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Singuru MMR, Liao YC, Lin GMH, Chen WT, Lin YH, To CT, Liao WC, Hsu CH, Chuang MC. Engineered multivalent DNA capsules for multiplexed detection of genotoxicants via versatile controlled release mechanisms. Biosens Bioelectron 2022; 216:114608. [DOI: 10.1016/j.bios.2022.114608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 11/28/2022]
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Khalil C, Al Hageh C, Korfali S, Khnayzer RS. Municipal leachates health risks: Chemical and cytotoxicity assessment from regulated and unregulated municipal dumpsites in Lebanon. CHEMOSPHERE 2018; 208:1-13. [PMID: 29857206 DOI: 10.1016/j.chemosphere.2018.05.151] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 05/15/2023]
Abstract
The proper management of municipal waste is critical for resource recovery, sustainability and health. Lebanon main approach for managing its municipal waste consisted of landfill disposal with minimal recycling capacity. This approach contributed to exceeding the holding capacity of existing landfills leading eventually to their closures. The closure of a major landfill (Naameh landfill) servicing Beirut and Mount Lebanon areas led to municipal wastes piling in the streets and forests for more than a year in 2016. The main problem identified in the municipal wastes consisted of untreated leachates (from regulated and unregulated dumpsites) going straight into the Mediterranean Sea. Therefore leachate samples were collected and subjected to chemical characterization followed by biological assessment. The chemical characterization and profiling of the Lebanese leachates were compared to results reported in Lebanon, Europe and United States as well as to the toxicity reference values (TRV). The biological assessment was conducted in vitro using human derived immortalized cell cultures. This strategy revealed significant alarming cellular organelles and DNA damages using in vitro cytotoxicity assays (MTS and comet assay). The significant damages observed at the cellular level prompted further animal model investigations using BALB/c mice. The animal data pointed to significant upregulation of liver activity enzymes coupled with significant damage expression in liver spleen and bone marrow DNA. The presented research clearly indicated that there is an urgent need for development of national waste strategies for proper treatment and disposal of municipal waste leachates in Lebanon.
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Affiliation(s)
- Christian Khalil
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon.
| | - Cynthia Al Hageh
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon
| | - Samira Korfali
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon
| | - Rony S Khnayzer
- Department of Natural Sciences, Lebanese American University, Chouran, Beirut 1102-2801, Lebanon
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Khalil C, Shebaby W. UVB damage onset and progression 24 h post exposure in human-derived skin cells. Toxicol Rep 2017; 4:441-449. [PMID: 28959672 PMCID: PMC5615164 DOI: 10.1016/j.toxrep.2017.07.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/21/2017] [Accepted: 07/22/2017] [Indexed: 12/14/2022] Open
Abstract
UVB radiation (280–320 nm) exposure and cellular damages assessment in vitro. Damage progression assessed immediately and 24 h post exposure using cultured human cells with more prominent damages expressed 24 h post exposure. Cytotoxicity assessment investigated mitochondria, lysosomes, cell membrane and, DNA damages. The research reported significant cellular and DNA damages in addition to upregulation and downregulation of various apoptotic proteins.
The focus of this research was on UVB radiation (280–320 nm) responsible for cellular changes in skin of acute and chronically exposed individuals. This study investigated the acute cellular damages triggered by UVB exposure of cultured human fibroblasts and keratinocyte cells immediately and 24 h post exposure in order to understand damage onset and progression. The study evaluated a number of cellular parameters including mitochondria, lysosomes, cell membrane, DNA damages as well as pro and anti-apoptotic protein expression levels. Cellular organelle damages were assessed by a battery of in vitro toxicological assays using MTS and Neutral red cytotoxicity assays. Cell membrane damages were also assessed by measuring lactate dehydrogenase (LDH) enzyme leakage from UVB exposed cells. Lastly DNA damages was assessed using the comet assay while protein expression was evaluated using Western Blot. In this study we reported in all our assay systems (MTS, NR and LDH) that cellular damages were UVB dose dependent with damages amplified 24 h post exposure. Our results also indicated that incubation of exposed cells for a period of 24 h increased the sensitivity of the assay systems used. The increased sensitivity in detecting early cytotoxic damages was manifested though organelle damage measurement at very low doses which were not manifested immediately post exposure. The data also indicated that HaCaT cells were most sensitive in detecting UVB triggered damages immediately and 24 h post exposure using the MTS assay. We also established upregulation and downregulation of various apoptotic proteins at various time points post exposure. The presented data clearly indicated the need for a comprehensive assessment of UVB damages 4 and 24 h post exposure due to the different assay sensitivities in addition to various signaling mechanisms activated at different time points post exposure.
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Affiliation(s)
- Christian Khalil
- School of Arts and Sciences, Department of Natural Sciences, Lebanese American University (LAU), Byblos, Lebanon.,Institute of Environmental Studies, University of New South Wales (UNSW), Sydney, Australia
| | - Wassim Shebaby
- School of Arts and Sciences, Department of Natural Sciences, Lebanese American University (LAU), Byblos, Lebanon
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Goyal S, Amar SK, Dwivedi A, Mujtaba SF, Kushwaha HN, Chopra D, Pal MK, Singh D, Chaturvedi RK, Ray RS. Photosensitized 2-amino-3-hydroxypyridine-induced mitochondrial apoptosis via Smac/DIABLO in human skin cells. Toxicol Appl Pharmacol 2016; 297:12-21. [DOI: 10.1016/j.taap.2016.02.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 02/12/2016] [Accepted: 02/25/2016] [Indexed: 01/21/2023]
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Garbati MR, Hays LE, Rathbun RK, Jillette N, Chin K, Al-Dhalimy M, Agarwal A, Newell AEH, Olson SB, Bagby GC. Cytokine overproduction and crosslinker hypersensitivity are unlinked in Fanconi anemia macrophages. J Leukoc Biol 2015; 99:455-65. [PMID: 26432900 DOI: 10.1189/jlb.3a0515-201r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/15/2015] [Indexed: 01/13/2023] Open
Abstract
The Fanconi anemia proteins participate in a canonical pathway that repairs cross-linking agent-induced DNA damage. Cells with inactivated Fanconi anemia genes are universally hypersensitive to such agents. Fanconi anemia-deficient hematopoietic stem cells are also hypersensitive to inflammatory cytokines, and, as importantly, Fanconi anemia macrophages overproduce such cytokines in response to TLR4 and TLR7/8 agonists. We questioned whether TLR-induced DNA damage is the primary cause of aberrantly regulated cytokine production in Fanconi anemia macrophages by quantifying TLR agonist-induced TNF-α production, DNA strand breaks, crosslinker-induced chromosomal breakage, and Fanconi anemia core complex function in Fanconi anemia complementation group C-deficient human and murine macrophages. Although both M1 and M2 polarized Fanconi anemia cells were predictably hypersensitive to mitomycin C, only M1 macrophages overproduced TNF-α in response to TLR-activating signals. DNA damaging agents alone did not induce TNF-α production in the absence of TLR agonists in wild-type or Fanconi anemia macrophages, and mitomycin C did not enhance TLR responses in either normal or Fanconi anemia cells. TLR4 and TLR7/8 activation induced cytokine overproduction in Fanconi anemia macrophages. Also, although TLR4 activation was associated with induced double strand breaks, TLR7/8 activation was not. That DNA strand breaks and chromosome breaks are neither necessary nor sufficient to account for the overproduction of inflammatory cytokines by Fanconi anemia cells suggests that noncanonical anti-inflammatory functions of Fanconi anemia complementation group C contribute to the aberrant macrophage phenotype and suggests that suppression of macrophage/TLR hyperreactivity might prevent cytokine-induced stem cell attrition in Fanconi anemia.
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Affiliation(s)
- Michael R Garbati
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Laura E Hays
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - R Keaney Rathbun
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Nathaniel Jillette
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Kathy Chin
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Muhsen Al-Dhalimy
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Anupriya Agarwal
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Amy E Hanlon Newell
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Susan B Olson
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Grover C Bagby
- *Northwest Veterans Affairs Cancer Research Center, Portland, Oregon, USA; Oregon Health & Science University, Portland, Oregon, USA; and Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
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Duffy K, Grossman D. The dysplastic nevus: from historical perspective to management in the modern era: part I. Historical, histologic, and clinical aspects. J Am Acad Dermatol 2012; 67:1.e1-16; quiz 17-8. [PMID: 22703915 PMCID: PMC3625372 DOI: 10.1016/j.jaad.2012.02.047] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 02/14/2012] [Accepted: 02/17/2012] [Indexed: 10/28/2022]
Abstract
Since its description in the 1970s, the dysplastic nevus has been a source of confusion, and whether it represents a precursor to melanoma remains a controversial subject. Although a Consensus Conference in 1992 recommended that the term "dysplastic nevus" no longer be used, the histologic diagnosis continues to present a therapeutic quandary for dermatologists and other physicians, and there remains significant variation in clinical management. In part I of this continuing medical education review, we will discuss the historical origins of the term, the evidence for its distinct histologic basis, and its clinical significance.
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Affiliation(s)
- Keith Duffy
- Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
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Silva JH, Sá BCD, Avila ALRD, Landman G, Duprat Neto JP. Atypical mole syndrome and dysplastic nevi: identification of populations at risk for developing melanoma - review article. Clinics (Sao Paulo) 2011; 66:493-9. [PMID: 21552679 PMCID: PMC3072014 DOI: 10.1590/s1807-59322011000300023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 11/24/2010] [Indexed: 11/21/2022] Open
Abstract
Atypical Mole Syndrome is the most important phenotypic risk factor for developing cutaneous melanoma, a malignancy that accounts for about 80% of deaths from skin cancer. Because the diagnosis of melanoma at an early stage is of great prognostic relevance, the identification of Atypical Mole Syndrome carriers is essential, as well as the creation of recommended preventative measures that must be taken by these patients.
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Novel HSP90 inhibitors, NVP-AUY922 and NVP-BEP800, radiosensitise tumour cells through cell-cycle impairment, increased DNA damage and repair protraction. Br J Cancer 2010; 102:1578-91. [PMID: 20502461 PMCID: PMC2883148 DOI: 10.1038/sj.bjc.6605683] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: Heat-shock protein 90 (Hsp90) has a crucial role in both the stabilisation and regulation of various proteins, including those related to radioresistance. Inhibition of Hsp90 may therefore provide a strategy for enhancing the radiosensitivity of tumour cells. This study explores the responses of four tumour cell lines (A549, GaMG, HT 1080 and SNB19) to combined treatment with ionising radiation (IR) and two novel inhibitors of Hsp90, NVP-AUY922 and NVP-BEP800. The techniques used included cell and colony counts, expression of Hsp90, Hsp70, Akt, survivin, cleaved caspase 3, p53, cell-cycle progression and associated proteins. DNA damage was analysed by histone γH2AX and Comet assays. Results: We found that NVP-AUY922 and NVP-BEP800 enhanced radiosensitivity in all tested cell lines. In contrast, only two cell lines (HT 1080 and GaMG) exhibited an increased rate of apoptosis after drug pretreatment, as revealed by western blot. In all tested cell lines, the expression of histone γH2AX, a marker of DNA double-strand breaks, after combined drug-IR treatment was higher and its decay rate was slower than those after each single treatment modality. Drug-IR treatment also resulted in impaired cell-cycle progression, as indicated by S-phase depletion and G2/M arrest. In addition, the cell cycle-associated proteins, Cdk1 and Cdk4, were downregulated after Hsp90 inhibition. Interpretation: These findings show that the novel inhibitors of Hsp90 can radiosensitise tumour cell lines of different entities through destabilisation and depletion of several Hsp90 client proteins, thus causing the depletion of S phase and G2/M arrest, increased DNA damage and repair protraction and, to some extent, apoptosis. The results might have important implications for the radiotherapy of solid tumours.
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Friedman RJ, Farber MJ, Warycha MA, Papathasis N, Miller MK, Heilman ER. The "dysplastic" nevus. Clin Dermatol 2009; 27:103-15. [PMID: 19095156 DOI: 10.1016/j.clindermatol.2008.09.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Dysplastic nevi have become an increasing focus clinically, with evidence that they are associated with a higher risk of developing melanoma. However, there still is contention regarding the significance of dysplastic nevi. This contribution provides an overview of the history, epidemiology, genetics, clinical and histologic features, and procedures for clinical management of dysplastic nevi. Since dysplastic nevi were described originally in 1978, a great deal of research has examined the epidemiology of these lesions and the genetic factors related to the development of dysplastic nevi. However, there is disagreement regarding the clinical management of dysplastic nevi and the histologic definition of dysplastic nevi. Current recommendations include preventative measures, such as sun protection and careful surveillance and biopsies of suspicious lesions as needed. The advent of new technologies, such as computer-vision systems, have the potential to significantly change treatment of dysplastic nevi in the future.
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Affiliation(s)
- Robert J Friedman
- Department of Dermatology, New York University School of Medicine, New York, NY 10016, USA.
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Sommers C, Geveke D, Pulsfus S, Lemmenes B. Inactivation ofListeria innocuaon Frankfurters by Ultraviolet Light and Flash Pasteurization. J Food Sci 2009; 74:M138-41. [DOI: 10.1111/j.1750-3841.2009.01107.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mohseni-Meybodi A, Mozdarani H, Mozdarani S. DNA damage and repair of leukocytes from Fanconi anaemia patients, carriers and healthy individuals as measured by the alkaline comet assay. Mutagenesis 2008; 24:67-73. [PMID: 18836100 DOI: 10.1093/mutage/gen052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Fanconi anaemia (FA) patients show cellular sensitivity to a variety of clastogens and prominently to cross-linking agents. Although there is a long-standing clinical impression of radiosensitivity, in vitro studies have yielded conflicting results. In this study, initial radiation-induced DNA damage and kinetics of DNA repair in (60)Co gamma-irradiated leukocytes from healthy volunteers, FA patients and heterozygotes were assessed using alkaline comet assay. Results showed higher levels of baseline DNA damage in leukocytes of patients and heterozygotes than in controls. Gamma-ray-induced initial DNA damage in leukocytes of FA cases was not significantly different from that of healthy donors and heterozygotes. However, after a repair time of 4 h, following irradiation, samples from the healthy individuals and carriers showed less residual DNA damage in their leukocytes, whereas FA patients revealed more DNA damages than their baseline. Although similar initial induced DNA damage was observed for all groups, the repair kinetics of radiation-induced DNA damage of leukocytes from FA patients was statistically different from healthy and carrier subjects. These findings may suggest that hypersensitivity of FA cells to cross-linking and clastogenic agents might be due to inefficient and delayed repair machinery of these cells. Also, the amount of residual DNA damage after irradiation could be used as a putative predictor of FA screening and cellular radiosensitivity.
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Affiliation(s)
- Anahita Mohseni-Meybodi
- Department of Medical Genetics, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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Smit NPM, van Nieuwpoort FA, Marrot L, Out C, Poorthuis B, van Pelt H, Meunier JR, Pavel S. Increased melanogenesis is a risk factor for oxidative DNA damage--study on cultured melanocytes and atypical nevus cells. Photochem Photobiol 2008; 84:550-5. [PMID: 18435613 DOI: 10.1111/j.1751-1097.2007.00242.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Melanin synthesis is an oxygen-dependent process that acts as a potential source of reactive oxygen species (ROS) inside pigment-forming cells. The synthesis of the lighter variant of melanin, pheomelanin, consumes cysteine and this may limit the capacity of the cellular antioxidative defense. We show that tyrosine-induced melanogenesis in cultured normal human melanocytes (NHM) is accompanied by increased production of ROS and decreased concentration of intracellular glutathione. Clinical atypical (dysplastic) nevi (DN) regularly contain more melanin than do normal melanocytes (MC). We also show that in these cultured DN cells three out of four exhibit elevated synthesis of pheomelanin and this is accompanied by their early senescence. By using various redox-sensitive molecular probes, we demonstrate that cultured DN cells produce significantly more ROS than do normal MC from the same donor. Our experiments employing single-cell gel electrophoresis (comet assay) usually reveal higher fragmentation of DNA in DN cells than in normal MC. Even if in some cases the normal alkaline comet assay shows no differences in DNA fragmentation between DN cells and normal MC, the use of the comet assay with formamidopyrimidine DNA glycosylase can disclose that the DNA of the cultured DN cells harbor more oxidative damage than the DNA of normal MC from the same person.
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Affiliation(s)
- Nico P M Smit
- Department of Clinical Chemistry, Leiden University Medical Center, Leiden, The Netherlands.
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Jean S, De Méo M, Sabatier AS, Laget M, Hubaud JC, Verrando P, Duménil G. Evaluation of Sunscreen Protection in Human Melanocytes Exposed to UVA or UVB Irradiation Using the Alkaline Comet Assay¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740417eospih2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Marrot L, Belaïdi JP, Jones C, Perez P, Meunler JR. Molecular Responses to Stress Induced in Normal Human Caucasian Melanocytes in Culture by Exposure to Simulated Solar UV¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb00196.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kowalczuk CI, Priestner MC, Pearson AJ, Saunders RD, Bouffler SD. Wavelength dependence of cellular responses in human melanocytes and melanoma cells following exposure to ultraviolet radiation. Int J Radiat Biol 2007; 82:781-92. [PMID: 17148262 DOI: 10.1080/09553000600930111] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To examine the wavelength dependence of cellular responses in human melanocytes and human melanoma cells exposed to ultraviolet radiation (UVR). MATERIALS AND METHODS Primary human melanocytes and G361 human melanoma cells were exposed to ultraviolet-C (UVC), ultraviolet-B (UVB), or ultraviolet-A (UVA) radiation. Dose-response relationships for clonal cell survival were assessed, and flow cytometry was used to monitor cell cycle distributions for up to one week post-irradiation. Chromosomal aberrations were scored in exposed and unexposed melanoma cells. RESULTS G361 melanoma cells were more sensitive than melanocytes to killing by UVB and UVC radiation. This difference in sensitivity between cell types was much less marked following UVA irradiation. The melanoma cells showed a sustained, dose-dependent G2/M block following exposure with all wavelengths; in addition, transit through S phase was slowed following UVA irradiation. There was no apparent block to G1 cells entering S phase at any wavelength. Melanocytes, on the other hand, showed a marked G1 arrest, particularly following UVA irradiation. Cytogenetic results showed a dose-dependent increase in chromatid-type aberrations, mostly gaps, breaks and exchanges, in exposed melanoma cells. CONCLUSION These results show that G361 malignant melanoma cells have lost the ability to regulate the cell cycle at the G1/S checkpoint and are more sensitive than melanocytes to cell killing by UVC and UVB but not UVA radiation. Similarly, exposure of these melanoma cells to UVC and UVB, and to a much lesser extent UVA, induced chromatid aberrations. UVA nevertheless induced strong cell cycle delays in both cell types, indicating that UVA exposure can significantly affect genome metabolism.
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Affiliation(s)
- C I Kowalczuk
- Health Protection Agency, Centre for Radiation, Chemical and Environmental Hazards, Radiation Protection Division, Chilton, Didcot, Oxfordshire, UK.
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Bürger S, Schindler D, Fehn M, Mühl B, Mahrhofer H, Flentje M, Hoehn H, Seemanová E, Djuzenova CS. Radiation-induced DNA damage and repair in peripheral blood mononuclear cells from Nijmegen breakage syndrome patients and carriers assessed by the Comet assay. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2006; 47:260-70. [PMID: 16470524 DOI: 10.1002/em.20202] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Nijmegen breakage syndrome (NBS) patients and carriers are predisposed to malignancy and are often treated with X-irradiation. In the present study, the single-cell gel electrophoresis (Comet) assay was used to examine radiation-induced DNA damage and repair in peripheral blood mononuclear cells from NBS patients (n=13) and carriers (n=36) of six unrelated families. Cells from apparently healthy donors (n=10) and from breast cancer patients with normal clinical radiosensitivity (n=10) served as controls. Cells were irradiated with 5 Gy of X-rays and assayed for initial DNA damage and for residual DNA damage after 40 min of repair; the kinetics of DNA repair also was estimated. In addition, the nuclear area of unirradiated cells was extracted from the Comet data. The initial radiation-induced DNA fragmentation indicated that cells from members of two out of six NBS families were significantly more sensitive to X-irradiation than cells from the controls. Cells from four NBS families had longer DNA repair half-time values, while cells from five NBS families had significantly increased residual DNA damage following repair. The mean nuclear area of unirradiated cells processed in the Comet assay was 1.3-fold higher in cells from all NBS families than in the controls (P<0.05). Notably, the Comet assay parameters (initial and residual DNA damage and the repair kinetics) of irradiated NBS cells predicted the carrier status of the majority (86%) of blindly tested individuals. The prediction of NBS status was higher if the nuclear area of unirradiated cells was used as the endpoint. The results of this study suggest that the impaired radiation response of NBS cells should be taken into account if radiotherapy of NBS patients and carriers is required.
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Affiliation(s)
- Susann Bürger
- Klinik für Strahlentherapie der Universität Würzburg, Würzburg, Germany
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Cramers P, Atanasova P, Vrolijk H, Darroudi F, van Zeeland AA, Huiskamp R, Mullenders LHF, Kleinjans JCS. Pre-exposure to Low Doses: Modulation of X-Ray-Induced DNA Damage and Repair? Radiat Res 2005; 164:383-90. [PMID: 16187740 DOI: 10.1667/rr3430.1] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The adaptive response to ionizing radiation may be mediated by the induction of antioxidant defense mechanisms, accelerated repair or altered cell cycle progression after the conditioning dose. To gain new insight into the mechanism of the adaptive response, nondividing lymphocytes and fibroblasts were used to eliminate possible contributions of cell cycle effects. The effect of conditioning doses of 0.05 or 0.1 Gy followed by challenging doses up to 8 Gy (with a 4-h interval between exposures) on induction and repair of DNA damage was determined by single-cell gel electrophoresis (comet assay), premature chromosome condensation, and immunofluorescence labeling for gamma-H2AX. The conditioning dose reduced the induction of DNA strand breaks, but the kinetics of strand break rejoining was not influenced by the conditioning dose in nondividing cells of either cell type. We conclude that adaptation in nondividing cells is not mediated by enhanced strand break rejoining and that protection against the induction of DNA damage is rather small. Therefore, the adaptive response is most likely a reflection of perturbation of cell cycle progression.
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Affiliation(s)
- Patricia Cramers
- Department of Toxicogenetics, Leiden University Medical Center, Leiden, The Netherlands
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Nijsten T, Leys C, Verbruggen K, Verlinden V, Drieghe J, Stas M, Lambert J, DeGreef H, Garmyn M. Case-control study to identify melanoma risk factors in the Belgian population: the significance of clinical examination. J Eur Acad Dermatol Venereol 2005; 19:332-9. [PMID: 15857460 DOI: 10.1111/j.1468-3083.2005.01196.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Although numerous studies have evaluated risk factors associated with cutaneous malignant melanoma (CMM), no such study has been carried out in Belgium. OBJECTIVES To identify individuals who are at high risk of developing malignant melanoma in Belgium, which could enhance the efficacy of screening interventions and avoid unnecessary skin inspections. STUDY DESIGN/SETTING/SUBJECTS: We prospectively included patients who were diagnosed with invasive malignant melanoma between 1998 and 2001 at the Department of Dermatology in a case-control study. Controls were selected from the outpatient dermatology clinic. Participants were interviewed and clinically examined by a dermatologist. We asked questions concerning most known risk factors associated with malignant melanoma such as phenotypical and skin characteristics, and environmental and lifestyle exposures. To adjust for confounding variables and to estimate odds ratios (ORs) and 95% confidence intervals (CIs), a multivariate model was used. RESULTS Although sunburn in childhood and substantial occupational solar exposure were modestly, but significantly, associated with malignant melanoma risk, clinical examination yielded several stronger risk factors. In a multivariate model, which adjusted for age, gender and skin phototype, phenotypical characteristics such as skin, hair and eye colour were significantly associated with the development of malignant melanoma. In the multivariate model, people with three or more atypical naevi were at more than 10-fold risk of developing a malignant melanoma (> or = 3 atypical naevi; adjusted OR = 11.40, 95% CI = 4.79-17.53) compared to those without an atypical naevus. The presence of one or more palpable naevi on the upper extremities or having solar lentigines increased the odds of developing malignant melanoma at least twofold. CONCLUSIONS In Belgium, risk factors associated with malignant melanoma appear to be in accordance with previous studies. To assess peoples' risk profile, clinical skin examination is likely to yield the most important sporadic malignant melanoma risk factors. Therefore, focusing screening campaigns on individuals with predefined findings on skin self-examination may increase its efficacy.
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Affiliation(s)
- T Nijsten
- Department of Dermatology, University Hospital Antwerp, Wilrijkstraat 10, B-Julien Lambert 2650 Edegem, Belgium
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Marrot L, Belaïdi JP, Jones C, Perez P, Meunier JR. Molecular Responses to Stress Induced in Normal Human Caucasian Melanocytes in Culture by Exposure to Simulated Solar UV¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-10-13-ra-343.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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20
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Smit N, Vicanova J, Cramers P, Vrolijk H, Pavel S. The Combined Effects of Extracts Containing Carotenoids and Vitamins E and C on Growth and Pigmentation of Cultured Human Melanocytes. Skin Pharmacol Physiol 2004; 17:238-45. [PMID: 15452410 DOI: 10.1159/000080217] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Accepted: 05/11/2004] [Indexed: 11/19/2022]
Abstract
In the present study, we investigated the effects of tomato extract (TE) containing lycopene and palm fruit extract (PE) rich in carotenoids on the growth and pigmentation of melanocyte cultures of Caucasian origin. The extracts were tested at different concentrations and in combination with vitamins E and C. Melanocytes with basic and increased (tyrosine-induced) pigmentation were treated in short-term and long-term experiments. Prevention of UVA-induced DNA damage was studied by using the comet assay. Melanocytes with stimulated melanin production showed reduced growth. Incubation of the cells with TE/PE (20/4 microg/ml) in combination with 35 microM vitamin E and 100 microM vitamin C (COMB 20/4) reduced this growth inhibition, especially in the long-term cultures. Increased production of melanin pigment was obtained when the cells were treated with 2.5 x and 10 x higher concentrations of the TE/PE and the same concentration of vitamins E and C (COMB 50/10 and 200/40). Reduced DNA damage was found after UVA irradiation in cells preincubated with COMB 50/10. The results indicate that the presence of carotenoids from TE and PE in combination with vitamins E and C may influence growth and pigmentation in melanocyte monocultures. Depending on the concentration of the carotenoid mixtures, their presence may provide some protection against the melanogenic intermediates and/or exogenous DNA damage.
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Affiliation(s)
- N Smit
- Department of Clinical Chemistry, Leiden University Medical Centre, Leiden, The Netherlands.
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21
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Shapiro M, Chren MM, Levy RM, Elder DE, LeBoit PE, Mihm MC, Margolis DJ, Gimotty PA, Ming ME. Variability in nomenclature used for nevi with architectural disorder and cytologic atypia (microscopically dysplastic nevi) by dermatologists and dermatopathologists. J Cutan Pathol 2004; 31:523-30. [PMID: 15268706 DOI: 10.1111/j.0303-6987.2004.00216.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Although a nevus with the microscopic features of a "dysplastic nevus" is commonly seen, the nomenclature used to describe such a lesion has been thought to be inconsistent. A 1992 National Institutes of Health (NIH) Consensus Conference sought to unify nomenclature and suggested that the term "nevus with architectural disorder" be used along with a comment on melanocytic atypia. METHODS We performed a cross-sectional mail survey to determine preferred terminology as well as the level of adherence to the NIH-recommended nomenclature. All 856 active members of the American Society of Dermatopathology (ASDP) and 1100 (13.0%) of the 8471 active members of the American Academy of Dermatology (AAD) were surveyed. RESULTS Five hundred and thirty-three ASDP members and 483 AAD members who fulfilled eligibility criteria completed the questionnaire. The term "dysplastic nevus" was favored by the largest number of responders (favored by 39.1% of ASDP members and 62.3% of AAD members), while the 1992 NIH Consensus Conference-recommended terminology was the second most popular term (25.3% of ASDP and 15.1% of AAD members). Dermatopathologists (OR = 1.9, p = 0.0001) and those who had dual training in dermatology and dermatopathology (OR = 1.6, p = 0.02 for ASDP members; OR = 2.3, p = 0.02 for AAD members) were more likely to adhere to the 1992 NIH Consensus Conference nomenclature. CONCLUSIONS Despite attempts to unify nomenclature for microscopically dysplastic nevi through the NIH Consensus Conference, wide variation in terminology persists.
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Affiliation(s)
- Michael Shapiro
- Department of Dermatology, University of Pennsylvania School of Medicine, 3600 Spruce Street, Philadelphia, PA 19104, USA
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22
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Pavel S, van Nieuwpoort F, van der Meulen H, Out C, Pizinger K, Cetkovská P, Smit NPM, Koerten HK. Disturbed melanin synthesis and chronic oxidative stress in dysplastic naevi. Eur J Cancer 2004; 40:1423-30. [PMID: 15177503 DOI: 10.1016/j.ejca.2003.11.035] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Accepted: 11/17/2003] [Indexed: 11/20/2022]
Abstract
Dysplastic naevi (DN) are a known risk factor for malignant melanoma. Their occurrence is closely connected with the degree of skin pigmentation. People with a light complexion are more likely to develop DN than dark-skinned individuals. We examined the proposition that DN exhibit altered melanin formation, which may be involved in their malignant transformation. X-ray microanalysis was used to study the composition of melanosomes from DN and to compare the results with those obtained from melanomas, banal (dermal) naevi and normal cutaneous melanocytes. We analysed sulphur (an indicator of phaeomelanin) and two metals, iron and calcium, involved in oxidative stress. FACS analysis of dihydrorhodamine-123-labelled cells was employed to quantify differences in the production of radical oxygen species in DN cells and normal skin melanocytes. A significantly higher sulphur content was found in melanosomes from DN cells and melanoma cells when compared with normal melanocytes and naevus cells from banal naevi. In addition, melanosomes of DN cells and melanoma cells contained higher amounts of iron and calcium. In the case of calcium, this was associated with a significantly elevated cytoplasmic concentration. FACS analysis showed that DN cells exhibited higher concentrations of radical oxygen species than normal skin melanocytes from the same individuals. We propose that increased phaeomelanogenesis in DN cells is connected with oxidative imbalance, which is reflected by increased intracellular concentrations of reactive oxygen species and raised calcium and iron concentrations. We show that the metabolic alterations in DN cells resemble those found in melanoma cells. Our findings provide support for the idea that DN cells are true precursor lesions of melanoma.
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Affiliation(s)
- Stan Pavel
- Department of Dermatology, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
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23
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Abstract
There are few areas in dermatology that provoke as much controversy as dysplastic nevus. Over the past decade, there have been significant strides made in terms of understanding the biology and etiology of the lesion. Distinct and reliable clinical and histologic features have been delineated. In this article, the management of patients with dysplastic nevi and the role for dermoscopy, photographic surveillance, genetic mapping and counseling, chemoprevention, and nevi removal are discussed.
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Affiliation(s)
- Thomas G Salopek
- Division of Dermatology and Cutaneous Sciences, University of Alberta, 2-125 Clinical Sciences Building, Edmonton, Alberta, Canada, T6G 2G3.
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24
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Abstract
An overview of keratinocyte and melanocyte function is provided. The processes of cutaneous ageing and photoageing are defined, and age-associated modulations in gene expression are described. The changes in keratinocytes and melanocytes that occur with skin ageing and photoageing and the characteristics of chronologically aged vs. photoaged skin are delineated. Mutations that are found in malignant and premalignant tumors of epidermal origin are described.
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Affiliation(s)
- M Yaar
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118-2394, USA
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25
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Jean S, De Méo M, Sabatier AS, Laget M, Hubaud JC, Verrando P, Duménil G. Evaluation of sunscreen protection in human melanocytes exposed to UVA or UVB irradiation using the alkaline comet assay. Photochem Photobiol 2001; 74:417-23. [PMID: 11594055 DOI: 10.1562/0031-8655(2001)074<0417:eospih>2.0.co;2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The in vivo assessment of sunscreen protection does not include the photogenotoxicity of UVA or UVB solar radiation. Using the comet assay we have developed a simple and rapid technique to quantify sunscreen efficacy against DNA damage induced by UV light. Cutaneous human melanocytes from primary cultures were embedded in low-melting point (LPM) agarose and exposed to UVA (0.8 J/cm2) or to UVB (0.06 J/cm2) through a quartz slide covered with 10 microL volumes of sunscreens. DNA single-strand breaks induced directly by UVA at 4 degrees C and indirectly through nucleotide excision repair by UVB following a 35 min incubation period at 37 degrees C were quantified using the comet assay. Tail moments (TM) (tail length x %tail DNA) of 100 cells/sample were determined by image analysis. DNA damage was evaluated with a nonlinear regression analysis on the normalized distribution frequencies of TM using a chi 2 function. The coefficients of genomic protection (CGP) were defined as the percentage of inhibition of DNA lesions caused by the sunscreens. Twenty-one sunscreens were evaluated, and the calculated CGP were compared with the in vivo sun protective factor (SPF) and with the protection factor UVA (PFA). Nonlinear relationships were found between SPF and CGPUVB and between PFA and CGPUVA.
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Affiliation(s)
- S Jean
- Laboratoire de Biogénotoxicologie et Mutagenèse Environnementale (EA1784), Faculté de Pharmacie, Université de la Méditerranée, 27 Bd Jean Moulin, 13385 Marseille, France
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26
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Abstract
DNA repair and immune surveillance are established mechanisms that secure a programmed escape from the evolution of cancer (PEEC) by healing and elimination, respectively. Evasive transdifferentiation, i.e. silencing of carcinogenic events, is an emerging concept with potentially broad applicability that paradigmatically includes the claim that common acquired melanocytic nevi represent a programmed rescue from malignity for initiated melanocytes. This hypothesis is difficult to test. Research into the molecular mechanisms that govern the development of acquired melanocytic nevi, however, should result in the identification of a molecular master switch and an associated set of genes that - beyond the processes involved in apoptosis - may help bypass carcinogenesis and may be of therapeutic benefit in the future.
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Affiliation(s)
- S Goerdt
- Department of Dermatology, Venerology, and Allergology, University Medical Center Mannheim, Ruprecht-Karls University Heidelberg, Mannheim, Germany.
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27
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Salti GI, Kichina JV, Das Gupta TK, Uddin S, Bratescu L, Pezzuto JM, Mehta RG, Constantinou AI. Betulinic acid reduces ultraviolet-C-induced DNA breakage in congenital melanocytic naeval cells: evidence for a potential role as a chemopreventive agent. Melanoma Res 2001; 11:99-104. [PMID: 11333133 DOI: 10.1097/00008390-200104000-00003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Melanoma transformation progresses in a multistep fashion from precursor lesions such as congenital naevi. Exposure to ultraviolet (UV) light promotes this process. Betulinic acid (BA) was identified by our group as a selective inhibitor of melanoma that functions by inducing apoptosis. The present study was designed to investigate the effect of BA and UV-C (254 nm) on cultured congenital melanocytic naevi (CMN) cells, using the single-cell gel electrophoresis (comet) assay to detect DNA damage. Exposure to UV light induced a 1.7-fold increase in CMN cells (P = 0.008) when compared with controls. When a p53 genetic suppressor element that encodes a dominant negative polypeptide (termed GSE56) was introduced into the CMN cells, the transfected cells were more sensitive to UV-induced DNA breakage. This suggests that p53 can protect against UV-induced DNA damage and subsequent melanoma transformation. Pretreatment with BA (3 microm) for 48 h resulted in a 25.5% reduction in UV-induced DNA breakage in the CMN cells (P = 0.023), but no changes were observed in the transfected cells. However, Western blot analysis revealed no changes in the p53 or p21 levels in BA-treated cells, suggesting that BA might mediate its action via a non-p53 pathway. These data indicate that BA may have an application as a chemopreventive agent in patients with congenital naevi.
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Affiliation(s)
- G I Salti
- Department of Surgical Oncology, College of Medicine, University of Illinois at Chicago, 60612, USA.
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28
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Djuzenova CS, Rothfuss A, Oppitz U, Spelt G, Schindler D, Hoehn H, Flentje M. Response to X-irradiation of Fanconi anemia homozygous and heterozygous cells assessed by the single-cell gel electrophoresis (comet) assay. J Transl Med 2001; 81:185-92. [PMID: 11232640 DOI: 10.1038/labinvest.3780226] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Fanconi anemia (FA) is an autosomal recessive disorder characterized by bone marrow failure and cancer susceptibility. Patient cells are sensitive to a variety of clastogens, most prominently cross-linking agents. Although there is the long-standing clinical impression of radiosensitivity, in vitro studies have yielded conflicting results. We exposed peripheral blood mononuclear cells from FA patients and carriers to x-rays and determined their DNA damage and repair profiles using the alkaline single-cell gel electrophoresis (comet) assay. Studies were carried out in two independent series of experiments by two laboratories using different protocols. The cells of both FA patients and carriers showed uniformly high initial DNA damage rates as assessed by the total initial tail moment. In addition, the average residual tail moment at 30 to 50 minutes and the repair half-time parameters were significantly elevated. These findings suggest an increased release of fragmented DNA following x-ray exposure in cells that carry one or two mutations in one of the FA genes. The comet assay may be a useful adjunct for heterozygote detection in families of FA patients.
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Affiliation(s)
- C S Djuzenova
- Klinik für Strahlentherapie der Universität Würzburg, Germany
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29
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Marrot L, Belaidi JP, Meunier JR, Perez P, Agapakis-Causse C. The Human Melanocyte as a Particular Target for UVA Radiation and an Endpoint for Photoprotection Assessment. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb03347.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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Rojas E, Lopez MC, Valverde M. Single cell gel electrophoresis assay: methodology and applications. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 722:225-54. [PMID: 10068143 DOI: 10.1016/s0378-4347(98)00313-2] [Citation(s) in RCA: 356] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The single cell gel electrophoresis or Comet assay is a sensitive, reliable, and rapid method for DNA double- and single-strand breaks, alkali-labile sites and delayed repair site detection, in eukaryotic individual cells. Given its overall characteristics, this method has been widely used over the past few years in several different areas. In this paper we review the studies published to date about the principles, the basic methodology with currently used variations. We also explore the applications of this assay in: genotoxicology, clinical area, DNA repair studies, environmental biomonitoring and human monitoring.
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Affiliation(s)
- E Rojas
- Departamento de Genética y Toxicología Ambiental, Instituto de Investigaciones Biomedicas, UNAM, Mexico DF, Mexico
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31
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Tzung TY, Rünger TM. Assessment of DNA Damage Induced by Broadband and Narrowband UVB in Cultured Lymphoblasts and Keratinocytes Using the Comet Assay. Photochem Photobiol 1998. [DOI: 10.1111/j.1751-1097.1998.tb09107.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Griffiths HR, Mistry P, Herbert KE, Lunec J. Molecular and cellular effects of ultraviolet light-induced genotoxicity. Crit Rev Clin Lab Sci 1998; 35:189-237. [PMID: 9663376 DOI: 10.1080/10408369891234192] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Exposure to the solar ultraviolet spectrum that penetrates the Earth's stratosphere (UVA and UVB) causes cellular DNA damage within skin cells. This damage is elicited directly through absorption of energy (UVB), and indirectly through intermediates such as sensitizer radicals and reactive oxygen species (UVA). DNA damage is detected as strand breaks or as base lesions, the most common lesions being 8-hydroxydeoxyguanosine (8OHdG) from UVA exposure and cyclobutane pyrimidine dimers from UVB exposure. The presence of these products in the genome may cause misreading and misreplication. Cells are protected by free radical scavengers that remove potentially mutagenic radical intermediates. In addition, the glutathione-S-transferase family can catalyze the removal of epoxides and peroxides. An extensive repair capacity exists for removing (1) strand breaks, (2) small base modifications (8OHdG), and (3) bulky lesions (cyclobutane pyrimidine dimers). UV also stimulates the cell to produce early response genes that activate a cascade of signaling molecules (e.g., protein kinases) and protective enzymes (e.g., haem oxygenase). The cell cycle is restricted via p53-dependent and -independent pathways to facilitate repair processes prior to replication and division. Failure to rescue the cell from replication block will ultimately lead to cell death, and apoptosis may be induced. The implications for UV-induced genotoxicity in disease are considered.
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33
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Abrahams PJ, Houweling A, Cornelissen-Steijger PD, Jaspers NG, Darroudi F, Meijers CM, Mullenders LH, Filon R, Arwert F, Pinedo HM, Natarajan AP, Terleth C, Van Zeeland AA, van der Eb AJ. Impaired DNA repair capacity in skin fibroblasts from various hereditary cancer-prone syndromes. Mutat Res 1998; 407:189-201. [PMID: 9637247 DOI: 10.1016/s0921-8777(98)00009-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Host-cell reactivation (HCR) of UV-C-irradiated herpes simplex virus type 1 (HSV-1) has been determined in skin fibroblasts from the following hereditary cancer-prone syndromes: aniridia (AN), dysplastic nevus syndrome (DNS), Von Hippel-Lindau syndrome (VHL), Li-Fraumeni syndrome (LFS) and a family with high incidence of breast and ovarian cancer. Cells from AN, DNS or VHL patients were found to exhibit heterogeneity in HCR. Cells from individuals belonging to an LFS family show reduced HCR in all cases where the cells were derived from persons carrying one mutated p53 allele, whereas cells derived from members with two wild-type alleles show normal HCR. LFS cells with reduced HCR also reveal reduced genome overall repair, and a slower gene-specific repair of the active adenosine deaminase (ADA) gene, but little if any repair of the inactive 754 gene. In the breast/ovarian cancer family, reduced HCR is observed in skin fibroblasts derived from both afflicted and unaffected individuals. In addition, these cells display lower survival after exposure to UV-C and exhibit higher levels of SCEs than those in normal cells. These observations indicate that various hereditary cancer-prone syndromes, carrying mutations in different tumor-suppressor genes, exhibit an unexplained impairment of the capacity to repair UV-damaged DNA.
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Affiliation(s)
- P J Abrahams
- MGC-Department of Molecular Cell Biology, Laboratory for Molecular Carcinogenesis, Leiden University Medical Centre, Netherlands.
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34
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Lehmann J, Pollet D, Peker S, Steinkraus V, Hoppe U. Kinetics of DNA strand breaks and protection by antioxidants in UVA- or UVB-irradiated HaCaT keratinocytes using the single cell gel electrophoresis assay. Mutat Res 1998; 407:97-108. [PMID: 9637238 DOI: 10.1016/s0921-8777(97)00064-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of this study was to characterize the genotoxic action of UVA and UVB in human keratinocytes by application of the single cell gel electrophoresis assay (SCGE assay). Dose dependence of DNA damage, the time course of its repair, and the influence of cellular antioxidant status were assessed. Irradiation with UVA or UVB both resulted in a dose-dependent increase in the level of DNA damage. A time course study to evaluate the repair kinetics in keratinocytes irradiated with 5 J/cm2 UVA revealed an immediate occurrence of DNA effects which subsequently disappeared within about 1 h, indicating removal of DNA lesions. This rapid repair of DNA damage is consistent with the observation that 5 J/cm2 UVA did not impair cellular viability. In contrast, exposure to 15 mJ/cm2 UVB resulted in a prolonged repair of DNA damage which lasted about 25 h. Thus, the repair kinetics of UVA- and UVB-induced DNA damage clearly differed from each other, implicating the induction of different types of DNA lesions by UVA and UVB. Neither a pretreatment with Mg-ascorbyl phosphate or D,L-alpha-tocopherol, nor depletion of endogenous glutathione altered cellular sensitivity to UVB. In contrast, the DNA damaging effects of UVA could be counteracted by a pretreatment with these antioxidants. These observations confirm that the UVA-induced effects on DNA are related to radical mediated strand breaks and DNA lesions forming alkali-labile sites. The UVB-induced effects mainly occur as a consequence of excision repair-related strand breaks. The observed repair kinetics of DNA lesions and the influence of cellular antioxidant status may help to elucidate protective mechanisms against the carcinogenic effects of UV radiation present in sunlight.
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Affiliation(s)
- J Lehmann
- Paul Gerson Unna-Skin Research Centre, Beiersdorf AG, Hamburg, Germany
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35
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Wenczl E, Pool S, Timmerman AJ, van der Schans GP, Roza L, Schothorst AA. Physiological doses of ultraviolet irradiation induce DNA strand breaks in cultured human melanocytes, as detected by means of an immunochemical assay. Photochem Photobiol 1997; 66:826-30. [PMID: 9421969 DOI: 10.1111/j.1751-1097.1997.tb03232.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An immunochemical assay, i.e. sandwich enzyme-linked immunosorbent assay, has been modified to detect UV-induced damage in cellular DNA of monolayer-grown human melanocytes. The method is based on the binding of a monoclonal antibody to single-stranded DNA. The melanocytes derived from human foreskin of skin type II individuals were suspended and exposed to UVA, UVB, solar-simulated light or gamma-rays. Following physiological doses of UVA, UVB or solar-simulated light, a dose-related DNA unwinding comprising a considerable number of single-strand breaks (ssb) was observed. No correlation was found between different seeded cell densities or different culturing periods and the UVA sensitivity of the cells. After UVA irradiation, 0.07 ssb/10(10) Da/kJ/m2 were detected and after UVB irradiation 1.9 ssb/10(10) Da/kJ/m2 were seen. One minimal erythema dose of solar-simulated light induced 2.25 ssb/10(10) Da. Our results from melanocytes expressed in ssb/Da DNA are comparable and have the same sensitivity toward UVA as well as toward UVB as nonpigmented skin cells. As low doses of UVA have already been shown to induce detectable numbers of ssb, this assay is of great interest for further investigations about the photoprotecting and/or photosensitizing effects of melanins in human melanocytes derived from different skin types.
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Affiliation(s)
- E Wenczl
- Department of Dermatology, Kun Street Hospital, Budapest, Hungary
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