title: Cytochrome P450 expression and metabolic activation of cooked food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in MCF10A breast epithelial cells.
abstract: The cytochrome P450 expression profile was determined in the MCF10A human breast epithelial cell line, as was the ability of this cell line to catalyze the bioactivation of the cooked food mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Using non-quantitative reverse transcription-polymerase chain reaction (RT-PCR), transcripts for CYP1B1, CYP2J2, CYP2R1, CYP2U1, CYP2W1, CYP4B1, CYP4F, CYP4V2, CYP4X1 and CYP4Z1 were detected in both sub-confluent and confluent MCF10A cells. By contrast, CYP1A2 mRNA was detected only in confluent MCF10A cells, while CYP1A1, CYP2S1 and CYP2F1 were detected predominantly or exclusively in sub-confluent cultures. 2,3,7,8-Tetrachlorodibenzo-p-dioxin treatment of confluent MCF10A cells markedly induced microsomal ethoxyresorufin O-deethylase activity and CYP1A1, CYP1A2 and CYP1B1 mRNA levels, as determined by real-time RT-PCR, while treatment with 10(-4)M PhIP had little effect on these P450 transcript levels. Treatment of confluent MCF10A cells with PhIP (10(-4)M) for 24, 48 or 72 h produced time-dependent increases in the amounts of DNA adducts, as measured by (32)P-post-labeling. These results indicate that multiple P450s, including those known to catalyze PhIP N-oxidation, are expressed in MCF10A cells, and that this non-neoplastic human breast epithelial cell line contains sufficient enzymatic machinery to support PhIP bioactivation and generate DNA damage.
authors.affiliation: Environmental Toxicology Program, College of Pharmacy and Pharmaceutical Sciences, Florida A and M University, Tallahassee, FL 32307, USA.
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Thomas
authors.forename: Mario R
authors.initials: MR
authors.lastname: Green
authors.forename: Chantell
authors.initials: C
authors.lastname: Wilson
authors.forename: Amy L
authors.initials: AL
authors.lastname: Weckle
authors.forename: Zhengbo
authors.initials: Z
authors.lastname: Duanmu
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kocarek
authors.forename: Melissa
authors.initials: M
authors.lastname: Runge-Morris
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001711:Biotransformation; D001940:Breast / Q000166:cytology*; D002384:Catalysis; D002478:Cells, Cultured; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics / Q000378:metabolism; D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics / Q000378:metabolism; D065633:Cytochrome P-450 CYP1B1; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000633:toxicity*; D009153:Mutagens / Q000633:toxicity; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D007093:Imidazoles; D009153:Mutagens; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine; D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D019363:Cytochrome P-450 CYP1A1; D019388:Cytochrome P-450 CYP1A2; D065633:Cytochrome P-450 CYP1B1