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Seo B, Yang S, Cho E, Qureshi AA, Han J. Association of sun-seeking behaviors with indoor tanning behavior in US white females during high school/college in Nurses' Health Study II. BMC Public Health 2024; 24:162. [PMID: 38212727 PMCID: PMC10785486 DOI: 10.1186/s12889-024-17716-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 01/09/2024] [Indexed: 01/13/2024] Open
Abstract
BACKGROUND Frequent exposure to ultraviolet light has more detrimental and longer-term effects on the skin in early life than in adulthood. Teenagers with strong sun-seeking behaviors may be more likely to use an indoor tanning bed than those who seek less sun. We aimed to examine associations between sun-seeking behaviors and indoor tanning behavior during high school/college in US females. METHODS In this cross-sectional study, we used data from The Nurses' Health Study II, a large prospective cohort of US female nurses. We included a total of 81,746 white females who provided responses on the average annual frequency of indoor tanning during high school/college. Our study exposures were number of times/week spent outdoors in a swimsuit and percentage of time wearing sunscreen at the pool/beach as a teenager, weekly hours spent outdoors in direct sunlight during the daytime during high school/college, and number of severe sunburns that blistered between ages 15-20 years. The main outcome was annual frequency of indoor tanning bed usage during high school/college. RESULTS In multivariable-adjusted logistic regression, we demonstrated positive associations between sun-seeking behaviors and indoor tanning use. Specifically, teenagers who spent 7 times/week outdoors in a swimsuit (adjusted odds ratio [aOR], 95% confidence interval [CI] for daily vs. <1/week: 2.68, 1.76-4.09) were more likely to use indoor tanning beds ≥ 12 times/year. Teenagers with ≥ 10 sunburns (aOR, 95% CI for ≥ 10 vs. never: 2.18, 1.53-3.10) were more likely to use indoor tanning beds ≥ 12 times/year. Also, teenagers/undergraduates who spent ≥ 5 h/week outdoors in direct sunlight (aOR, 95% CI for ≥ 5 h/week vs. <1 h/week: 2.18, 1.39-3.44) were more likely to use indoor tanning ≥ 12 times/year. However, there was not a significant association between average usage of sunscreen at the pool/beach and average usage of indoor tanning beds. Multivariable-adjusted linear regression models also showed similar results. CONCLUSIONS Teenagers who spent more time outdoors in a swimsuit/direct sunlight or got more sunburns tended to use indoor tanning more frequently. These findings provide evidence that teenagers with stronger sun-seeking behaviors may have more exposure to artificial ultraviolet radiation as well.
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Affiliation(s)
- Bojung Seo
- Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University, 1050 Wishard Blvd, Health Sciences Building, RG 6124, Indianapolis, IN, 46202, USA
| | - Sheng Yang
- Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University, 1050 Wishard Blvd, Health Sciences Building, RG 6124, Indianapolis, IN, 46202, USA
| | - Eunyoung Cho
- Department of Dermatology, Alpert Medical School of Brown University, Providence, RI, USA
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, USA
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN, USA
| | - Abrar A Qureshi
- Department of Dermatology, Alpert Medical School of Brown University, Providence, RI, USA
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, USA
| | - Jiali Han
- Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University, 1050 Wishard Blvd, Health Sciences Building, RG 6124, Indianapolis, IN, 46202, USA.
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN, USA.
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, USA.
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Seo B, Yang S, Cho E, Qureshi AA, Han J. Association of sun-seeking behaviors with indoor tanning habit in US females. RESEARCH SQUARE 2023:rs.3.rs-2899336. [PMID: 37293104 PMCID: PMC10246252 DOI: 10.21203/rs.3.rs-2899336/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Frequent exposure to ultraviolet light in early life has more detrimental and long-term effects on skin than in adulthood. Teenagers with strong sun-seeking behaviors may be more likely to use an indoor tanning bed than those who seek less sun, probably due to addictiveness of ultraviolet exposure. We aimed to examine associations between sun exposure behaviors and average annual indoor tanning usage frequency during high school/college in US females. Methods In this cross-sectional study, we used data from The Nurses' Health Study II, a large prospective cohort of US female nurses. We included a total of 81,746 white females who answered the average annual frequency of indoor tanning during high school/college. Our study exposures were average weekly time spent outdoors in a swimsuit and average percentage of time of wearing sunscreen at the pool or beach during their teenage years, average weekly hours spent outdoors in direct sunlight in daytime during high school/college, and the number of severe sunburns which blistered between ages 15-20. Main outcomes was average annual frequency of indoor tanning bed usage during high school/college. Results In multivariable-adjusted logistic regression, we demonstrated positive associations between the sun exposure behaviors and the indoor tanning habit. Specifically, teenagers who spent daily outdoors in a swimsuit (adjusted odds ratio [aOR], 95% confidence interval [CI] for daily vs. <1/week: 2.68, 1.76-4.09) or who had ≥ 10 sunburns that blistered (aOR, 95% CI for ≥ 10 vs. never: 2.18, 1.53-3.10) were more likely to use indoor tanning beds ≥ 12 times/year. Also, teenagers/undergraduates who spent ≥ 5hours/week outdoors in direct sunlight during daytime used indoor tanning ≥ 12 times/year (aOR, 95% CI: 2.18, 1.39-3.44) than those who spent < 1/week. However, there was not a significant association between average uses of sunscreen at the pool/beach and indoor tanning bed. Multivariable-adjusted linear regression models also showed similar results. Conclusions Teenagers who spent more time outdoors or got more sunburns tended to use indoor tanning more frequently. These findings provide evidence that teenagers with strong sun-seeking behaviors may have excessive exposure to artificial ultraviolet radiation as well.
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Rinck-Junior JA, Torricelli C, Gomez GVB, Oliveira C, Moraes AM, Lourenço GJ, Lima CSP. Influence of functional variants Asp312Asn and Lys751Gln of Xeroderma Pigmentosum Group D (XPD) and Glutathione S-transferase Mu 1 (GSTM1) and Theta 1 (GSTT1) genes on cutaneous melanoma susceptibility and prognosis. Exp Dermatol 2020; 28:631-635. [PMID: 30883948 DOI: 10.1111/exd.13914] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/15/2019] [Accepted: 02/28/2019] [Indexed: 12/19/2022]
Abstract
We aimed to evaluate whether variants in repair (XPD Asp312Asn, XPD Lys751Gln) and detoxification (GSTM1, GSTT1) genes alter risk, clinicopathological aspects and survival of cutaneous melanoma (CM). Genotyping was performed in 229 CM patients and 258 controls. Individuals with XPD 312Asp/Asn or Asn/Asn plus GSTT1 null genotype were under 2.00 (95% CI: 1.06-3.79), and XPD 312Asn/Gln haplotype was under 1.44-fold (95% CI: 0.99-2.08) increased risks to CM than others. Individuals with GSTM1 plus GSTT1 null genotype had 9.61-fold (95% CI: 2.28-40.38) increased risk of metastatic CM. At 60 months of follow-up, patients with XPD 751Gln/Gln plus GSTT1 null and GSTM1 null plus GSTT1 null genotype presented 7.36 and 3.05 more chances of evolving to death in multivariate Cox analysis, respectively. In conclusion, our data indicate, for the first time, that specific variant combinations of XPD, GSTM1 and GSTT1 may increase susceptibility to CM and influence patients' clinicopathological features and survival.
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Affiliation(s)
- José Augusto Rinck-Junior
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas, Campinas, São Paulo, Brazil
| | - Caroline Torricelli
- Faculty of Medical Sciences, Laboratory of Cancer Genetics, University of Campinas, Campinas, São Paulo, Brazil
| | - Gabriela Vilas Bôas Gomez
- Faculty of Medical Sciences, Laboratory of Cancer Genetics, University of Campinas, Campinas, São Paulo, Brazil
| | - Cristiane Oliveira
- Faculty of Medical Sciences, Laboratory of Cancer Genetics, University of Campinas, Campinas, São Paulo, Brazil
| | - Aparecida Machado Moraes
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas, Campinas, São Paulo, Brazil
| | - Gustavo Jacob Lourenço
- Faculty of Medical Sciences, Laboratory of Cancer Genetics, University of Campinas, Campinas, São Paulo, Brazil
| | - Carmen Silvia Passos Lima
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas, Campinas, São Paulo, Brazil.,Faculty of Medical Sciences, Laboratory of Cancer Genetics, University of Campinas, Campinas, São Paulo, Brazil
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DNA damage and repair measured by comet assay in cancer patients. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 843:95-110. [DOI: 10.1016/j.mrgentox.2019.05.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 05/14/2019] [Accepted: 05/18/2019] [Indexed: 02/08/2023]
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Seleit I, Bakry OA, Al-Sharaky DR, Ragab RAA, Al-Shiemy SA. Evaluation of Hypoxia Inducible Factor-1α and Glucose Transporter-1 Expression in Non Melanoma Skin Cancer: An Immunohistochemical Study. J Clin Diagn Res 2017; 11:EC09-EC16. [PMID: 28764171 DOI: 10.7860/jcdr/2017/25077.10022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/13/2017] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Hypoxia Inducible Factor-1 (HIF-1) is a mediator enabling cell adaptation to hypoxia. It plays its role mainly through transcription of many target genes including Glucose Transporter-1 (GLUT-1) gene. AIM The present work aimed at evaluating the pattern and distribution of HIF-1α and GLUT-1 in each case and control. MATERIALS AND METHODS A case-control and retrospective study was conducted on archival blocks diagnosed from pathology department as, Basal Cell Carcinoma (BCC, 20 cases), cutaneous Squamous Cell Carcinoma (SCC, 20 cases) and 20 normal site-matched skin biopsies from age and gender-matched healthy subjects as a control. Evaluation of both HIF-1α and GLUT1 expression using standard immunohistochemical techniques was performed on cut sections from selected paraffin embedded blocks. RESULTS HIF-1α was expressed in 90%, 35% and 100% of normal skin, BCC and SCC tumour islands respectively. It was up regulated in both BCC and SCC compared with normal skin (p= 0.001, p<0.001 respectively). GLUT-1 was expressed in 100%, 70% and 100% of normal skin, BCC and SCC tumour islands respectively. It was down regulated in Non Melanoma Skin Cancer (NMSC) cases compared with normal skin (p=0.004). HIF-1α and GLUT-1 localization in tumour nests was central, peripheral or central and peripheral. Both HIF-1α and GLUT-1 showed variable expression in stroma, adnexa and inflammatory cells. No significant correlation was found between Histo (H) score or expression percentage values of HIF-1α and those of GLUT-1 in tumour islands or in overlying epidermis either in BCC or SCC. CONCLUSION HIF-1α may have a role in NMSC pathogenesis through adaptation to hypoxia which results from excessive proliferation. GLUT-1 down regulation in NMSC may be explained by its consumption by proliferating tumour cells. The expression of HIF-1α and GLUT-1 in normal epidermis, stromal and adnexal structures needs further research.
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Affiliation(s)
- Iman Seleit
- Professor, Department of Dermatology, Andrology and S.T.Ds, Faculty of Medicine Menoufia University, Egypt
| | - Ola Ahmed Bakry
- Assistant Professor, Department of Dermatology, Andrology and S.T.Ds, Faculty of Medicine, Menoufia University, Egypt
| | - Dalia Rifaat Al-Sharaky
- Assistant Professor, Department of Pathology, Faculty of Medicine, Menoufia University, Egypt
| | - Rania Abdel Aziz Ragab
- Resident, Department of Dermatology, Andrology and S.T.Ds, Faculty of Medicine, Menoufia University, Egypt
| | - Shimaa Ahmed Al-Shiemy
- Resident, Department of Dermatology, Andrology and S.T.Ds, Faculty of Medicine, Menoufia University, Egypt
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Villaruz LC, Huang G, Romkes M, Kirkwood JM, Buch SC, Nukui T, Flaherty KT, Lee SJ, Wilson MA, Nathanson KL, Benos PV, Tawbi HA. MicroRNA expression profiling predicts clinical outcome of carboplatin/paclitaxel-based therapy in metastatic melanoma treated on the ECOG-ACRIN trial E2603. Clin Epigenetics 2015; 7:58. [PMID: 26052356 PMCID: PMC4457092 DOI: 10.1186/s13148-015-0092-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/27/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Carboplatin/paclitaxel (CP), with or without sorafenib, result in objective response rates of 18-20 % in unselected chemotherapy-naïve patients. Molecular predictors of survival and response to CP-based chemotherapy in metastatic melanoma (MM) are critical to improving the therapeutic index. Intergroup trial E2603 randomized MM patients to CP with or without sorafenib. Expression data were collected from pre-treatment formalin-fixed paraffin-embedded (FFPE) tumor tissues from 115 of 823 patients enrolled on E2603. The selected patients were balanced across treatment arms, BRAF status, and clinical outcome. We generated data using Nanostring array (microRNA (miRNA) expression) and DNA-mediated annealing, selection, extension and ligation (DASL)/Illumina microarrays (HT12 v4) (mRNA expression) with protocols optimized for FFPE samples. Integrative computational analysis was performed using a novel Tree-guided Recursive Cluster Selection (T-ReCS) [1] algorithm to select the most informative features/genes, followed by TargetScan miRNA target prediction (Human v6.2) and mirConnX [2] for network inference. RESULTS T-ReCS identified PLXNB1 as negatively associated with progression-free survival (PFS) and miR-659-3p as the primary miRNA associated positively with PFS. miR-659-3p was differentially expressed based on PFS but not based on treatment arm, BRAF or NRAS status. Dichotomized by median PFS (less vs greater than 4 months), miR-659-3p expression was significantly different. High miR-659-3p expression distinguished patients with responsive disease (complete or partial response) from patients with stable disease. miR-659-3p predicted gene targets include NFIX, which is a transcription factor known to interact with c-Jun and AP-1 in the context of developmental processes and disease. CONCLUSIONS This novel integrative analysis implicates miR-659-3p as a candidate predictive biomarker for MM patients treated with platinum-based chemotherapy and may serve to improve patient selection.
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Affiliation(s)
- Liza C Villaruz
- University of Pittsburgh Cancer Institute, Pittsburgh, PA USA
| | - Grace Huang
- University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Marjorie Romkes
- University of Pittsburgh Cancer Institute, Pittsburgh, PA USA
| | - John M Kirkwood
- University of Pittsburgh Cancer Institute, Pittsburgh, PA USA
| | - Shama C Buch
- University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Tomoko Nukui
- University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Keith T Flaherty
- University of Pennsylvania, Philadelphia, PA USA.,Massachusetts General Hospital, Boston, MA USA
| | | | - Melissa A Wilson
- University of Pennsylvania, Philadelphia, PA USA.,New York University, New York, NY USA
| | | | | | - Hussein A Tawbi
- University of Pittsburgh Cancer Institute, Pittsburgh, PA USA
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Danialan R, Gopinath A, Phelps A, Murphy M, Grant-Kels JM. Accurate identification of melanoma tumor margins: a review of the literature. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.12.33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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O'Brien KM, Orlow I, Antonescu CR, Ballman K, McCall L, DeMatteo R, Engel LS. Gastrointestinal stromal tumors, somatic mutations and candidate genetic risk variants. PLoS One 2013; 8:e62119. [PMID: 23637977 PMCID: PMC3630216 DOI: 10.1371/journal.pone.0062119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/18/2013] [Indexed: 02/07/2023] Open
Abstract
Gastrointestinal stromal tumors (GISTs) are rare but treatable soft tissue sarcomas. Nearly all GISTs have somatic mutations in either the KIT or PDGFRA gene, but there are no known inherited genetic risk factors. We assessed the relationship between KIT/PDGFRA mutations and select deletions or single nucleotide polymorphisms (SNPs) in 279 participants from a clinical trial of adjuvant imatinib mesylate. Given previous evidence that certain susceptibility loci and carcinogens are associated with characteristic mutations, or "signatures" in other cancers, we hypothesized that the characteristic somatic mutations in the KIT and PDGFRA genes in GIST tumors may similarly be mutational signatures that are causally linked to specific mutagens or susceptibility loci. As previous epidemiologic studies suggest environmental risk factors such as dioxin and radiation exposure may be linked to sarcomas, we chose 208 variants in 39 candidate genes related to DNA repair and dioxin metabolism or response. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association between each variant and 7 categories of tumor mutation using logistic regression. We also evaluated gene-level effects using the sequence kernel association test (SKAT). Although none of the association p-values were statistically significant after adjustment for multiple comparisons, SNPs in CYP1B1 were strongly associated with KIT exon 11 codon 557-8 deletions (OR = 1.9, 95% CI: 1.3-2.9 for rs2855658 and OR = 1.8, 95% CI: 1.2-2.7 for rs1056836) and wild type GISTs (OR = 2.7, 95% CI: 1.5-4.8 for rs1800440 and OR = 0.5, 95% CI: 0.3-0.9 for rs1056836). CYP1B1 was also associated with these mutations categories in the SKAT analysis (p = 0.002 and p = 0.003, respectively). Other potential risk variants included GSTM1, RAD23B and ERCC2. This preliminary analysis of inherited genetic risk factors for GIST offers some clues about the disease's genetic origins and provides a starting point for future candidate gene or gene-environment research.
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Affiliation(s)
- Katie M. O'Brien
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Irene Orlow
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Cristina R. Antonescu
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Karla Ballman
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Linda McCall
- American College of Surgeons Oncology Group, Durham, North Carolina, United States of America
| | - Ronald DeMatteo
- Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Lawrence S. Engel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Zhou X, Li N, Wang Y, Wang Y, Zhang X, Zhang H. Effects of X-irradiation on mitochondrial DNA damage and its supercoiling formation change. Mitochondrion 2011; 11:886-92. [DOI: 10.1016/j.mito.2011.07.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 05/04/2011] [Accepted: 07/22/2011] [Indexed: 01/18/2023]
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Svobodová A, Vostálová J. Solar radiation induced skin damage: review of protective and preventive options. Int J Radiat Biol 2010; 86:999-1030. [PMID: 20807180 DOI: 10.3109/09553002.2010.501842] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE Solar energy has a number of short- and long-term detrimental effects on skin that can result in several skin disorders. The aim of this review is to summarise current knowledge on endogenous systems within the skin for protection from solar radiation and present research findings to date, on the exogenous options for such skin photoprotection. RESULTS Endogenous systems for protection from solar radiation include melanin synthesis, epidermal thickening and an antioxidant network. Existing lesions are eliminated via repair mechanisms. Cells with irreparable damage undergo apoptosis. Excessive and chronic sun exposure however can overwhelm these mechanisms leading to photoaging and the development of cutaneous malignancies. Therefore exogenous means are a necessity. Exogenous protection includes sun avoidance, use of photoprotective clothing and sufficient application of broad-spectrum sunscreens as presently the best way to protect the skin. However other strategies that may enhance currently used means of protection are being investigated. These are often based on the endogenous protective response to solar light such as compounds that stimulate pigmentation, antioxidant enzymes, DNA repair enzymes, non-enzymatic antioxidants. CONCLUSION More research is needed to confirm the effectiveness of new alternatives to photoprotection such as use of DNA repair and antioxidant enzymes and plant polyphenols and to find an efficient way for their delivery to the skin. New approaches to the prevention of skin damage are important especially for specific groups of people such as (young) children, photosensitive people and patients on immunosuppressive therapy. Changes in public awareness on the subject too must be made.
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Affiliation(s)
- Alena Svobodová
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 3, Olomouc, Czech Republic.
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Effects of ginsenoside Rg2 on the ultraviolet B-induced DNA damage responses in HaCaT cells. Naunyn Schmiedebergs Arch Pharmacol 2010; 382:89-101. [PMID: 20508917 DOI: 10.1007/s00210-010-0522-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 05/01/2010] [Indexed: 01/17/2023]
Abstract
Our previous study demonstrated the increase in the repair of UVB damage by mRg2, a mixture of ginsenosides containing 60% Rg2 in NIH3T3 cells. In the present study, the effects of purified Rg2 on the repair and apoptosis in ultraviolet B (UVB)-exposed HaCaT cells were investigated on gene expression levels. When cells were exposed to UVB and post-incubated in normal medium for 24 h, the cell viability decreased to about 50% of that in nontreated control. When Rg2 was post-incubated, however, the UVB-induced cytotoxicity was significantly prevented in an Rg2 concentration- and time-dependent manner. The apoptotic nuclear fragmentation resulting from UVB exposure was also significantly protected by the Rg2 post-incubation. Microarray analysis showed that the genes stimulated by the Rg2-alone treatment include those involved in p53 signaling pathway such as GADD45alpha, GADD45beta, and cell communication genes. RT-PCR analysis showed that the Rg2-alone treatment slightly upregulated the p53 and GADD45 transcript and protein levels by about 1.5-fold as compared with the nontreated control. The mRNA levels of p53 and GADD45 in cells exposed to UVB and post-incubated with Rg2 for 24 h decreased in an Rg2 concentration-dependent manner as compared with that post-incubated in normal medium. However, the mRNA level of the UVB-exposed cells post-incubated with 5 microM retinol was essentially the same as that post-incubated in normal medium. Time course experiment showed that the mRNA levels of p53 and GADD45 in UVB-exposed cells were upregulated by post-incubation with 50 microM Rg2 until 6 and 9 h, respectively, and then gradually decreased until 24 h. By Western blot analysis, it was also revealed that the Rg2 post-incubation decreases the expression of p53, phospho-p53, GADD45, and ATM in UVB-exposed cells. Time course analysis also indicated that these decreased expressions were due to the earlier upregulation of p53 and GADD45 proteins. When UVB-exposed cells were post-incubated with Rg2 for 24 h after UVB exposure, the level of remaining cyclobutane pyrimidine dimers decreased in both Rg2 concentration- and time-dependent manner. All these results suggest that Rg2 protects cells against UVB-induced genotoxicity by increasing DNA repair, in possible association with modulation of protein levels involved in p53 signaling pathway.
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Current World Literature. Curr Opin Support Palliat Care 2009; 3:305-12. [DOI: 10.1097/spc.0b013e3283339c93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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