PHOSPHODIESTERASE SPECIFIC INHIBITORS CONTROL CELL-GROWTH OF A HUMAN NEUROEPITHELIOMA CELL-LINE

The effects of cyclic nucleotide phosphodiesterase (PDE) inhibitors on cell proliferation of SK-N-MC human neuroepithelioma cell line was st udied. Clonal density experiments in the presence of 100 mu M rolipram and zaprinast showed respectively 27% and 91% inhibition. The effects of PDE inhibitors were then investigated on crude cell extracts; the calculated IC50 were 32 mu M for zaprinast and 16 n M for DC-TA-46; th e latter inhibitor was used instead of rolipram for its higher efficac y. Dose-response experiments in clonal density conditions showed IC50 of 5 mu M and 1.8 mu M in the presence respectively of zaprinast and r olipram. These data show that both inhibitors are effective in reducin g cell growth, although the response was quantitatively different.