Effects of compounds 4a on cell morphology. Cultured MCF-7aro cells were examined in the absence (A, B) or in the presence of 25 μM of 4a (C, D) in a medium containing 1 nM T for 72 hr. Wright staining shows that cells treated with 4a have condensed and marginalized chromatin (arrowheads) and cytoplasm vacuolization (arrows) (C) in comparison to the control cells (A). Nuclear morphological changes in MCF-7aro cells were demonstrated by Hoechst 33258 staining under the fluorescence microscope. Untreated cells exhibited normal nuclear morphology and the presence of abundant mitotic figures (open arrows) (B). Treatment with 4a induced chromatin condensation (arrows) (D).