Comparative metabolism of DDAO benzoate in liver microsomes from various species. (October 2017)

• Record Type: Journal Article
• Authors: Ma, Hong-Ying; Yang, Jia-Da; Hou, Jie; Zou, Li-Wei; Jin, Qiang; Hao, Da-Cheng; Ning, Jing; Ge, Guang-Bo; Yang, Ling
• Is Part Of: Toxicology in vitro. Volume 44(2017)
• Page Start: 280
• Page End: 286
• Publication Date: 2017-10
• Subjects: DDAB 6, 8-Dichloro-9, 9-dimethyl-7-oxo-7, 9-dihydroacridin-2-yl benzoate -- DDAO 1, 3-Dichloro-9, 9-dimethyl-9H-acridin-2(7)-one -- BNPP Bis(p–nitrophenyl) phosphate -- EDTA Ethylenedi-aminetetraacetic acid -- LPA Loperamide -- EDTA Ethylene diamine tetraacetic acid -- HA Huperzine A -- CEs Carboxylesterases -- CE2 Carboxylesterase 2 -- hCE2 Human carboxylesterase 2 -- hCE1 Human carboxylesterase 1 -- CyLM Cynomolgus monkey liver microsome -- MLM Mouse liver microsome -- PLM Pig liver microsome -- HLM Human liver microsome -- DLM Dog liver microsome -- RLM Rat liver microsome; DDAB hydrolysis -- Carboxylesterase 2 (CE2) -- Species differences -- Liver microsomes; Toxicity testing -- In vitro -- Periodicals; Toxicology -- Periodicals; 615.9
• DOI: 10.1016/j.tiv.2017.06.020
• Languages: English
• ISSNs: 0887-2333

Abstract

Abstract: DDAB (6, 8-dichloro-9, 9-dimethyl-7-oxo-7, 9-dihydroacridin-2-yl benzoate) is a newly developed near-infrared fluorescent probe for human carboxylesterase 2 (hCE2), exhibiting high specificity and good reactivity for real-time monitoring the enzymatic activities of hCE2 in complex biological systems. In order to explore the applicability of DDAB in commonly used animal species, the interspecies difference in DDAB hydrolysis was carefully investigated by using liver microsomes from human and five experimental animals including mouse, rat, dog, minipig and monkey. Metabolite profiling demonstrated that DDAB hydrolysis could be catalyzed by all tested liver microsomes from different animals but displayed significant difference in the reaction rate. Chemical inhibition assays demonstrated that carboxylesterases (CEs) were the major enzymes involved in DDAB hydrolysis in all tested liver microsomes, indicating that DDAB was a selective substrate of CEs in a variety of mammals. However, the differential effects of loperamide (LPA, a specific inhibitor against hCE2) on DDAB hydrolysis among various species were observed. The apparent kinetic parameters and the maximum intrinsic clearances ( CL max ) for DDAB hydrolysis in liver microsomes from different animals were determined, and the order of CL max values for the formation of DDAO was CyLM > MLM ≈ PLM > RLM > HLM ≈ DLM. These findings were helpful for the rational use of DDAB as an imaging tool for CE2 in different mammals, as well as for translational researches on the function of mammalian CEs and CE2-associated drug-drug interactions. Highlights: DDAB could be hydrolyzed by liver microsomes from various animal species. Mammalian carboxylesterases (CEs) were the major enzymes involved in DDAB hydrolysis. Loperamide displayed different inhibitory effects on DDAB hydrolysis in different species. DDAB displayed similar apparent substrate affinity towards mammalian CEs from different species