RT Journal Article
SR Electronic
T1 UDP-Glucuronosyltransferase 1A10: Activity against the Tobacco-Specific Nitrosamine, 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol, and a Potential Role for a Novel UGT1A10 Promoter Deletion Polymorphism in Cancer Susceptibility
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 484
OP 490
DO 10.1124/dmd.109.030569
VO 38
IS 3
A1 Rene M. Balliet
A1 Gang Chen
A1 Ryan W. Dellinger
A1 Philip Lazarus
YR 2010
UL http://dmd.aspetjournals.org/content/38/3/484.abstract
AB The extrahepatic UDP-glucuronosyltransferase 1A10 (UGT1A10) is a phase II metabolizing enzyme that is active against a number of potent carcinogens. In the present study, UGT1A10 was examined for activity against 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), the major procarcinogenic metabolite of the potent tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and the promoter region of UGT1A10 was examined for variants that could lead to altered UGT1A10 expression. UGT1A10-overexpressing cell homogenates exhibited high O-glucuronidation activity against NNAL (KM = 5.95 mM). A 2000-base pair (bp) product corresponding to the UGT1A10 proximal promoter region was polymerase chain reaction (PCR)-amplified using genomic DNA from 97 white subjects, and 42 of these were sequenced. In addition to a previously reported C/G single-nucleotide polymorphism at −1271 bp (rs2741032), a novel 1664-bp deletion located between nucleotides −190 to −1856 relative to the UGT1A10 translation start site was identified. Using real-time multiplex PCR, this deletion exhibited a prevalence of 0.022 in whites (n = 156) and 0.056 in blacks (n = 133). To determine whether either polymorphism altered gene expression, in vitro assays were performed using luciferase constructs containing up to 2000 bp of the proximal UGT1A10 promoter. Constructs containing the 1664-bp deletion exhibited a significant (p = 0.009) 3-fold increase in luciferase activity compared with constructs containing the wild-type UGT1A10 promoter. No effect on luciferase activity was observed for the UGT1A10−1271G promoter variant. These data are consistent with previous studies that indicate the presence of a transcriptional repressor element within the newly identified deletion and that this deletion polymorphism may contribute to altered UGT1A10 expression and altered carcinogen detoxification between individuals. Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics