(2023-2.1.2-KDP-2023-00016) Támogató: Kulturális és Innovációs Minisztérium Nemzeti
Kutatási Fejlesztési és Innovációs Alap
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 Kp,uu,brain 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. IC50 comparison between
orthologs is complex; correlation with transporter abundance data is not necessarily
proportional and requires the understanding of modes of transporter inhibition.
