TY - JOUR
T1 - Systematic Evaluation of Tyrosine Kinase Inhibitors as OATP1B1 Substrates Using a Competitive Counterflow Screen
AU - Drabison, Thomas
AU - Boeckman, Mike
AU - Yang, Yan
AU - Huang, Kevin M.
AU - de Bruijn, Peter
AU - Nepal, Mahesh R.
AU - Silvaroli, Josie A.
AU - Chowdhury, Anika T.
AU - Eisenmann, Eric D.
AU - Cheng, Xiaolin
AU - Pabla, Navjotsingh
AU - Mathijssen, Ron H.J.
AU - Baker, Sharyn D.
AU - Hu, Shuiying
AU - Sparreboom, Alex
AU - Talebi, Zahra
N1 - Publisher Copyright:
© 2024 The Authors.
PY - 2024/9/23
Y1 - 2024/9/23
N2 - Although the primary elimination pathway for most tyrosine kinase inhibitors (TKI) involves CYP3A4-mediated metabolism, the mechanism by which these agents are brought into hepatocytes remains unclear. In this study, we optimized and validated a competitive counterflow (CCF) assay to examine TKIs as substrates of the hepatic uptake transporter OATP1B1. The CCF method was based on the stimulated efflux of radiolabeled estradiol-17β-glucuronide under steady-state conditions in HEK293 cells engineered to overexpress OATP1B1. Of the 62 approved TKIs examined, 13 agents were identified as putative substrates of OATP1B1, and pazopanib was selected as a representative hit for further validation studies. The transport of pazopanib by OATP1B1 was confirmed by decreased activity of its target VEGFR2 in OATP1B1-overexpressing cells, but not cells lacking OATP1B1, consistent with molecular docking analyses indicating an overlapping binding orientation on OATP1B1 with the known substrate estrone-3-sulfate. In addition, the liver-to-plasma ratio of pazopanib in vivo was decreased in mice with a deficiency of the orthologous transporters, and this was accompanied by diminished pazopanib-induced hepatotoxicity, as determined by changes in the levels of liver transaminases. Our study supports the utility of CCF assays to assess substrate affinity for OATP1B1 within a large set of agents in the class of TKIs and sheds light on the mechanism by which these agents are taken up into hepatocytes in advance of metabolism.
AB - Although the primary elimination pathway for most tyrosine kinase inhibitors (TKI) involves CYP3A4-mediated metabolism, the mechanism by which these agents are brought into hepatocytes remains unclear. In this study, we optimized and validated a competitive counterflow (CCF) assay to examine TKIs as substrates of the hepatic uptake transporter OATP1B1. The CCF method was based on the stimulated efflux of radiolabeled estradiol-17β-glucuronide under steady-state conditions in HEK293 cells engineered to overexpress OATP1B1. Of the 62 approved TKIs examined, 13 agents were identified as putative substrates of OATP1B1, and pazopanib was selected as a representative hit for further validation studies. The transport of pazopanib by OATP1B1 was confirmed by decreased activity of its target VEGFR2 in OATP1B1-overexpressing cells, but not cells lacking OATP1B1, consistent with molecular docking analyses indicating an overlapping binding orientation on OATP1B1 with the known substrate estrone-3-sulfate. In addition, the liver-to-plasma ratio of pazopanib in vivo was decreased in mice with a deficiency of the orthologous transporters, and this was accompanied by diminished pazopanib-induced hepatotoxicity, as determined by changes in the levels of liver transaminases. Our study supports the utility of CCF assays to assess substrate affinity for OATP1B1 within a large set of agents in the class of TKIs and sheds light on the mechanism by which these agents are taken up into hepatocytes in advance of metabolism.
UR - http://www.scopus.com/inward/record.url?scp=85204819625&partnerID=8YFLogxK
U2 - 10.1158/2767-9764.CRC-24-0332
DO - 10.1158/2767-9764.CRC-24-0332
M3 - Article
C2 - 39207193
AN - SCOPUS:85204819625
SN - 2767-9764
VL - 4
SP - 2489
EP - 2497
JO - Cancer Research Communications
JF - Cancer Research Communications
IS - 9
ER -