Expression of the bcl-2 family of genes in the course of keratinocyte differentiation.
Bcl-2 and its homologous proteins play an important role in the control of apoptosis, mainly at the level of mitochondria. Their relationship to differentiation as well as regulation by retinoids in certain cell types has been recently reported. We examined the expression of the bcl-2 family oncoproteins bax, bak, bcl-2, bcl-xL, and mcl-1 in the course of differentiation of human keratinocytes cultured at low- (0.15 mM) and high- (1.87 mM) calcium concentrations. The pro-apoptotic bax showed an increase in expression during the first six days of culture, whereas bak remained stable until day 10 when it increased only slightly in both low- and high-calcium treated cells. The expression of anti-apoptotic bcl-xL increased during the first four days of culture, with a more pronounced increase in low- than in high-calcium treated keratinocytes. Apoptosis-suppressing bcl-2 and mcl-1 proteins did not change significantly in our culture experiment. None of the examined proteins of the bcl-2 family appeared altered upon addition of all-trans retinoic acid (10(-6) M) to the culture medium. We compare the results of our in vitro study with the expression of the bcl-2 family proteins in normal epidermis.
Thomková
H
H
Department of Dermatology, Okayama University Medical School, 2-5-1 Shikata-cho, 700-8558, Okayama City, Japan.
Fujimoto
W
W
Arata
J
J
D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000378:metabolism*; D007633:Keratins / Q000096:biosynthesis; D008565:Membrane Proteins / Q000096:biosynthesis; D005810:Multigene Family; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000096:biosynthesis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D014212:Tretinoin / Q000494:pharmacology; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
C494772:BAK1 protein, human; C494826:BAX protein, human; C494811:BCL2L1 protein, human; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D014212:Tretinoin; D007633:Keratins; D002118:Calcium