P8.114 Control of androgen receptor expression in human skin cells and in a reconstituted human epidermis model with antisense oligonucleotides

S.Fimmel, F. Bonté*, R. Kurfürst*, Ch.C. Zouboulis

Department of Dermatology, Charité University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany; * LVMH, Research and Development, St. Jean de Braye, France

Target cell responsiveness to a hormonal signal is a product of both cellular concentrations of the hormone ligand and the corresponding receptor. The effects of androgens are mediated by their binding to nuclear androgen receptor (AR) molecules. Androgen activity on the skin can be inhibited by systemic administration of AR antagonists. AR are present in the skin and local synthesis of androgens takes place in sebocytes, while they are degraded in keratinocytes. Purpose of this work was to investigate AR regulation by antisense molecules as well as their biological effect on cultured human sebocytes, genital skin keratinocytes and reconstructed human epidermis (SkinEthic model). Human SZ95 sebocytes exhibited similar binding constants to primary genital fibroblasts in a competitive binding assay. AR protein expression was inhibited by cationic lipid mediated transient transfection with thioat antisense oligonucleotides and 2‘-O-methyl-RNA antisense. An AR protein inhibition of 89% in SZ95 sebocytes and 25% in genital keratinocytes was detected 17 h after a 4 h-transfection. In the reconstructed epidermis model antisense oligonucleotides decreased AR expression at levels varying between 46% and 70%. For an effectiveness longer than 24 h transfection must be repeated. Translocation of active AR from cytoplasma into nucleus was visualized by immunofluorescence with a Cy3-labeled antisense molecule. Biological effect of the androgens testosterone and 5-dihydrotestosterone, namely increased proliferation and differentiation of epithelial cells, were inhibited significantly by selective antisense molecules which caused AR protein reduction. The successful inhibition of AR expression in cultured skin cells and reconstructed human epidermis are the first steps to develop topically efficient oligonucleotide-bearing compounds.