title: Skin response to a carcinogen involves the xenobiotic receptor pregnane X receptor.
abstract: Skin is in daily contact with potentially harmful molecules from the environment such as cigarette smoke, automobile emissions, industrial soot and groundwater. Pregnane X receptor (PXR) is a transcription factor expressed in liver and intestine that is activated by xenobiotic chemicals including drugs and environmental pollutants. Topical application of the tumor initiator 7,12-dimethylbenz(a)anthracene (DMBA) enhances Pxr, Cyp1a1, Cyp1b1 and Cyp3a11, but not Ahr expression in the skin. Surprisingly, DMBA-induced Pxr upregulation is largely impaired in Langerin(+) cell-depleted skin, suggesting that DMBA mainly triggers Pxr in Langerin(+) cells. Furthermore, PXR deficiency protects from DNA damage in epidermal cells but to a lesser extent than aryl hydrocarbon receptor (AHR) deficiency. Interestingly, skin exposure to low doses of DMBA induces migration of PXR-deficient but not of wild-type and AHR-deficient Langerhans cells (LCs). PXR-humanized mice show a marked increase in DNA damage to epidermal cells after topical application of DMBA, demonstrating relevance of these findings in human tissue. This is the first report suggesting that carcinogens might trigger PXR in epidermal cells, particularly in LCs, thus leading to DNA damage. Further studies are required to better delineate the role of PXR in cutaneous carcinogenesis.
authors.affiliation: Department of Dermatology and Venereology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Elentner
authors.affiliation: Department of Dermatology and Venereology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Daniela
authors.initials: D
authors.lastname: Ortner
authors.affiliation: Institute for Molecular Medicine, University Medical Center of the Johannes, Gutenberg-University Mainz, Mainz, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Clausen
authors.affiliation: Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Gonzalez
authors.affiliation: Department of Biochemistry, Molecular Biology and Genetic, Faculty of Sciences, University of Extremadura, Badajoz, Spain.
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Fernández-Salguero
authors.affiliation: Department of Dermatology and Venereology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schmuth
authors.affiliation: Department of Dermatology and Venereology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Dubrac
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity*; D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D002465:Cell Movement; D004249:DNA Damage; D007801:Langerhans Cells / Q000378:metabolism; D008810:Mice, Inbred C57BL; D000077297:Pregnane X Receptor; D011987:Receptors, Steroid / Q000378:metabolism*; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D002273:Carcinogens; D000077297:Pregnane X Receptor; D011987:Receptors, Steroid; D015127:9,10-Dimethyl-1,2-benzanthracene
keywords: DNA damage; H2AX; Langerhans cells; pregnane X receptor; skin