Cytochrome P450-mediated epoxidation of 2-aminothiazole-based AKT inhibitors: identification of novel GSH adducts and reduction of metabolic activation through structural changes guided by in silico and in vitro screening.
A 2-aminothiazole derivative 1 was developed as a potential inhibitor of the oncology target AKT, a serine/threonine kinase. When incubated in rat and human liver microsomes in the presence of NADPH, 1 underwent significant metabolic activation on its 2-aminothiazole ring, leading to substantial covalent protein binding. Upon addition of glutathione, covalent binding was reduced significantly, and multiple glutathione adducts were detected. Novel metabolites from the in vitro incubates were characterized by LC-MS and NMR to discern the mechanism of bioactivation. An in silico model was developed based on the proposed mechanism and was employed to predict bioactivation in 23 structural analogues. The predictions were confirmed empirically for the bioactivation liability, in vitro, by LC-MS methods screening for glutathione incorporation. New compounds were identified with a low propensity for bioactivation.
Subramanian
Raju
R
Pharmacokinetics and Drug Metabolism and Chemistry Research and Discovery, Amgen Inc, One Amgen Center Drive, M/S 30E-2-B, Thousand Oaks, California 91320, USA. rajus@amgen.com
Lee
Matthew R
MR
Allen
John G
JG
Bourbeau
Matthew P
MP
Fotsch
Christopher
C
Hong
Fang-Tsao
FT
Tadesse
Seifu
S
Yao
Guomin
G
Yuan
Chester C
CC
Surapaneni
Sekhar
S
Skiles
Gary L
GL
Wang
Xianghong
X
Wohlhieter
G Erich
GE
Zeng
Qingping
Q
Zhou
Yihong
Y
Zhu
Xiaochun
X
Li
Chun
C
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D015394:Molecular Structure; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors*; D051381:Rats; D013844:Thiazoles / Q000009:adverse effects* / Q000737:chemistry* / Q000378:metabolism
D004852:Epoxy Compounds; D013844:Thiazoles; C004483:2-aminothiazole; D003577:Cytochrome P-450 Enzyme System; D051057:Proto-Oncogene Proteins c-akt; D005978:Glutathione