The SenCeeTox® assay

Abstract

Chemical sensitization is a complex biological process initiated by electrophilic substances and several assaults to different cell types. One prominent intracellular pathway involved is the Nrf2/Keap1 signaling pathway which is triggered and expression of genes containing the Electrophilic/Aromatic Response Element (EpRE/ARE) in their promotor region is activated. As a cellular defense mechanism the products of these genes act to reduce the oxidative stress and to detoxify the xenobiotic. The SenCeeTox assay can be performed on a monolayer culture of a keratinocyte cell line, HaCaT, or can be applied in a more advanced reconstituted epidermis model, which allows the testing of finished products, extracts. Changes in gene expression profiles of 11 genes containing the EpRE/ARE in their promotors are monitored and the protein reactivity of the test articles based on their direct reaction with glutathione is measured. Molecular descriptors are taken into account to allow the calculation of a predicted LLNA EC3 value in mM using a pattern recognition model and by combining the data of protein reactivity with the gene expression and cell viability data.