Author/Editor		Ačimovič, J; Korošec, T; Seliškar, M; Bjorkhem, I; Monostory, K; Szabo, P; Pascussi, JM; Belic, A; Kocjan, D; Urleb, U; Rozman, D
Title		Inhibition of human sterol delta 7-reductase and other post-lanosterol enzymes by 2-(4-phenethylpiperazin-1-yl)-1-(pyridine-3-yl)ethanol (LK-980), a novel inhibitor of cholesterol synthesis
Type		članek
Source		Drug Metab Dispos
Vol. and No.		Letnik 43, št. 1
Publication year		2011
Volume		str. 69-90
Language		eng
Abstract		Novel potential inhibitors of the post-squalene portion of cholesterol synthesis were screened in HepG2 cells. 2-(4-phenethylpiperazin-1-yl)-1-(pyridine-3-yl)ethanol (LK-980) was identified as a perspective compound and was characterized further in cultures of human primary hepatocytes from seven donors. In vitro kinetic measurements show that half life of LK-980 is at least 4.3 h. LK-980 does not induce cytochrome P450 3A4 (CYP3A4) mRNA nor enzyme activity. Target prediction was performed by gas chromatography-mass spectrometry (GC-MS) allowing simultaneous separation and quantification of nine late cholesterol intermediates. Experiments indicated that human sterol delta 7-reductase (DHCR7) is the major target of LK-980 (34-fold increase of 7-dehydrocholesterol), while human sterol delta 14-reductase (DHCR14), human sterol delta 24-reductase (DHCR24) and human sterol C5-desaturase (SC5DL) represent minor targets. In the absence of purified enzymes, we used the mathematical model of cholesterol synthesis to evaluate if indeed more than a single enzyme is inhibited. In silico inhibition of only DHCR7 modifies the flux of cholesterol intermediates, resulting in sterol profile that does not support experimental data. Partial inhibition of the DHCR14, DHCR24 and SC5DL steps, in addition to DHCR7, supports the experimental sterol profile. In conclusion, we provide experimental and computational evidence that LK-980, a novel inhibitor from the late portion of cholesterol synthesis, inhibits primarily DHCR7 and to a lesser extent three other enzymes from this pathway.