10A.ErbB2 cells transfected with expression vectors encoding the indicated forms of β-catenin, or treated with 25 μM iCRT14 or 100 nM PF-3758309 (PF), were plated atop reconstituted basement membrane. Cells were stimulated with vehicle or 1 μM AP1510 on day 3, and fixed on day 12 were stained with Oregon green-phalloidin, Ki-67, or anti-cleaved caspase-3. Percentage of unilamellar acini, Ki-67-positive, and anti-cleaved caspase-3-positive acini were scored based on assessment of 50 to 60 acini per well. Bar, 50 μm.