Role in a Testing Strategy
Toxicity to the genome encompasses gene mutation, clastogenicity and aneugenicity and is caused by diverse mechanisms. Therefore, no single assay can reliably detect all classes of genotoxic agents. International guidelines thus recommend the use of a battery of genotoxicity tests covering all genotoxicity endpoints. These guidelines, in general, foresee in vitro testing first. The initial in vitro battery, usually consisting of two or three assays, shows high sensitivity in terms of correct prediction of in vivo genotoxicants and carcinogens. However, the specificity (the ability to correctly identify in vivo non-genotoxic noncarcinogens) of such an in vitro battery has shown to be low. This often leads to in vivo follow-up testing (so-called ‘tier 2’ testing) that may be unnecessary since the relevance of the positive in vitro findings in the initial testing battery can now also be checked with newly developed in vitro methods. For dermally exposed chemicals, the previously described 3D human reconstructed skin-based micronucleus and comet assays are suggested as a replacement of the ‘tier 2’ studies currently often performed with animals. In the sense of the 3Rs (refine, reduce, replace) they can therefore be seen as a direct replacement of animal studies and can be used for following up unfavourable results from the ‘tier 1’ in vitro battery.
- 1.Kirkland D, Aardema M, Müller L, Hayashi M. Evaluation of the ability of a battery of three in vitro genotoxicity tests to discriminate rodent carcinogens and non-carcinogens II. Further analysis of mammalian cell results, relative predictivity and tumour profiles. Mutat Res. 2006;608(1):29–42.CrossRefPubMedGoogle Scholar
- 3.Pfuhler S, Kirst A, Aardema M, Banduhn N, Goebel C, Araki D, Costabel-Farkas M, Dufour E, Fautz R, Harvey J, Hewitt NJ, Hibatallah J, Carmichael P, Macfarlane M, Reisinger K, Rowland J, Schellauf F, Schepky A, Scheel J. A tiered approach to the use of alternatives to animal testing for the safety assessment of cosmetics: genotoxicity. A COLIPA analysis. Regul Toxicol Pharmacol. 2010;57(2–3):315–24.CrossRefPubMedGoogle Scholar
- 5.Elespuru RK, Agarwal R, Atrakchi AH, Bigger CA, Heflich RH, Jagannath DR, Levy DD, Moore MM, Ouyang Y, Robison TW, Sotomayor RE, Cimino MC, Dearfield KL. Current and future application of genetic toxicity assays: the role and value of in vitro mammalian assays. Toxicol Sci. 2009;109:172–9.CrossRefPubMedGoogle Scholar
- 7.Fowler P, Smith R, Smith K, Young J, Jeffrey L, Kirkland D, Pfuhler S, Carmichael P. Reduction of misleading ("false") positive results in mammalian cell genotoxicity assays. II. Importance of accurate toxicity measurement. Mutat. Res. 2012;747(1):104–17.Google Scholar
- 10.Zeiger E, Gollapudi B, Aardema MJ, Auerbach S, Boverhof D, Custer L, Dedon P, Honma M, Ishida S, Kasinski AL, Kim JH, Manjanatha MG, Marlowe J, Pfuhler S, Pogribny I, Slikker W, Stankowski LF Jr, Tanir JY, Tice R, van Benthem J, White P, Witt KL, Thybaud V. Opportunities to integrate new approaches in genetic toxicology: an ILSI-HESI workshop report. Environ Mol Mutagen. 2015;56:277–85.CrossRefPubMedGoogle Scholar
- 11.Pfuhler S, Fellows M, van Benthem J, Corvi R, Curren R, Dearfield K, Fowler P, Frötschl R, Elhajouji A, Le Hégarat L, Kasamatsu T, Kojima H, Ouédraogo G, Scott A, Speit G. In vitro genotoxicity test approaches with better predictivity: summary of an IWGT workshop. Mutat Res. 2011;723:101–7.CrossRefPubMedGoogle Scholar
- 12.Hewitt NJ, Edwards RJ, Fritsche E, Goebel C, Aeby P, Scheel J, Reisinger K, Ouédraogo G, Duche D, Eilstein J, Latil A, Kenny J, Moore C, Kuehnl J, Barroso J, Fautz R, Pfuhler S. Use of human in vitro skin models for accurate and ethical risk assessment: metabolic considerations. Toxicol Sci. 2013;133:209–17.CrossRefPubMedGoogle Scholar
- 13.SCCS. ADDENDUM to the SCCS's Notes of Guidance (NoG) for the Testing of Cosmetic Ingredients and their Safety Evaluation, 8th Revision (SCCS/1501/12) 2014. http://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_156.pdf.
- 14.SCCS. Scientific Committee on Consumer Safety. Opinion on Basic Brown 17 COLIPA No. B007. SCCS/1531/14. Adopted on 24 Mar 2014, revision of 18 Jun 2014. 2014. http://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_152.pdf.