Fig. 5

β₂AR signaling induces tumor cell invasion and metastasis from primary mammary tumors. a Representative image of the orthotopic metastasis model. Luciferase-tagged tumor cells were injected into the fourth mammary fat pad (PT) and spontaneous metastases to the lymph node and lung (Met) were detected by optical bioluminescence imaging. Lower body exposure: 1 second. Upper body exposure: 60 seconds. Black bar separates images taken with two different exposures. b Mice were treated daily with 5 mg/kg formoterol (or saline vehicle) during tumor development and the effect of distant metastasis was quantified over time by bioluminescence imaging and expressed relative to primary tumor size. N = 5 at each time-point. c Primary tumors were resected from the mammary fat pad of vehicle vs. formoterol-treated mice at day 10 after tumor cell injection and embedded in a three-dimensional collagen matrix. Invasion of LifeAct-GFP⁺ tumor cells beyond explant boundaries into the surrounding collagen (arrows) was imaged over 8 days by confocal microscopy and quantified. N = 5 at each time point. Error bars: SEM. ***p <0.001