A. Model of OPN cleavages and its functional modulation by thrombin and carboxypeptidase N or B2. OPN-FL=OPN-full length; OPN-R=OPN-Arg; OPN-L=OPN-Leu. DC=dendritic cells. B. Time course (min) of thrombin treatment (10 nM) of E. coli produced GST-OPN-FL and GST-OPN-FLR153A analyzed by SDS-PAGE. FL=full length, NTF=N-terminal fragment, CTF=C-terminal fragment. C. Daily determination of B16 tumor volume grown on WT (blue), OPN-KI (green) and OPN-KO (red) mice. ++: p<0.01 WT vs. OPN-KI, +++: p<0.001 WT vs. OPN-KI, +++: p<0.0001 WT vs. OPN-KI, *: p<0.05 WT vs. OPN-KO, **: p<0.01 WT vs. OPN-KO, ****: p<0.0001 WT vs. OPN-KO. D. B16 tumor weight after sacrifice. *: p<0.05 WT vs. OPN-KI, **: p<0.01 WT vs. OPN-KO. E. Lungs from mice sacrificed 15 days after tumor injection i.v. F. Number of visible metastatic lung nodules in mice sacrificed 13 days after tumor injection i.v. G. Melanin content of lungs in mice sacrificed 13 days after tumor injection i.v. . All data are shown as mean ± SEM. Statistical significance was calculated by one-way ANOVA followed by Tukey’s multiple comparison test. **: p<0.01 WT vs. OPN-KI or OPN-KO, ****: p<0.0001 WT vs. OPN-KI or OPN-KO.