Pharmacogenetics and Genomics. 21(2):55–65, FEBRUARY 2011
DOI: 10.1097/FPC.0b013e328341db05
,
PMID: 21164388
Issn Print: 1744-6872
Publication Date: February 2011
Characterization of UDP-glucuronosyltransferase 2A1 (UGT2A1) variants and their potential role in tobacco carcinogenesis
Ryan Bushey;Gang Chen;Andrea Blevins-Primeau;Jacek Krzeminski;Shantu Amin;Philip Lazarus;
+ Author Information
aMolecular Epidemiology and Cancer Control ProgrambChemical Carcinogenesis and Chemoprevention Program, Penn State Cancer InstitutecDepartments of PharmacologydPublic Health Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, Pennsylvania, USA
Abstract
To examine UGT2A1 expression in human tissues, determine its glucuronidation activity against tobacco carcinogens, and assess the potential functional role of UGT2A1 missense single nucleotide polymorphisms on UGT2A1 enzyme activity.Reverse transcription polymerase chain reaction and real time polymerase chain reaction were used to assess UGT2A1 gene expression in various human tissues. A glucuronidation assay measured by reverse phase ultra-performance liquid chromatography was used to determine UGT2A1 activity.UGT2A1 was expressed in aerodigestive tract tissues including trachea, larynx, tonsil, lung, and colon; no expression was observed in breast, whole brain, pancreas, prostate, kidney, liver, or esophagus. UGT2A1 exhibited highest expression in the lung, followed by trachea >tonsil >larynx >colon >olfactory tissue. Cell homogenates prepared from wildtype UGT2A175Lys308Gly overexpressing HEK293 cells showed significant glucuronidation activity against a variety of polycyclic aromatic hydrocarbons including, 1-hydroxy-benzo(a)pyrene, benzo(a)pyrene-7,8-diol, and 5-methylchrysene-1,2-diol. No activity was observed in UGT2A1 overexpressing cell homogenate against substrates that form N-glucuronides, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), nicotine, or N-OH-2-amino-1-methyl-6-phenylimidazo [4,5–b] pyridine (N-OH PhIP). A significant (P<0.05) decrease (approximately 25%) in glucuronidation activity (Vmax/KM) was observed against all polycyclic aromatic hydrocarbons substrates for the UGT2A175Arg308Gly variant compared with homogenates from wildtype UGT2A175Lys308Gly; no activity was observed for cell homogenates overexpressing the UGT2A175Lys308Arg variant for all substrates tested.These data suggest that UGT2A1 is an important detoxification enzyme in the metabolism of polycyclic aromatic hydrocarbons within target tissues for tobacco carcinogens and functional polymorphisms in UGT2A1 may play a role in tobacco-related cancer risk.
