Constitutive androstane receptor (CAR) is a key regulator of xenobiotic and endobiotic metabolism. Together with pregnane X (PXR) and aryl hydrocarbon (AHR) receptors, it is referred to as "xenobiotic receptor". The unique properties of human CAR, such as its high constitutive activity, both direct (ligand-binding domain-dependent) and indirect activation have hindered the discovery of direct selective human CAR ligands. Herein, we report a novel class of direct human CAR agonists in a group of 2-(3-methoxyphenyl)quinazoline derivatives. The compounds are even more potent activators of human CAR than is prototype 6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime (CITCO). The three most potent ligands are at the same time extremely potent activators of the other xenobiotic or hormonal receptors, namely PXR, AHR, and vitamin D receptor, which regulate major xenobiotic-metabolizing enzymes and efflux transporters. Thus, the novel CAR ligands can be also considered as constituting the first class of potent pan-xenobiotic receptor ligands that can serve as potential antidotes boosting overall metabolic elimination of xenobiotic or toxic compounds.

Institute of Molecular and Translation Medicine Faculty of Medicine Palacky University in Olomouc Hnevotinska 5 CZ 779 00 Olomouc Czech Republic

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