1
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Zhivagui M, Hoda A, Valenzuela N, Yeh YY, Dai J, He Y, Nandi SP, Otlu B, Van Houten B, Alexandrov LB. DNA damage and somatic mutations in mammalian cells after irradiation with a nail polish dryer. Nat Commun 2023; 14:276. [PMID: 36650165 PMCID: PMC9845303 DOI: 10.1038/s41467-023-35876-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 01/05/2023] [Indexed: 01/19/2023] Open
Abstract
Ultraviolet A light is commonly emitted by UV-nail polish dryers with recent reports suggesting that long-term use may increase the risk for developing skin cancer. However, no experimental evaluation has been conducted to reveal the effect of radiation emitted by UV-nail polish dryers on mammalian cells. Here, we show that irradiation by a UV-nail polish dryer causes high levels of reactive oxygen species, consistent with 8-oxo-7,8-dihydroguanine damage and mitochondrial dysfunction. Analysis of somatic mutations reveals a dose-dependent increase of C:G>A:T substitutions in irradiated samples with mutagenic patterns similar to mutational signatures previously attributed to reactive oxygen species. In summary, this study demonstrates that radiation emitted by UV-nail polish dryers can both damage DNA and permanently engrave mutations on the genomes of primary mouse embryonic fibroblasts, human foreskin fibroblasts, and human epidermal keratinocytes.
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Affiliation(s)
- Maria Zhivagui
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, 92093, USA.,Department of Bioengineering, UC San Diego, La Jolla, CA, 92093, USA.,Moores Cancer Center, UC San Diego, La Jolla, CA, 92037, USA
| | - Areebah Hoda
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, 92093, USA
| | | | - Yi-Yu Yeh
- Department of Bioengineering, UC San Diego, La Jolla, CA, 92093, USA
| | - Jason Dai
- Department of Bioengineering, UC San Diego, La Jolla, CA, 92093, USA
| | - Yudou He
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, 92093, USA.,Department of Bioengineering, UC San Diego, La Jolla, CA, 92093, USA.,Moores Cancer Center, UC San Diego, La Jolla, CA, 92037, USA
| | - Shuvro P Nandi
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, 92093, USA.,Department of Bioengineering, UC San Diego, La Jolla, CA, 92093, USA.,Moores Cancer Center, UC San Diego, La Jolla, CA, 92037, USA
| | - Burcak Otlu
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, 92093, USA.,Department of Bioengineering, UC San Diego, La Jolla, CA, 92093, USA.,Moores Cancer Center, UC San Diego, La Jolla, CA, 92037, USA
| | - Bennett Van Houten
- UPMC-Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Ludmil B Alexandrov
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, 92093, USA. .,Department of Bioengineering, UC San Diego, La Jolla, CA, 92093, USA. .,Moores Cancer Center, UC San Diego, La Jolla, CA, 92037, USA.
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2
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Mechanistic investigation of the deamination reaction of 6-thioguanine: a theoretical study. Struct Chem 2022. [DOI: 10.1007/s11224-022-02121-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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3
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Huo B, Zhang X, Wang C, Wang H, Zhu G, Zhu W, Zhu A, Mei H, Li L. Mechanistic Insight into the Photoinduced Damage of an Unnatural Base Pair. Chemistry 2022; 28:e202201730. [DOI: 10.1002/chem.202201730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Bianbian Huo
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
- State Key Laboratory of Cell Differentiation Regulation and Target Drug Henan Normal University Xinxiang Henan 453007 P. R. China
| | - Xiguang Zhang
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
| | - Chao Wang
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
| | - Honglei Wang
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
- State Key Laboratory of Cell Differentiation Regulation and Target Drug Henan Normal University Xinxiang Henan 453007 P. R. China
| | - Gongming Zhu
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
| | - Wuyuan Zhu
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
| | - Anlian Zhu
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
| | - Hui Mei
- Shenzhen Key Laboratory of Synthetic Genomics Guangdong Provincial Key Laboratory of Synthetic Genomics CAS Key Laboratory of Quantitative Engineering Biology Shenzhen Institute of Synthetic Biology Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 P. R. China
| | - Lingjun Li
- Department Henan Key Laboratory of Organic Functional Molecule and Drug Innovation Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals School of Chemistry and Chemical Engineering Key Laboratory of Green Chemical Media and Reactions Ministry of Education Henan Normal University Xinxiang Henan 453007 P. R. China
- State Key Laboratory of Cell Differentiation Regulation and Target Drug Henan Normal University Xinxiang Henan 453007 P. R. China
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4
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Al-Adra D, Al-Qaoud T, Fowler K, Wong G. De Novo Malignancies after Kidney Transplantation. Clin J Am Soc Nephrol 2022; 17:434-443. [PMID: 33782034 PMCID: PMC8975024 DOI: 10.2215/cjn.14570920] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cancer is an important outcome after kidney transplantation because it is the second leading cause of death in most Western countries. The excess risk of cancer after transplantation is approximately two to three times higher than the age- and sex-matched general population, driven largely by viral- and immune-related cancers. Once cancer develops, outcomes are generally poor, particularly for those with melanoma, renal cell carcinoma, and post-transplant lymphoproliferative disease. More importantly, effective screening and treatment strategies are limited in this high-risk population. In this review, we begin with a patient's journey that maps the experience of living with a kidney transplant and understand the patient's knowledge, education, and experience of cancer in the context of transplantation. The epidemiology and burden of cancer in recipients of kidney transplants, along with the up-to-date screening and treatment strategies, are discussed. We also focus on the current understanding of optimal care for recipients of kidney transplants who are living with cancer from the patients' perspectives.
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Affiliation(s)
- David Al-Adra
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Talal Al-Qaoud
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Kevin Fowler
- The Voice of the Patient, Inc., Columbia, Missouri
| | - Germaine Wong
- Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia .,Centre for Kidney Research, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales, Australia.,Centre for Transplant and Renal Research, Westmead Hospital, Westmead, New South Wales, Australia
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5
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Valverde D, Mai S, Sanches de Araújo AV, Canuto S, González L, Borin AC. On the population of triplet states of 2-seleno-thymine. Phys Chem Chem Phys 2021; 23:5447-5454. [PMID: 33650609 DOI: 10.1039/d1cp00041a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The population and depopulation mechanisms leading to the lowest-lying triplet states of 2-Se-Thymine were studied at the MS-CASPT2/cc-pVDZ level of theory. Several critical points on different potential energy hypersurfaces were optimized, including minima, conical intersections, and singlet-triplet crossings. The accessibility of all relevant regions on the potential energy hypersurfaces was investigated by means of minimum energy paths and linear interpolation in internal coordinates techniques. Our analysis indicates that, after the population of the bright S2 state in the Franck-Condon region, the first photochemical event is a barrierless evolution towards one of its two minima. After that, three viable photophysical deactivation paths can take place. In one of them, the population in the S2 state is transferred to the T2 state via intersystem crossing and subsequently to the T1 state by internal conversion. Alternatively, the S1 state could be accessed by internal conversion through two distinct conical intersections with S2 state followed by singlet-triplet crossing with the T2 state. The absence of a second minimum on the T1 state and a small energy barrier on pathway along the potential energy surface towards the ground state from the lowest triplet state are attributed as potential reasons to explain why the lifetime of the triplet state of 2-Se-Thymine might be reduced in comparison with its thio-analogue.
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Affiliation(s)
- Danillo Valverde
- Institute of Physics, University of São Paulo, Rua do Matão 1371. 05508-090, São Paulo, SP, Brazil
| | - Sebastian Mai
- Photonics Institute, Vienna University of Technology, Gußhausstraße 27-29, 1040 Vienna, Austria and Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria.
| | | | - Sylvio Canuto
- Institute of Physics, University of São Paulo, Rua do Matão 1371. 05508-090, São Paulo, SP, Brazil
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria.
| | - Antonio Carlos Borin
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748. 05508-000, São Paulo, SP, Brazil.
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6
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Ritter A, Badir S, Mansour M, Segal Z, Ad-El D, Bachar G, Shpitzer T, Popovtzer A, Mizrachi A. Solid organ transplantation worsens the prognosis of patients with cutaneous squamous cell carcinoma of the head and neck region-Comparison between solid organ transplant recipients and immunocompetent patients. Head Neck 2020; 43:884-894. [PMID: 33247523 DOI: 10.1002/hed.26546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 10/25/2020] [Accepted: 11/09/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Cutaneous squamous cell carcinoma of the head and neck (CSCC-HN) appears to behave more aggressively in immunosuppressed patients. We aimed to investigate this hypothesis by comparing solid organ transplant recipients (SOTR) with CSCC-HN to immunocompetent patients. METHODS A retrospective comparative study was conducted for SOTR and immunocompetent patients who were treated for CSCC-HN. RESULTS A total of 177 SOTR and 157 immunocompetent patients with CSCC-HN were included. Lymph node metastases were more common in the SOTR group (9% vs 3%), and distant metastases occurred only in SOTR (3% of patients). SOTR had a higher rate of recurrences (19% vs 10%), which were mostly regional (7%) and distant (3%). The 2-year disease-specific survival of SOTR was lower (93% vs 100%). CONCLUSIONS SOTR with CSCC-HN has significantly worse outcomes compared to immunocompetent patients. Solid-organ transplantation should be regarded as a negative prognostic factor in patients with CSCC-HN.
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Affiliation(s)
- Amit Ritter
- Department of Otolaryngology Head and Neck Surgery, Rabin Medical Center, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Samih Badir
- Department of Otolaryngology Head and Neck Surgery, Rabin Medical Center, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Muhammad Mansour
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Plastic Surgery and Burns, Rabin Medical Center, Petah Tikva, Israel
| | - Zvi Segal
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Plastic Surgery and Burns, Rabin Medical Center, Petah Tikva, Israel
| | - Dean Ad-El
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Plastic Surgery and Burns, Rabin Medical Center, Petah Tikva, Israel
| | - Gideon Bachar
- Department of Otolaryngology Head and Neck Surgery, Rabin Medical Center, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Thomas Shpitzer
- Department of Otolaryngology Head and Neck Surgery, Rabin Medical Center, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Aron Popovtzer
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Davidoff Cancer Center, Rabin Medical Center, Petah Tikva, Israel
| | - Aviram Mizrachi
- Department of Otolaryngology Head and Neck Surgery, Rabin Medical Center, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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7
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Huo Z, Li C, Xu X, Ge F, Wang R, Wen Y, Peng H, Wu X, Liang H, Peng G, Li R, Huang D, Chen Y, Zhong R, Cheng B, Xiong S, Lin W, He J, Liang W. Cancer Risks in Solid Organ Transplant Recipients: Results from a Comprehensive Analysis of 72 Cohort Studies. Oncoimmunology 2020; 9:1848068. [PMID: 33299661 PMCID: PMC7714465 DOI: 10.1080/2162402x.2020.1848068] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Understanding the cancer risks in different transplant recipients helps early detection, evaluation, and treatment of post-transplant malignancies. Therefore, we performed a meta-analysis to determine the cancer risks at multiple sites for solid organ transplant recipients and their associations with tumor mutation burden (TMB), which reflects the immunogenicity. A comprehensive search of PubMed, Web of Science, EMBASE, Medline, and Cochrane Library was conducted. Random effects models were used to calculate the standardized incidence ratios (SIRs) versus the general population and determine the risks of different cancers. Linear regression (LR) was used to analyze the association between the SIRs and TMBs. Finally, seventy-two articles met our criteria, involving 2,105,122 solid organ transplant recipients. Compared with the general population, solid organ transplant recipients displayed a 2.68-fold cancer risk (SIR 2.68; 2.48–2.89; P <.001), renal transplant recipients displayed a 2.56-fold cancer risk (SIR 2.56; 2.31–2.84; P <.001), liver transplant recipients displayed a 2.45-fold cancer risk (SIR 2.45; 2.22–2.70; P <.001), heart and/or lung transplant recipients displayed a 3.72-fold cancer risk (SIR 3.72; 3.04–4.54; P <.001). The correlation coefficients between SIRs and TMBs were 0.68, 0.64, 0.59, 0.79 in solid organ recipients, renal recipients, liver recipients, heart and/or lung recipients, respectively. In conclusion, our study demonstrated that solid organ transplant recipients displayed a higher risk of some site-specific cancers, providing individualized guidance for clinicians to early detect, evaluate, and treat cancer among solid organ transplantation recipients. In addition, the increased cancer risk of solid organ transplant recipients is associated with TMB, suggesting that iatrogenic immunosuppression may contribute to the increased cancer risk in transplant recipients. (PROSPERO ID CRD42020160409).
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Affiliation(s)
- Zhenyu Huo
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Caichen Li
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Xin Xu
- Department of Transplantation, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Fan Ge
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,First Clinical School, Guangzhou Medical University, Guangzhou, China
| | - Runchen Wang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Yaokai Wen
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Haoxin Peng
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Xiangrong Wu
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Hengrui Liang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Guilin Peng
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Run Li
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Danxia Huang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ying Chen
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ran Zhong
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Bo Cheng
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Shan Xiong
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Weiyi Lin
- First Clinical School, Guangzhou Medical University, Guangzhou, China
| | - Jianxing He
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Wenhua Liang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
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8
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Ge F, Li C, Xu X, Huo Z, Wang R, Wen Y, Peng H, Wu X, Liang H, Peng G, Li R, Huang D, Chen Y, Xiong S, Zhong R, Cheng B, Li J, He J, Liang W. Cancer risk in heart or lung transplant recipients: A comprehensive analysis of 21 prospective cohorts. Cancer Med 2020; 9:9595-9610. [PMID: 33047902 PMCID: PMC7774758 DOI: 10.1002/cam4.3525] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/18/2022] Open
Abstract
We performed a meta-analysis to determine cancer risks at multiple sites and their associations with tumor mutation burden (TMB), an index for immunogenicity, in heart or lung transplant recipients. A comprehensive search of PubMed, Web of Science, EMBASE, and Medline was conducted. Random effects models were used to calculate standardized incidence ratios (SIRs) versus the general population and to determine the risks of different cancers. Weighted linear regression (WLR) was used to analyze the associations between the SIRs and TMBs. (PROSPERO CRD42020159599). Data from 21 studies including 116,438 transplant recipients (51,173 heart transplant recipients and 65,265 lung transplant recipients) with a total follow-up of 601,330.7 person-years were analyzed. Compared with the general population, heart transplant recipients displayed a 3.13-fold higher cancer risk [SIR: 3.13; 95% confidence interval (CI): 2.38-4.13; p < 0.001]; lung transplant recipients displayed a 4.28-fold higher cancer risk [SIR: 4.28; 95% CI: 3.18-5.77; p < 0.001]. The correlation coefficients were 0.54 (p = 0.049) and 0.79 (p < 0.001) in heart and lung transplant recipients, respectively, indicating that 29% and 63% of the differences in the SIRs for cancer types might be explained by the TMBs. Our study demonstrated that both heart and lung transplant recipients displayed a higher risk of certain site-specific cancers. These findings can provide individualized guidance for clinicians for detection of cancer among heart or lung transplantation recipients. In addition, we provided evidence that increased risks of post-transplant cancers can be attributed to immunosuppression.
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Affiliation(s)
- Fan Ge
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,First Clinical School, Guangzhou Medical University, Guangzhou, China
| | - Caichen Li
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Xin Xu
- Department of Transplantation, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zhenyu Huo
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Runchen Wang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Yaokai Wen
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Haoxin Peng
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Xiangrong Wu
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Nanshan School, Guangzhou Medical University, Guangzhou, China
| | - Hengrui Liang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Guilin Peng
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Run Li
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Danxia Huang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ying Chen
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Department of Transplantation, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Shan Xiong
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ran Zhong
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Bo Cheng
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jianfu Li
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jianxing He
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Wenhua Liang
- Department of Thoracic Surgery and Oncology, China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
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9
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Yamada M, Mohammed Y, Prow TW. Advances and controversies in studying sunscreen delivery and toxicity. Adv Drug Deliv Rev 2020; 153:72-86. [PMID: 32084432 DOI: 10.1016/j.addr.2020.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/02/2020] [Accepted: 02/10/2020] [Indexed: 02/04/2023]
Abstract
This review critically evaluates the sunscreen delivery and toxicity field. We chose to focus on approved sunscreens in this review. Optimal sunscreen use prevents skin cancer and photoageing but there is an important knowledge gap in sunscreen/skin interactions. Sunscreen delivery is a key for efficacy, but studying sunscreen delivery is not straightforward. We review the strengths and weaknesses of in vitro, excised skin and clinical approaches. Understanding positive and negative sunscreen effects on skin homeostasis is also challenging. The results in this field, especially in vitro testing, are controversial and experimental design varies widely which further supports disparities between some findings. We hypothesize that bias towards showing sunscreen toxicity to increase impact could be problematic. We explore that perception through a detailed review of experimental design, especially in cell culture models. Our conclusion is that emerging, non- and minimally invasive technologies are enabling new approaches to volunteer studies that could significantly improve knowledge of sunscreen delivery and interactions.
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10
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Mortality Associated With Development of Squamous Cell Cancer in Patients With Inflammatory Bowel Diseases Receiving Treatment With Thiopurines. Clin Gastroenterol Hepatol 2019; 17:2262-2268. [PMID: 30853615 DOI: 10.1016/j.cgh.2019.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Treatment with thiopurines is associated with an increased risk of squamous cell carcinoma of the skin (SCC) in patients with inflammatory bowel diseases (IBD). We studied outcomes of patients with IBD who developed SCC while receiving thiopurine therapy. METHODS We conducted a retrospective cohort study of 54,919 patients with IBD followed in the nationwide Veterans Affairs Healthcare System from January 1, 2000, through May 23, 2018. From this cohort, we created a sub-cohort of patients with an incident diagnosis of SCC, confirmed by review of patients' medical records; we identified those who had received treatment with thiopurines (exposed group) vs those treated with mesalamine and no prior exposure to thiopurines or tumor necrosis factor antagonists (unexposed group). The primary outcome was death associated with SCC (SCC mortality). We collected data on baseline demographic features, exposure to ultraviolet light, Charlson comorbidity index, smoking status, and environmental exposures. Follow up began at the time of incident SCC diagnosis and ended at death or last recorded date in the health system. Cause-specific hazard models were used to estimate the adjusted and unadjusted hazard ratio (HRs), with 95% CIs, for SCC mortality. RESULTS We identified 467 patients with incident SCC and included 449 patients (161 exposed and 288 unexposed) in our final analysis. Eleven patients from complications of SCC (8 in the exposed group and 3 in the unexposed group). The estimated 5- and 10-year cumulative mortality values were 2.9% and 2.9% in the exposed group and 0.4% and 0.9% in the unexposed group, respectively. The unadjusted and adjusted cause-specific HRs for SCC mortality associated with exposure were 7.0 (95% CI, 1.8-28.0; P = .006) and 8.0 (95% CI, 2.0-32.8; P = .004), respectively. CONCLUSIONS Although the cause-specific mortality is relatively low, patients with IBD exposed to thiopurines who develop SCC have an increased risk of SCC-associated death compared to patients exposed to only mesalamine.
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Puza CJ, Beasley GM, Barbas AS, Mosca PJ. Type of Organ Transplanted Impacts the Risk and Presentation of Cutaneous Squamous Cell Carcinoma in Transplant Recipients. EXP CLIN TRANSPLANT 2019; 18:93-97. [PMID: 30968759 DOI: 10.6002/ect.2018.0238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES Transplant immunosuppression increases the risk of cutaneous squamous cell carcinoma by 65- to 200-fold. Our objective was to investigate the impact of the type of organ transplanted on the risk and presentation of cutaneous squamous cell carcinoma. MATERIALS AND METHODS The retrospective database of the Duke University Health System was queried to identify patients who underwent an organ transplant from 1996 to 2016. Data regarding transplant outcomes, cutaneous squamous cell carcinoma, immunosuppressive regimens, and survival were recorded. We used chi-square tests, analysis of variance, and unpaired t tests to compare the incidence and presentation of cutaneous squamous cell carcinoma among organ types. RESULTS Of 3652 renal, hepatic, and cardiothoracic transplant patients identified, 142 patients developed at least 1 cutaneous squamous cell carcinoma. The incidence of cutaneous squamous cell carcinoma varied by type of organ transplanted, with 46 of 1684 (2.7%) renal transplant patients developing cutaneous squamous cell carcinoma, 33 of 804 (4.1%) hepatic transplant patients, and 63 of 1164 (5.4%) cardiothoracic transplant patients over the median follow-up time of 6.5 years. Incidence in the renal transplant versus the cardiothoracic transplant group was significantly different (P < .001). The time to presentation of cutaneous squamous cell carcinoma varied significantly by group, with the renal cohort presenting at 3.8 years compared with at 2.4 years in the cardiothoracic group and 2.1 years in the hepatic group (P < .001). CONCLUSIONS The type of organ transplanted confers a unique risk and presentation of cutaneous squamous cell carcinoma.
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Affiliation(s)
- Charles J Puza
- From the Duke University School of Medicine, Duke University Health System, Durham, North Carolina, USA
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12
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Miyata S, Tanabe S, Isozaki T, Xu YZ, Suzuki T. Characteristics of the excited triplet states of thiolated guanosine derivatives and singlet oxygen generation. Photochem Photobiol Sci 2018; 17:1469-1476. [PMID: 30280174 DOI: 10.1039/c8pp00240a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Thioguanine is sensitive to UVA light and generates singlet molecular oxygen (1O2*) when exposed to UVA. Three thioguanosine derivatives, 2',3',5'-tri-O-acetyl-6-thioguanosine (ta6TGuo), 2',3',5'-tri-O-acetyl-8-thioguanosine (ta8TGuo), and 2',3',5'-tri-O-acetyl-6,8-dithioguanosine (taDTGuo) were explored photophysically and photochemically. Nanosecond transient absorption and time-resolved near-infrared emission measurements were carried out to investigate the characteristics of their excited triplet states in acetonitrile solution. The quantum yield of intersystem crossing (ΦISC), the intrinsic decay rate constant (k0), the quenching rate constant by 3O2 (kq) and the self-quenching rate constant (kSQ) of their triplet states were all determined. From the precise analysis of the quantum yield of 1O2* generation (ΦΔ) against the concentration of dissolved molecular oxygen, the fraction of the triplet states quenched by dissolved oxygen which gives rise to 1O2* formation (SΔ) was successfully obtained with high accuracy. The ΦΔ values at low oxygen concentrations reveal that these thioguanosines, particularly taDTGuo, can still effectively generate 1O2* at low molecular oxygen concentrations like carcinomatous microenvironments. These findings indicate that taDTGuo would perform well as a potential agent for photo-induced cancer therapies.
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Affiliation(s)
- Shoma Miyata
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan.
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Ashwood B, Pollum M, Crespo-Hernández CE. Photochemical and Photodynamical Properties of Sulfur-Substituted Nucleic Acid Bases. Photochem Photobiol 2018; 95:33-58. [PMID: 29978490 DOI: 10.1111/php.12975] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 06/28/2018] [Indexed: 12/25/2022]
Abstract
Sulfur-substituted nucleobases (a.k.a., thiobases) are among the world's leading prescriptions for chemotherapy and immunosuppression. Long-term treatment with azathioprine, 6-mercaptopurine and 6-thioguanine has been correlated with the photoinduced formation of carcinomas. Establishing an in-depth understanding of the photochemical properties of these prodrugs may provide a route to overcoming these carcinogenic side effects, or, alternatively, a basis for developing effective compounds for targeted phototherapy. In this review, a broad examination is undertaken, surveying the basic photochemical properties and excited-state dynamics of sulfur-substituted analogs of the canonical DNA and RNA nucleobases. A molecular-level understanding of how sulfur substitution so remarkably perturbs the photochemical properties of the nucleobases is presented by combining experimental results with quantum-chemical calculations. Structure-property relationships demonstrate the impact of site-specific sulfur substitution on the photochemical properties, particularly on the population of the reactive triplet state. The value of fundamental photochemical investigations for driving the development of ultraviolet-A chemotherapeutics is showcased. The most promising photodynamic agents identified thus far have been investigated in various carcinoma cell lines and shown to decrease cell proliferation upon exposure to ultraviolet-A radiation. Overarching principles have been elucidated for the impact that sulfur substitution of the carbonyl oxygen has on the photochemical properties of the nucleobases.
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Affiliation(s)
- Brennan Ashwood
- Department of Chemistry, Case Western Reserve University, Cleveland, OH
| | - Marvin Pollum
- Department of Chemistry, Case Western Reserve University, Cleveland, OH
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14
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Cutaneous Complications in Recipients of Lung Transplants: A Pictorial Review. Chest 2018; 155:178-193. [PMID: 30201407 DOI: 10.1016/j.chest.2018.08.1060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/16/2018] [Indexed: 12/26/2022] Open
Abstract
Lung transplant is now an established modality for a broad spectrum of end-stage pulmonary diseases. According to the International Society for Heart and Lung Transplantation Registry, more than 50,000 lung transplants have been performed worldwide, with nearly 11,000 recipients of lung transplants alive in the United States. With the increasing use of lung transplant, pulmonologists must be cognizant of the common as well as the unique posttransplant dermatologic complications. Immunosuppression, infections, and a variety of medications and environmental exposures can contribute to these complications. This review aims to provide representative pictures and describe the pathogenesis, epidemiologic characteristics, and clinical manifestations of dermatologic complications encountered among recipients of lung transplants.
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15
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Puza CJ, Myers SA, Cardones AR, Beasley GM, Mosca PJ. The impact of transplant rejection on cutaneous squamous cell carcinoma in renal transplant recipients. Clin Exp Dermatol 2018; 44:265-269. [PMID: 29952022 DOI: 10.1111/ced.13699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND The incidence of cutaneous squamous cell carcinoma (cSCC) is markedly increased in renal transplant recipients compared with that of the nontransplant population. AIM To investigate whether there is a relationship between transplant rejection and cSCC. METHODS The Duke Enterprise Data Unified Content Explorer historical database was used to identify patients who had undergone a renal transplant at Duke University Hospital during a 20-year period. Data on patient demographics, transplant dates, first rejection episodes, first cSCC development, medication, laboratory results and survival were recorded. RESULTS In total, 1684 patients were identified, of whom 126 (7.5%) experienced an episode of rejection and 46 (4.0%) developed a cSCC after transplant. The incidence of cSCC was significantly greater in the rejection group, with 8.7% of patients developing cSCC compared with 2.2% in the no-rejection group (P < 0.001). Median lag time to cSCC was shorter in the rejection group (2.5 years; age 0.4-9.0 years) than the no-rejection group (4.2 years; range 1.3-20.4 years) (P < 0.03). CONCLUSIONS Transplant rejection is associated with both a higher incidence and an accelerated time course for development of cSCC following renal transplantation. Close dermatological surveillance should be considered following an episode of rejection in this patient population.
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Affiliation(s)
- C J Puza
- Duke University School of Medicine, Durham, NC, USA
| | - S A Myers
- Department of Dermatology, Duke Medical Center, Durham, NC, USA
| | - A R Cardones
- Department of Dermatology, Duke Medical Center, Durham, NC, USA
| | - G M Beasley
- Department of Surgery, Duke Medical Center, Durham, NC, USA
| | - P J Mosca
- Department of Surgery, Duke Medical Center, Durham, NC, USA
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16
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Miyata S, Yamada T, Isozaki T, Sugimura H, Xu YZ, Suzuki T. Absorption Characteristics and Quantum Yields of Singlet Oxygen Generation of Thioguanosine Derivatives. Photochem Photobiol 2018; 94:677-684. [DOI: 10.1111/php.12900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/17/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Shoma Miyata
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Takeshi Yamada
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Tasuku Isozaki
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Hideyuki Sugimura
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
| | - Yao-Zhong Xu
- School of Life, Health and Chemical Sciences; the Open University; Milton Keynes UK
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science; Aoyama Gakuin University; Sagamihara Kanagawa Japan
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17
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Miyata S, Hoshino M, Isozaki T, Yamada T, Sugimura H, Xu YZ, Suzuki T. Acid Dissociation Equilibrium and Singlet Molecular Oxygen Quantum Yield of Acetylated 6,8-Dithioguanosine in Aqueous Buffer Solution. J Phys Chem B 2018; 122:2912-2921. [DOI: 10.1021/acs.jpcb.8b00517] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Shoma Miyata
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan
| | - Mina Hoshino
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan
| | - Tasuku Isozaki
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan
| | - Takeshi Yamada
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan
| | - Hideyuki Sugimura
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan
| | - Yao-Zhong Xu
- School of Life, Health and Chemical Sciences, The Open University, Milton Keynes MK7 6AA, U.K
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan
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18
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Mittal A, Colegio OR. Skin Cancers in Organ Transplant Recipients. Am J Transplant 2017; 17:2509-2530. [PMID: 28556451 DOI: 10.1111/ajt.14382] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 05/05/2017] [Accepted: 05/19/2017] [Indexed: 02/06/2023]
Abstract
Long-term utilization of immunosuppression in organ transplant recipients (OTRs) leads to decreased immune-mediated tumor surveillance and development of malignant tumors. A delicate balance needs to be maintained in the intensity of immunosuppression to keep the risk of malignancy low without jeopardizing life-saving graft function. OTRs are prone to developing skin cancers that exhibit unique epidemiologic, pathophysiologic, and prognostic characteristics. In this review, we discuss the most commonly reported skin cancers in OTRs: squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Kaposi sarcoma, Merkel cell carcinoma, and malignant melanoma (MM). Tumors in this high-risk population are aggressive and may respond poorly to standard therapies; however, new targeted therapies are promising. Checkpoint inhibitor antibodies have been used for treatment of cutaneous SCC, Merkel cell carcinoma, and MM; epidermal growth factor receptor inhibitors have been used for cutaneous SCC; hedgehog pathway inhibitors have been used for BCC; and BRAF and MEK inhibitors are being used increasingly in the management of MM. Guidelines for dermatologic screening are variable and primarily based on expert opinion. Prospective evidence-based trials by multidisciplinary groups are needed to better define surveillance schedules for pre- and posttransplant cutaneous malignancies.
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Affiliation(s)
- A Mittal
- Departments of Dermatology, Yale University School of Medicine, New Haven, CT
| | - O R Colegio
- Departments of Dermatology, Yale University School of Medicine, New Haven, CT.,Departments of Pathology, Yale University School of Medicine, New Haven, CT.,Departments of Surgery, Yale University School of Medicine, New Haven, CT.,Yale Cancer Center, Yale University School of Medicine, New Haven, CT.,Yale-New Haven Transplantation Center, Yale University School of Medicine, New Haven, CT
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19
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Bhattacharyya K, Datta A. Visible-Light-Mediated Excited State Relaxation in Semi-Synthetic Genetic Alphabet: d5SICS and dNaM. Chemistry 2017; 23:11494-11498. [PMID: 28675549 DOI: 10.1002/chem.201702583] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Indexed: 12/17/2022]
Abstract
The excited state dynamics of an unnatural base pair (UBP) d5SICS/dNaM were investigated by accurate ab-initio calculations. Time-dependent density functional and high-level multireference calculations (MS-CASPT2) were performed to elucidate the excitation of this UBP and its excited state relaxation mechanism. After excitation to the bright state S2 (ππ*), it decays to the S1 state and then undergoes efficient intersystem crossing to the triplet manifold. The presence of sulfur atom in d5SICS leads to strong spin-orbit coupling (SOC) and a small energy gap that facilitates intersystem crossing from S1 (ns π*) to T2 (ππ*) followed by internal conversion to T1 state. Similarly in dNaM, the deactivation pathway follows analogous trends. CASPT2 calculations suggest that the S1 (ππ*) state is a dark state below the accessible S2 (ππ*) bright state. During the ultrafast deactivation, it exhibits bond length inversion. From S1 state, significant SOC leads the population transfer to T3 due to a smaller energy gap. Henceforth, fast internal conversion occurs from T3 to T2 followed by T1 . From time-dependent trajectory surface hopping dynamics, it is found that excited state relaxation occurs on a sub-picosecond timescale in d5SICS and dNaM. Our findings strongly suggest that there is enough energy available in triplet state of UBP to generate reactive oxygen species and induce phototoxicity with respect to cellular DNA.
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Affiliation(s)
- Kalishankar Bhattacharyya
- Department of Spectroscopy, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, 700032, Kolkata, West Bengal, India
| | - Ayan Datta
- Department of Spectroscopy, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, 700032, Kolkata, West Bengal, India
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20
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Brem R, Guven M, Karran P. Oxidatively-generated damage to DNA and proteins mediated by photosensitized UVA. Free Radic Biol Med 2017; 107:101-109. [PMID: 27989755 PMCID: PMC5462485 DOI: 10.1016/j.freeradbiomed.2016.10.488] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 11/19/2022]
Abstract
UVA accounts for about 95% of the solar ultraviolet (UV) radiation that reaches Earth and most likely contributes to human skin cancer risk. In contrast to UVB, which comprises the remaining 5% and is absorbed by DNA nucleobases to cause direct photodamage, UVA damages DNA indirectly. It does this largely through its interactions with cellular chromophores that act as photosensitisers to generate reactive oxygen species. Exogenously supplied chemicals, including some widely-prescribed medicines, may also act as photosensitisers and these drugs are associated with an increased risk of sun-related cancer. Because they amplify the effects of UVA on cells, they provide a means to investigate the mechanisms and effects of UVA-induced photodamage. Here, we describe some of the major lesions induced by two groups of UVA photosensitisers, the DNA thionucleotides and the fluoroquinolone antibiotics. In thionucleotides, replacement of the oxygen atoms of canonical nucleobases by sulfur converts them into strong UVA chromophores that can be incorporated into DNA. The fluoroquinolones are also UVA chromophores. They are not incorporated into DNA and induce a different range of DNA damages. We also draw attention to the potentially important contribution of photochemical protein damage to the cellular effects of photosensitised UVA. Proteins targeted for oxidation damage include DNA repair factors and we suggest that UVA-mediated protein damage may contribute to sunlight-induced cancer risk.
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Affiliation(s)
- Reto Brem
- The Francis Crick Institute, 1, Midland Road, London NW1 1AT, UK
| | - Melisa Guven
- The Francis Crick Institute, 1, Midland Road, London NW1 1AT, UK
| | - Peter Karran
- The Francis Crick Institute, 1, Midland Road, London NW1 1AT, UK.
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21
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Gilhooley E, Farrelly A, Connolly C, Tobin AM. Attitudes towards sun exposure in inflammatory bowel disease patients taking azathioprine. Ir J Med Sci 2017; 186:321-322. [DOI: 10.1007/s11845-016-1426-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/15/2016] [Indexed: 10/22/2022]
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22
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Pirillo J, Mazzone G, Russo N, Bertini L. Photophysical Properties of S, Se and Te-Substituted Deoxyguanosines: Insight into Their Ability To Act as Chemotherapeutic Agents. J Chem Inf Model 2017; 57:234-242. [DOI: 10.1021/acs.jcim.6b00486] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jenny Pirillo
- Dipartimento
di Chimica e Tecnologie Chimiche, University of Calabria, Via P. Bucci, 87036 Rende, Italy
| | - Gloria Mazzone
- Dipartimento
di Chimica e Tecnologie Chimiche, University of Calabria, Via P. Bucci, 87036 Rende, Italy
| | - Nino Russo
- Dipartimento
di Chimica e Tecnologie Chimiche, University of Calabria, Via P. Bucci, 87036 Rende, Italy
| | - Luca Bertini
- Department
of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza
della Scienza 2, I-20126 Milano, Italy
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Physician Perspectives on Unresolved Issues in the Management of Ulcerative Colitis: The UC Horizons Project. Inflamm Bowel Dis 2016; 22:583-98. [PMID: 26529561 DOI: 10.1097/mib.0000000000000617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND There is still uncertainty about what constitutes the best therapeutic practice in ulcerative colitis (UC). OBJECTIVE The purpose of the "UC Horizons Project" was to raise a series of questions regarding the management of UC to provide responses based on the best scientific evidence available. METHODS The 11 members of the scientific committee prepared draft answers to the 10 questions from available evidence after a literature search. A total of 48 Spanish gastroenterology specialists nationwide participated in the project. The national meeting discussed the 10 issues in working groups and reached consensus regarding the recommendations by anonymous, interactive vote following the Delphi methodology. Final answers were developed, based on evidence and clinical experience of the participants. RESULTS All the recommendations achieved a high level of agreement in the plenary vote, although the quality of the evidence was markedly heterogeneous. The lowest percentage of agreement corresponded to the questions with the weakest level of evidence, highlighting the necessity of conducting further studies in these areas. The recommendations focused on (1) aminosalicylates therapy (regarding dose and appropriateness of coadministration with thiopurines), (2) corticosteroid therapy (regarding dose and route of administration), (3) thiopurine treatment (regarding indications and possibility of withdrawal), (4) anti-tumor necrosis factor therapy (regarding appropriateness of combination with thiopurines, intensification, or discontinuation of treatment), and (5) colorectal cancer (regarding risk and time trends). CONCLUSIONS The UC Horizons Project raised a series of eminently practical questions about the management of UC and provided responses based on the best scientific evidence available.
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Coghill AE, Johnson LG, Berg D, Resler AJ, Leca N, Madeleine MM. Immunosuppressive Medications and Squamous Cell Skin Carcinoma: Nested Case-Control Study Within the Skin Cancer after Organ Transplant (SCOT) Cohort. Am J Transplant 2016; 16:565-73. [PMID: 26824445 PMCID: PMC5500236 DOI: 10.1111/ajt.13596] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/16/2015] [Accepted: 10/17/2015] [Indexed: 01/25/2023]
Abstract
Organ transplant recipients (OTRs) have a substantially elevated risk of squamous cell skin carcinoma (SCSC), largely attributed to immunosuppressive medications used to prevent graft rejection, although data to support the role of newer drugs in SCSC risk are sparse. We investigated the association between immunosuppressive medications and SCSC risk among cardiac and renal transplant recipients in the SCOT cohort study. Incident cases were ascertained through medical record review after self-report of skin biopsy (n = 170). Controls without SCSC (n = 324) were matched to cases on sex, age, race, transplant year, hospital, donor type, organ transplanted, and time between transplantation and interview. Conditional logistic regression was used to evaluate the association between specific medications and SCSC. Users of the antimetabolite azathioprine were more than twice as likely to develop SCSC (odds ratio [OR] = 2.67, 95% confidence interval [CI] 1.23-5.76). In contrast, the newer antimetabolite preparations (i.e., mycophenolic acid [MPA]) were associated with lower SCSC risk (OR = 0.45, 95% CI 0.29-0.69). This inverse association between MPA and SCSC persisted among OTRs with no history of azathioprine use, even after adjustment for simultaneous use of the calcineurin inhibitor tacrolimus (OR = 0.52, 95% CI 0.32-0.84). Our data suggest that the increased risk of SCSC historically associated with azathioprine is not seen in OTRs prescribed newer regimens, including MPA and tacrolimus.
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Affiliation(s)
- Anna E. Coghill
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | | | - Dan Berg
- University of Washington Department of Medicine, Seattle, WA
| | - Alexa J. Resler
- Fred Hutchinson Cancer Research Center, Seattle WA,University of Washington School of Public Health, Seattle, WA
| | - Nicolae Leca
- University of Washington Department of Medicine, Seattle, WA
| | - Margaret M. Madeleine
- Fred Hutchinson Cancer Research Center, Seattle WA,University of Washington School of Public Health, Seattle, WA
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Abstract
Ulcerative colitis (UC) and Crohn's disease (CD) are chronic inflammatory disorders, which require long term treatment to achieve remission and to prevent relapses and cancer. While current therapies are effective in most cases, they can have rare but serious side effects and are often associated with high costs. On the other hand, early discontinuation of an effective treatment may lead to a quick relapse and to complications at the restart of therapy. Therefore it is essential to determine the optimal duration of maintenance therapy, but clear guidelines are missing. The most important questions when deciding whether to continue or withdraw therapy in quiescent UC and CD patients are the efficacy of the continuous treatment to maintain remission in the long term, the frequency and severity of side effects, and the chance of relapse after discontinuation of therapy. This review summarizes the current knowledge on these topics with respect to 5-aminosalicylates, thiopurines, methotrexate, and biological therapies and collects information regarding when and in which specific patient groups, in the absence of risk factors, can withdrawal of therapy be considered without a high risk of relapse. Additionally, the particular aspect of colorectal cancer prevention by current therapies will also be discussed.
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26
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Brem R, Zhang X, Xu YZ, Karran P. UVA photoactivation of DNA containing halogenated thiopyrimidines induces cytotoxic DNA lesions. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 145:1-10. [PMID: 25747491 PMCID: PMC4376468 DOI: 10.1016/j.jphotobiol.2015.02.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 02/10/2015] [Accepted: 02/12/2015] [Indexed: 11/20/2022]
Abstract
Growing cells incorporate thio-iodo-deoxyuridine and thio-bromo-deoxyuridine into DNA. They are non-toxic but act as powerful UVA photosensitisers. UVA lesions include DNA-protein and DNA–DNA crosslinks. Singlet oxygen is involved in the formation of this potentially lethal damage. Thio-halo-deoxynucleosides offer a potential selective therapeutic option.
Photochemotherapy, the combination of a photosensitiser and ultraviolet (UV) or visible light, is an effective treatment for skin conditions including cancer. The high mutagenicity and non-selectivity of photochemotherapy regimes warrants the development of alternative approaches. We demonstrate that the thiopyrimidine nucleosides 5-bromo-4-thiodeoxyuridine (SBrdU) and 5-iodo-4-thiodeoxyuridine (SIdU) are incorporated into the DNA of cultured human and mouse cells where they synergistically sensitise killing by low doses of UVA radiation. The DNA halothiopyrimidine/UVA combinations induce DNA interstrand crosslinks, DNA-protein crosslinks, DNA strand breaks, nucleobase damage and lesions that resemble UV-induced pyrimidine(6-4)pyrimidone photoproducts. These are potentially lethal DNA lesions and cells defective in their repair are hypersensitive to killing by SBrdU/UVA and SIdU/UVA. DNA SIdU and SBrdU generate lethal DNA photodamage by partially distinct mechanisms that reflect the different photolabilities of their C–I and C–Br bonds. Although singlet oxygen is involved in photolesion formation, DNA SBrdU and SIdU photoactivation does not detectably increase DNA 8-oxoguanine levels. The absence of significant collateral damage to normal guanine suggests that UVA activation of DNA SIdU or SBrdU might offer a strategy to target hyperproliferative skin conditions that avoids the extensive formation of a known mutagenic DNA lesion.
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Affiliation(s)
- Reto Brem
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts. EN6 3LD, UK.
| | - Xiaohui Zhang
- College of Environment and Chemical Engineering, Dalian University, Dalian 116622, China
| | - Yao-Zhong Xu
- Department of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
| | - Peter Karran
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts. EN6 3LD, UK
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Zhang XH, Yin HY, Trigiante G, Brem R, Karran P, Pitak MB, Coles SJ, Xu YZ. 5-Iodo-4-thio-2′-deoxyuridine: Synthesis, Structure, and Cytotoxic Activity. CHEM LETT 2015. [DOI: 10.1246/cl.140965] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Xiao-Hui Zhang
- College of Environment and Chemical Engineering, Dalian University
| | - Hong-Yan Yin
- College of Environment and Chemical Engineering, Dalian University
| | | | - Reto Brem
- Cancer Research UK London Research Institute, Clare Hall Laboratories
| | - Peter Karran
- Cancer Research UK London Research Institute, Clare Hall Laboratories
| | - Mateusz B. Pitak
- UK National Crystallography Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton
| | - Simon J. Coles
- UK National Crystallography Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton
| | - Yao-Zhong Xu
- Department of Life, Health and Chemical Sciences, the Open University
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Gómez-García M, Cabello-Tapia MJ, Sánchez-Capilla AD, Teresa-Galván JD, Redondo-Cerezo E. Thiopurines related malignancies in inflammatory bowel disease: Local experience in Granada, Spain. World J Gastroenterol 2013; 19:4877-86. [PMID: 23946592 PMCID: PMC3740417 DOI: 10.3748/wjg.v19.i30.4877] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 08/25/2012] [Accepted: 09/12/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the incidence of neoplasms in inflammatory bowel disease (IBD) patients and the potential causative role of thiopurines.
METHODS: We performed an observational descriptive study comparing the incidence of malignancies in IBD patients treated with thiopurines and patients not treated with these drugs. We included 812 patients which were divided in two groups depending on whether they have received thiopurines or not. We have studied basal characteristics of both groups (age when the disease was diagnosed, sex, type of IBD, etc.) and treatments received (Azathioprine, mercaptopurine, infliximab, adalimumab or other immunomodulators), as well as neoplasms incidence. Univariate analysis was performed with the student t test, χ2 test or Wilcoxon exact test as appropriate. A logistic regression analysis was performed as multivariate analysis. Statistical significance was establish at P values of less than 0.05, and 95%CI were used for the odds ratios.
RESULTS: Among 812 patients included, 429 (52.83%) have received thiopurines: 79.5% azathioprine, 14% mercaptopurine and 6.5% both drugs. 44.76% of patients treated with thiopurines and 46, 48% of patients who did not receive this treatment were women (P > 0.05). The proportion of ulcerative colitis patients treated with thiopurines was 30.3% compare to 66. 67% of patients not treated (P < 0.001). Mean azathioprine dose was 123.79 ± 36.5 mg/d (range: 50-250 mg/d), mean usage time was 72.16 ± 55.7 mo (range: 1-300 mo) and the accumulated dose along this time was 274.32 ± 233.5 g (1.5-1350 g). With respect to mercaptopurine, mean dose was 74.7 ± 23.9 mg/d (range: 25-150 mg/d), mean usage time of 23.37 ± 27.6 mo (range: 1-118 mo), and the accumulated dose along this time was 52.2 ± 63.5 g (range: 1.5-243 g). Thiopurine S-methyltransferase activity was tested in 66% of patients treated with thiopurines, among which 98.2% had an intermediate or high activity. Among the patients treated with thiopurines, 27.27% (112 patients) and 11.66% (50 patients) received treatment with Infliximab and Adalimumab respectively, but only 1.83% (7 patients) and 0.78% (3 patients) received these drugs in the group of patients who did not received thiopurines (P < 0.001 and P < 0.001 respectively). Finally, 6.8% (29 patients) among those treated with thiopurines have received other immunesupresants (Methotrexate, Tacrolimus, Cyclosporin), compare to 1% (4 patients) of patients not treated with thiopurines (P < 0.001). Among patients treated with thiopurines, 3.97% developed a malignancy, and among those not treated neoplasms presented in 8.1% (P = 0.013). The most frequent neoplasms were colorectal ones (12 cases in patients not treated with thiopurines but none in treated, P < 0.001) followed by non-melanoma skin cancer (8 patients in treated with thiopurines and 6 in not treated, P > 0.05).
CONCLUSION: In our experience, thiopurine therapy did not increase malignancies development in IBD patients, and was an efective and safe treatment for these diseases.
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Abstract
Skin manifestations are common in patients suffering from inflammatory bowel disease (IBD) and can be associated with the disease itself, with nutritional deficiencies, or with therapy. All drugs currently used for treating IBD have the potential to cause dermatologic manifestations that can have a wide range of clinical presentations, from mild drug eruptions to potentially life-threatening immune-mediated reactions. The wider use of thiopurines and anti-tumor necrosis factor in the past years has led to the recognition of 2 more skin complications of IBD therapy: the potentially disfiguring non-melanoma skin cancer associated with the current or past use of thiopurines and the paradoxical new onset or exacerbation of anti-tumor necrosis factor-associated psoriasis. Despite being rare, these complications can be severe and lead to therapy discontinuation, and therefore, gastroenterologists need to become familiar with their epidemiology, diagnosis, and management. Herein, we reviewed the skin side effects of IBD therapy, specially focusing in thiopurines and anti-tumor necrosis factor therapy and in the recently described skin cancer and psoriasis, and we tried to advance some practical algorithms that can provide some help to the clinicians dealing with these complications in their day-by-day practice.
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30
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Bär F, Sina C, Fellermann K. Thiopurines in inflammatory bowel disease revisited. World J Gastroenterol 2013; 19:1699-1706. [PMID: 23555158 PMCID: PMC3607746 DOI: 10.3748/wjg.v19.i11.1699] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/15/2012] [Indexed: 02/06/2023] Open
Abstract
Although a great variety of new drugs have been introduced for the therapy of inflammatory bowel diseases so far, a definite cure of the disease is still out of scope. An anti-inflammatory approach to induce remission followed by maintenance therapy with immunosupressants is still the mainstay of therapy. Thiopurines comprising azathioprine and its active metabolite mercaptopurine as well as tioguanine, are widely used in the therapy of chronic active inflammatory bowel disease (IBD). Their steroid sparing potential and efficacy in remission maintenance are out of doubt. Unfortunately, untoward adverse events are frequently observed and may preclude further administration or be life threatening. This review will focus on new aspects of thiopurine therapy in IBD, its efficacy and safety.
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Zou X, Zhao H, Yu Y, Su H. Formation of Guanine-6-sulfonate from 6-Thioguanine and Singlet Oxygen: A Combined Theoretical and Experimental Study. J Am Chem Soc 2013; 135:4509-15. [DOI: 10.1021/ja400483j] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiaoran Zou
- Beijing
National Laboratory for Molecular Sciences
(BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Hongmei Zhao
- Beijing
National Laboratory for Molecular Sciences
(BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Youqing Yu
- Beijing
National Laboratory for Molecular Sciences
(BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Hongmei Su
- Beijing
National Laboratory for Molecular Sciences
(BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
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32
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You C, Dai X, Yuan B, Wang Y. Effects of 6-thioguanine and S6-methylthioguanine on transcription in vitro and in human cells. J Biol Chem 2012; 287:40915-23. [PMID: 23076150 DOI: 10.1074/jbc.m112.418681] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Thiopurine drugs are extensively used as chemotherapeutic agents in clinical practice, even though there is concern about the risk of therapy-related cancers. It has been previously suggested that the cytotoxicity of thiopurine drugs involves their metabolic activation, the resultant generation of 6-thioguanine ((S)G) and S(6)-methylthioguanine (S(6)mG) in DNA, and the futile mismatch repair triggered by replication-induced (S)G:T and S(6)mG:T mispairs. Disruption of transcription is known to be one of the major consequences of DNA damage induced by many antiviral and antitumor agents; however, it remains undefined how (S)G and S(6)mG compromise the efficiency and fidelity of transcription. Using our recently developed competitive transcription and adduct bypass assay, herein we examined the impact of (S)G and S(6)mG on transcription in vitro and in human cells. Our results revealed that, when situated on the transcribed strand, S(6)mG exhibited both inhibitory and mutagenic effects during transcription mediated by single-subunit T7 RNA polymerase or multisubunit human RNA polymerase II in vitro and in human cells. Moreover, we found that the impact of S(6)mG on transcriptional efficiency and fidelity is modulated by the transcription-coupled nucleotide excision repair capacity. In contrast, (S)G did not considerably compromise the efficiency or fidelity of transcription, and it was a poor substrate for NER. We propose that S(6)mG might contribute, at least in part, to thiopurine-mediated cytotoxicity through inhibition of transcription and to potential therapy-related carcinogenesis via transcriptional mutagenesis.
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Affiliation(s)
- Changjun You
- Department of Chemistry, University of California, Riverside, California 92521-0403, USA
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33
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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.
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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
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34
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Kalra S, Knatko EV, Zhang Y, Honda T, Yamamoto M, Dinkova-Kostova AT. Highly potent activation of Nrf2 by topical tricyclic bis(cyano enone): implications for protection against UV radiation during thiopurine therapy. Cancer Prev Res (Phila) 2012; 5:973-81. [PMID: 22659146 DOI: 10.1158/1940-6207.capr-12-0041] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chronic treatment with azathioprine, a highly effective anti-inflammatory and immunosuppressive agent, profoundly increases the risk for development of unusually aggressive cutaneous squamous cell carcinoma. Its ultimate metabolite, 6-thioguanine (6-TG) nucleotide, is incorporated in DNA of skin cells, and upon exposure to UVA radiation, causes oxidative stress, followed by damage of DNA and associated proteins. The acetylenic tricyclic bis(cyano enone) TBE-31 is a strong inhibitor of inflammation and a potent inducer of the Keap1/Nrf2/ARE pathway, which orchestrates the expression of a large network of cytoprotective genes. We now report that long-term (five days per week for four weeks) topical daily applications of small (200 nmol) quantities of TBE-31 cause a robust systemic induction of the Keap1/Nrf2/ARE pathway and decreases the 6-TG incorporation in DNA of skin, blood, and liver of azathioprine-treated mice, indicating extraordinary bioavailability and efficacy. In addition, TBE-31, at nanomolar concentrations, protects cells with 6-TG in their genomic DNA against oxidative stress caused by UVA radiation through induction of the Keap1/Nrf2/ARE pathway. At the same 6-TG DNA levels, Keap1-knockout cells, in which the pathway is constitutively upregulated, are highly resistant to UVA radiation-induced oxidative stress. The protective effects of both the Keap1-knockout genotype and TBE-31 are completely lost in the absence of transcription factor Nrf2. Our findings suggest that compounds of this kind are excellent candidates for mechanism-based chemoprotective agents against conditions in which oxidative stress and inflammation underlie disease pathogenesis. Moreover, their potential skin patch incorporation for transdermal delivery is an exciting possibility.
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Affiliation(s)
- Sukirti Kalra
- Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, Scotland, UK
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35
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Kuschal C, Thoms KM, Schubert S, Schäfer A, Boeckmann L, Schön MP, Emmert S. Skin cancer in organ transplant recipients: effects of immunosuppressive medications on DNA repair. Exp Dermatol 2012; 21:2-6. [PMID: 22151386 DOI: 10.1111/j.1600-0625.2011.01413.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
UV-induced skin cancers comprise a major problem in organ transplant recipients (OTRs). Cyclosporin A, a calcineurin inhibitor, is used as a standard immunosuppressant and clearly increases the skin cancer risk. Azathioprine does not appear to result in such an increase in skin cancer risk, and mTOR inhibitors are associated with an even lesser skin cancer risk. The underlying molecular mechanisms of these clinically important differences among immunosuppressants are still unclear and may relate to other than immunological effects. Insights may be gained by the multistep skin cancer theory and xeroderma pigmentosum, where defective nucleotide excision repair (NER) results in a cellular mutator phenotype and cutaneous carcinogenesis. This viewpoint assay summarizes current knowledge about the influence of the most commonly used immunosuppressive drugs in OTRs on DNA repair. Calcineurin inhibition results in a 200-fold increased skin cancer risk compared with the normal population and inhibits NER. The skin cancer risk under azathioprine is threefold less compared with calcineurin inhibitors, which may relate to inhibition of only the last step of NER, i.e. gap filling. mTOR inhibitors do not reduce NER in the global genome and can inhibit the growth of already initiated tumors, which may account for the markedly reduced skin cancer risk compared with calcineurin inhibitors. We conclude that OTRs may benefit from treatment regimens other than calcineurin inhibitors and speculate that a targeted modulation of calcineurin-dependent signalling may prevent UV-induced tumor formation by enhancing NER not only in OTRs but also in the general population, at least in part.
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Affiliation(s)
- Christiane Kuschal
- Department of Dermatology, Venerology, and Allergology, Georg-August-University, Goettingen, Germany
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36
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Meggitt SJ, Anstey AV, Mohd Mustapa MF, Reynolds NJ, Wakelin S. British Association of Dermatologists' guidelines for the safe and effective prescribing of azathioprine 2011. Br J Dermatol 2012; 165:711-34. [PMID: 21950502 DOI: 10.1111/j.1365-2133.2011.10575.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- S J Meggitt
- Department of Dermatology, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne NE1 4LP, UK.
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37
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Abstract
Thiopurines are prescribed frequently as medication for cancer and for inflammatory disorders. One of them, azathioprine, has been the immunosuppressant of choice for organ transplant recipients for many years. Thiopurine use is associated with elevated sun sensitivity and skin cancer risk. Skin sensitization is selective for UVA. 6-TG integrates into DNA and unlike the canonical DNA bases, it is a strong UVA chromophore with an absorbance maximum at 342 nm. DNA 6-TG is a photosensitizer and a source of reactive oxygen species. Reactive oxygen that is generated from the photochemical activation of DNA 6-TG causes extensive damage to DNA and proteins. This damage is mutagenic and extremely toxic to cultured human cells. Here we describe some of the lesions that are known to be generated from UVA irradiation of DNA 6-TG. We discuss how this photochemical damage might contribute to the toxic effect of thiopurine/UVA treatment on cultured cells and to the high risk of skin cancer in thiopurine-treated patients.
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Affiliation(s)
- Reto Brem
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts, UK.
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38
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Hofbauer GFL, Attard NR, Harwood CA, McGregor JM, Dziunycz P, Iotzova-Weiss G, Straub G, Meyer R, Kamenisch Y, Berneburg M, French LE, Wüthrich RP, Karran P, Serra AL. Reversal of UVA skin photosensitivity and DNA damage in kidney transplant recipients by replacing azathioprine. Am J Transplant 2012; 12:218-25. [PMID: 21943390 DOI: 10.1111/j.1600-6143.2011.03751.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Azathioprine is associated with enhanced skin photosensitivity to ultraviolet A (UVA) and leads to incorporation of 6-thioguanine (6-TG) into DNA of dividing cells. Unlike canonical DNA, 6-TG DNA is damaged by UVA, which comprises more than 90% of the ultraviolet reaching earth. Skin photosensitivity to UVA and UVB was measured in 48 kidney transplant patients immunosuppressed either by azathioprine (n = 32) or mycophenolate (n = 16). In 23 patients, azathioprine was subsequently replaced by mycophenolate and skin photosensitivity, DNA 6-TG content in peripheral blood mononuclear cells, and susceptibility to UVA-induced DNA damage were monitored for up to 2 years. The mean minimal erythema dose to UVA on azathioprine was twofold lower than on mycophenolate. Three months after replacing azathioprine by mycophenolate mofetil, the minimal erythema dose to UVA had increased from 15 to 25 J/cm(2) (p < 0.001) accompanied by reduced DNA 6-TG content. P53 protein expression in irradiated skin indicated reduced susceptibility to UVA-induced DNA damage. 6-TG DNA in peripheral blood mononuclear cells remained measurable for over 2 years. Replacing azathioprine selectively reduced the skin photosensitivity to UVA, attenuated UVA-induced skin DNA damage, and is likely based on incorporated 6-TG in DNA.
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Affiliation(s)
- G F L Hofbauer
- Department of Dermatology, University Hospital Zürich, Switzerland.
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39
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Attard NR, Karran P. UVA photosensitization of thiopurines and skin cancer in organ transplant recipients. Photochem Photobiol Sci 2012; 11:62-8. [PMID: 21860872 DOI: 10.1039/c1pp05194f] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 07/21/2011] [Indexed: 01/31/2023]
Abstract
The thiopurines azathioprine, 6-mercaptopurine and 6-thioguanine (6-TG) are important medications for cancer and inflammatory disorders. They are also widely prescribed as immunosuppressants in organ transplant patients. Their metabolism results in the incorporation of 6-TG into patients' DNA, and this increases skin sensitivity to incident UVA. Unlike the canonical DNA bases, which do not absorb UVA to a significant degree, DNA 6-TG is a strong UVA chromophore. It acts as a Type II UVA photosensitizer, and the combination of 6-TG and UVA treatment induces a synergistic toxicity in cultured human cells. Here, we review some of the damage that this interaction causes. Photochemical activation of DNA 6-TG triggers DNA and protein oxidation; it induces DNA breakage, DNA crosslinking, oxidation of DNA bases and the covalent attachment of proteins to DNA. Many of these photochemical DNA lesions are difficult for cells to deal with, and we review the evidence linking thiopurine immunosuppression with genome instability and the high incidence of skin cancer in organ transplant recipients.
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Affiliation(s)
- Natalie R Attard
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, UK
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40
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Martínez-Fernández L, González L, Corral I. An ab initio mechanism for efficient population of triplet states in cytotoxic sulfur substituted DNA bases: the case of 6-thioguanine. Chem Commun (Camb) 2012; 48:2134-6. [DOI: 10.1039/c2cc15775f] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Daehn I, Brem R, Barkauskaite E, Karran P. 6-Thioguanine damages mitochondrial DNA and causes mitochondrial dysfunction in human cells. FEBS Lett 2011; 585:3941-6. [PMID: 22062154 DOI: 10.1016/j.febslet.2011.10.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/24/2011] [Accepted: 10/25/2011] [Indexed: 12/31/2022]
Abstract
The anticancer and immunosuppressant thiopurines cause 6-thioguanine (6-TG) to accumulate in nuclear DNA. We report that 6-TG is also readily incorporated into mitochondrial DNA (mtDNA) where it is rapidly oxidized. The oxidized forms of mtDNA 6-TG inhibit replication by DNA Pol-γ. Accumulation of oxidized 6-TG is associated with reduced mtDNA transcription, a decline in mitochondrial protein levels, and loss of mitochondrial function. Ultraviolet A radiation (UVA) also oxidizes mtDNA 6-TG. Cells without mtDNA are less sensitive to killing by a combination of 6-TG and UVA than their mtDNA-containing counterparts, indicating that photochemical mtDNA 6-TG oxidation contributes to 6-TG-mediated UVA photosensitization.
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Affiliation(s)
- Ilse Daehn
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts, UK.
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42
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Abstract
Thiopurines were examined for their ability to produce singlet oxygen ((1)O(2)) with UVA light. The target compounds were three thiopurine prodrugs, azathioprine (Aza), 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG), and their S-methylated derivatives of 6-methylmercaptopurine (me6-MP) and 6-methylthioguanine (me6-TG). Our results showed that these thiopurines were efficient (1)O(2) sensitizers under UVA irradiation but rapidly lost their photoactivities for (1)O(2) production over time by a self-sensitized photooxidation of sulfur atoms in the presence of oxygen and UVA light. The initial quantum yields of (1)O(2) production were determined to be in the range of 0.30-0.6 in aqueous solutions. Substitution of a hydrogen atom with a nitroimidazole or methyl group at S decreased the efficacy of photosensitized (1)O(2) production as found for Aza, me6-MP and me6-TG. (1)O(2)-induced formation of 8-oxo-7,8-dihydro-2'-dexyguanosine (8-oxodGuo) was assessed by incubation of 6-methylthiopurine/UVA-treated calf thymus DNA with human repair enzyme 8-oxodGuo DNA glycosylase (hOGG1), followed by apurinic (AP) site determination. Because more 8-oxodGuo was formed in Tris D(2)O than in Tris H(2)O, (1)O(2) is implicated as a key species in the reaction. These findings provided quantitative information on the photosensitization efficacy of thiopurines and to some extent revealed the correlations between photoactivity and phototoxicity.
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43
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Brem R, Daehn I, Karran P. Efficient DNA interstrand crosslinking by 6-thioguanine and UVA radiation. DNA Repair (Amst) 2011; 10:869-76. [PMID: 21723207 DOI: 10.1016/j.dnarep.2011.05.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 05/24/2011] [Accepted: 05/31/2011] [Indexed: 10/18/2022]
Abstract
Patients taking the immunosuppressant and anticancer thiopurines 6-mercaptopurine, azathioprine or 6-thioguanine (6-TG), develop skin cancer at a very high frequency. Their DNA contains 6-TG which absorbs ultraviolet A (UVA) radiation, and their skin is UVA hypersensitive, consistent with the formation of DNA photodamage. Here we demonstrate that UVA irradiation of 6-TG-containing DNA causes DNA interstrand crosslinking. In synthetic duplex oligodeoxynucleotides, the interstrand crosslinks (ICLs) can form between closely opposed 6-TG bases and, in a less favoured reaction, between 6-TG and normal bases on the opposite strand. In vivo, UVA irradiation of cultured cells containing 6-TG-substituted DNA also causes ICL formation and induces the chromosome aberrations that are characteristically associated with this type of DNA lesion. 6-TG/UVA activates the Fanconi anemia (FA) pathway via monoubiquitination of the FANCD2 protein. Cells defective in the FA pathway or other factors involved in ICL processing, such as XPF and DNA Polζ, are all hypersensitive to killing by 6-TG/UVA-consistent with a significant contribution of photochemical ICLs to the cytotoxicity of this treatment. Our findings suggest that sunlight-exposed skin of thiopurine treated patients may experience chronic photochemical DNA damage that requires constant intervention of the FA pathway.
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Affiliation(s)
- Reto Brem
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
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44
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Gueranger Q, Kia A, Frith D, Karran P. Crosslinking of DNA repair and replication proteins to DNA in cells treated with 6-thioguanine and UVA. Nucleic Acids Res 2011; 39:5057-66. [PMID: 21398635 PMCID: PMC3130278 DOI: 10.1093/nar/gkr112] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 02/11/2011] [Accepted: 02/14/2011] [Indexed: 12/15/2022] Open
Abstract
The DNA of patients taking immunosuppressive and anti-inflammatory thiopurines contains 6-thioguanine (6-TG) and their skin is hypersensitive to ultraviolet A (UVA) radiation. DNA 6-TG absorbs UVA and generates reactive oxygen species that damage DNA and proteins. Here, we show that the DNA damage includes covalent DNA-protein crosslinks. An oligonucleotide containing a single 6-TG is photochemically crosslinked to cysteine-containing oligopeptides by low doses of UVA. Crosslinking is significantly more efficient if guanine sulphonate (G(SO3))--an oxidized 6-TG and a previously identified UVA photoproduct--replaces 6-TG, suggesting that G(SO3) is an important reaction intermediate. Crosslinking occurs via oligopeptide sulphydryl and free amino groups. The oligonucleotide-oligopeptide adducts are heat stable but are partially reversed by reducing treatments. UVA irradiation of human cells containing DNA 6-TG induces extensive heat- and reducing agent-resistant covalent DNA-protein crosslinks and diminishes the recovery of some DNA repair and replication proteins from nuclear extracts. DNA-protein crosslinked material has an altered buoyant density and can be purified by banding in cesium chloride (CsCl) gradients. PCNA, the MSH2 mismatch repair protein and the XPA nucleotide excision repair (NER) factor are among the proteins detectable in the DNA-crosslinked material. These findings suggest that the 6-TG/UVA combination might compromise DNA repair by sequestering essential proteins.
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Affiliation(s)
| | | | | | - Peter Karran
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, EN6 3LD, UK
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Reichardt C, Guo C, Crespo-Hernández CE. Excited-State Dynamics in 6-Thioguanosine from the Femtosecond to Microsecond Time Scale. J Phys Chem B 2011; 115:3263-70. [DOI: 10.1021/jp112018u] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Christian Reichardt
- Department of Chemistry and the Center for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Cao Guo
- Department of Chemistry and the Center for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Carlos E. Crespo-Hernández
- Department of Chemistry and the Center for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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Zhang Y, Zhu X, Smith J, Haygood MT, Gao R. Direct observation and quantitative characterization of singlet oxygen in aqueous solution upon UVA excitation of 6-thioguanines. J Phys Chem B 2011; 115:1889-94. [PMID: 21294562 DOI: 10.1021/jp109590t] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The incorporation of 6-thioguanine (6-TG) into DNA increases the risk of (1)O(2)-initiated skin cancer. We herein provide the first report on quantitative characterization of the photoactivity of 6-thioguanines including 6-TG and 6-thioguanosine. Time-resolved singlet oxygen luminescence was observed directly for the first time after UVA irradiation of 6-thioguanines in both CHCN(3) and aqueous solutions. Their photosensitization was characterized by the quantum yield of singlet oxygen production, showing a dramatic decrease over time from the initial 0.49-0.58 to zero. Experiments performed on both 6-TG and 6-thioguanosine did not show any significant difference in the quantum yield of singlet oxygen production, indicating that there was no potential participation of 7H- and 9H-tautomers. Our findings provide a primary basis for a better understanding of molecular events of thiopurine drugs in biological systems.
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Affiliation(s)
- Yazhou Zhang
- Department of Chemistry and Biochemistry, Jackson State University, Jackson, Mississippi 39217, USA
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Dela Cruz JM, McMullen JD, Williams RM, Zipfel WR. Feasibility of using multiphoton excited tissue autofluorescence for in vivo human histopathology. BIOMEDICAL OPTICS EXPRESS 2010; 1:1320-1330. [PMID: 21258552 PMCID: PMC3018110 DOI: 10.1364/boe.1.001320] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 10/27/2010] [Accepted: 10/29/2010] [Indexed: 05/18/2023]
Abstract
Rapid and direct imaging of microscopic tissue morphology and pathology can be achieved by multiphoton imaging of intrinsic tissue fluorophores and second harmonic signals. Engineering parameters for developing this technology for clinical applications include excitation levels and collection efficiencies required to obtain diagnostic quality images from different tissue types and whether these levels are mutagenic. Here we provide data on typical average powers required for high signal-to-noise in vivo tissue imaging and assess the risk potential of these irradiance levels using a mammalian cell gene mutation assay. Exposure times of ~16 milliseconds per cell to 760 nm, ~200 fs raster-scanned laser irradiation delivered through a 0.75 NA objective produced negligible mutagenicity at powers up to about 50 mW.
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Affiliation(s)
| | - Jesse D. McMullen
- Department of Biomedical Engineering, Cornell University, Ithaca NY 14853
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | | | - Warren R. Zipfel
- Department of Biomedical Engineering, Cornell University, Ithaca NY 14853
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
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Ren X, Xu YZ, Karran P. Photo-oxidation of 6-thioguanine by UVA: the formation of addition products with low molecular weight thiol compounds. Photochem Photobiol 2010; 86:1038-45. [PMID: 20573042 DOI: 10.1111/j.1751-1097.2010.00771.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The thiopurine, 6-thioguanine (6-TG) is present in the DNA of patients treated with the immunosuppressant and anticancer drugs azathioprine or mercaptopurine. The skin of these patients is selectively sensitive to UVA radiation-which comprises >90% of the UV light in incident sunlight-and they suffer high rates of skin cancer. UVA irradiation of DNA 6-TG produces DNA lesions that may contribute to the development of cancer. Antioxidants can protect 6-TG against UVA but 6-TG oxidation products may undergo further reactions. We characterize some of these reactions and show that addition products are formed between UVA-irradiated 6-TG and N-acetylcysteine and other low molecular weight thiol compounds including β-mercaptoethanol, cysteine and the cysteine-containing tripeptide glutathione (GSH). GSH is also adducted to 6-TG-containing oligodeoxynucleotides in an oxygen- and UVA-dependent nucleophilic displacement reaction that involves an intermediate oxidized 6-TG, guanine sulfonate (G(SO3) ). These photochemical reactions of 6-TG, particularly the formation of a covalent oligodeoxynucleotide-GSH complex, suggest that crosslinking of proteins or low molecular weight thiol compounds to DNA may be a previously unrecognized hazard in sunlight-exposed cells of thiopurine-treated patients.
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Affiliation(s)
- Xiaolin Ren
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts, UK
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Brem R, Li F, Montaner B, Reelfs O, Karran P. DNA breakage and cell cycle checkpoint abrogation induced by a therapeutic thiopurine and UVA radiation. Oncogene 2010; 29:3953-63. [PMID: 20440263 PMCID: PMC2901207 DOI: 10.1038/onc.2010.140] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 03/05/2010] [Accepted: 03/18/2010] [Indexed: 12/13/2022]
Abstract
The frequency of squamous cell skin carcinoma in organ transplant patients is around 100-fold higher than normal. This dramatic example of therapy-related cancer reflects exposure to sunlight and to immunosuppressive drugs. Here, we show that the interaction between low doses of UVA, the major ultraviolet component of incident sunlight, and 6-TG, a UVA chromophore that is introduced into DNA by one of the most widely prescribed immunosuppressive drugs, causes DNA single- and double-strand breaks (DSB). S phase cells are particularly vulnerable to this DNA breakage and cells defective in rejoining of S-phase DSB are hypersensitive to the combination of low-dose UVA and DNA 6-TG. 6-TG/UVA-induced DNA lesions provoke canonical DNA damage responses involving activation of the ATM/Chk2 and ATR/Chk1 pathways and appropriate cell cycle checkpoints. Higher levels of photochemical DNA damage induce a proteasome-mediated degradation of Chk1 and checkpoint abrogation that is consistent with persistent unrepaired DNA damage. These findings indicate that the interaction between UVA and an immunosuppressant drug causes photochemical DNA lesions, including DNA breaks, and can compromise cell cycle checkpoints. These two properties could contribute to the high risk of sunlight-related skin cancer in long-term immunosuppressed patients.
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Affiliation(s)
| | | | - Beatriz Montaner
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts EN6 3LD
| | | | - Peter Karran
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Herts EN6 3LD
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Smith MA, Irving PM, Marinaki AM, Sanderson JD. Review article: malignancy on thiopurine treatment with special reference to inflammatory bowel disease. Aliment Pharmacol Ther 2010; 32:119-30. [PMID: 20412066 DOI: 10.1111/j.1365-2036.2010.04330.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Immunosuppression is a risk factor for carcinogenesis. Thiopurines specifically contribute to this. As thiopurines are used more aggressively in the treatment of IBD, it is likely that we will see more thiopurine-related malignancy. AIM To review the literature, exploring how immunosuppression, thiopurines specifically, might cause cancer and which malignancies occur in practice, placing specific emphasis on IBD cohorts. METHODS Search terms included 'malignancy' 'cancer' 'azathioprine' 'mercaptopurine' 'tioguanine (thioguanine)' 'thiopurine' and 'inflammatory bowel disease' 'Crohn's disease' 'ulcerative colitis'. We also searched for specific cancers (lymphoma, colorectal cancer, skin cancer, cervical cancer) and reviewed the reference lists of the articles detected. RESULTS Immunosuppression is associated with an increased risk of cancer. Thiopurines are associated with specific additional risks. In IBD cohorts, very few thiopurine-related malignancies have been reported. However, studies suggest a relative risk of 4-5 for lymphoma. This still translates into a low actual risk, (one extra lymphoma in every 300-1400 years of thiopurine treatment). CONCLUSIONS Whilst we must be aware of this risk and counsel our patients appropriately, thiopurines remain a mainstay of IBD therapy. We present practical advice aimed at minimizing our patients' risk of developing malignancy, whilst optimizing the benefits that thiopurines can provide.
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Affiliation(s)
- M A Smith
- Department of Gastroenterology Guy's & St. Thomas' NHS Foundation Trust, London, UK
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