TY - JOUR T1 - Disposition of Mianserin and Cyclizine in UGT2B10-Overexpressing Human Embryonic Kidney 293 Cells: Identification of UGT2B10 as a Novel N-Glucosidation Enzyme and Breast Cancer Resistance Protein as an N-Glucoside Transporter JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 970 LP - 979 DO - 10.1124/dmd.118.080804 VL - 46 IS - 7 AU - Danyi Lu AU - Dong Dong AU - Qian Xie AU - Zhijie Li AU - Baojian Wu Y1 - 2018/07/01 UR - http://dmd.aspetjournals.org/content/46/7/970.abstract N2 - UDP-glucuronosyltransferases (UGTs) play an important role in the metabolism and detoxification of amine-containing chemicals; however, the disposition mechanisms for amines via UGT metabolism are not fully clear. We aimed to investigate a potential role of UGT2B10 in N-glucosidation and to determine the transporters for the excretion of N-glucosides. We first established a human embryonic kidney cell line 293 (HEK293) that stably overexpressed UGT2B10. Incubation of mianserin or cyclizine with the cells generated one N-glucuronide and one N-glucoside. Chemical inhibition (using specific chemical inhibitor Ko143) and biologic inhibition [using specific short hairpin RNA of breast cancer resistance protein (BCRP)] resulted in a significant reduction in efflux of N-glucuronide. Similar results were observed when multidrug resistance–associated protein (MRP4) was inhibited. Furthermore, inhibition of BCRP led to increased intracellular N-glucoside, whereas inhibition of MRP4 caused no changes in disposition of N-glucoside. Overall, the data indicated that BCRP, not MRP4, was responsible for the excretion of N-glucosides, whereas both BCRP and MRP4 contributed to excretion of N-glucuronides. Interestingly, downregulation of N-glucuronidation led to increased N-glucosidation in the cells, supporting the glucosidation as a potential complementary pathway for conventional glucuronidation. In conclusion, UGT2B10 was for the first time identified as an N-glucosidation enzyme. Generated N-glucosides were excreted primarily by the BCRP transporter. ER -