Classification of In Vitro Genotoxicants Requiring Metabolic Activation Using a Multiplexed Assay (MultiFlow®)

ICEM 2022 -- Early screening for in vitro genotoxicity can remove potential hazards and identify lead candidates for further development. The in vitro micronucleus (MN) assay is routinely used to screen compounds for induction of chromosome damage; however, MN can arise via non-DNA reactive modes of actions that can be important information for identifying compounds to progress. Assays that provide genotoxic mode of action information and are less impacted by non-genotoxic mechanisms (e.g., high levels of cytotoxicity, damage to non-DNA targets) offer useful tools to identify genotoxins early in compound development. The in vitro MultiFlow® assay (Litron Laboratories) is a multiplexed flow cytometric assay based on changes in γH2AX, p53, phospo-histone H3 and polyploidy in treated Human TK6 cells for prediction of genotoxic mode of action (aneugenic, clastogenic or non-genotoxic). The MultiFlow® assay was qualified at Labcorp using a diverse set of 24 compounds, including 8 clastogen