uPAR silencing inhibits migration and metastasis of OS.

<p><b>(A)</b> Migration of KHOS WT and KHOS uPAR-KD in the absence (control) or presence of 100 nM uPA (5.4 μg/mL). Percentage migration is normalized against KHOS. Bars: SEM. ***<i>P</i> < 0.0002. <b>(B)</b> Migration of KHOS wild-type and uPAR-KD cells in the presence of growth medium (control), 100 nM uPA amino terminal fragment (ATF) or high molecular weight (HMW) uPA. Percentage migration is normalized against KHOS. Migration experiments were performed in triplicate at least twice. Bars: SEM. ***<i>P</i> ≤ 0.0002. <b>(C)</b> Reduction of Erk1/2 phosphorylation in uPAR-KD cells but not in WT after 24 h treatment with 100 nM rh-uPA. <b>(D)</b> Metastatic burden (% area of lung covered by metastatic lesions/% total lung area) in mice (<i>n</i> = 5) injected with KHOS WT, uPAR-KD or uPAR-SCR cells. *<i>P =</i> 0.013. Bars: SEM. <b>(E)</b> Quantitative image analysis of DAB-stained FFPE sections of KHOS WT primary tumour and the corresponding lungs after immunohistochemistry with goat anti-human uPAR (Santa Cruz), 1:100. <b>(F)</b> Western blot showing expression of CD63 in KHOS-secreted extracellular vesicles (EV) but not in KHOS whole cell extract (WCE), and expression of uPA in both EV and WCE.