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Schuler M, Tomlinson L, Homiski M, Cheung J, Zhan Y, Coffing S, Engel M, Rubitski E, Seitis G, Hales K, Robertson A, Vispute S, Cook J, Radi Z, Hollingshead B. Experiments in the EpiDerm 3D Skin In Vitro Model and Minipigs In Vivo Indicate Comparatively Lower In Vivo Skin Sensitivity of Topically Applied Aneugenic Compounds. Toxicol Sci 2021; 180:103-121. [PMID: 33481035 DOI: 10.1093/toxsci/kfaa189] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Risk management of in vitro aneugens for topically applied compounds is not clearly defined because there is no validated methodology to accurately measure compound concentration in proliferating stratum basale keratinocytes of the skin. Here, we experimentally tested several known aneugens in the EpiDerm reconstructed human skin in vitro micronucleus assay and compared the results to flow cytometric mechanistic biomarkers (phospho-H3; MPM2, DNA content). We then evaluated similar biomarkers (Ki-67, nuclear area) using immunohistochemistry in skin sections of minipigs following topical exposure the potent aneugens, colchicine, and hesperadin. Data from the EpiDerm model showed positive micronucleus responses for all aneugens tested following topical or direct media dosing with similar sensitivity when adjusted for applied dose. Quantitative benchmark dose-response analysis exhibited increases in the mitotic index biomarkers phospho-H3 and MPM2 for tubulin binders and polyploidy for aurora kinase inhibitors are at least as sensitive as the micronucleus endpoint. By comparison, the aneugens tested did not induce histopathological changes, increases in Ki-67 immunolabeling or nuclear area in skin sections from the in vivo minipig study at doses in significant excess of those eliciting a response in vitro. Results indicate the EpiDerm in vitro micronucleus assay is suitable for the hazard identification of aneugens. The lack of response in the minipig studies indicates that the barrier function of the minipig skin, which is comparable to human skin, protects from the effects of aneugens in vivo. These results provide a basis for conducting additional studies in the future to further refine this understanding.
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Affiliation(s)
- Maik Schuler
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Lindsay Tomlinson
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Michael Homiski
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Jennifer Cheung
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Yutian Zhan
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Stephanie Coffing
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Maria Engel
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Elizabeth Rubitski
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Gary Seitis
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Katherine Hales
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Andrew Robertson
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Saurabh Vispute
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Jon Cook
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Zaher Radi
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
| | - Brett Hollingshead
- Pfizer Worldwide Research and Development, Groton, Connecticut 06340 and Cambridge, Massachusetts 02139, USA
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Abstract
Background Catechins, which are polyphenol compounds found in many plants and are an important component of tea leaves, are strong anti-oxidants. Research Many studies seek to enhance the effects of catechins on the human body and boost their protective power against UV radiation. There are many examples of the positive anti-microbial, anti-viral, anti-inflammatory, anti-allergenic, and anti-cancer effects of catechins. Catechins increase the penetration and absorption of healthy functional foods and bio cosmetics into the body and the skin, thus improving their utility. High value-added anti-oxidant substances have been extracted from food and plant sludge, and experiments have shown that catechins are safe when applied to the human body. The stability of catechins is very important for their absorption into the human body and the effectiveness of their anti-oxidant properties. Conclusion Continued research on the strong anti-oxidant effects of catechins is expected to result in many advances in the food, cosmetics, and pharmaceutical industries.
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Croaker A, King GJ, Pyne JH, Anoopkumar-Dukie S, Simanek V, Liu L. Carcinogenic potential of sanguinarine, a phytochemical used in 'therapeutic' black salve and mouthwash. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 774:46-56. [PMID: 29173498 DOI: 10.1016/j.mrrev.2017.09.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 08/17/2017] [Accepted: 09/02/2017] [Indexed: 02/07/2023]
Abstract
Black salves are escharotic skin cancer therapies in clinical use since the mid 19th century. Sanguinaria canadensis, a major ingredient of black salve formulations, contains a number of bioactive phytochemicals including the alkaloid sanguinarine. Despite its prolonged history of clinical use, conflicting experimental results have prevented the carcinogenic potential of sanguinarine from being definitively determined. Sanguinarine has a molecular structure similar to known polyaromatic hydrocarbon carcinogens and is a DNA intercalator. Sanguinarine also generates oxidative and endoplasmic reticulum stress resulting in the unfolded protein response and the formation of 8-hydroxyguanine genetic lesions. Sanguinarine has been the subject of contradictory in vitro and in vivo genotoxicity and murine carcinogenesis test results that have delayed its carcinogenic classification. Despite this, epidemiological studies have linked mouthwash that contains sanguinarine with the development of oral leukoplakia. Sanguinarine is also proposed as an aetiological agent in gallbladder carcinoma. This literature review investigates the carcinogenic potential of sanguinarine. Reasons for contradictory genotoxicity and carcinogenesis results are explored, knowledge gaps identified and a strategy for determining the carcinogenic potential of sanguinarine especialy relating to black salve are discussed. As patients continue to apply black salve, especially to skin regions suffering from field cancerization and skin malignancies, an understanding of the genotoxic and carcinogenic potential of sanguinarine is of urgent clinical relevance.
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Affiliation(s)
- Andrew Croaker
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia; Wesley Medical Research Institute, Wesley Hospital, Auchenflower, QLD, Australia; Quality Use of Medicines Network, Queensland, Australia
| | - Graham J King
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia
| | - John H Pyne
- School of Medicine, University of Queensland, St Lucia, QLD, Australia
| | - Shailendra Anoopkumar-Dukie
- Quality Use of Medicines Network, Queensland, Australia; School of Pharmacy and Pharmacology, Griffith University, Gold Coast Campus, Gold Coast, QLD, Australia
| | - Vilim Simanek
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic
| | - Lei Liu
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia.
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Liu Z, Liu D, Cheng J, Mei S, Fu Y, Lai W, Wang Y, Xu Y, Vo TD, Lynch BS. Lipid-soluble green tea extract: Genotoxicity and subchronic toxicity studies. Regul Toxicol Pharmacol 2017; 86:366-373. [DOI: 10.1016/j.yrtph.2017.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 03/30/2017] [Accepted: 04/02/2017] [Indexed: 12/24/2022]
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The EpiDerm™ 3D human reconstructed skin micronucleus (RSMN) assay: Historical control data and proof of principle studies for mechanistic assay adaptations. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2016; 805:25-37. [DOI: 10.1016/j.mrgentox.2016.05.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 05/11/2016] [Accepted: 05/11/2016] [Indexed: 11/24/2022]
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Chapman KE, Thomas AD, Wills JW, Pfuhler S, Doak SH, Jenkins GJS. Automation and validation of micronucleus detection in the 3D EpiDerm™ human reconstructed skin assay and correlation with 2D dose responses. Mutagenesis 2014; 29:165-75. [PMID: 24675152 PMCID: PMC3983754 DOI: 10.1093/mutage/geu011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent restrictions on the testing of cosmetic ingredients in animals have resulted in the need to test the genotoxic potential of chemicals exclusively in vitro prior to licensing. However, as current in vitro tests produce some misleading positive results, sole reliance on such tests could prevent some chemicals with safe or beneficial exposure levels from being marketed. The 3D human reconstructed skin micronucleus (RSMN) assay is a promising new in vitro approach designed to assess genotoxicity of dermally applied compounds. The assay utilises a highly differentiated in vitro model of the human epidermis. For the first time, we have applied automated micronucleus detection to this assay using MetaSystems Metafer Slide Scanning Platform (Metafer), demonstrating concordance with manual scoring. The RSMN assay’s fixation protocol was found to be compatible with the Metafer, providing a considerably shorter alternative to the recommended Metafer protocol. Lowest observed genotoxic effect levels (LOGELs) were observed for mitomycin-C at 4.8 µg/ml and methyl methanesulfonate (MMS) at 1750 µg/ml when applied topically to the skin surface. In-medium dosing with MMS produced a LOGEL of 20 µg/ml, which was very similar to the topical LOGEL when considering the total mass of MMS added. Comparisons between 3D medium and 2D LOGELs resulted in a 7-fold difference in total mass of MMS applied to each system, suggesting a protective function of the 3D microarchitecture. Interestingly, hydrogen peroxide (H2O2), a positive clastogen in 2D systems, tested negative in this assay. A non-genotoxic carcinogen, methyl carbamate, produced negative results, as expected. We also demonstrated expression of the DNA repair protein N-methylpurine-DNA glycosylase in EpiDerm™. Our preliminary validation here demonstrates that the RSMN assay may be a valuable follow-up to the current in vitro test battery, and together with its automation, could contribute to minimising unnecessary in vivo tests by reducing in vitro misleading positives.
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Affiliation(s)
- K E Chapman
- DNA Damage Research Group, Institute of Life Science, College of Medicine, Swansea University, Singleton Park, Swansea, Wales, SA2 8PP, UK
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