VEGF dependency for mitogenic signaling in EC from sunitinib-sensitive but not sunitinib-resistant tumors. (A) Correlation of VEGF levels and sunitinib sensitivity (R = −0.73 and P = 0.0008). (B) Western blot analysis of HUVEC pretreated with Ve, Su (100 nM), dovitinib (Do; 500 nM), or PD173074 (PD; 50 nM) and then stimulated with conditioned media from the indicated RCC. “(S)” and “(R)” indicate sunitinib-sensitive and -resistant RCC lines, respectively. −, cells in the same base medium that was used to collect RCC-conditioned media.