Retinoid-induced inhibition of growth and reduction of spreading of human epidermal cells in culture.

The effect of various retinoids (retinol, all-trans-retinoic acid, etretinate, 13-cis-retinoic acid and an arotinoid, Ro-13-6298) on cultured human epidermal cells has been investigated. Cell growth was inhibited in a dose-dependent fashion by retinol, all-trans-retinoic acid and 13-cis-retinoic acid, but to a lesser extent by etretinate. The arotinoid showed an enhancing effect on cell growth. The area of cells on the culture dish was reduced by all the retinoids in a dose-dependent fashion, but the arotinoid was especially active in this respect even at very low concentrations. The measurement of cell volume by cell size frequency analysis, using a Coulter counter channelyzer, showed no differences compared with control cultures, and so the reduction of cell area was considered to be due to reduced 'spreading' of cells on the substrate. These results suggest that the retinoids interfere with cell-to-cell and cell-to-substratum attachment. It is possible that the change in membrane configuration is responsible for the inhibition of cell proliferation in our culture system.