TY - JOUR
T1 - Activation of aflatoxin B1 by expression of human CYP1A2 polymorphisms in Saccharomyces cerevisiae
AU - Fasullo, Michael
AU - Smith, Autumn
AU - Egner, Patricia
AU - Cera, Cinzia
N1 - Funding Information:
This research was supported by grants RO1 CA 39416 and PO1 ES00605 (PE) from the National Institutes of Health . We thank Kathleen Chamberlin for her comments on this manuscript.
PY - 2014/2
Y1 - 2014/2
N2 - Human susceptibility to environmental carcinogens is highly variable and depends on multiple genetic factors, including polymorphisms in cytochrome P450 genes. Although epidemiological studies have identified individual polymorphisms in cytochrome P450 genes that may alter cancer risk, there is often conflicting data about whether such polymorphisms alter the genotoxicity of environmental carcinogens. This is particularly true of the CYP1A2 polymorphisms that confer differential activation of multiple human carcinogens. To determine whether a single cytochrome P450 polymorphism confers higher levels of carcinogen-associated genotoxicity, we chose an organism that lack enzymes to metabolically activate aflatoxins and expressed individual human P450 genes in budding yeast. We measured the frequencies of recombination, Rad51 foci formation, 7-methoxyresorufin O-demethylase activities, and the concentrations of carcinogen-associated DNA adducts in DNA repair proficient yeast expressing P450 polymorphisms after exposure to aflatoxin B1 (AFB1).We measured growth of rad4 rad51 cells expressing CYP1A2 polymorphisms while exposed to AFB1. We observed that there was significantly less AFB1-associated genotoxicity in yeast expressing CYP1A2 I386F, while yeast expressing CYP1A2 C406Y exhibited intermediate levels of genotoxicity compared to yeast expressing CYP1A2 D348N or wild type. We conclude that differences in carcinogen genotoxicity can be observed in yeast expressing different CYP1A2 alleles. This is the first report that carcinogen-associated P450 polymorphisms can be studied in yeast.
AB - Human susceptibility to environmental carcinogens is highly variable and depends on multiple genetic factors, including polymorphisms in cytochrome P450 genes. Although epidemiological studies have identified individual polymorphisms in cytochrome P450 genes that may alter cancer risk, there is often conflicting data about whether such polymorphisms alter the genotoxicity of environmental carcinogens. This is particularly true of the CYP1A2 polymorphisms that confer differential activation of multiple human carcinogens. To determine whether a single cytochrome P450 polymorphism confers higher levels of carcinogen-associated genotoxicity, we chose an organism that lack enzymes to metabolically activate aflatoxins and expressed individual human P450 genes in budding yeast. We measured the frequencies of recombination, Rad51 foci formation, 7-methoxyresorufin O-demethylase activities, and the concentrations of carcinogen-associated DNA adducts in DNA repair proficient yeast expressing P450 polymorphisms after exposure to aflatoxin B1 (AFB1).We measured growth of rad4 rad51 cells expressing CYP1A2 polymorphisms while exposed to AFB1. We observed that there was significantly less AFB1-associated genotoxicity in yeast expressing CYP1A2 I386F, while yeast expressing CYP1A2 C406Y exhibited intermediate levels of genotoxicity compared to yeast expressing CYP1A2 D348N or wild type. We conclude that differences in carcinogen genotoxicity can be observed in yeast expressing different CYP1A2 alleles. This is the first report that carcinogen-associated P450 polymorphisms can be studied in yeast.
KW - Aflatoxin B
KW - Budding yeast
KW - Cytochrome P450
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U2 - 10.1016/j.mrgentox.2014.01.009
DO - 10.1016/j.mrgentox.2014.01.009
M3 - Article
C2 - 24472830
AN - SCOPUS:84894051044
VL - 761
SP - 18
EP - 26
JO - Mutation Research - Genetic Toxicology and Environmental Mutagenesis
JF - Mutation Research - Genetic Toxicology and Environmental Mutagenesis
SN - 1383-5718
ER -