Expression patterns of S100A7 (psoriasin) and S100A9 (calgranulin-B) in keratinocyte differentiation

• S100 proteins are involved in many biological processes. S100A7 and S100A9 have been shown to be markedly upregulated both in ductal carcinoma in situ of the breast and in psoriasis. We have examined the relationship between keratinocyte differentiation and the expression of the two proteins. Using Western blot analysis and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), both S100A7 and S100A9 were shown to be induced in normal primary keratinocytes (HEKn), when differentiation was promoted by high extracellular calcium, loss of contact with extracellular matrix and confluent conditions, as previously reported for S100A7 in mammary epithelial cells. Differentiation was confirmed by using RT-PCR for the differentiation marker keratin-1. Using immunohistochemistry with monoclonal antibodies, we compared the expression of the two proteins in a spectrum of conditions of dysregulated keratinocyte differentiation. We found a strikingly similar distribution of the proteins. Their expression correlated with the degree of keratinocyte differentiation. They were both absent in undifferentiated basalioma and strongly expressed in carcinoma in situ, as well as in keratoacanthoma and differentiated squamous cell carcinoma. In normal epithelium, they were expressed in the superficial, differentiated region of the epithelium rather than in the basal region. These findings support the hypothesis that these two S100 proteins are involved in keratinocyte differentiation.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Dermatologi och venereologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Dermatology and Venereal Diseases (hsv//eng)

Keyword

Blotting

Western

Calcium-Binding Proteins/*metabolism

Calgranulin B/*metabolism

Carcinoma in Situ/metabolism/pathology

Carcinoma

Basal Cell/metabolism/pathology

Carcinoma

Squamous Cell/metabolism/pathology

Cell Differentiation/physiology

Cell Line

Computer Systems

Humans

Immunohistochemistry

Keratinocytes/*cytology/metabolism/*pathology

Keratoacanthoma/metabolism/pathology

Polymerase Chain Reaction

Reverse Transcriptase Polymerase Chain Reaction

Skin Neoplasms/metabolism/pathology

Publication and Content Type

ref (subject category)

art (subject category)