Trémezaygues L, Seifert M, Tilgen W, Reichrath J. 1,25-dihydroxyvitamin D(3) protects human keratinocytes against UV-B-induced damage: In vitro analysis of cell viability/proliferation, DNA-damage and -repair.
Dermatoendocrinol 2011;
1:239-45. [PMID:
20592798 DOI:
10.4161/derm.1.4.9705]
[Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2009] [Accepted: 08/04/2009] [Indexed: 11/19/2022]
Abstract
The skin is the only organ that has the capacity to photo-synthesize the biological active vitamin D metabolite 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] from 7-dehydocholesterol (7-DHC), following exposure to ultraviolet (UV)-B irradiation. The aim of the present work was to investigate the capacity of 1,25(OH)(2)D(3) to protect human keratinocytes (HaCaT) and squamous cell carcinoma cell lines (SCL-1) against the hazardous effects of UV-B irradiation. Human keratinocytes (HaCaT) and squamous cell carcinoma cell lines (SCL-1) were pretreated with 1,25(OH)(2)D(3) over 48 hours and then irradiated once with UVB-radiation. We evaluated the results of several assays (colony-forming-unit-culture assay, WST-1-assay and crystal violet assay), comparing viability/proliferation in 1,25(OH)(2)D(3)-pretreated cells with controls that were pretreated with the carrier substance ethanol alone. Additionally, we analyzed the effects of 1,25(OH)(2)D(3) on UV-induced DNA damage in HaCaT-keratinocytes by detection of cyclobutane pyrimidine dimers (CPDs) via dot blot analysis. We prove that 1,25(OH)(2)D(3), in a concentration of 10(-7) M, protects human keratinocytes (HaCaT) as well as squamous cell carcinoma cell lines (SCL-1) against the hazardous effects of UV-B-radiation (100 J/cm(2)-1,000 J/cm(2)) in vitro. Moreover, we demonstrate that the number of CPDs induced in HaCaT-keratinocytes after irradiation with UV-B (100 J/cm(2)-1,000 J/cm(2)) was decreased after pretreatment with 1,25(OH)(2)D(3), as compared to carrier-treated controls. Analysis of the time course revealed that the elimination of UV-B-induced DNA-damage in HaCaT-keratinocytes occurs quicker when cells are pretreated with 1,25(OH)(2)D(3) (as compared to controls). To put it in a nutshell, our data support the hypothesis that 1,25(OH)(2)D(3) protects cultured human keratinocytes against the hazardous effects of UV-B radiation.
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