Fig. 4

β₂AR-induced invadopodia formation is dependent on Src and increases tumor cell invasion in a three-dimensional collagen matrix. a Representative time series images acquired by confocal microscopy showing the effect of formotorol or isoproterenol (Iso) ± 0.05 μM ICI-118551 (ICI) on development of cell protrusions. Time in hours is indicated. b Graphical representation of track measurements is shown for 20 cells in each condition. c Quantification of cell displacement from the point of origin. d, e Representative maximum intensity projections of LifeAct-GFP⁺ MDA-MB-231 cells treated with 0.5 μM PP2 ± 0.5 μM formoterol and examined for active invadopodia. Inset shows GFP+ green puncta (active invadopodia that have degraded underlying matrix) or yellow puncta (inactive invadopodia where GFP+ puncta have not degraded the underlying red fluorescent matrix). Scale bar: 10 μm, or 5 μm for inset panels. e The percentage of invadopodia positive cells was quantified. N >80 cells per condition. f Graphical representation of track measurements after cells were embedded in 1 mg/ml collagen matrix and treated with 0.5μΜ formoterol ± PP2 Src inhibitor. N = 20 cells per condition. Error bars: SEM. *p <0.05 and **p <0.01