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Expression of Bcl‐2 and Bax in cultured normal human keratinocytes and melanocytes: relationship to differentiation and melanogenesis
Author(s) -
SERMADIRAS S.,
DUMAS M.,
JOLYBERVILLIE R.,
BONTÉ F.,
MEYBECK A.,
RATINAUD M.H.
Publication year - 1997
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 - 10.1046/j.1365-2133.1997.19812085.x
Subject(s) - microbiology and biotechnology , keratinocyte , biology , cancer research , cell culture , genetics
Summary Keratinocyte differentiation and melanogenesis are two major cellular processes by which the epidermal compartment of the skin acquires its protective properties. Bcl‐2, an oncoprotein involved in the regulation of apoptosis, has been shown to be expressed by keratinocytes and melanocytes. To determine whether Bcl‐2 and Bax, a protein which heterodimerizes with Bcl‐2, may control these epidermal functions, we investigated the expression of these two oncogenes in cultivated human keratinocytes and melanocytes from the same donors, respectively induced to differentiate and to produce melanin. As determined by cytometry, we observed that these two cell types constitutively express the two proto‐oncogenes. Quantification of Bcl‐2 antige n sites per cell showed that Bcl‐2 expression is higher in keratinocytes than in melanocytes. An increase in transglutaminase activity, a marker of keratinocyte terminal differentiation initiating cornified envelope formation, was accompained by a decrease in Bcl‐2 levels without significant modification of Bax expression. In paralleled Bcl‐2 down‐regulation and Bax up‐regulatin. This led us to conclude that the expression of these two oncogenes and their cellular ratio are closely involved in keratinocyte differentiation and melanogenesis.