Em��ke S��skuti: Charles River Laboratories Hungary, H-1117 Budapest, Hungary.
N��ra Szilv��sy: Charles River Laboratories Hungary, H-1117 Budapest, Hungary.
Csilla Temesszentandr��si-Ambrus: Charles River Laboratories Hungary, H-1117 Budapest, Hungary. ORCID
Zolt��n Urb��n: Charles River Laboratories Hungary, H-1117 Budapest, Hungary.
Oliv��r Cs��kv��ri: Charles River Laboratories Hungary, H-1117 Budapest, Hungary.
Zolt��n Szab��: Department of Medical Chemistry, Albert Szent-Gy��rgyi Medical School, University of Szeged, H-6720 Szeged, Hungary. ORCID
G��bor Kecskem��ti: Department of Medical Chemistry, Albert Szent-Gy��rgyi Medical School, University of Szeged, H-6720 Szeged, Hungary. ORCID
��va Pusztai: Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, H-1111 Budapest, Hungary. ORCID
Zsuzsanna G��borik: Charles River Laboratories Hungary, H-1117 Budapest, Hungary.
Implementing the 3R initiative to reduce animal experiments in brain penetration prediction for CNS-targeting drugs requires more predictive in vitro and in silico models. However, animal studies are still indispensable to obtaining brain concentration and determining the prediction performance of in vitro models. To reveal species differences and provide reliable data for IVIVE, in vitro models are required. Systems overexpressing MDR1 and BCRP are widely used to predict BBB penetration, highlighting the impact of the in vitro system on predictive performance. In this study, endogenous Abcb1 knock-out MDCKII cells overexpressing MDR1 of human, mouse, rat or cynomolgus monkey origin were used. Good correlations between ERs of 83 drugs determined in each cell line suggest limited species specificities. All cell lines differentiated CNS-penetrating compounds based on ERs with high efficiency and sensitivity. The correlation between in vivo and predicted K was the highest using total ER of human MDR1 and BCRP and optimized scaling factors. MDR1 interactors were tested on all MDR1 orthologs using digoxin and quinidine as substrates. We found several examples of inhibition dependent on either substrate or transporter abundance. In summary, this assay system has the potential for early-stage brain penetration screening. IC comparison between orthologs is complex; correlation with transporter abundance data is not necessarily proportional and requires the understanding of modes of transporter inhibition.
