Figure 5. HBEGF expression increases basal invadopodium formation and matrix degradation.

Representative images of invadopodia and matrix degradation for MTLn3 ErbB1 (A) and MDA-MB 231 (B) transductants. Invadopodia are defined as areas of cortactin and Tks5 co-localized puncta, examples of which are indicated by the red arrows. Scale bar, 25um. C, quantitation of the total number of invadopodia per cell for MTLn3 and MDA-MB 231 transductants. D, quantitation of total degradation area per field of view for MTLn3 (16 hours) and MDA-MB 231 (4 hours) transductants. All values were normalized to the corresponding control. E, cortactin activation measured as relative level of phosphorylation as described in Materials and Methods. F, quantitation of total number of invadopodia per cell after treatment with DMSO or 1uM Iressa for 15 minutes. G, quantitation of total number of invadopodia per cell after treatment with vehicle or 2ug/mL CRM197 for 15 minutes. H, quantitation of total number of invadopodia per cell after treatment with DMSO or 20uM SRCI1 for the duration of the invadopodium formation and matrix degradation assay (16 hours for MTLn3s and 4 hours for MDA-MB 231s). I, quantitation of total degradation area per field of view for HBEGF expressing transductants after treatment with DMSO or 20uM SrcI1. Three independent experiments were performed for each condition (N = 3), and for each independent experiment, eight to ten random fields of view were imaged for further data analysis. Data are means and SEM; *p < 0.05, **p < 0.01, ***p < 0.001 by t- test.