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S100A9 has a protective role in inflammation‐induced skin carcinogenesis
Author(s) -
McNeill Eileen,
Hogg Nancy
Publication year - 2014
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.28725
Subject(s) - s100a9 , inflammation , immune system , proinflammatory cytokine , s100a8 , carcinogenesis , keratinocyte , cancer research , skin cancer , biology , immunology , pathology , medicine , cancer , cell culture , genetics
The S100A8/A9 heterodimer is expressed by myeloid cells where its function has been extensively investigated. Immune cell S100A8/A9 promotes proinflammatory effects, and its absence is often associated with lack of leukocyte recruitment resulting in protection in terms of disease progression. S100A8/A9 is also expressed by certain epithelia, either constitutively as in mucosal epithelia or following stimulation as in skin keratinocytes. The role of the heterodimer in this context has not been as frequently explored. In this study, the incidence of skin papillomas induced by 7,12‐dimethylbenz( a )anthracene (DMBA)/12‐ O ‐tetradecanoylphorbol‐13‐acetate (TPA) in S100a9 −/− mice has been investigated. Unlike the immune disorders and certain models of cancer, absence of S100A8/A9 caused an increased incidence in skin of papillomas and, subsequently, squamous cell carcinomas. Although associated in S100a9 −/− mice with increased recruitment of neutrophils and T cells, a bone marrow chimera experiment revealed the major defect to be primarily due to the absence of S100A8/A9 in the skin keratinocytes. S100a9 −/− skin displayed enhanced Ki‐67 expression over the time period of appearance of the papillomas suggesting an effect of S100A8/A9 in regulating proliferation in the epidermal layer. Thus, despite immune cell recruitment in S100a9 −/− mouse skin that might have been predicted to promote tumor growth, it was the absence of S100A8/A9 in skin keratinocytes that dominated in terms of papilloma formation. The study highlights the importance of the S100A8/A9‐expressing skin epidermal layer in controlling skin tumor formation and suggests that the influence of the heterodimer is dependent on the tissue context in which it is expressed.