Fig. 4. Influence of PN-1 on uPAR-dependent cell adhesion on VN. (A) Adhesion of uPAR-transfected BAF3 cells to VN-coated wells (2 µg/ml) in the presence of uPA (50 nM) as well as different concentrations of PN-1. The dotted line indicates the level of basal adhesion in the absence of any test substances. (B) Adhesion of uPAR-BAF3 cells to VN-coated wells in the absence (control) or presence of uPA, ATF or Gly158ScuPA (each at 50 nM) in the absence of any further additions (dotted bars) or the presence of PN-1 (100 nM) (hatched bars). (C) Adhesion of uPAR-BAF3 cells to VN-coated wells in the absence (control) or presence of uPA (50 nM), PN-1 (50 nM) or a combination of uPA (50 nM) and PN-1 (50 nM) in the absence of any further additions (dotted bars) or the presence of thrombin (50 nM) (hatched bars). uPA and PN-1 or uPA, PN-1 and thrombin were preincubated for 60 minutes at room temperature to allow complex formation before addition to the cell adhesion assay. (D) U937 cells were differentiated overnight with vitamin D3 and TGFß prior to the assay. Time-dependent adhesion of cells to VN in the presence of uPA (50 nM; solid circle) or uPA/PN-1 (50 nM each; solid square). Cell adhesion was measured as absorbance at 590 nm and is expressed as mean ± s.e.m. (n=3) of triplicate wells. Similar results were obtained in three separate experiments.