Using the HepaCometChip Assay for Broad-Spectrum DNA Damage Analysis

Application of HepaRG cells for genotoxicity assessment: a review

There has been growing interest in the use of human-derived metabolically competent cells for genotoxicity testing. The HepaRG cell line is considered one of the most promising cell models because it is TP53-proficient and retains many characteristics of primary human hepatocytes. In recent years, HepaRG cells, cultured in both a traditional two-dimensional (2D) format and as more advanced in-vivo-like 3D spheroids, have been employed in assays that measure different types of genetic toxicity endpoints, including DNA damage, mutations, and chromosomal damage. This review summarizes published studies that have used HepaRG cells for genotoxicity assessment, including cell model evaluation studies and risk assessment for various compounds. Both 2D and 3D HepaRG models can be adapted to several high-throughput genotoxicity assays, generating a large number of data points that facilitate quantitative benchmark concentration modeling. With further validation, HepaRG cells could serve as a unique, human-based new alternative methodology for in vitro genotoxicity testing.

Genotoxicity assessment in HepaRG™ cells as a new approach methodology follow up to a positive response in the human TK6 cell micronucleus assay: Naphthalene case study

We are evaluating the use of metabolically competent HepaRG™ cells combined with CometChip® for DNA damage and the micronucleus (MN) assay as a New Approach Methodology (NAM) alternative to animals for follow up genotoxicity assessment to in vitro positive genotoxic response. Naphthalene is genotoxic in human TK6 cells inducing a nonlinear dose-response for the induction of micronuclei in the presence of rat liver S9. of naphthalene. In HepaRG™ cells, naphthalene genotoxicity was assessed using either 6 (CometChip™) or 12 concentrations of naphthalene (MN assay) with the top dose used for assessment of genotoxicity for the Comet and MN assay was 1.25 and 1.74 mM respectively, corresponding to approximately 45% cell survival. In contrast to human TK6 cell with S9, naphthalene was not genotoxic in either the HepaRG™ MN assay or the Comet assay using CometChip®. The lack of genotoxicity in both the MN and comet assays in HepaRG™ cells is likely due to Phase II enzymes removing phenols preventing further bioactivation to quinones and efficient detoxication of naphthalene quinones or epoxides by glutathione conjugation. In contrast to CYP450 mediated metabolism, these Phase II enzymes are inactive in rat liver S9 due to lack of appropriate cofactors causing a positive genotoxic response. Rat liver S9-derived BMD10 over-predicts naphthalene genotoxicity when compared to the negative genotoxic response observed in HepaRG™ cells. Metabolically competent hepatocyte models like HepaRG™ cells should be considered as human-relevant NAMs for use genotoxicity assessments to reduce reliance on rodents.