title: Nickel-induced down-regulation of ΔNp63 and its role in the proliferation of keratinocytes.
abstract: Epidemiological, animal, and cell studies have demonstrated that nickel compounds are human carcinogens. The mechanisms of their carcinogenic actions remain to be investigated. p63, a close homologue of the p53 tumor suppressor protein, has been linked to cell fate determination and/or maintenance of self-renewing populations in several epithelial tissues, including skin, mammary gland, and prostate. ΔNp63, a dominant negative isoform of p63, is amplified in a variety of epithelial tumors including squamous cell carcinomas and carcinomas of the prostate and mammary glands. The present study shows that nickel suppressed ΔNp63 expression in a short-time treatment (up to 48 h). Nickel treatment caused activation of NF-κB. Blockage of NF-κB partially reversed nickel-induced ΔNp63 suppression. Nickel decreased interferon regulatory factor (IRF) 3 and IRF7, IKKε, and Sp100. Over-expression of IRF3 increased ΔNp63 expression suppressed by nickel. Nickel was able to activate p21, and its activation was offset by the over-expression of ΔNp63. In turn, elevated p63 expression counteracted the ability of nickel to restrict cell growth. The present study demonstrated that nickel decreased interferon regulatory proteins IRF3 and IRF7, and activated NF-κB, resulting in ΔNp63 suppression and then p21 up-regulation. ΔNp63 plays an important role in nickel-induced cell proliferation.
authors.affiliation: Department of Preventive Medicine and Environmental Health, University of Kentucky, 121 Washington Avenue, Lexington, KY 40536, USA. zhuo.zhang@uky.edu
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Wenqi
authors.initials: W
authors.lastname: Li
authors.forename: Senping
authors.initials: S
authors.lastname: Cheng
authors.forename: Hua
authors.initials: H
authors.lastname: Yao
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Chang
authors.forename: Zunji
authors.initials: Z
authors.lastname: Ke
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Young-Ok
authors.initials: YO
authors.lastname: Son
authors.forename: Jia
authors.initials: J
authors.lastname: Luo
authors.forename: Xianglin
authors.initials: X
authors.lastname: Shi
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000502:physiology; D015603:Keratinocytes / Q000187:drug effects* / Q000502:physiology; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000502:physiology; D016328:NF-kappa B / Q000378:metabolism; D009532:Nickel / Q000633:toxicity*; D015398:Signal Transduction / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
chemical_list: C493956:CDKN1A protein, human; C081876:CKAP4 protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C494232:IRF3 protein, human; D050838:Interferon Regulatory Factor-3; D008565:Membrane Proteins; D016328:NF-kappa B; D016159:Tumor Suppressor Protein p53; D009532:Nickel