ST-3 over-expression results in an increased cell number in vitro. A) Cell morphology of representative clones of MDA-MB-231 and MCF-7 cells transfected with ST-3 expression plasmid or empty vector (mock) in 3D matrigel cultures. MDA-MB-231 clones show typical invasive structures, whereas MCF-7 cells formed rounded spheroids. Clusters appeared to be slightly larger in ST-3 transfected clones. Morphology seems not to be influenced by ST-3 over-expression. Original magnification: 20×. B) OD 490 nm, which is proportional to cell numbers is shown for MDA-MB-231 and MCF-7 cell clones. A pool of equal parts of three clones was grown for 7 days in matrigel cultures with media containing 1% FCS with and without supplementation of: AG-538 [100 μM], IGF-1 [50 ng/ml] and Z-VAD [50 μM]. Equal seeding for ST-3 and mock clones was confirmed at day 0. Stars represent significant differences in the cell number of mock and ST-3 transfected cells (p-value ≤ 0.05).