Effect of tamoxifen, ethylenedioxy-P4, and C6-ceramide on 2780AD cell growth and morphology. Cells (200,000/well) were seeded in 6-well plates and exposed the following day to C6-ceramide (10 μg/ml), tamoxifen (5 μM), ethylenedioxy-P4 (0.2 μM), or the combinations designated, for 24 hr. Photomicrographs were taken to document growth and morphological characteristics. Ethanol (0.2%) was present in control cultures. C6-cer, C6-ceramide; P4, ethylenedioxy-P4.