Abstract
Cytochrome P450 1B1 (CYP1B1), a phase I enzyme, is involved in the activation of a broad spectrum of procarcinogens. An association of the Cyp1B1 L432V polymorphism with diverse types of cancer, as well as an impact on the catalytic activity of the enzyme, has been described. To show the functional impact of the allelic variant Cyp1B1*3, we investigated the quantitative Cyp1B1 mRNA expression in a population of smokers, nonsmokers, and ex-smokers and determined their genotypes. Detection of the L432V polymorphism in exon 3 of the Cyp1B1 gene was performed by rapid capillary polymerase chain reaction (PCR) with melting curve analysis. For quantitative comparison of Cyp1B1 mRNA levels, real-time PCR was performed using SYBR Green fluorescence in a LightCycler system. Calculations of expression were made with the 2–ΔΔCT method. In comparing relative Cyp1B1 mRNA expression, highly significant differences between the two homozygote genotypes *1/*1 and *3/*3 (0.185 ± 0.027, n = 118 versus 0.071 ± 0.013, n = 56; p = 0.000), as well as between the heterozygote genotype *1/*3 and the homozygote genotype *3/*3 (0.178 ± 0.025, n = 171 versus 0.071 ± 0.013, n = 56; p = 0.000), were revealed. Significant differences between the genotypes were also detected within the subgroups of smokers, nonsmokers, and ex-smokers. No significant differences were determined in comparing the relative Cyp1B1 mRNA expression with regard to tobacco smoke exposure. Our results suggest that genotypes carrying the C allele (*1/*1 and *1/*3) at Cyp1B1 L432V polymorphism have a significantly higher Cyp1B1 mRNA expression compared with the genotype without the C allele (*3/*3). Gene expression of Cyp1B1 mRNA cannot be used as a biomarker for exposure of tobacco smoke.
Footnotes
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Some of the results are included in the following thesis: Hadzaad B (2009) Genexpression der Cytochrome P450 1B1 und 2E1 in Abhăngigkeit einer PAH-Einwirkung infolge Rauchens sowie der individuellen Suszeptibilität. Ph.D. thesis, Justus-Leibig-Universität Gießen, Gießen, Germany.
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.109.027060.
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ABBREVIATIONS: P450, cytochrome P450; PAH, polycyclic aromatic hydrocarbon; AhR, aromatic hydrocarbon receptor; TCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin; PCR, polymerase chain reaction; B2M, β-2-microglobulin.
- Accepted April 3, 2009.
- Received February 6, 2009.
- The American Society for Pharmacology and Experimental Therapeutics
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