Figure 3.

Western blot analysis showed high levels of MET expression in HT-29 > Huh-7 > HepG2 cells and minimal MET expression in LNCaP cells as control (A). Representative confocal microscopic images of in vitro binding assay showed that incubation of the neoplastic cells with MET targeting probe results in enhanced fluorescence signal on the cells surface, confirming its binding to the receptor. Addition of HGF results in internalization of the probe by MET expressing tumor cells (HT-29, Huh-7 and HepG2) and no appreciable fluorescence signal intensity over background in control LNCaP cells (B&C). The level of MET protein expression (MET/beta-actin) measured by Western blot is significantly correlated to the fluorescence signal intensity measured after incubation of the cells with probe (R²=0.99, p < 0.0001) (D).