Evaluation of CYP1A1 and CYP2B1/2 m-RNA Induction in Rat Liver Slices Using the NanoString® Technology: A Novel Tool for Drug Discovery Lead Optimization

Cytochrome P450 (CYP) induction in rodents and humans is considered a liability for new chemical entities (NCEs) in drug discovery. In particular, CYP1A1 and CYP2B1/2 have been associated with the induction of liver tumors in oncogenicity studies during safety evaluation studies of potential drugs. In our laboratory, real time PCR (Taqman®) has been used to quantify the induction of rat hepatic CYP1A1 and CYP2B1/2 in precision-cut rat liver slices. A novel technology that does not require m-RNA isolation or RT-PCR, (developed by NanoString Technologies®) has been investigated to quantify CYP1A1 and CYP2B1/2 induction in rat liver slices. Seventeen commercially available compounds were evaluated using both Taqman® and NanoString® technologies. Precision-cut rat liver slices were incubated with individual compounds for 24 hr at 37°C in a humidified CO2 incubator and CYP1A1 and CYP2B1/2 m-RNA molecules were quantified. The results from the NanoString® technology were similar to those of the Taqman® with a high degree of correlation for both CYP isoforms (r2>0.85). Therefore, NanoString provides an additional new technology to evaluate the induction of CYP1A1 and 2B1/2, as well as potentially other enzymes or transporters in rat liver slices.