TY - JOUR
T1 - Glucuronidation of PhIP and N-OH-PhIP by UDP-glucuronosyltransferase 1A10
AU - Dellinger, Ryan W.
AU - Chen, Gang
AU - Blevins-Primeau, Andrea S.
AU - Krzeminski, Jacek
AU - Amin, Shantu
AU - Lazarus, Philip
N1 - Funding Information:
National Institutes of Health, Department of Health and Human Services [Public Health Service grants R01-DE13158 (National Institute for Dental and Craniofacial Research) and P01-CA68384 (National Cancer Institute)] to P.L.; two formula grants under the Pennsylvania Department of Health, Health Research Formula Funding Program (State of PA, Act 2001-77-part of the PA tobacco settlement legislation) to P.L. and S.A.
PY - 2007/11
Y1 - 2007/11
N2 - The UDP-glucuronosyltransferase (UGT) 1A10 is an extra-hepatic enzyme that plays an important role in the glucuronidation of a variety of endogenous and exogenous substances and is expressed throughout the aerodigestive and digestive tracts. Two classes of carcinogens that target the colon, heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons, are known to be detoxified by the UGT family of enzymes. Recently, our laboratory demonstrated that UGT1A10 has considerably more activity against polycyclic aromatic hydrocarbons in vitro than any other UGT family member. In this study, we focused on the glucuronidation of the HCA, 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP), and its bioactivated metabolite, N-hydroxy-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP). We demonstrated that UGT1A10 exhibited a significantly higher glucuronidation rate against PhIP and N -OH-PhIP than any other UGT family member in vitro using whole-cell homogenates of HEK293 cells over-expressing individual UGTs. Kinetic analysis revealed a 9- and 22-fold higher level of activity for UGT1A10 homogenates as compared with the next most active UGT, UGT1A1, against N -OH-PhIP as determined by maximum rate/apparent Michaelis constant (Vmax/ KM) at the N3 and N2 positions, respectively. The polymorphic UGT1A10139Lys variant exhibited a 2- to 16-fold decrease in glucuronidation activity against PhIP and N-OH-PhIP, as compared with the wild-type UGT1A10139Glu isoform. These data suggest that UGT1A10 is the most active UGT against PhIP and N-OH-PhIP and that UGT1A10 may play an important role in susceptibility to HCA-induced colon cancer.
AB - The UDP-glucuronosyltransferase (UGT) 1A10 is an extra-hepatic enzyme that plays an important role in the glucuronidation of a variety of endogenous and exogenous substances and is expressed throughout the aerodigestive and digestive tracts. Two classes of carcinogens that target the colon, heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons, are known to be detoxified by the UGT family of enzymes. Recently, our laboratory demonstrated that UGT1A10 has considerably more activity against polycyclic aromatic hydrocarbons in vitro than any other UGT family member. In this study, we focused on the glucuronidation of the HCA, 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP), and its bioactivated metabolite, N-hydroxy-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP). We demonstrated that UGT1A10 exhibited a significantly higher glucuronidation rate against PhIP and N -OH-PhIP than any other UGT family member in vitro using whole-cell homogenates of HEK293 cells over-expressing individual UGTs. Kinetic analysis revealed a 9- and 22-fold higher level of activity for UGT1A10 homogenates as compared with the next most active UGT, UGT1A1, against N -OH-PhIP as determined by maximum rate/apparent Michaelis constant (Vmax/ KM) at the N3 and N2 positions, respectively. The polymorphic UGT1A10139Lys variant exhibited a 2- to 16-fold decrease in glucuronidation activity against PhIP and N-OH-PhIP, as compared with the wild-type UGT1A10139Glu isoform. These data suggest that UGT1A10 is the most active UGT against PhIP and N-OH-PhIP and that UGT1A10 may play an important role in susceptibility to HCA-induced colon cancer.
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U2 - 10.1093/carcin/bgm164
DO - 10.1093/carcin/bgm164
M3 - Article
C2 - 17638922
AN - SCOPUS:35549008096
SN - 0143-3334
VL - 28
SP - 2412
EP - 2418
JO - Carcinogenesis
JF - Carcinogenesis
IS - 11
ER -