Fig 1.

Motesanib in vitro activity on VEGFR2 signaling and interaction with radiation. (A) Impact of motesanib on VEGF-stimulated HUVEC proliferation. Cells were grown in EBM-2 basal medium with 2% FBS, without exogenous growth factors. VEGF stimulation was 25 ng/ml every 24 hours x 4 days. Final DMSO concentration was 0.25% in all wells. Data points represent the mean crystal violet staining intensity (6 wells per condition) +/− SEM. (B) Motesanib blocks VEGFR2 kinase activity. VEGFR2 kinase activity was determined in presence of serial dilutions of motesanib. (C) Motesanib blocks VEGF stimulation of VEGFR2 phosphorylation in HUVECs. HUVECs were pretreated with motesanib for 24 hours, collected after stimulation with 50 ng/ml VEGF x 45 min. IP = immunoprecipitation; IB = immunoblot. (D) HUVECs seeded day 0, exposed to motesanib or DMSO days 1–4, and radiated x 2 on days 1 and 3 were harvested and counted via trypan blue exclusion. Points represent mean of 3 plates per condition at days 1, 3, and 4, +/− SEM