ToxTracker EMP (enhanced metabolization protocol) is a modified ToxTracker protocol to investigate the genotoxic potential of N-nitrosamines (NAs) in the presence of exogeneous metabolism. This enhanced protocol, which may be used across mammalian cell systems, greatly improves bioactivation of NAs and increases the sensitivity of ToxTracker to detect the harmful effects of these metabolites. EMP was developed to address the lack of a standard experimental design for biotransforming NAs in mammalian cell culture.

ToxTracker EMP

ToxTracker EMP uses the two genotoxicity GFP reporter cell lines (Bscl2-GFP and Rtkn-GFP) from the standard ToxTracker assay. Since rat S9 liver fraction has a limited ability to biotransform NAs, EMP uses hamster S9 with an optimized pre-incubation, set of cofactors, and exposure times.

With ToxTracker EMP, N-nitrosodimethylamine (NDMA) induced genotoxicity was detected at ~200-fold lower concentrations when compared to standard S9 exposures. This method was also validated by testing a subset of well-established genotoxic and non-genotoxic NAs based on results from the Enhanced Ames Test (Geijer et al, 2025).

Testing services at Toxys

ToxTracker EMP is available as a contracted service from Toxys. Assay readouts include cytotoxicity data and assessment of genotoxicity in the absence and presence of the EMP, with benchmark dose (BMD) analysis of each substance. An example report can be requested in advance.

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ToxTracker EMP page
ToxTracker EMP flyer
ToxTracker EMP publication
ToxTracker EMP video
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