15270-30-1Relevant articles and documents
The roles of breast cancer resistance protein (BCRP/ABCG2) and multidrug resistance-associated proteins (MRPs/ABCCs) in the excretion of cycloicaritin-3-O-glucoronide in UGT1A1-overexpressing HeLa cells
Li, Shishi,Xu, Jinjin,Yao, Zhihong,Hu, Liufang,Qin, Zifei,Gao, Hao,Krausz, Kristopher W.,Gonzalez, Frank J.,Yao, Xinsheng
, p. 45 - 56 (2018)
Cycloicaritin is a bioactive natural phenolic compound from Epimedium species. However, the glucuronidation and excretion which would influence oral bioavailability and pharmacokinetics of cycloicaritin still remain unknown. Here we aimed to establish UGT1A1 stably transfected HeLa cells, and to determine the contributions of BCRP and MRPs transporters to excretion of cycloicaritin-3-O-glucuronide. First, β-estradiol was used to validate the expression of active UGT1A1 protein in engineered HeLa1A1 cells. Furthermore, Ko143 (5 and 20 μM) led to a significant decrease (42.4%–63.8%, p a significant reduction (46.8%–64.8%, p a simple and practical tool to study UGT1A1-mediated glucuronidation and to characterize BCRP and MRPs-mediated glucuronide transport at a cellular level.
Characterization of the zebrafish Ugt repertoire reveals a new class of drug-metabolizing UDP glucuronosyltransferases
Wang, Yuanming,Huang, Haiyan,Wu, Qiang
, p. 62 - 75 (2014/06/10)
The zebrafish genome contains a gene superfamily of 40 Ugt genes that can be divided into Ugt1, Ugt2, and Ugt5 families. Because the encoded zebrafish UDP glucuronosyltransferase (UGT) proteins do not display orthologous relationships to any of the mammalian and avian UGT enzymes based on molecular phylogeny, it is difficult to predict their substrate specificity. Here, we mapped their tissue-specific expression patterns. We showed that the zebrafish UGT enzymes can be glycosylated. We determined their substrate specificity and catalytic activity toward diverse aglycone substrates. Specifically, we measured mRNA levels of each of the 40 zebrafish Ugt genes in 11 adult tissues and found that they are expressed in a tissue-specific manner. Moreover, functional analyses with the donor of UDP glucuronic acid (UDPGA) for each of the 40 zebrafish UGT proteins revealed their substrate specificity toward 10 important aglycones. In particular, UGT1A1, UGT1A7, and UGT1B1 displayed good glucuronidation activities toward most phenolic aglycones (4-methylumbelliferone, 4-nitrophenol, 1-naphthol, bisphenol A, and mycophenolic acid) and the two carboxylic acids (bilirubin and diclofenac). Importantly, some members of the UGT5, a novel UGT family identified recently, are capable of glucuronidating multiple aglycones with the donor cofactor of UDPGA. In particular, UGT5A5, UGT5B2, and UGT5E1 glucuronidate phenols and steroids with high specificity toward steroid hormones of estradiol and testosterone and estrogenic alkylphenols 4-tert-octylphenol. These results shed new insights into the mechanisms by which fish species defend themselves against vast numbers of xenobiotics via glucuronidation conjugations and may facilitate the establishment of zebrafish as a model vertebrate in toxicological, developmental, and pathologic studies. Copyright
Optimized assays for human UDP-glucuronosyltransferase (UGT) activities: Altered alamethicin concentration and utility to screen for UGT inhibitors
Walsky, Robert L.,Bauman, Jonathan N.,Bourcier, Karine,Giddens, Georgina,Lapham, Kimberly,Negahban, Andre,Ryder, Tim F.,Obach, R. Scott,Hyland, Ruth,Goosen, Theunis C.
experimental part, p. 1051 - 1065 (2012/09/10)
The measurement of the effect of new chemical entities on human UDP-glucuronosyltransferase (UGT) marker activities using in vitro experimentation represents an important experimental approach in drug development to guide clinical drug-interaction study designs or support claims that no in vivo interaction will occur. Selective high-performance liquid chromatography-tandem mass spectrometry functional assays of authentic glucuronides for five major hepatic UGT probe substrates were developed: β-estradiol- 3-glucuronide (UGT1A1), trifluoperazine-N-glucuronide (UGT1A4), 5-hydroxytryptophol-O-glucuronide (UGT1A6), propofol-O-glucuronide (UGT1A9), and zidovudine-5′-glucuronide (UGT2B7). High analytical sensitivity permitted characterization of enzyme kinetic parameters at low human liver microsomal and recombinant UGT protein concentration (0.025 mg/ml), which led to a new recommended optimal universal alamethicin activation concentration of 10 μg/ml for microsomes. Alamethicin was not required for recombinant UGT incubations. Apparent enzyme kinetic parameters, particularly for UGT1A1 and UGT1A4, were affected by nonspecific binding. Unbound intrinsic clearance for UGT1A9 and UGT2B7 increased significantly after addition of 2% bovine serum albumin, with minimal changes for UGT1A1, UGT1A4, and UGT1A6. Eleven potential UGT and cytochrome P450 inhibitors were evaluated as UGT inhibitors, resulting in observation of nonselective UGT inhibition by chrysin, mefenamic acid, silibinin, tangeretin, ketoconazole, itraconazole, ritonavir, and verapamil. The pan-cytochrome P450 inhibitor, 1-aminobenzotriazole, minimally inhibited UGT activities and may be useful in reaction phenotyping of mixed UGT and cytochrome P450 substrates. These methods should prove useful in the routine assessments of the potential for new drug candidates to elicit pharmacokinetic drug interactions via inhibition of human UGT activities and the identification of UGT enzyme-selective chemical inhibitors. Copyright
