Phosphoinositide-3 kinase activity is necessary for the disruption of epithelial architecture. (a) Acini were grown for 10 days and then treated with diluent, 100 nM 4-hydroxytamoxifen (4-HT) or 100 nM 4-HT and inhibitor. U0126 (10 μM) and LY294002 (50 μM) were used. Fresh media with diluent, with 4-HT or with 4-HT and inhibitor was added after 24 hours primary treatment, and acini were cultured for another 24 hours (48 hours total treatment time). Bar = 150 μM. DIC, differential interference contrast microscopy; DMSO, dimethylsulfoxide. (b) Day 10 Raf:ER-H2B:GFP acini were treated with diluent, 100 nM 4-HT or 100 nM 4-HT and 50 μM LY294002 (phosphoinositide-3 kinase inhibitor) for 24 hours and then imaged for 20 hours at 30-minute intervals. The total movement of the cells of a representative acinus from each condition from three independent experiments is shown. The H2B:GFP-labeled nuclei are at white and are located at their respective positions at the end of the 20 hours of imaging. Colored scale bar represents increasing time. Results shown are representative of at least 10 acini imaged per condition in three independent experiments.