Figure 3. c-Met antibodies inhibit HGF-dependent tubulogenesis in HepG2 cells. (A) HGF induces tubulogenesis of HepG2 cells that is inhibited by c-Met antibodies. HepG2 cells grown in matrigel for 4 d form colonies lacking tubular extensions (top left panel). Plating cells with 50 ng/ml HGF induces tubulogenesis (top right panel), and plating cells with 50 ng/ml HGF and 1 μg/ml CE-310083 dramatically inhibited tubule formation (bottom right panel). Treatment of cells with antibody alone (50 µg/ml CE-3100833, bottom left panel) did not induce tubule formation. (B) c-Met antibodies antagonize tubule formation in a dose-dependent manner. Various concentrations of c-Met or KLH antibodies were plated with HGF (50 ng/ml) and after 4 d tubulogenesis of HepG2 cells was quantitated by image analysis of tubule length normalized to colony size (dLength/cArea).