Figure 5: Matriptase mediates pro-HGF-induced invasion in human breast cancer cells.

SUM229 cells were grown on culture plates and matriptase was silenced (Mat KD) using synthetic RNA duplexes (b,b′,b′′). A %GC matched RNA duplex was used as negative control (a,a′,a′′). Cells were allowed to form spheroids in 3D rBM overlay culture for 24 h before addition of either pro-HGF (a′,b′), HGF (a′′,b′′) or no growth factors (a,b) and imaged by confocal microscopy. When no growth factors were added, control and Mat KD spheroids remained intact. In contrast, addition of pro-HGF-induced extensive invasive outgrowths in matriptase-sufficient control cells (a′), whereas the majority of Mat KD spheroids remained intact (b′). Both control and Mat KD spheroids responded to active two-chain HGF (a′′,b′′). Cells were labelled with Cell Tracker Orange and nuclei with Hoechst (blue). (c) 3D rBM cell cultures were scored for the number of intact spheroids when left untreated (black bars) or exposed to either active HGF (white bars) or pro-HGF (white bars). Data represent mean of the number of intact spheroids before treatment relative to the number after treatment (triplicates; *P<0.04, Student’s t-test). Error bars represent s.d. Scale bars, 50 μm. Data are representative of four independent experiments.