(a) Western-blotting analysis of PDGFR-α/-β and phosphorylated PDGFR-β (p-PDGFR-β). Human dermal fibroblast cells were treated with or without 5 μM SU9518 for 1 hour before 10 Gy irradiation. Whole cell lysates of fibroblasts were collected for protein content and separated by SDS-PAGE and transferred to nitrocellulose. The amount of PDGFR and phosphorylated PDGFR was visualized with anti-PDGFR-α, anti-PDGFR-β or anti-phosphorylated PDGFR-β antibodies, respectively. Radiation-induced PDGFR phosphorylation was markedly inhibited by SU9518. (b) Immunocytochemistry of human primary dermal fibroblast cells. Fibroblasts were analyzed as untreated (control), after SU9518 (5 μM), irradiation (10Gy) or combined SU9518 and radiation treatment. The cells were incubated 6 hours post radiation and stained with the polyclonal rabbit anti-PDGFR-β/anti-p-PDGFR-β antibody followed by incubation with Alexa Fluor 488 goat anti-rabbit secondary antibody. For nuclear localization the cells were counterstained with propidium jodide (red color). Immunofluorescence staining for PDGFR-β/p-PDGFR-β was indicated by green fluorescence. Irradiation-induced phosphorylation of PDGFR-β and that was substantially inhibited by SU9518. Scale bar presents 25 μm.