Effects of the combined treatment with SU and NaBu on the phosphorylation of PDGFR-β, as a target of RTK signaling. The 786-O cells were treated with 1.5 µM SU, 1.3 mM NaBu or both for 24 h. The cell lysates were immunoprecipitated using an anti-PDGFR-β antibody, and immunoblot analysis was performed using an anti-p-Tyr antibody. SU, sunitinib; NaBu, sodium butyrate; cont, control; PDGFR-β, platelet-derived growth factor receptor-β; p-Tyr, phosphorylated tyrosine.