1
|
Abstract
Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.
Collapse
Affiliation(s)
- Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Frank H Quina
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Maurício S Baptista
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| |
Collapse
|
2
|
Rodríguez-Muñiz GM, Gomez-Mendoza M, Miro P, García-Orduña P, Sastre G, Miranda MA, Marin ML. Topology and Excited State Multiplicity as Controlling Factors in the Carbazole-Photosensitized CPD Formation and Repair. J Org Chem 2022; 87:11433-11442. [PMID: 35980822 PMCID: PMC9447287 DOI: 10.1021/acs.joc.2c00942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Photosensitized thymine<>thymine (Thy<>Thy)
formation and
repair can be mediated by carbazole (Cbz). The former occurs from
the Cbz triplet excited state via energy transfer, while the latter
takes place from the singlet excited state via electron transfer.
Here, fundamental insight is provided into the role of the topology
and excited state multiplicity, as factors governing the balance between
both processes. This has been achieved upon designing and synthesizing
different isomers of trifunctional systems containing one Cbz and
two Thy units covalently linked to the rigid skeleton of the natural
deoxycholic acid. The results shown here prove that the Cbz photosensitized
dimerization is not counterbalanced by repair when the latter, instead
of operating through-space, has to proceed through-bond.
Collapse
Affiliation(s)
- Gemma M Rodríguez-Muñiz
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Miguel Gomez-Mendoza
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Paula Miro
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Pilar García-Orduña
- Dpto. Química Inorgánica, ISQCH-Instituto de Síntesis Química y Catálisis Homogénea, Facultad de Ciencias, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - German Sastre
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Miguel A Miranda
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - M Luisa Marin
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| |
Collapse
|
3
|
Wang J, Yano S, Xie K, Ohata Y, Hara T. Genome-Wide RNA Sequencing Analysis in Human Dermal Fibroblasts Exposed to Low-Dose Ultraviolet A Radiation. Genes (Basel) 2022; 13:genes13060974. [PMID: 35741736 PMCID: PMC9222854 DOI: 10.3390/genes13060974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 02/01/2023] Open
Abstract
Ultraviolet A (UVA) radiation can pass through the epidermis and reach the dermal skin layer, contributing to photoaging, DNA damage, and photocarcinogenesis in dermal fibroblasts. High-dose UVA exposure induces erythema, whereas low-dose, long-term UVA exposure causes skin damage and cell senescence. Biomarkers for evaluating damage caused by low-dose UVA in fibroblasts are lacking, making it difficult to develop therapeutic agents for skin aging and aging-associated diseases. We performed RNA-sequencing to investigate gene and pathway alterations in low-dose UVA-irradiated human skin-derived NB1RGB primary fibroblasts. Differentially expressed genes were identified and subjected to Gene Ontology and reactome pathway analysis, which revealed enrichment in genes in the senescence-associated secretory phenotype, apoptosis, respiratory electron transport, and transcriptional regulation by tumor suppressor p53 pathways. Insulin-like growth factor binding protein 7 (IGFBP7) showed the lowest p-value in RNA-sequencing analysis and was associated with the senescence-associated secretory phenotype. Protein–protein interaction analysis revealed that Fos proto-oncogene had a high-confidence network with IGFBP7 as transcription factor of the IGFBP7 gene among SASP hit genes, which were validated using RT-qPCR. Because of their high sensitivity to low-dose UVA radiation, Fos and IGFBP7 show potential as biomarkers for evaluating the effect of low-dose UVA radiation on dermal fibroblasts.
Collapse
|
4
|
Baptista MS, Cadet J, Greer A, Thomas AH. Photosensitization Reactions of Biomolecules: Definition, Targets and Mechanisms. Photochem Photobiol 2021; 97:1456-1483. [PMID: 34133762 DOI: 10.1111/php.13470] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/13/2021] [Indexed: 02/07/2023]
Abstract
Photosensitization reactions have been demonstrated to be largely responsible for the deleterious biological effects of UV and visible radiation, as well as for the curative actions of photomedicine. A large number of endogenous and exogenous photosensitizers, biological targets and mechanisms have been reported in the past few decades. Evolving from the original definitions of the type I and type II photosensitized oxidations, we now provide physicochemical frameworks, classifications and key examples of these mechanisms in order to organize, interpret and understand the vast information available in the literature and the new reports, which are in vigorous growth. This review surveys in an extended manner all identified photosensitization mechanisms of the major biomolecule groups such as nucleic acids, proteins, lipids bridging the gap with the subsequent biological processes. Also described are the effects of photosensitization in cells in which UVA and UVB irradiation triggers enzyme activation with the subsequent delayed generation of superoxide anion radical and nitric oxide. Definitions of photosensitized reactions are identified in biomolecules with key insights into cells and tissues.
Collapse
Affiliation(s)
| | - Jean Cadet
- Département de Médecine Nucléaire et de Radiobiologie, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Alexander Greer
- Department of Chemistry, Brooklyn College, Brooklyn, NY, USA.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, USA
| | - Andrés H Thomas
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CCT La Plata-CONICET, La Plata, Argentina
| |
Collapse
|
5
|
Muruzabal D, Collins A, Azqueta A. The enzyme-modified comet assay: Past, present and future. Food Chem Toxicol 2020; 147:111865. [PMID: 33217526 DOI: 10.1016/j.fct.2020.111865] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 11/08/2020] [Accepted: 11/13/2020] [Indexed: 12/17/2022]
Abstract
The enzyme-modified comet assay was developed in order to detect DNA lesions other than those detected by the standard version (single and double strand breaks and alkali-labile sites). Various lesion-specific enzymes, from the DNA repair machinery of bacteria and humans, have been combined with the comet assay, allowing detection of different oxidized and alkylated bases as well as cyclobutane pyrimidine dimers, mis-incorporated uracil and apurinic/apyrimidinic sites. The enzyme-modified comet assay has been applied in different fields - human biomonitoring, environmental toxicology, and genotoxicity testing (both in vitro and in vivo) - as well as in basic research. Up to now, twelve enzymes have been employed; here we describe the enzymes and give examples of studies in which they have been applied. The bacterial formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII) have been extensively used while others have been used only rarely. Adding further enzymes to the comet assay toolbox could potentially increase the variety of DNA lesions that can be detected. The enzyme-modified comet assay can play a crucial role in the elucidation of the mechanism of action of both direct and indirect genotoxins, thus increasing the value of the assay in the regulatory context.
Collapse
Affiliation(s)
- Damián Muruzabal
- Universidad de Navarra, Department of Pharmacology and Toxicology, Faculty of Pharmacy and Nutrition, Irunlarrea 1, 310008, Pamplona, Spain
| | - Andrew Collins
- Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Sognsvannsveien 9, 0372, Oslo, Norway
| | - Amaya Azqueta
- Universidad de Navarra, Department of Pharmacology and Toxicology, Faculty of Pharmacy and Nutrition, Irunlarrea 1, 310008, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
| |
Collapse
|
6
|
Fidrus E, Ujhelyi Z, Fehér P, Hegedűs C, Janka EA, Paragh G, Vasas G, Bácskay I, Remenyik É. Silymarin: Friend or Foe of UV Exposed Keratinocytes? Molecules 2019; 24:molecules24091652. [PMID: 31035502 PMCID: PMC6540143 DOI: 10.3390/molecules24091652] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/19/2019] [Accepted: 04/24/2019] [Indexed: 12/19/2022] Open
Abstract
The application of natural plant extracts in UV-protection is popular and intensively studied. Silymarin (from Silibum marianum), a naturally occurring polyphenol, has recently received attention due to its antioxidant, anti-inflammatory and anti-apoptotic effects. However, its role in the UV-mediated keratinocyte cell response is still controversial. In this study, we investigated the effects of Silibum marianum extracts with different origins and formulations on UVA-exposed HaCaT keratinocytes in vitro. Our results show, that silymarin treatment caused an inverse dose-dependent photosensitivity relationship (at higher doses, a decrease in cell viability and ROS production) after UVA exposure. The attenuation of the UVA-induced ROS generation after silymarin treatment was also observed. Moreover, silymarin pre-treatment increased the cyclobutane pyrimidine dimer photolesions in keratinocytes after UVA exposure. These results indicated the dual role of silymarin in UVA-exposed keratinocytes. It scavenges ROS but still induces phototoxicity. Based on our results dermatological applications of silymarin and related compounds should be considered very carefully.
Collapse
Affiliation(s)
- Eszter Fidrus
- Department of Dermatology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary.
| | - Zoltán Ujhelyi
- Department of Pharmaceutical Technology, University of Debrecen, Nagyerdei körút 98, 4032 Debrecen, Hungary.
| | - Pálma Fehér
- Department of Pharmaceutical Technology, University of Debrecen, Nagyerdei körút 98, 4032 Debrecen, Hungary.
| | - Csaba Hegedűs
- Department of Dermatology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary.
| | - Eszter Anna Janka
- Department of Dermatology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary.
| | - György Paragh
- Departments of Dermatology and Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA.
| | - Gábos Vasas
- Department of Pharmacognosy, University of Debrecen, Nagyerdei körút 98, 4032 Debrecen, Hungary.
| | - Ildikó Bácskay
- Department of Pharmaceutical Technology, University of Debrecen, Nagyerdei körút 98, 4032 Debrecen, Hungary.
| | - Éva Remenyik
- Department of Dermatology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary.
| |
Collapse
|
7
|
Arisi M, Zane C, Caravello S, Rovati C, Zanca A, Venturini M, Calzavara-Pinton P. Sun Exposure and Melanoma, Certainties and Weaknesses of the Present Knowledge. Front Med (Lausanne) 2018; 5:235. [PMID: 30214901 PMCID: PMC6126418 DOI: 10.3389/fmed.2018.00235] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/03/2018] [Indexed: 12/15/2022] Open
Abstract
Sun exposure is the main risk factor for cutaneous malignant melanoma (CMM). However, the UV-related pathogenetic mechanisms leading to CMM are far to be fully elucidated. In this paper we will focus on what we still don't fully know about the relationship between UVR and CMM. In particular, we will discuss: the action spectrum of human CMM, how different modalities of exposure (continuous/ intermittent; erythemal/ suberythemal) relate to different CMM variants, the preferential UVR induced DNA mutations observed in different CMM variants, the role of UV-related and UV-unrelated genetic damages in the same melanoma cells. Moreover, we will debate the importance of UVA induced oxidative and anaerobic damages to DNA and other cell structures and the role of melanins, of modulation of innate and acquired immunity, of vitamin D and of chronic exposure to phototoxic drugs and other xenobiotics. A better understanding of these issues will help developing more effective preventative strategies and new therapeutic approaches.
Collapse
Affiliation(s)
- Mariachiara Arisi
- Department of Dermatology, Spedali Civili di Brescia, University of Brescia, Brescia, Italy
| | - Cristina Zane
- Department of Dermatology, Spedali Civili di Brescia, University of Brescia, Brescia, Italy
| | - Simone Caravello
- Department of Dermatology, Spedali Civili di Brescia, University of Brescia, Brescia, Italy
| | - Chiara Rovati
- Department of Dermatology, Spedali Civili di Brescia, University of Brescia, Brescia, Italy
| | - Arianna Zanca
- Department of Dermatology, Spedali Civili di Brescia, University of Brescia, Brescia, Italy
| | - Marina Venturini
- Department of Dermatology, Spedali Civili di Brescia, University of Brescia, Brescia, Italy
| | | |
Collapse
|
8
|
Delinasios GJ, Karbaschi M, Cooke MS, Young AR. Vitamin E inhibits the UVAI induction of "light" and "dark" cyclobutane pyrimidine dimers, and oxidatively generated DNA damage, in keratinocytes. Sci Rep 2018; 8:423. [PMID: 29323251 PMCID: PMC5764969 DOI: 10.1038/s41598-017-18924-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 12/20/2017] [Indexed: 01/08/2023] Open
Abstract
Solar ultraviolet radiation (UVR)-induced DNA damage has acute, and long-term adverse effects in the skin. This damage arises directly by absorption of UVR, and indirectly via photosensitization reactions. The aim of the present study was to assess the effects of vitamin E on UVAI-induced DNA damage in keratinocytes in vitro. Incubation with vitamin E before UVAI exposure decreased the formation of oxidized purines (with a decrease in intracellular oxidizing species), and cyclobutane pyrimidine dimers (CPD). A possible sunscreening effect was excluded when similar results were obtained following vitamin E addition after UVAI exposure. Our data showed that DNA damage by UVA-induced photosensitization reactions can be inhibited by the introduction of vitamin E either pre- or post-irradiation, for both oxidized purines and CPD (including so-called “dark” CPDs). These data validate the evidence that some CPD are induced by UVAI initially via photosensitization, and some via chemoexcitation, and support the evidence that vitamin E can intervene in this pathway to prevent CPD formation in keratinocytes. We propose the inclusion of similar agents into topical sunscreens and aftersun preparations which, for the latter in particular, represents a means to mitigate on-going DNA damage formation, even after sun exposure has ended.
Collapse
Affiliation(s)
- George J Delinasios
- King's College London, St John's Institute of Dermatology, 9th Floor, Tower Wing, Guy's Hospital; Great Maze Pond, London, SE1 9RT, UK.,International Institute of Anticancer Research, Kapandriti, 19014, Greece
| | - Mahsa Karbaschi
- Oxidative Stress Group, Department of Cancer Studies, University Hospitals of Leicester NHS Trust, Leicester, UK.,Oxidative Stress Group, Department of Environmental Health Sciences; and Biomolecular Sciences Institute, Florida International University, University Park, 11200 SW 8th Street, Miami, Fl, 33199, USA
| | - Marcus S Cooke
- Oxidative Stress Group, Department of Cancer Studies, University Hospitals of Leicester NHS Trust, Leicester, UK. .,Department of Genetics, University of Leicester, Leicester Royal Infirmary, University Hospitals of Leicester NHS Trust, Leicester, UK. .,Oxidative Stress Group, Department of Environmental Health Sciences; and Biomolecular Sciences Institute, Florida International University, University Park, 11200 SW 8th Street, Miami, Fl, 33199, USA.
| | - Antony R Young
- King's College London, St John's Institute of Dermatology, 9th Floor, Tower Wing, Guy's Hospital; Great Maze Pond, London, SE1 9RT, UK.
| |
Collapse
|
9
|
Tewari A, Grage MML, Harrison GI, Sarkany R, Young AR. UVA1 is skin deep: molecular and clinical implications. Photochem Photobiol Sci 2013. [PMID: 23192740 DOI: 10.1039/c2pp25323b] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Long wavelength UVA1 (340-400 nm) is the main component of terrestrial UVR and is increasingly used in skin phototherapy. Its damage to critical biomolecules such as DNA has been widely attributed to its ability to generate reactive oxygen species (ROS) via other chromophores. However recent studies in vitro and in vivo have shown that UVA1 has a specific ability to generate cyclobutane pyrimidine dimers (CPD), especially thymine dimers (T<>T), and that this is probably due to direct absorption of UVR. The CPD has been implicated in many aspects of skin cancer. Measuring UVB-induced CPD in the epidermis and dermis in vivo shows that, as expected, the skin attenuates UVB. In contrast, our data show that this is not the case with UVA1: in fact there is more damage with increased skin depth. This suggests that the basal layer, which contains keratinocyte stem cells and melanocytes, is more vulnerable to the carcinogenic effects of UVA1 than would be predicted by mouse models. These data support the continuing trend for better UVA1 protection by sunscreens.
Collapse
Affiliation(s)
- Angela Tewari
- King's College London (KCL), King's College London School of Medicine, Division of Genetics and Molecular Medicine, St John's Institute of Dermatology, London, UK.
| | | | | | | | | |
Collapse
|
10
|
Haylett AK, Felton S, Denning DW, Rhodes LE. Voriconazole-induced photosensitivity: photobiological assessment of a case series of 12 patients. Br J Dermatol 2012; 168:179-85. [PMID: 22860570 DOI: 10.1111/j.1365-2133.2012.11196.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Voriconazole, a broad-spectrum triazole antifungal agent increasingly used to treat aspergillosis, has been linked with acute photosensitivity and skin carcinogenesis. The action spectrum of the photosensitivity is unknown, while an indirect retinol effect secondary to the antifungal's impact on CYP450 enzymes has been proposed to contribute to the underlying mechanism. OBJECTIVES To perform a detailed photobiological assessment of the photosensitivity presenting in a series of 12 patients treated with voriconazole. METHODS Minimal erythemal dose thresholds (MED) to narrow wavebands of ultraviolet (UV) A, UVB and visible light were determined. Provocation testing was performed to broadband UVA (310-400 nm) and to solar-simulated radiation (SSR) (290-400 nm). Patients underwent routine photopatch testing and laboratory investigations including serum vitamin A (retinol). RESULTS Patients (eight men, four women; median age 54years, range 40-63) experienced moderate-severe cutaneous erythema (n = 12), burning pain (n=5), itching (n=3), scaling (n=5), vesiculation (n=5) and oedema (n=1) following sunlight exposure; increased lentigines (n=4) and actinic cheilitis (n = 4) were also observed. While the majority (n=8) of patients showed normal MED thresholds to monochromator phototesting to UVB, UVA and visible light, a low MED to UVA was observed in four patients. Repeated provocation testing with broadband UVA and SSR provoked an abnormal erythema in eight and 10 patients, respectively. Serum retinol levels were mildly elevated in two patients but normal in the majority. CONCLUSION UVA sensitivity is the predominant finding in acute voriconazole-induced photosensitivity. We found little evidence of elevated circulating retinol as the causal factor. Patients with voriconazole-induced photosensitivity require education in appropriate UVA protective measures in addition to consideration of skin surveillance for malignant sequelae.
Collapse
Affiliation(s)
- A K Haylett
- Photobiology Unit, Dermatology Centre, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Trust, Stott Lane, Manchester M6 8HD, U.K
| | | | | | | |
Collapse
|
11
|
Cadet J, Mouret S, Ravanat JL, Douki T. Photoinduced damage to cellular DNA: direct and photosensitized reactions. Photochem Photobiol 2012; 88:1048-65. [PMID: 22780837 DOI: 10.1111/j.1751-1097.2012.01200.x] [Citation(s) in RCA: 209] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The survey focuses on recent aspects of photochemical reactions to cellular DNA that are implicated through the predominant formation of mostly bipyrimidine photoproducts in deleterious effects of human exposure to sunlight. Recent developments in analytical methods have allowed accurate and quantitative measurements of the main DNA photoproducts in cells and human skin. Highly mutagenic CC and CT bipyrimidine photoproducts, including cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are generated in low yields with respect to TT and TC photoproducts. Another striking finding deals with the formation of Dewar valence isomers, the third class of bipyrimidine photoproducts that is accounted for by UVA-mediated isomerization of initially UVB generated 6-4PPs. Cyclobutadithymine (T<>T) has been unambiguously shown to be involved in the genotoxicity of UVA radiation. Thus, T<>T is formed in UVA-irradiated cellular DNA according to a direct excitation mechanism with a higher efficiency than oxidatively generated DNA damage that arises mostly through the Type II photosensitization mechanism. C<>C and C<>T are repaired at rates intermediate between those of T<>T and 6-4TT. Evidence has been also provided for the occurrence of photosensitized reactions mediated by exogenous agents that act either in an independent way or through photodynamic effects.
Collapse
Affiliation(s)
- Jean Cadet
- Laboratoire Lésions des Acides Nucléiques, SCIB-UMR-E n°3, CEA/UJF, Institut Nanosciences et Cryogénie, CEA/Grenoble, Grenoble Cedex, France
| | | | | | | |
Collapse
|
12
|
Swalwell H, Latimer J, Haywood RM, Birch-Machin MA. Investigating the role of melanin in UVA/UVB- and hydrogen peroxide-induced cellular and mitochondrial ROS production and mitochondrial DNA damage in human melanoma cells. Free Radic Biol Med 2012; 52:626-634. [PMID: 22178978 DOI: 10.1016/j.freeradbiomed.2011.11.019] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 11/08/2011] [Accepted: 11/14/2011] [Indexed: 11/29/2022]
Abstract
Skin cancer incidence is dramatically increasing worldwide, with exposure to ultraviolet radiation (UVR) a predominant factor. The UVA component initiates oxidative stress in human skin, although its exact role in the initiation of skin cancer, particularly malignant melanoma, remains unclear and is controversial because there is evidence for a melanin-dependent mechanism in UVA-linked melanoma studies. Nonpigmented (CHL-1, A375), moderately pigmented (FM55, SKmel23), and highly pigmented (FM94, hyperpigmented FM55) human melanoma cell lines have been used to investigate UVA-induced production of reactive oxygen species using FACS analysis, at both the cellular (dihydrorhodamine-123) and the mitochondrial (MitoSOX) level, where most cellular stress is generated. For the first time, downstream mtDNA damage (utilizing a quantitative long-PCR assay) has been investigated. Using UVA, UVB, and H(2)O(2) as cellular stressors, we have explored the dual roles of melanin as a photoprotector and photosensitizer. The presence of melanin has no influence over cellular oxidative stress generation, whereas, in contrast, melanin protects against mitochondrial superoxide generation and mtDNA damage (one-way ANOVA with post hoc Tukey's analysis, P<0.001). We show that if melanin binds directly to DNA, it acts as a direct photosensitizer of mtDNA damage during UVA irradiation (P<0.001), providing evidence for the dual roles of melanin.
Collapse
Affiliation(s)
- Helen Swalwell
- Department of Dermatological Sciences, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Jennifer Latimer
- Department of Dermatological Sciences, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Rachel M Haywood
- RAFT Leopold Muller Building, Mount Vernon Hospital, Northwood, Middlesex HA6 2RN, UK
| | - Mark A Birch-Machin
- Department of Dermatological Sciences, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| |
Collapse
|
13
|
UVA1 induces cyclobutane pyrimidine dimers but not 6-4 photoproducts in human skin in vivo. J Invest Dermatol 2011; 132:394-400. [PMID: 21975824 DOI: 10.1038/jid.2011.283] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
UVB readily induces cyclobutane pyrimidine dimers, mainly thymine dimers (TTs), and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) in DNA. These lesions result in "UVB signature mutations" found in skin cancers. We have investigated the induction of TTs and 6-4PPs in human skin in vivo by broadband UVA1, and have compared this with comparable erythemal doses of monochromatic UVB (300 nm). In vitro and ex vivo studies have shown the production of TTs, without 6-4PPs, by UVA1. We show that UVA1 induces TTs, without 6-4PPs, in the epidermis of healthy volunteers in vivo, whereas UVB induced both photoproducts. UVB induced more TTs than UVA1 for the same level of erythema. The level of UVA1-induced TTs increased with epidermal depth in contrast to a decrease that was seen with UVB. UVA1- and UVB-induced TTs were repaired in epidermal cells at a similar rate. The mechanism by which UVA1 induces TTs is unknown, but a lack of intra-individual correlation between our subjects' UVB and UVA1 minimal erythema doses implies that UVA1 and UVB erythema occur by different mechanisms. Our data suggest that UVA1 may be more carcinogenic than has previously been thought.
Collapse
|
14
|
Abstract
DNA damage induced by photosensitization is not only responsible for the genotoxic effects of various types of drugs in the presence of light, but is also relevant for some of the adverse effects of sunlight, in particular in the UVA and visible range of the spectrum. The types of DNA modifications induced are very diverse and include pyrimidine dimers, covalent adducts, various base modifications generated by oxidation, single-strand breaks and (regular and oxidized) sites of base loss. The ratios in which the various modifications are formed (damage spectra) can be regarded as a fingerprint of the damaging mechanism. Here, we describe the damage spectra of various classes of photosensitizers in relation to the underlying damaging mechanisms. In mammalian cells irradiated with solar radiation, damage at wavelengths <400 nm is characteristic for a (not yet identified) endogenous type-I or type-II photosensitizer. In the UVA range, however, both direct DNA excitation and photosensitized damage appear to be relevant, and there are indications that other chromophore(s) are involved than in the visible range.
Collapse
Affiliation(s)
- Bernd Epe
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55099, Mainz, Germany.
| |
Collapse
|
15
|
Cuquerella MC, Lhiaubet-Vallet V, Bosca F, Miranda MA. Photosensitised pyrimidine dimerisation in DNA. Chem Sci 2011. [DOI: 10.1039/c1sc00088h] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|