Structure-activity relationships for interaction with multidrug resistance protein 2 (ABCC2/MRP2): the role of torsion angle for a series of biphenyl-substituted heterocycles.
Multidrug resistance protein 2 (ABCC2/MRP2) is an ATP-binding cassette transporter involved in the absorption, distribution, and excretion of drugs and xenobiotics. Identifying compounds that are ABCC2/MRP2 substrates and/or inhibitors and understanding their structure-activity relationships (SARs) are important considerations in the selection and optimization of drug candidates. In the present study, the interactions between ABCC2/MRP2 and a series of biphenyl-substituted heterocycles were evaluated using Caco-2 cells and human ABCC2/MRP2 gene-transfected Madin-Darby canine kidney cells. It was observed that ABCC2/MRP2 transport and/or inhibition profile, both in nature and in magnitude, depends strongly on the substitution patterns of the biphenyl system. In particular, different ortho-substitutions cause various degrees of twisting between the two-phenyl rings, resulting in changing interactions between the ligands and ABCC2/MRP2. The compounds with small ortho functions (hydrogen, fluorine, and oxygen) and, thus, the ones displaying the smallest torsion angles of biphenyl (37-45 degrees) are neither substrates nor inhibitors of human ABCC2/MRP2. The transporter interactions increase as the steric bulkiness of the ortho-substitutions increase. When the tested compounds are 2-methyl substituted biphenyls, they exhibit moderate torsion angles (54-65 degrees) and behave as ABCC2/MRP2 substrates as well as mild inhibitors [10-40% compared with 3-[[3-[2-(7-chloroquinolin-2-yl)vinyl]phenyl]-(2-dimethylcarbamoylethyl-sulfanyl)methylsulfanyl] propionic acid (MK571)]. For the 2,2'-dimethyl substituted biphenyls, the torsions are enhanced (78-87 degrees) and so is the inhibition of ABCC2/MRP2. This class of compounds behaves as strong inhibitors of ABCC2/MRP2. These results can be used to define the three-dimensional structural requirements of ABCC2/MRP2 interaction with their substrates and inhibitors, as well as to provide SAR guidance to support drug discovery.
Lai
Yurong
Y
Pharmacokinetic, Dynamics, & Metabolism, Pfizer, Inc. St Louis Laboratory, Chesterfield, MO 63017, USA. yurong.lai@pfizer.com
Xing
Li
L
Poda
Gennadiy I
GI
Hu
Yiding
Y
D000818:Animals; D001713:Biphenyl Compounds / Q000737:chemistry* / Q000378:metabolism*; D018938:Caco-2 Cells; D004285:Dogs; D005452:Fluoresceins / Q000378:metabolism; D006801:Humans; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D013329:Structure-Activity Relationship
D001713:Biphenyl Compounds; D005452:Fluoresceins; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C000715087:ABCC2 protein, human; C007740:fluorexon