Understand potential skin sensitization using our in vitro KeratinoSens™ skin sensitization assay performed in accordance with OECD guidance.
Skin sensitization assessment using KeratinoSens™ is in our portfolio of in vitro topical services for the cosmetics/personal care, chemical and pharmaceutical industries.
Small electrophilic substances such as skin sensitizers can act on the sensor protein Keap1 (Kelch-like ECH-associated protein 1), by e.g., covalent modification of its cysteine residue, resulting in its dissociation from the transcription factor Nrf2 (nuclear factor-erythroid 2-related factor 2). The dissociated Nrf2 can then activate ARE-dependent genes such as those coding for phase II detoxifying enzymes
4OECD Guideline for the Testing of Chemicals. Draft Proposal for a New Test Guideline: In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test Method, May 2014
Cell Line | KeratinoSens™ cell line |
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Analysis | Induction of luciferase reporter gene expression and cell viability |
Test Article Concentrations | 12 concentrations in triplicate in 3 independently performed experiments Highest concentration: 2000 µM (according to OECD guideline, dependent on customer requirements) |
Time Points | 48 hrs |
Quality Controls | Vehicle control: 1% DMSO (vehicle) Positive control: cinnamic aldehyde Negative control: sodium dodecyl sulfate |
Data Delivery | Dose response curves for cell viability and luciferase reporter gene expression MEC (minimum effective concentration), AC50, IC30 and maximum response (%) for cell viability EC1.5, AC50 and maximum response (Imax) for luciferase gene expression as well as sensitising potential classification |
Literature Data4,5,6 | Cyprotex Data | ||||||
---|---|---|---|---|---|---|---|
Compound | In vivo | Classification | EC1.5* (µM) | IC50 (µM) | Classification | EC1.5* (µM) | IC50 (µM) |
Non-sensitizing compounds | |||||||
Isopropanol | Non-sensitizer | Negative | >1000 | >1000 | Negative | >1000 | >1000 |
Salicylic acid | Non-sensitizer | Negative | >1000 | >1000 | Negative | >1000 | >1000 |
Lactic acid | Non-sensitizer | Negative | >1000 | >1000 | Negative | >1000 | >1000 |
Glycerol | Non-sensitizer | Negative | >1000 | >1000 | Negative | >1000 | >1000 |
Sodium dodecyl sulphate | Non-sensitizer | Negative | NR | NR | Negative | >31 | 54 |
Sensitizing compounds | |||||||
Cinnamyl alcohol | Weak | Positive | 25-175 | >1000 | Positive | 119 | >1000 |
Ethylene glycol dimethacrylate | Weak | Positive | 5-125 | >500 | Positive | 39 | 810 |
2-Mercaptobenzothiazole | Moderate | Positive | 50-250 | >500 | Positive | 1187 | 1025 |
Methyldibromo glutaronitrile | Strong | Positive | <20 | 20-100 | Positive | 9.1 | 25 |
4-Methylaminophenol | Strong | Positive | <12.5 | 20-200 | Positive | 3.3 | 15 |
2,4 Dinitro-1-chlorobenzene | Extreme | Positive | <12.5 | 5-20 | Positive | 1.5 | 8 |
Cinnamic aldehyde | Weak | Positive | NR | NR | Positive | 13 | 100 |
2,3 Butanedione | Weak | Positive | <100 | NR | Positive | 54 | 370 |
1 Emter R et al., (2010) Performance of a novel keratinocyte-based reporter cell line to screen skin sensitizers in vitro. Toxicol Appl Pharmacol 245(3); 281-290
2 Natsch A et al., (2010) The Nrf2-Keap1-ARE toxicity pathway as a cellular sensor for skin sensitizers – Functional relevance and hypothesis on innate reactions to skin sensitizers. Toxicol Sci 113(2); 284-292
3 Dinkova-Kostova AT et al., (2005) The role of Keap1 in cellular protective responses. Chem Res Toxicol 18(12); 1779-1791
4 OECD Guideline for the Testing of Chemicals. In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test Method, Adopted February 2015
5 Bauch C et al., (2012) Putting the parts together: Combining in vitro methods to test for skin sensitizing potentials. Regul Toxicol Pharmacol 63(3); 489-504
6 Natsch A et al., (2011) The intra- and inter-laboratory reproducibility and predictivity of the KeratinoSens assay to predict skin sensitizers in vitro: Results of a ring-study in five laboratories. Toxicol In Vitro 25(3); 733-744
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