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Differential induction of CYP1A1 and CYP1B1 in normal human mammary cells exposed to benzo[a]pyrene.
Keshava C; Whipkey DL; Weston A
Proceedings of the American Association for Cancer Research. 1st ed. Philadelphia, PA: American Association for Cancer Research, 2003 Mar; 44:1218
Induction of CYP1A1 and CYP1B1 could potentially have a direct role (through carcinogen exposure and activation) and an indirect role (through perturbation of steroid metabolism) in human breast carcinogenesis. A panel of 22 primary normal human mammary epithelial cell (NHMEC) strains were developed from tissues discarded at reduction mammoplasty. All women were healthy and tissues were obtained through the Cooperative Human Tissue Network (sponsored by NCI/NDRI). Each cell strain was treated with benzo[a]pyrene (BP; 4uM) for 12 hours. Transcription was monitored using high density oligonucleotide arrays (Affymetrix, HuGeneFL). Total RNA was used for the preparation of labeled targets that were hybridized to microarrays containing probes representing more than 6800 human genes and expressed sequence tags. In all cell strains CYP1A1 [X02612, Cytochrome P(1)-450] transcripts were below the limit of detection before treatment. Similarly, CYP1B1 (U03688) transcripts were also below the limit of detection in 8 out of 22 cell strains before treatment. For 14 of the 22 cell strains CYP1A1 mRNA levels were clearly induced by BP, however, 8 cell strains had basal or reduced levels of CYP1A1 expression following BP exposure. Microarray data for CYP1B1 showed an increase in expression in all cell strains following BP exposure. Nine out of 22 cell strains had at least 5 fold increase in CYP1B1 transcripts and 18 of them had at least 2 fold increase. Microarray expression data for CYP1B1 have been confirmed using quantitative real-time PCR. Since CYP1B1 is thought to be transcriptionally activated by polycyclic aromatic hydrocarbons via the Ah receptor complex, expression of Ah receptor and the aryl hydrocarbon receptor nuclear translocator (ARNT) was analyzed. Altered transcription of these receptors was not observed. These studies provide a complimentary approach to molecular epidemiology for the investigation of differential susceptibility to chemical carcinogens, and specifically polycyclic aromatic hydrocarbons.
Mammary glands; Carcinogenesis; Genes; Exposure levels; Quantitative analysis; Polycyclic aromatic hydrocarbons; Epidemiology
Abstract; Conference/Symposia Proceedings
Research Tools and Approaches: Cancer Research Methods
94th Annual Meeting, Proceedings of the American Association for Cancer Research
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