Identification of a prevalent functional missense polymorphism in the UGT2B10 gene and its association with UGT2B10 inactivation against tobacco-specific nitrosamines.
OBJECTIVE
To study the potential association between UDP-glucuronosyltransferase (UGT)2B10 genotypes and [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol] NNAL-N-glucuronidation activity in human liver microsomes (HLM) and to identify potential functional polymorphisms.


METHODS
A total of 77 subjects were genotyped for three UGT2B10 tagging single nucleotide polymorphisms NNAL-N-glucuronidation activity in HLM was determined by high-pressure liquid chromatography and analyzed by UGT2B10 haplotypes.


RESULTS
Four common UGT2B10 haplotypes (termed A through D) were identified. Haplotype C was found to be significantly (P<0.001) associated with lower NNAL-N-glucuronidation in HLM. A 1.8-fold and 12-fold reduction in NNAL-N-glucuronidation levels and a 1.7-fold and 11-fold reduction in the ratio of NNAL-N-Gluc: NNAL-O-Gluc, were observed in HLM from subjects with one and two copies of UGT2B10 haplotype C, respectively. A novel polymorphism resulting in an aspartic acid to tyrosine amino acid change at codon 67 of the UGT2B10 complementary DNA was identified exclusively in subjects with a haplotype C. Unlike the high activity observed in microsomes from HEK293 cells over expressing the wild-type UGT2B10(67Asp) variant, microsomes from HEK293 cells over expressing the UGT2B10(67Tyr) variant exhibited minimal glucuronide formation activity against NNAL or other tobacco-specific nitrosamines tested in vitro.


CONCLUSIONS
The UGT2B10(67Tyr) variant corresponding to the UGT2B10 haplotype C is a functional single nucleotide polymorphism that may be responsible for inter individual variation in NNAL-N-glucuronidation activity and may increase susceptibility to smoking-related cancers.
Chen
Gang
G
Cancer Prevention and Control Program, Penn State Cancer Institute, Department of Public Health Sciences, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA.
Dellinger
Ryan W
RW
Gallagher
Carla J
CJ
Sun
Dongxiao
D
Lazarus
Philip
P
D019943:Amino Acid Substitution; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D014453:Glucuronosyltransferase / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D006239:Haplotypes; D006801:Humans; D008099:Liver / Q000201:enzymology; D020125:Mutation, Missense; D009369:Neoplasms / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D009602:Nitrosamines / Q000378:metabolism*; D010597:Pharmacogenetics; D020641:Polymorphism, Single Nucleotide; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D012907:Smoking / Q000009:adverse effects / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana
D017931:DNA Primers; D018076:DNA, Complementary; D009602:Nitrosamines; D011994:Recombinant Proteins; D014453:Glucuronosyltransferase