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Loss of Fas-Ligand Expression in Mouse Keratinocytes during UV Carcinogenesis


Ouhtit, A and Gorny, A and Muller, HK and Hill, LL and Owen-Schaub, L and Ananthaswamy, HN, Loss of Fas-Ligand Expression in Mouse Keratinocytes during UV Carcinogenesis, American Journal of Pathology, 157, (6) pp. 1975-1981. ISSN 0002-9440 (2000) [Refereed Article]

DOI: doi:10.1016/S0002-9440(10)64836-5


Skin cells containing excessive ultraviolet (UV) radiation-induced DNA damage are eliminated by apoptosis that involves the p53 pathway and Fas/Fas-Ligand (Fas-L) interactions. To determine whether dysregulation of apoptosis plays a role in skin cancer development through disruption of Fas/Fas-L interactions, hairless SKH-hr1 mice were exposed to chronic UV irradiation from Kodacel-filtered FS40 lamps for 30 weeks. Their skin was analyzed for the presence of sunburn cells (apoptotic keratinocytes) and for Fas and Fas-L expression at various time points. A dramatic decrease in the numbers of morphologically identified sunburn cells and TUNEL-positive cells was detected as early as 1 week after chronic UV exposure began. After 4 weeks of chronic UV exposure, these cells were barely detectable. This defect in apoptosis was paralleled by an initial decrease in Fas-L expression during the first week of chronic UV irradiation and a complete loss of expression after 4 weeks. Fas expression, however, increased during the course of chronic UV exposure.p53 mutations were detected in the UV-irradiated epidermis as early as 1 week after irradiation began and continued to accumulate with further UV exposure. Mice exposed to chronic UV began to develop skin tumors after approximately 8 weeks, and all mice had multiple skin tumors by 24 weeks. Most of the tumors expressed Fas but not Fas-L. We conclude that chronic UV exposure may induce a loss of Fas-L expression and a gain in p53 mutations, leading to dysregulation of apoptosis, expansion of mutated keratinocytes, and initiation of skin cancer.

Item Details

Item Type:Refereed Article
Research Division:Health Sciences
Research Group:Nursing
Research Field:Mental health nursing
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Muller, HK (Professor Konrad Muller)
ID Code:19115
Year Published:2000
Web of Science® Times Cited:60
Deposited By:Pathology
Deposited On:2000-08-01
Last Modified:2001-05-04

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