Figure 1|. uPAR is a cell surface and secreted biomarker of senescence.

(a) Flow cytometric analysis of mouse uPAR (m.uPAR) expression on Kras^G12D;p53^−/− murine lung adenocarcinoma cells (KP) induced to senesce by treatment with MEK and CDK4/6 inhibitors as compared to controls. Representative results of n=3 independent experiments. Levels of soluble uPAR (suPAR) as determined by ELISA in the supernatant of senescent or proliferating KP cells. Representative results of n=2 independent experiments. (b) Flow cytometric analysis comparing human uPAR (h.uPAR) expression on primary human melanocytes induced to senesce by continuous passage with proliferating controls. Representative results of n=2 independent experiments. Levels of suPAR in the supernatant of senescent (Passage 15 = P.15) or proliferating (Passage 2 = P.2) primary human melanocytes. Representative results of n=2 independent experiments. (c) Immunohistochemical stainings of h.uPAR and SA-β-Gal of a patient-derived xenograft (PDX) from human lung adenocarcinoma orthotopically injected into NSG mice after treatment with vehicle or combined MEK and CDK4/6 inhibitors; representative of n=2 independent experiments (n=3 mice per group). (d) Co-immunofluorescence (IF) staining of m.uPAR (red) and NRAS (green) in the livers of mice 6 days after hydrodynamic tail vein injection of a plasmid encoding NRAS^G12V or NRAS^G12V;D38A. Representative results of n=3 independent experiments (n=5 mice per group). (e) Co-IF staining of m.uPAR (red) and smooth muscle actin (green) in the livers of mice 6 weeks after semi-weekly i.p. treatment with CCl₄ (n=7 mice) or vehicle (n=4 mice). Representative results of n=3 independent experiments.