Fig. 9. Pre-incubation with HGF and M-CSF induces an increase in cell motility toward OPN, in a _vß₃- and a PI-3-kinase-dependent manner. (A) Migration towards OPN. Human osteoclast-like cells (open bars) preincubated with AP5 in buffer without calcium, HGF (5 ng/ml) or M-CSF (0.5 nM) are allowed to migrate for 6 hours toward OPN (10 µg/ml), coated on the bottom membrane of a transwell plate (8 µm pore size). All three treatments significantly increased (P<0.001) migration toward OPN compared with vehicle alone (CTR) (open bars). Cell migration was inhibited by the _vß₃- blocking mAb LM609 (hatched bars), indicating specific involvement of the integrin _vß₃, and by the PI 3-kinase inhibitor wortmannin (cross-hatched bars). (B) Migration toward LN. Migration of human osteoclast-like cells toward LN is not enhanced by growth factor or AP5 pre-treatment (open bars) nor decreased by LM609 (hatched bars) or wortmannin (cross-hatched bars). In all experiments cells that migrated were viewed at 300x magnification, and the number of cells per field was counted.