Figure 3.

Adhesion of RCC cells to extracellular matrix proteins is down‐regulated by VPA or VPA‐IFN‐α. Caki‐1 cells were pre‐treated with low (0.25 mM) or high (1 mM) concentrations of VPA, applied alone or in combination with IFN‐α. Non‐treated cells served as the controls. Cells were then added to immobilized fibronectin, laminin or collagen at a density of 0.5 × 10⁶ cells/well for 60 min. Plastic dishes were used to evaluate unspecific binding (background control). Non‐adherent tumour cells were washed off in each sample, the remaining cells were fixed and counted in five different fields (5 × 0.25 mm²) using a phase contrast microscope. Mean values were calculated from the five counts. Specific adhesion capacity (background adhesion on plastic surface was subtracted from adhesion to matrix proteins) is depicted as% binding and related to non‐treated controls which were set to 100%. * indicates significant difference to controls. # indicates significant differences between VPA monotherapy and VPA‐IFN‐α combination therapy. If VPA‐IFN‐α combination therapy was not superior to the VPA monotherapy but evoked significant differences to the untreated controls, figure symbols were also marked with *.