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Characterization of the ultraviolet B and X‐ray response of primary cultured epidermal cells from patients with disseminated superficial actinic porokeratosis
Author(s) -
D'Errico M.,
Teson M.,
Calcagnile A.,
Corona R.,
Didona B.,
Meschini R.,
Zambruno G.,
Dogliotti E.
Publication year - 2004
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.2004.05714.x
Subject(s) - keratinocyte , epidermis (zoology) , pathology , dyskeratosis , carcinogenesis , photodermatosis , biology , hyperkeratosis , microbiology and biotechnology , cell culture , gene , medicine , xeroderma pigmentosum , dna repair , anatomy , genetics
Summary Background Disseminated superficial actinic porokeratosis (DSAP) is the most common porokeratosis and is characterized by multiple keratotic lesions which tend to occur at sun‐exposed sites. A mild hypersensitivity to X‐rays has been reported for DSAP‐derived fibroblasts and frequent over‐expression of p53 has been found in lesional epidermis. Objectives In order to clarify whether genome maintenance mechanisms might be compromised in this disease the following approaches were undertaken: (i) primary cultured keratinocytes and fibroblasts from DSAP patients were characterized for ultraviolet (UV) B and X‐ray response; (ii) 15 lesions were studied for p53 mutations, and (iii) the differentiation status of DSAP‐derived keratinocytes was evaluated. Methods Primary cultures of keratinocytes and fibroblasts were established from lesional and nonlesional skin biopsies of two subjects with DSAP. p53 mutations were analysed by DNA sequencing of the conserved region of the TP53 gene. Differentiation was evaluated both in stratified epithelial sheets from confluent keratinocyte cultures and in organotypic skin cultures. Results The cytotoxic and apoptotic response to UVB or X‐irradiation was similar in DSAP‐derived keratinocytes and fibroblasts when compared with normal cells. Two of 15 lesions examined presented p53 mutations located at nondipyrimidine sites. A strikingly decreased expression of filaggrin was observed both in reconstructed epidermis and in reconstructed skin. Conclusions The UVB and X‐ray response of DSAP‐derived keratinocytes and fibroblasts indicates that the actinic character of this skin pathology is not due to radiation hypersensitivity. In agreement with this finding, mutations in the p53 gene, which are often associated with UV‐related skin carcinogenesis, were rarely detected in DSAP lesions and were not UV‐specific. Reconstructed epidermis and reconstructed skin models successfully reproduced the main features of this genodermatosis, showing that DSAP‐derived keratinocytes bear an inherent defect in the terminal differentiation programme.