, GO, Brazil
| | - Thiago Lopes Rocha
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, GO, Brazil; Post-Graduation Program in Genetics and Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Guilherme Malafaia
- Biological Research Laboratory, Post-Graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus, Urutaí, GO, Brazil; Post-Graduation Program in Genetics and Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil.
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Klotho-Mediated Changes in Shelterin Complex Promote Cytotoxic Autophagy and Apoptosis in Amitriptyline-Treated Hippocampal Neuronal Cells. Mol Neurobiol 2019; 56:6952-6963. [DOI: 10.1007/s12035-019-1575-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 03/20/2019] [Indexed: 12/29/2022]
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Guo X, Ni J, Liang Z, Xue J, Fenech MF, Wang X. The molecular origins and pathophysiological consequences of micronuclei: New insights into an age-old problem. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 779:1-35. [PMID: 31097147 DOI: 10.1016/j.mrrev.2018.11.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 02/07/2023]
Abstract
Micronuclei (MN), the small nucleus-like bodies separated from the primary nucleus, can exist in cells with numerical and/or structural chromosomal aberrations in apparently normal tissues and more so in tumors in humans. While MN have been observed for over 100 years, they were merely and constantly considered as passive indicators of chromosome instability (CIN) for a long time. Relatively little is known about the molecular origins and biological consequences of MN. Rapid technological advances are helping to close these gaps. Very recent studies provide exciting evidence that MN act as key platform for chromothripsis and a trigger of innate immune response, suggesting that MN could affect cellular functions by both genetic and nongenetic means. These previously unappreciated findings have reawakened widespread interests in MN. In this review, the diverse mechanisms leading to MN generation and the complex fate profiles of MN are discussed, together with the evidence for their contribution to CIN, inflammation, senescence and cell death. Moreover, we put this knowledge together into a speculative perspective on how MN may be responsible for cancer development and how their presence may influence the choice of treatment. We suggest that the heterogeneous responses to MN may function physiological to ensure the arrestment, elimination and immune clearance of damaged cells, but pathologically, may enable the survival and oncogenic transformation of cells bearing CIN. These insights not only underscore the complexity of MN biology, but also raise a host of new questions and provide fertile ground for future research.
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Affiliation(s)
- Xihan Guo
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan, 650500, China
| | - Juan Ni
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan, 650500, China
| | - Ziqing Liang
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan, 650500, China
| | - Jinglun Xue
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Michael F Fenech
- University of South Australia, Adelaide, SA, 5000, Australia; Genome Health Foundation, North Brighton, SA, 5048, Australia.
| | - Xu Wang
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, Yunnan, 650500, China.
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17
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Gashi G, Mahovlić V, Manxhuka-Kerliu S, Podrimaj-Bytyqi A, Gashi L, Elezaj IR. The association between micronucleus, nucleoplasmic bridges, and nuclear buds frequency and the degree of uterine cervical lesions. Biomarkers 2018; 23:364-372. [PMID: 29338484 DOI: 10.1080/1354750x.2018.1428828] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIM The loss of genomic stability plays an important role in carcinogenesis. Therefore, it is imperative to use certain biomarkers of DNA damage due to genomic instability in order to predict cancer risk. The aim of this study was the evaluation of genomic instability in patients with cervical lesions. MATERIALS AND METHODS We investigated the genetic damages in 80 subjects: 40 patients with high-grade squamous intraepithelial lesions (HSIL), 20 patients with invasive squamous cervical cancer (SCC) and 20 healthy women with a biomarker in two different tissues; the micronucleus (MN) test in peripheral blood lymphocytes (PBL), and in buccal exfoliated cells (BEC). This study also examined the frequency of other nuclear anomalies such as nucleoplasmic bridges (NPBs) and nuclear bunds (NBUDs) in PBL. RESULTS The frequency of MN in BEC, MN in PBL, NPB in PBL and NBUD in PBL were significantly higher (p < 0.001), in patients compared to controls. The DNA damages in BEC and PBL were correlated positively with histological grade of cervical lesions. CONCLUSION Although larger studies are needed, our data support the predictive value of MN, NPB and NBUD as biomarkers of genomic instability for evaluation of risk level of cancer diseases.
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Affiliation(s)
- Goneta Gashi
- a Department of Pathology, Faculty of Medicine , University of Prishtina , Prishtina , Kosovo
| | - Vesna Mahovlić
- b Department of Pathology and Cytology , Clinical Unit of Gynecological Cytology, University Hospital Center , Zagreb , Croatia
| | - Suzana Manxhuka-Kerliu
- a Department of Pathology, Faculty of Medicine , University of Prishtina , Prishtina , Kosovo
| | - Arjeta Podrimaj-Bytyqi
- a Department of Pathology, Faculty of Medicine , University of Prishtina , Prishtina , Kosovo
| | - Luljeta Gashi
- c Department of Radiology, Faculty of Medicine , University of Prishtina , Prishtina , Kosovo
| | - Isa R Elezaj
- d Department of Biology, Faculty of Natural Sciences , University of Prishtina , Prishtina , Kosovo
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18
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Coluzzi E, Buonsante R, Leone S, Asmar AJ, Miller KL, Cimini D, Sgura A. Transient ALT activation protects human primary cells from chromosome instability induced by low chronic oxidative stress. Sci Rep 2017; 7:43309. [PMID: 28240303 PMCID: PMC5327399 DOI: 10.1038/srep43309] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 01/25/2017] [Indexed: 12/22/2022] Open
Abstract
Cells are often subjected to the effect of reactive oxygen species (ROS) as a result of both intracellular metabolism and exposure to exogenous factors. ROS-dependent oxidative stress can induce 8-oxodG within the GGG triplet found in the G-rich human telomeric sequence (TTAGGG), making telomeres highly susceptible to ROS-induced oxidative damage. Telomeres are nucleoprotein complexes that protect the ends of linear chromosomes and their dysfunction is believed to affect a wide range of cellular and/or organismal processes. Acute oxidative stress was shown to affect telomere integrity, but how prolonged low level oxidative stress, which may be more physiologically relevant, affects telomeres is still poorly investigated. Here, we explored this issue by chronically exposing human primary fibroblasts to a low dose of hydrogen peroxide. We observed fluctuating changes in telomere length and fluctuations in the rates of chromosome instability phenotypes, such that when telomeres shortened, chromosome instability increased and when telomeres lengthened, chromosome instability decreased. We found that telomere length fluctuation is associated with transient activation of an alternative lengthening of telomere (ALT) pathway, but found no evidence of cell death, impaired proliferation, or cell cycle arrest, suggesting that ALT activation may prevent oxidative damage from reaching levels that threaten cell survival.
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Affiliation(s)
- Elisa Coluzzi
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
| | - Rossella Buonsante
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Stefano Leone
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
| | - Anthony J. Asmar
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Kelley L. Miller
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Daniela Cimini
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
- Biocomplexity Institute, Virginia Tech, 1015 Life Science Circle, Blacksburg, VA, 24061, USA
| | - Antonella Sgura
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
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López González EC, Larriera A, Siroski PA, Poletta GL. Micronuclei and other nuclear abnormalities on Caiman latirostris (Broad-snouted caiman) hatchlings after embryonic exposure to different pesticide formulations. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 136:84-91. [PMID: 27821305 DOI: 10.1016/j.ecoenv.2016.10.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 10/26/2016] [Accepted: 10/27/2016] [Indexed: 06/06/2023]
Abstract
This study aimed to evaluate the embryotoxicity and genotoxicity of pesticide commercial formulations widely used in soybean crops through the Micronucleus (MN) test and other Nuclear Abnormalities (NAs) in erythrocytes of broad-snouted caiman (Caiman latirostris), exposed by topical application through the eggshell. Embryos were exposed (during all incubation: 70 days approximately) to sub-lethal concentrations of two glyphosate formulations PanzerGold® (PANZ) and Roundup® Full II (RU) (500, 750, 1000µg/egg); to the endosulfan (END) formulation Galgofan® and the cypermethrin (CYP) formulation Atanor® (1, 10, 100, and 1000µg/ egg). Blood samples were taken at the moment of hatching from the spinal vein for the application of the MN test and analysis of other NAs in erythrocytes, as markers of genotoxicity. Results indicated a significant increase in the frequency of MN for PANZ1000, END 10, CYP 1 and CYP 100 (p<0.05), and in the frequency of other NAs including Buds: END 100, 1000 and CYP 10 (p<0.05), eccentric nuclei: END 1, 10, 1000, CYP 10, 100, 1000 (p<0.01) and END 100 (p<0.05), notched nuclei: END 1, 10 (p<0.01) and END 1000, CYP 10, 100,1000 (p<0.05), and total nuclear abnormalities: END 1, 10, 100, 1000, CYP 10, 100 and 1000 (p<0.01), and the positive control (PC) (p<0.05), compared with the negative control. It was demonstrated a concentration dependent-effect in MN frequency only for PANZ (R2=0.98; p<0.01). Our study demonstrated that commercial formulations of pesticides induced genotoxic effects on C. latirostris, and NAs are a good indicator of genotoxicity in this specie.
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Affiliation(s)
- E C López González
- "Proyecto Yacaré'' - Lab. Zoología Aplicada: Anexo Vertebrados (FHUC-UNL/MMA), Av. Aristóbulo del Valle 8700, 3000 Santa Fe, Argetina; CONICET, Av Rivadavia 1917, C1033AAJ CABA, Argentina.
| | - A Larriera
- "Proyecto Yacaré'' - Lab. Zoología Aplicada: Anexo Vertebrados (FHUC-UNL/MMA), Av. Aristóbulo del Valle 8700, 3000 Santa Fe, Argetina
| | - P A Siroski
- "Proyecto Yacaré'' - Lab. Zoología Aplicada: Anexo Vertebrados (FHUC-UNL/MMA), Av. Aristóbulo del Valle 8700, 3000 Santa Fe, Argetina; CONICET, Av Rivadavia 1917, C1033AAJ CABA, Argentina; Instituto de Ciencias Veterinarias del Litoral (ICiVet-CONICET), Esperanza, Santa Fe, Argentina
| | - G L Poletta
- "Proyecto Yacaré'' - Lab. Zoología Aplicada: Anexo Vertebrados (FHUC-UNL/MMA), Av. Aristóbulo del Valle 8700, 3000 Santa Fe, Argetina; CONICET, Av Rivadavia 1917, C1033AAJ CABA, Argentina; Cát. Toxicol. y Bioq. Legal, FBCB-UNL, Ciudad Universitaria, Paraje El Pozo S/N, 3000 Santa Fe, Argentina
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20
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Andriani GA, Vijg J, Montagna C. Mechanisms and consequences of aneuploidy and chromosome instability in the aging brain. Mech Ageing Dev 2017; 161:19-36. [PMID: 27013377 PMCID: PMC5490080 DOI: 10.1016/j.mad.2016.03.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/17/2016] [Accepted: 03/19/2016] [Indexed: 01/31/2023]
Abstract
Aneuploidy and polyploidy are a form of Genomic Instability (GIN) known as Chromosomal Instability (CIN) characterized by sporadic abnormalities in chromosome copy numbers. Aneuploidy is commonly linked to pathological states. It is a hallmark of spontaneous abortions and birth defects and it is observed virtually in every human tumor, therefore being generally regarded as detrimental for the development or the maturation of tissues under physiological conditions. Polyploidy however, occurs as part of normal physiological processes during maturation and differentiation of some mammalian cell types. Surprisingly, high levels of aneuploidy are present in the brain, and their frequency increases with age suggesting that the brain is able to maintain its functionality in the presence of high levels of mosaic aneuploidy. Because somatic aneuploidy with age can reach exceptionally high levels, it is likely to have long-term adverse effects in this organ. We describe the mechanisms accountable for an abnormal DNA content with a particular emphasis on the CNS where cell division is limited. Next, we briefly summarize the types of GIN known to date and discuss how they interconnect with CIN. Lastly we highlight how several forms of CIN may contribute to genetic variation, tissue degeneration and disease in the CNS.
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Affiliation(s)
- Grasiella A Andriani
- Department of Genetics, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA; Department Ophthalmology and Visual Science, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA; Department of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Cristina Montagna
- Department of Genetics, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA; Department of Pathology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA.
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21
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Meenakshi C, Sivasubramanian K, Venkatraman B. Nucleoplasmic bridges as a biomarker of DNA damage exposed to radon. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2016; 814:22-28. [PMID: 28137364 DOI: 10.1016/j.mrgentox.2016.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 12/11/2016] [Accepted: 12/21/2016] [Indexed: 12/22/2022]
Abstract
Radon is a naturally occurring radionuclide in the environment, during decay it emits high linear energy transfer (LET) alpha particles. When radon exposure is accompanied by smoking it has been reported that lung cancer risk is higher. Blood samples were collected after prior consent, 25 smokers and 25 non smokers (only males) exposed in vitro to radon gas with doses ranging between 0.3-12.6mGy Ionizing radiation is a strong clastogenic agent and a potent inducer of MN. Cytokinesis-Blocked Micro Nucleus (CBMN) assay has proven to be a reliable, thoroughly validated and standardised technique in the field of radiation biology. In view of this, an invitro study has been undertaken using CBMN assay to suggest Nucleoplasmic bridges (NPBs) as a potential bio-dosimeter and to investigate the existence of a possible influence of smoking on genetic damage induced by ionizing radiation. The mean percentages frequencies of micronuclei, nucleoplasmic bridges and nuclear buds among the exposed smoker group were 4.82±0.271, 0.6±0.04 and 0.12±0.02 respectively and these values for exposed non-smoker group were 2.78±0.285, 0.4±0.04 and 0.06±0.01 respectively. Spearman rank correlation for the frequency of nucleoplasmic bridge with respect to dose was considered to be significant (P<0.05) in non-smokers. This study is first of its kind to investigate NPB as a biomarker of early DNA damage induced by radon.
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Affiliation(s)
- C Meenakshi
- Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, 603102, Tamilnadu, India.
| | - K Sivasubramanian
- Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, 603102, Tamilnadu, India
| | - B Venkatraman
- Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, 603102, Tamilnadu, India
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Fenech M, Knasmueller S, Bolognesi C, Bonassi S, Holland N, Migliore L, Palitti F, Natarajan AT, Kirsch-Volders M. Molecular mechanisms by which in vivo exposure to exogenous chemical genotoxic agents can lead to micronucleus formation in lymphocytes in vivo and ex vivo in humans. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 770:12-25. [DOI: 10.1016/j.mrrev.2016.04.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/18/2016] [Indexed: 12/24/2022]
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23
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Impaired nuclear functions in micronuclei results in genome instability and chromothripsis. Arch Toxicol 2016; 90:2657-2667. [PMID: 27542123 DOI: 10.1007/s00204-016-1818-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/04/2016] [Indexed: 12/25/2022]
Abstract
Micronuclei (MN) have generally been considered a consequence of DNA damage and, as such, have been used as markers of exposure to genotoxic agents. However, advances in DNA sequencing methods and the development of high-resolution microscopy with which to analyse chromosome dynamics in live cells have been fundamental in building a more refined view of the existing links between DNA damage and micronuclei. Here, we review recent progress indicating that defects of micronuclei affect basic nuclear functions, such as DNA repair and replication, generating massive damage in the chromatin of the MN. In addition, the physical isolation of chromosomes within MN offers an attractive mechanistic explanation for chromothripsis, a massive local DNA fragmentation that produces complex rearrangements restricted to only one or a few chromosomes. When micronuclear chromatin is reincorporated in the daughter cell nuclei, the under-replicated, damaged or rearranged micronuclear chromatin might contribute to genome instability. The traditional conception of micronuclei has been overturned, as they have evolved from passive indicators of DNA damage to active players in the formation of DNA lesions, thus unravelling previously unforeseen roles of micronuclei in the origins of chromosome instability.
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24
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Chromosome Bridges Maintain Kinetochore-Microtubule Attachment throughout Mitosis and Rarely Break during Anaphase. PLoS One 2016; 11:e0147420. [PMID: 26784746 PMCID: PMC4718638 DOI: 10.1371/journal.pone.0147420] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 01/04/2016] [Indexed: 11/19/2022] Open
Abstract
Accurate chromosome segregation during cell division is essential to maintain genome stability, and chromosome segregation errors are causally linked to genetic disorders and cancer. An anaphase chromosome bridge is a particular chromosome segregation error observed in cells that enter mitosis with fused chromosomes/sister chromatids. The widely accepted Breakage/Fusion/Bridge cycle model proposes that anaphase chromosome bridges break during mitosis to generate chromosome ends that will fuse during the following cell cycle, thus forming new bridges that will break, and so on. However, various studies have also shown a link between chromosome bridges and aneuploidy and/or polyploidy. In this study, we investigated the behavior and properties of chromosome bridges during mitosis, with the idea to gain insight into the potential mechanism underlying chromosome bridge-induced aneuploidy. We find that only a small number of chromosome bridges break during anaphase, whereas the rest persist through mitosis into the subsequent cell cycle. We also find that the microtubule bundles (k-fibers) bound to bridge kinetochores are not prone to breakage/detachment, thus supporting the conclusion that k-fiber detachment is not the cause of chromosome bridge-induced aneuploidy. Instead, our data suggest that while the microtubules bound to the kinetochores of normally segregating chromosomes shorten substantially during anaphase, the k-fibers bound to bridge kinetochores shorten only slightly, and may even lengthen, during anaphase. This causes some of the bridge kinetochores/chromosomes to lag behind in a position that is proximal to the cell/spindle equator and may cause the bridged chromosomes to be segregated into the same daughter nucleus or to form a micronucleus.
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Feijoo P, Terradas M, Soler D, Domínguez D, Tusell L, Genescà A. Breast primary epithelial cells that escape p16-dependent stasis enter a telomere-driven crisis state. Breast Cancer Res 2016; 18:7. [PMID: 26758019 PMCID: PMC4711177 DOI: 10.1186/s13058-015-0667-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/22/2015] [Indexed: 01/07/2023] Open
Abstract
Breast cancer is the most common malignant disease in women, but some basic questions remain in breast cancer biology. To answer these, several cell models were developed. Recently, the use of improved cell-culture conditions has enabled the development of a new primary cell model with certain luminal characteristics. This model is relevant because, after the introduction of a specific set of genetic elements, the transformed cells yielded tumors resembling human adenocarcinomas in mice. The use of improved cell-culture conditions supporting the growth of these breast primary epithelial cells was expected to delay or eliminate stress-induced senescence and lead to the propagation of normal cells. However, no studies have been carried out to investigate these points. Propagation of breast primary epithelial cells was performed in WIT medium on Primaria plates. Immunofluorescence, western blot and qRT-PCR were used to detect molecular markers, and to determine the integrity of DNA damage-response pathways. Promoter methylation of p16 (INK4a) was assessed by pyrosequencing. In order to obtain a dynamic picture of chromosome instability over time in culture, we applied FISH methodologies. To better link chromosome instability with excessive telomere attrition, we introduced the telomerase reverse transcriptase human gene using a lentiviral vector. We report here that breast primary epithelial cells propagated in vitro with WIT medium on Primaria plates express some luminal characteristics, but not a complete luminal lineage phenotype. They undergo a p16-dependent stress-induced senescence (stasis), and the cells that escape stasis finally enter a crisis state with rampant chromosome instability. Chromosome instability in these cells is driven by excessive telomere attrition, as distributions of chromosomes involved in aberrations correlate with the profiles of telomere signal-free ends. Importantly, ectopic expression of the human TERT gene rescued their chromosomal instability phenotype. Essentially, our data show that contrary to what was previously suggested, improved culture conditions to propagate in vitro mammary epithelial cells with some luminal characteristics do not prevent stress-induced senescence. This barrier is overcome by spontaneous methylation of the p16 (INK4a) promoter, allowing the proliferation of cells with telomere dysfunction and ensuing chromosome instability.
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Affiliation(s)
- Purificación Feijoo
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
| | - Mariona Terradas
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
| | - David Soler
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
| | - Daniel Domínguez
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
| | - Laura Tusell
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
| | - Anna Genescà
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
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Zhao F, Wang B, Zhang X, Tian H, Wang W, Ru S. Induction of DNA base damage and strand breaks in peripheral erythrocytes and the underlying mechanism in goldfish (Carassius auratus) exposed to monocrotophos. FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:613-624. [PMID: 25666866 DOI: 10.1007/s10695-015-0032-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 02/03/2015] [Indexed: 06/04/2023]
Abstract
Using goldfish (Carassius auratus) as the model animal, the present study revealed the types of the DNA damage induced by monocrotophos, a highly toxic organophosphorus pesticide, and explored the mechanism underlying the DNA-damaging effect of this pesticide. Results of the alkaline comet assay showed that global DNA damage (including single- and double-strand breaks and alkali-labile sites) in peripheral erythrocytes of goldfish, measured as olive tail moment, was significantly increased by exposure to 0.01, 0.10, and 1.00 mg/L monocrotophos for 24, 48, 96, and 168 h. In particular, alkali-labile sites rather than single- or double-strand breaks, distinguished by the alkaline, pH 12.1, and neutral comet assays, were mainly induced by monocrotophos at 48 h. Oxidative damage in DNA bases and telomeric DNA was investigated by using the alkaline comet assay combined with endonuclease III or formamidopyrimidine DNA glycosylase and with fluorescence in situ hybridization, respectively. Further, glutathione peroxidase activity significantly decreased at 24 h but increased at 96 and 168 h, and malondialdehyde concentrations significantly increased at 48 h but gradually decreased at 96 and 168 h, which indicated an over-production of reactive oxygen species (ROS) at short exposure durations, but effective scavenging at long exposure durations in the peripheral blood tissues. Accordingly, our results suggest that DNA damage induced by monocrotophos in fish blood cells is possibly due to the inhibition of ROS scavenging and resulted accumulation of ROS.
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Affiliation(s)
- Fei Zhao
- Marine Life Science College, Ocean University of China, 5 Yushan Road, Qingdao, 266003, Shandong Province, People's Republic of China
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Zeljezic D, Bjelis M, Mladinic M. Evaluation of the mechanism of nucleoplasmic bridge formation due to premature telomere shortening in agricultural workers exposed to mixed pesticides: indication for further studies. CHEMOSPHERE 2015; 120:45-51. [PMID: 24974313 DOI: 10.1016/j.chemosphere.2014.05.085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/27/2014] [Accepted: 05/31/2014] [Indexed: 06/03/2023]
Abstract
Agricultural workers are often exposed to high levels of pesticides over prolonged periods of time. We attempted to determine whether exposure to multiple pesticides shortens relative telomere length (RTL) and causes nucleoplasmic bridge (NPB) formation via the mechanism of telomere-end fusion in the lymphocytes of agricultural workers. For measuring RTL, we used quantitative fluorescent in situ hybridization, while NPB frequency was measured as part of the cytome assay. Multivariate analysis of variances taking into account confounding factors (age, gender, years of exposure, smoking, and alcohol intake) did not show a decrease, but rather an increase of RTL in agricultural workers compared to control individuals. In the exposed population, NPB frequency was significantly higher compared to controls (6 times, p<0.05). Multiple regression between NPB, RTL, and confounding factors was not significant. Using Spearman correlation, we did not find proof for our initial hypothesis. Our hypothesis that telomere shortening is a mechanism of NPB origin was not proven, indicating that telomere-end fusion is not a mechanism of NPB formation under our experimental conditions for agricultural workers.
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Affiliation(s)
- Davor Zeljezic
- Division for Mutagenesis, Institute for Medical Research and Occupational Health, Ksaverska 2, 10000 Zagreb, Croatia
| | - Marija Bjelis
- Economic High School Velika Gorica, Ulica Kralja Stjepana Tomaševića 21, 10410 Velika Gorica, Croatia
| | - Marin Mladinic
- Division for Mutagenesis, Institute for Medical Research and Occupational Health, Ksaverska 2, 10000 Zagreb, Croatia.
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Baršienė J, Butrimavičienė L, Michailovas A, Grygiel W. Assessing the environmental genotoxicity risk in the Baltic Sea: frequencies of nuclear buds in blood erythrocytes of three native fish species. ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:4078. [PMID: 25384369 DOI: 10.1007/s10661-014-4078-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 10/28/2014] [Indexed: 06/04/2023]
Abstract
Nuclear bud (NB) formation was investigated in blood erythrocytes of 1892 flounder Platichthys flesus, herring Clupea harengus, and eelpout Zoarces viviparus specimens that were collected at 82 sites representing different regions of the Baltic Sea in 2009-2011. This is the first attempt to evaluate the baseline levels of NB and rank the genotoxicity risk for native fish species. NB levels were compared to the previously published micronuclei (MN) data from the same individual fish specimens in order to compare the two methods of genotoxicity assessment and investigate the relationship between MN as the cytogenetic measure of genotoxicity and the DNA damage reflecting NB. In 2009-2011, elevated NB levels in 89.4% of flounder sampling groups indicated high and extremely high genotoxicity risk levels. Herring and eelpout sampling groups showed elevated levels of NB, 74.6 and 45.7%, respectively. In general, herring and eelpout NB measure was more sensitive as the genotoxicity biomarker than MN.
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Affiliation(s)
- Janina Baršienė
- Nature Research Centre, Akademijos 2, 08412, Vilnius, Lithuania
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Oxidative stress induces persistent telomeric DNA damage responsible for nuclear morphology change in mammalian cells. PLoS One 2014; 9:e110963. [PMID: 25354277 PMCID: PMC4212976 DOI: 10.1371/journal.pone.0110963] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/22/2014] [Indexed: 02/07/2023] Open
Abstract
One main function of telomeres is to maintain chromosome and genome stability. The rate of telomere shortening can be accelerated significantly by chemical and physical environmental agents. Reactive oxygen species are a source of oxidative stress and can produce modified bases (mainly 8-oxoG) and single strand breaks anywhere in the genome. The high incidence of guanine residues in telomeric DNA sequences makes the telomere a preferred target for oxidative damage. Our aim in this work is to evaluate whether chromosome instability induced by oxidative stress is related specifically to telomeric damage. We treated human primary fibroblasts (MRC-5) in vitro with hydrogen peroxide (100 and 200 µM) for 1 hr and collected data at several time points. To evaluate the persistence of oxidative stress-induced DNA damage up to 24 hrs after treatment, we analysed telomeric and genomic oxidative damage by qPCR and a modified comet assay, respectively. The results demonstrate that the genomic damage is completely repaired, while the telomeric oxidative damage persists. The analysis of telomere length reveals a significant telomere shortening 48 hrs after treatment, leading us to hypothesise that residual telomere damage could be responsible for the telomere shortening observed. Considering the influence of telomere length modulation on genomic stability, we quantified abnormal nuclear morphologies (Nucleoplasmic Bridges, Nuclear Buds and Micronuclei) and observed an increase of chromosome instability in the same time frame as telomere shortening. At subsequent times (72 and 96 hrs), we observed a restoration of telomere length and a reduction of chromosome instability, leaving us to conjecture a correlation between telomere shortening/dysfunction and chromosome instability. We can conclude that oxidative base damage leads to abnormal nuclear morphologies and that telomere dysfunction is an important contributor to this effect.
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Samassekou O, Bastien N, Lichtensztejn D, Yan J, Mai S, Drouin R. DifferentTP53mutations are associated with specific chromosomal rearrangements, telomere length changes, and remodeling of the nuclear architecture of telomeres. Genes Chromosomes Cancer 2014; 53:934-50. [DOI: 10.1002/gcc.22205] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 07/02/2014] [Indexed: 02/06/2023] Open
Affiliation(s)
- Oumar Samassekou
- Division of Genetics; Department of Pediatrics; Faculty of Medicine and Health Sciences; Université de Sherbrooke; Sherbrooke QC Canada
- Manitoba Institute of Cell Biology; CancerCare Manitoba; Department of Physiology; Faculty of Medicine, University of Manitoba; Winnipeg MB Canada
| | - Nathalie Bastien
- Division of Genetics; Department of Pediatrics; Faculty of Medicine and Health Sciences; Université de Sherbrooke; Sherbrooke QC Canada
| | - Daniel Lichtensztejn
- Manitoba Institute of Cell Biology; CancerCare Manitoba; Department of Physiology; Faculty of Medicine, University of Manitoba; Winnipeg MB Canada
| | - Ju Yan
- Division of Genetics; Department of Pediatrics; Faculty of Medicine and Health Sciences; Université de Sherbrooke; Sherbrooke QC Canada
| | - Sabine Mai
- Manitoba Institute of Cell Biology; CancerCare Manitoba; Department of Physiology; Faculty of Medicine, University of Manitoba; Winnipeg MB Canada
| | - Régen Drouin
- Division of Genetics; Department of Pediatrics; Faculty of Medicine and Health Sciences; Université de Sherbrooke; Sherbrooke QC Canada
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31
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Meier B, Cooke SL, Weiss J, Bailly AP, Alexandrov LB, Marshall J, Raine K, Maddison M, Anderson E, Stratton MR, Gartner A, Campbell PJ. C. elegans whole-genome sequencing reveals mutational signatures related to carcinogens and DNA repair deficiency. Genome Res 2014; 24:1624-36. [PMID: 25030888 PMCID: PMC4199376 DOI: 10.1101/gr.175547.114] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Mutation is associated with developmental and hereditary disorders, aging, and cancer. While we understand some mutational processes operative in human disease, most remain mysterious. We used Caenorhabditis elegans whole-genome sequencing to model mutational signatures, analyzing 183 worm populations across 17 DNA repair-deficient backgrounds propagated for 20 generations or exposed to carcinogens. The baseline mutation rate in C. elegans was approximately one per genome per generation, not overtly altered across several DNA repair deficiencies over 20 generations. Telomere erosion led to complex chromosomal rearrangements initiated by breakage–fusion–bridge cycles and completed by simultaneously acquired, localized clusters of breakpoints. Aflatoxin B1 induced substitutions of guanines in a GpC context, as observed in aflatoxin-induced liver cancers. Mutational burden increased with impaired nucleotide excision repair. Cisplatin and mechlorethamine, DNA crosslinking agents, caused dose- and genotype-dependent signatures among indels, substitutions, and rearrangements. Strikingly, both agents induced clustered rearrangements resembling “chromoanasynthesis,” a replication-based mutational signature seen in constitutional genomic disorders, suggesting that interstrand crosslinks may play a pathogenic role in such events. Cisplatin mutagenicity was most pronounced in xpf-1 mutants, suggesting that this gene critically protects cells against platinum chemotherapy. Thus, experimental model systems combined with genome sequencing can recapture and mechanistically explain mutational signatures associated with human disease.
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Affiliation(s)
- Bettina Meier
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Susanna L Cooke
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
| | - Joerg Weiss
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Aymeric P Bailly
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom; CRBM/CNRS UMR5237, University of Montpellier, Montpellier 34293, France
| | - Ludmil B Alexandrov
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
| | - John Marshall
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
| | - Keiran Raine
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
| | - Mark Maddison
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
| | - Elizabeth Anderson
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
| | - Michael R Stratton
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
| | - Anton Gartner
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom;
| | - Peter J Campbell
- Cancer Genome Project, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom; Department of Haematology, University of Cambridge, Cambridge CB2 0XY, United Kingdom; Department of Haematology, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
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Dynamic length changes of telomeres and their nuclear organization in chronic myeloid leukemia. Cancers (Basel) 2013; 5:1086-102. [PMID: 24202335 PMCID: PMC3795380 DOI: 10.3390/cancers5031086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 08/08/2013] [Accepted: 08/16/2013] [Indexed: 01/11/2023] Open
Abstract
Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the t(9;22) translocation. As in most cancers, short telomeres are one of the features of CML cells, and telomere shortening accentuates as the disease progresses from the chronic phase to the blastic phase. Although most individual telomeres are short, some of them are lengthened, and long individual telomeres occur non-randomly and might be associated with clonal selection. Telomerase is the main mechanism used to maintain telomere lengths, and its activity increases when CML evolves toward advanced stages. ALT might be another mechanism employed by CML cells to sustain the homeostasis of their telomere lengths and this mechanism seems predominant at the early stage of leukemogenesis. Also, telomerase and ALT might jointly act to maintain telomere lengths at the chronic phase, and as CML progresses, telomerase becomes the major mechanism. Finally, CML cells display an altered nuclear organization of their telomeres which is characterized by the presence of high number of telomeric aggregates, a feature of genomic instability, and differential positioning of telomeres. CML represents a good model to study mechanisms responsible for dynamic changes of individual telomere lengths and the remodeling of telomeric nuclear organization throughout cancer progression.
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Bhatia A, Kumar Y. Relevance of microscopic indicators of chromosomal instability in routine reporting of malignancies. Diagn Cytopathol 2013; 42:181-8. [PMID: 23754835 DOI: 10.1002/dc.23012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 02/22/2013] [Accepted: 04/04/2013] [Indexed: 11/12/2022]
Abstract
Chromosomal instability (CIN) is the defining feature of most human cancers. The role of CIN has been suggested in diagnosis and prognostication of the tumors since long. However, the molecular methods used for its identification are costly, require expertise and may not be available in many of the laboratories. Therefore, this article tries to revisit the already described morphological indicators of CIN like multipolar mitoses, chromatin bridges, chromatin strings, nuclear heterogeneity, laggards, nuclear buds, micronuclei, and multinucleated micronucleated cells. The role of above as morphological biomarkers in diagnosis and prognosis of various cancers has been reviewed and the possibility of their inclusion in day to day reporting of malignancies is also discussed.
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Affiliation(s)
- Alka Bhatia
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, 160012, India
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Gonzalez-Vasconcellos I, Anastasov N, Sanli-Bonazzi B, Klymenko O, Atkinson MJ, Rosemann M. Rb1 haploinsufficiency promotes telomere attrition and radiation-induced genomic instability. Cancer Res 2013; 73:4247-55. [PMID: 23687339 DOI: 10.1158/0008-5472.can-12-3117] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Germline mutations of the retinoblastoma gene (RB1) predispose to both sporadic and radiation-induced osteosarcoma, tumors characterized by high levels of genomic instability, and activation of alternative lengthening of telomeres. Mice with haploinsufficiency of the Rb1 gene in the osteoblastic lineage reiterate the radiation susceptibility to osteosarcoma seen in patients with germline RB1 mutations. We show that the susceptibility is accompanied by an increase in genomic instability, resulting from Rb1-dependent telomere erosion. Radiation exposure did not accelerate the rate of telomere loss but amplified the genomic instability resulting from the dysfunctional telomeres. These findings suggest that telomere maintenance is a noncanonical caretaker function of the retinoblastoma protein, such that its deficiency in cancer may potentiate DNA damage-induced carcinogenesis by promoting formation of chromosomal aberrations, rather than simply by affecting cell-cycle control.
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Hartwig FP, Collares T. Telomere dysfunction and tumor suppression responses in dyskeratosis congenita: balancing cancer and tissue renewal impairment. Ageing Res Rev 2013; 12:642-52. [PMID: 23541441 DOI: 10.1016/j.arr.2013.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/13/2013] [Accepted: 03/18/2013] [Indexed: 01/06/2023]
Abstract
Dyskeratosis congenita (DC) encompasses a large spectrum of diseases and clinical manifestations generally related to premature aging, including bone marrow failure and cancer predisposition. The major risk factor for DC is to carry germline telomere-related mutations - in telomerase or telomere shelterin genes - which results in premature telomere dysfunction, thus increasing the risk of premature aging impairments. Despite the advances that have been accomplished in DC research, the molecular aspects underlying the phenotypic variability of the disease remain poorly understood. Here different aspects of telomere biology, concerning adult stem cells senescence, tumor suppression and cancer are considered in the context of DC, resulting in two translational models: late onset of DC symptoms in telomere-related mutations carriers is a potential indicator of increased cancer risk and differences in tumor suppression capacities among the genetic subgroups are (at least partial) causes of different clinical manifestations of the disease. The limitations of both models are presented, and further experiments for their validation, as well as clinical implications, are discussed.
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36
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Wu J, Ji X, Zhu L, Jiang Q, Wen Z, Xu S, Shao W, Cai J, Du Q, Zhu Y, Mao J. Up-regulation of microRNA-1290 impairs cytokinesis and affects the reprogramming of colon cancer cells. Cancer Lett 2012; 329:155-63. [PMID: 23142292 DOI: 10.1016/j.canlet.2012.10.038] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/25/2012] [Accepted: 10/27/2012] [Indexed: 02/07/2023]
Abstract
Abnormal cytokinesis increases the possibility of nuclear fusion in tumor cells. However, the role of microRNAs (miRNAs) in abnormal cytokinesis is unclear. Here, we found that miR-1290 was significantly up-regulated in clinical colon cancer tissues. Up-regulation of miR-1290 postponed cytokinesis and led to the formation of multinucleated cells. KIF13B was a target of miR-1290 that was involved in aberrant cytokinesis. Furthermore, enforced expression of miR-1290 activated the Wnt pathway and increased the reprogramming-related transcript factors c-Myc and Nanog. Our results suggest that up-regulation of miR-1290 in colon cancer cells impaired cytokinesis and affected reprogramming.
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Affiliation(s)
- Jia Wu
- Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province 310009, China
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Anbumani S, Mohankumar MN. Gamma radiation induced micronuclei and erythrocyte cellular abnormalities in the fish Catla catla. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 122-123:125-132. [PMID: 22771702 DOI: 10.1016/j.aquatox.2012.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 06/06/2012] [Accepted: 06/06/2012] [Indexed: 06/01/2023]
Abstract
Ionizing radiation induced DNA damage in fishes is a scarcely studied topic and very few studies are available in fishes exposed to ionizing radiation using the erythrocyte micronucleus assay under laboratory conditions. Since radionuclides released accidentally or during a nuclear disaster can contaminate inland water bodies, biomonitoring methods are required for assessing the impacts of high and low levels of radiation that may ultimately result in ionizing radiation exposure to both humans and non-human biota. Fresh water fish, Catla catla were subjected to protracted (0.002 Gy/min) and acute (3.2 Gy/min) gamma radiation to a total dose of 5 Gy. Peripheral blood samples were collected at different intervals (days 3, 6, 12, 18, 30, 45, 90, 135, 202) and analyzed by the erythrocyte micronucleus assay. Nuclear anomalies observed were micronuclei (MN), deformed nuclei (DN), nuclear bud (NBu), nuclear bridge (NBr), vacuolated nucleus (VN), binucleated cell (BNC), apoptotic cells (AC) while cytoplasmic abnormalities detected were vacuolated cytoplasm (VC), anisochromasia (AN), echinocytes (EC) and enucleus (EN). Both exposures caused a statistically significant increase in nuclear and cytoplasmic abnormalities that correlated with micronucleus and other nuclear anomalies. However, the extent of damage is higher after an acute exposure lasting for a longer period leading to apoptosis. Nuclear and cytoplasmic abnormalities are the resultants of gamma radiation induced genotoxicity and cytotoxicity.
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Affiliation(s)
- S Anbumani
- Biodosimetry Laboratory, Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu 603102, India
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38
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Hartwig FP, Nedel F, Collares TV, Tarquinio SBC, Nör JE, Demarco FF. Telomeres and Tissue Engineering: The Potential Roles of TERT in VEGF-mediated Angiogenesis. Stem Cell Rev Rep 2012; 8:1275-81. [DOI: 10.1007/s12015-012-9414-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Terradas M, Martín M, Hernández L, Tusell L, Genescà A. Is DNA damage response ready for action anywhere? Int J Mol Sci 2012; 13:11569-11583. [PMID: 23109871 PMCID: PMC3472763 DOI: 10.3390/ijms130911569] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 09/06/2012] [Accepted: 09/07/2012] [Indexed: 11/16/2022] Open
Abstract
Organisms are continuously exposed to DNA damaging agents, consequently, cells have developed an intricate system known as the DNA damage response (DDR) in order to detect and repair DNA lesions. This response has to be rapid and accurate in order to keep genome integrity. It has been observed that the condensation state of chromatin hinders a proper DDR. However, the condensation state of chromatin is not the only barrier to DDR. In this review, we have collected data regarding the presence of DDR factors on micronuclear DNA lesions that indicate that micronuclei are almost incapable of generating an effective DDR because of defects in their nuclear envelope. Finally, considering the recent observations about the reincorporation of micronuclei to the main bulk of chromosomes, we suggest that, under certain circumstances, micronuclei carrying DNA damage might be a source of chromosome instability.
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Affiliation(s)
- Mariona Terradas
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +34-935-811-498; Fax: +34-935-812-295
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Pampalona J, Frías C, Genescà A, Tusell L. Progressive telomere dysfunction causes cytokinesis failure and leads to the accumulation of polyploid cells. PLoS Genet 2012; 8:e1002679. [PMID: 22570622 PMCID: PMC3343085 DOI: 10.1371/journal.pgen.1002679] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 03/14/2012] [Indexed: 11/18/2022] Open
Abstract
Most cancer cells accumulate genomic abnormalities at a remarkably rapid rate, as they are unable to maintain their chromosome structure and number. Excessively short telomeres, a known source of chromosome instability, are observed in early human-cancer lesions. Besides telomere dysfunction, it has been suggested that a transient phase of polyploidization, in most cases tetraploidization, has a causative role in cancer. Proliferation of tetraploids can gradually generate subtetraploid lineages of unstable cells that might fire the carcinogenic process by promoting further aneuploidy and genomic instability. Given the significance of telomere dysfunction and tetraploidy in the early stages of carcinogenesis, we investigated whether there is a connection between these two important promoters of chromosomal instability. We report that human mammary epithelial cells exhibiting progressive telomere dysfunction, in a pRb deficient and wild-type p53 background, fail to complete the cytoplasmatic cell division due to the persistence of chromatin bridges in the midzone. Flow cytometry together with fluorescence in situ hybridization demonstrated an accumulation of binucleated polyploid cells upon serial passaging cells. Restoration of telomere function through hTERT transduction, which lessens the formation of anaphase bridges by recapping the chromosome ends, rescued the polyploid phenotype. Live-cell imaging revealed that these polyploid cells emerged after abortive cytokinesis due to the persistence of anaphase bridges with large intervening chromatin in the cleavage plane. In agreement with a primary role of anaphase bridge intermediates in the polyploidization process, treatment of HMEC-hTERT cells with bleomycin, which produces chromatin bridges through illegimitate repair, resulted in tetraploid binucleated cells. Taken together, we demonstrate that human epithelial cells exhibiting physiological telomere dysfunction engender tetraploid cells through interference of anaphase bridges with the completion of cytokinesis. These observations shed light on the mechanisms operating during the initial stages of human carcinogenesis, as they provide a link between progressive telomere dysfunction and tetraploidy. Chromosome instability leads to the accumulation of chromosome number and structure aberrations that have been suggested as necessary for neoplastic transformation. Telomeres, specialized DNA–protein complexes localized at the physical ends of linear chromosomes, are crucial for maintaining chromosome stability. Massive chromosomal instability may occur when cells continuously proliferate in the absence of specific telomere elongation mechanisms. Besides telomere dysfunction, it has been suggested that a transient phase of tetraploidization has a causative role in cancer. This study provides a link between dysfunctional telomeres and the generation of tetraploids. Using a human mammary epithelial cell model, we show that diploid cells exhibiting progressive telomere dysfunction, in a p53 proficient background, engender tetraploid cells through cytokinesis failure. Our studies give new insights into the mechanisms that may facilitate the evolution of malignant phenotypes: telomere-dependent chromosome instability would engender tetraploid intermediates that, on division, would promote further cellular genome remodelling, which is needed at the early stages of tumour development in order for cells to become neoplasic.
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Affiliation(s)
| | | | | | - Laura Tusell
- Department of Cell Biology, Physiology, and Immunology, Bioscience School, Universitat Autònoma de Barcelona, Bellaterra, Spain
- * E-mail:
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Abstract
The unprecedented resolution of high-throughput genomics has enabled the recent discovery of a phenomenon by which specific regions of the genome are shattered and then stitched together via a single devastating event, referred to as chromothripsis. Potential mechanisms governing this process are now emerging, with implications for our understanding of the role of genomic rearrangements in development and disease.
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Chung SW, Cooper CR, Farach-Carson MC, Ogunnaike BA. A control engineering approach to understanding the TGF-β paradox in cancer. J R Soc Interface 2011; 9:1389-97. [PMID: 22188767 DOI: 10.1098/rsif.2011.0799] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
TGF-β, a key cytokine that regulates diverse cellular processes, including proliferation and apoptosis, appears to function paradoxically as a tumour suppressor in normal cells, and as a tumour promoter in cancer cells, but the mechanisms underlying such contradictory roles remain unknown. In particular, given that this cytokine is primarily a tumour suppressor, the conundrum of the unusually high level of TGF-β observed in the primary cancer tissue and blood samples of cancer patients with the worst prognosis, remains unresolved. To provide a quantitative explanation of these paradoxical observations, we present, from a control theory perspective, a mechanistic model of TGF-β-driven regulation of cell homeostasis. Analysis of the overall system model yields quantitative insight into how cell population is regulated, enabling us to propose a plausible explanation for the paradox: with the tumour suppressor role of TGF-β unchanged from normal to cancer cells, we demonstrate that the observed increased level of TGF-β is an effect of cancer cell phenotypic progression (specifically, acquired TGF-β resistance), not the cause. We are thus able to explain precisely why the clinically observed correlation between elevated TGF-β levels and poor prognosis is in fact consistent with TGF-β's original (and unchanged) role as a tumour suppressor.
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Affiliation(s)
- Seung-Wook Chung
- Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA
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Utani KI, Okamoto A, Shimizu N. Generation of micronuclei during interphase by coupling between cytoplasmic membrane blebbing and nuclear budding. PLoS One 2011; 6:e27233. [PMID: 22073297 PMCID: PMC3206950 DOI: 10.1371/journal.pone.0027233] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 10/12/2011] [Indexed: 11/22/2022] Open
Abstract
Micronucleation, mediated by interphase nuclear budding, has been repeatedly suggested, but the process is still enigmatic. In the present study, we confirmed the previous observation that there are lamin B1-negative micronuclei in addition to the positive ones. A large cytoplasmic bleb was found to frequently entrap lamin B1-negative micronuclei, which were connected to the nucleus by a thin chromatin stalk. At the bottom of the stalk, the nuclear lamin B1 structure appeared broken. Chromatin extrusion through lamina breaks has been referred to as herniation or a blister of the nucleus, and has been observed after the expression of viral proteins. A cell line in which extrachromosomal double minutes and lamin B1 protein were simultaneously visualized in different colors in live cells was established. By using these cells, time-lapse microscopy revealed that cytoplasmic membrane blebbing occurred simultaneously with the extrusion of nuclear content, which generated lamin B1-negative micronuclei during interphase. Furthermore, activation of cytoplasmic membrane blebbing by the addition of fresh serum or camptothecin induced nuclear budding within 1 to 10 minutes, which suggested that blebbing might be the cause of the budding. After the induction of blebbing, the frequency of lamin-negative micronuclei increased. The budding was most frequent during S phase and more efficiently entrapped small extrachromosomal chromatin than the large chromosome arm. Based on these results, we suggest a novel mechanism in which cytoplasmic membrane dynamics pulls the chromatin out of the nucleus through the lamina break. Evidence for such a mechanism was obtained in certain cancer cell lines including human COLO 320 and HeLa. The mechanism could significantly perturb the genome and influence cancer cell phenotypes.
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Affiliation(s)
- Koh-ichi Utani
- Graduate School of Biosphere Science, Hiroshima University, Higashi-hiroshima, Hiroshima, Japan
| | - Atsushi Okamoto
- Graduate School of Biosphere Science, Hiroshima University, Higashi-hiroshima, Hiroshima, Japan
| | - Noriaki Shimizu
- Graduate School of Biosphere Science, Hiroshima University, Higashi-hiroshima, Hiroshima, Japan
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Fenech M, Kirsch-Volders M, Natarajan AT, Surralles J, Crott JW, Parry J, Norppa H, Eastmond DA, Tucker JD, Thomas P. Molecular mechanisms of micronucleus, nucleoplasmic bridge and nuclear bud formation in mammalian and human cells. Mutagenesis 2011; 26:125-32. [PMID: 21164193 DOI: 10.1093/mutage/geq052] [Citation(s) in RCA: 817] [Impact Index Per Article: 62.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Micronuclei (MN) and other nuclear anomalies such as nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) are biomarkers of genotoxic events and chromosomal instability. These genome damage events can be measured simultaneously in the cytokinesis-block micronucleus cytome (CBMNcyt) assay. The molecular mechanisms leading to these events have been investigated over the past two decades using molecular probes and genetically engineered cells. In this brief review, we summarise the wealth of knowledge currently available that best explains the formation of these important nuclear anomalies that are commonly seen in cancer and are indicative of genome damage events that could increase the risk of developmental and degenerative diseases. MN can originate during anaphase from lagging acentric chromosome or chromatid fragments caused by misrepair of DNA breaks or unrepaired DNA breaks. Malsegregation of whole chromosomes at anaphase may also lead to MN formation as a result of hypomethylation of repeat sequences in centromeric and pericentromeric DNA, defects in kinetochore proteins or assembly, dysfunctional spindle and defective anaphase checkpoint genes. NPB originate from dicentric chromosomes, which may occur due to misrepair of DNA breaks, telomere end fusions, and could also be observed when defective separation of sister chromatids at anaphase occurs due to failure of decatenation. NBUD represent the process of elimination of amplified DNA, DNA repair complexes and possibly excess chromosomes from aneuploid cells.
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Affiliation(s)
- M Fenech
- Department of Nutritional Genomics and DNA Damage Diagnostics, Commonwealth Scientific and Industrial Research Organisation Food and Nutritional Sciences, Gate 13 Kintore Avenue, PO Box 10041, Adelaide BC, South Australia 5000, Australia.
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Stephens PJ, Greenman CD, Fu B, Yang F, Bignell GR, Mudie LJ, Pleasance ED, Lau KW, Beare D, Stebbings LA, McLaren S, Lin ML, McBride DJ, Varela I, Nik-Zainal S, Leroy C, Jia M, Menzies A, Butler AP, Teague JW, Quail MA, Burton J, Swerdlow H, Carter NP, Morsberger LA, Iacobuzio-Donahue C, Follows GA, Green AR, Flanagan AM, Stratton MR, Futreal PA, Campbell PJ. Massive genomic rearrangement acquired in a single catastrophic event during cancer development. Cell 2011; 144:27-40. [PMID: 21215367 PMCID: PMC3065307 DOI: 10.1016/j.cell.2010.11.055] [Citation(s) in RCA: 1700] [Impact Index Per Article: 130.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 11/03/2010] [Accepted: 11/24/2010] [Indexed: 12/13/2022]
Abstract
Cancer is driven by somatically acquired point mutations and chromosomal rearrangements, conventionally thought to accumulate gradually over time. Using next-generation sequencing, we characterize a phenomenon, which we term chromothripsis, whereby tens to hundreds of genomic rearrangements occur in a one-off cellular crisis. Rearrangements involving one or a few chromosomes crisscross back and forth across involved regions, generating frequent oscillations between two copy number states. These genomic hallmarks are highly improbable if rearrangements accumulate over time and instead imply that nearly all occur during a single cellular catastrophe. The stamp of chromothripsis can be seen in at least 2%–3% of all cancers, across many subtypes, and is present in ∼25% of bone cancers. We find that one, or indeed more than one, cancer-causing lesion can emerge out of the genomic crisis. This phenomenon has important implications for the origins of genomic remodeling and temporal emergence of cancer. PaperClip
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Genescà A, Pampalona J, Frías C, Domínguez D, Tusell L. Role of telomere dysfunction in genetic intratumor diversity. Adv Cancer Res 2011; 112:11-41. [PMID: 21925300 DOI: 10.1016/b978-0-12-387688-1.00002-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Most solid tumors are unable to maintain the stability of their genomes at the chromosome level. Indeed, cancer cells display highly rearranged karyotypes containing translocations, amplifications, deletions, and gains and losses of whole chromosomes, which reshuffle steadily. This chromosomal instability most likely occurs early in the development of cancer, and may represent an important step in promoting the multiple genetic changes required for the initiation and/or progression of the disease. Different mechanisms may underlie chromosome instability in cancer cells, but a prominent role for telomeres, the tip of linear chromosomes, has been determined. Telomeres are ribonucleoprotein structures that prevent natural chromosome ends being recognized as DNA double-strand breaks, by adopting a loop structure. Loss of telomere function appears from either alteration on telomere-binding proteins or from the progressive telomere shortening that normally occurs under physiological conditions in the majority of cells in tissues. Importantly, unmasked telomeres may either trigger the senescent phenotype that has been linked to the aging process or may initiate the chromosome instability needed for cancer development, depending on the integrity of the DNA damage checkpoint responses. Telomere dysfunction contributes to chromosome instability through end-to-end chromosome fusions entering breakage-fusion-bridge (BFB) cycles. Resolution of chromatin bridge intermediates is likely to contribute greatly to the generation of segmental chromosome amplification events, unbalanced chromosome rearrangements, and whole chromosome aneuploidy. Noteworthy is the fact that telomere length heterogeneity among individuals may directly influence the scrambling of the genome at tumor initiation. However, reiterated BFB cycles would randomly reorganize the cell karyotype, thus increasing the genetic diversity that characterizes tumor cells. Even though a direct link is still lacking, multiple evidence lead one to believe that telomere dysfunction directly contributes to cancer development in humans. The expansion of highly unstable cells due to telomere dysfunction enhances the genetic diversity needed to fuel specific mutations that may promote cell immortalization and the acquisition of a tumor phenotype.
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Pampalona J, Soler D, Genescà A, Tusell L. Whole chromosome loss is promoted by telomere dysfunction in primary cells. Genes Chromosomes Cancer 2010; 49:368-78. [PMID: 20088004 DOI: 10.1002/gcc.20749] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Errors in chromosome segregation during mitosis result in aneuploidy, which in humans may play a role in the onset of neoplasia by changing gene dosage. Nearly all solid tumors exhibit genomic instability at the chromosomal level, showing both structural and numerical chromosome abnormalities. Chromosomal instability occurs early in the development of cancer and may represent an important step in the initiation and/or progression of the disease. Telomere integrity appears to be a critical element in the genesis of structural chromosome imbalances, but it is still not clear whether it can also generate numerical chromosome aberrations. We investigated the possible relationship between telomere shortening and aneuploidy formation in human mammary epithelial cells using the cytokinesis-block micronucleus assay combined with fluorescent DNA probes. In this cell system, uncapped chromosomes fuse with each other resulting in dicentric chromosomes, which are known to be a source of new structural chromosome rearrangements. Here, we show that in primary epithelial cells, the chromosomes with short telomeres are more frequently involved in missegregation events than chromosomes of normal telomere length. Whole chromosome aneuploidy occurs through both nondisjunction and anaphase lagging of dicentric chromatids, which suggests that pulling anaphase bridges toward opposite poles can generate the necessary force for detaching a chromosome from the microtubules of one or both spindle poles. Therefore, telomere-driven instability can promote not only the appearance of chromosomal rearrangements but also the appearance of numerical chromosome aberrations that could favor cell immortalization and the acquisition of a tumor phenotype.
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Affiliation(s)
- Judit Pampalona
- Cell Biology Unit, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
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