Fig. 1. Laminin 5 induces E-cadherin-mediated intercellular adhesion in HT-29 cells. (A) Morphological changes: phase-contrast images of HT-29 cells grown in standard medium (HT-29), in differentiating medium for 10 days (HT-29 Gal), or on laminin 5 matrix in standard medium for 24 hours (HT-29 LN 5). Bars, 100 µm. (B) Cell aggregation assays. Upper panel: HT-29 cells grown on plastic (PL) or laminin 5 matrix (LN 5) for 48 hours were resuspended in PBS containing 10 mM Hepes + 2 mM CaCl₂. Suspensions were incubated for 60 minutes at 37°C in a gyratory shaker at 75 rpm. Cell aggregation was observed under phase contrast with a Zeiss Axiovert 135 inverted microscope. Lower panel: HT-29 cells grown for 48 hours on laminin 5 matrix were resuspended in PBS containing 10 mM Hepes + 2 mM CaCl₂ in the presence of 4 mM EDTA or 10 µg/ml blocking anti-human E-cadherin (HECD1) antibody and then assayed for cell aggregation. Aggregation of HT-29 cells cultured on laminin 5 matrix was mediated by E-cadherin. Bars, 100 µm.