INHIBITION OF CELLULAR GROWTH AND STEROID 11β-HYDROXYLATION INRAS-TRANSFORMED ADRENOCORTICAL CELLS BY THE FUNGAL TOXINS BETICOLINS

Abstract The proliferation of GM16 and 4CDTras-transformed newborn rat adrenocortical (RTAC) cells and Y1 mouse adrenal tumor cells was inhibited by beticolins, the fungal toxins extracted fromCercospora beticola, at submicromolar concentrations in a dose-dependent manner. Inhibitory concentrations for half the maximum inhibition were 150, 75 and 25 n M for beticolin-1 and 230, 150 and 50 n M for beticolin-2 in GM16, 4CDT and Y1 cells respectively. Beticolins strongly inhibited the production of 11β-hydroxysteroids on the second and third days of treatment in a dose-dependent manner between 0.1 and 1 μ M . Beticolins were shown by confocal microscopy to be localized in cytoplasmic organelle…