SU1498 is a selective inhibitor of the VEGFR2; inhibits Flk-1 with an IC₅₀ of value of 700 nM. IC50 & Target: IC50:700 nM (Flk-1)^[1] In Vitro: SU1498 stimulates accumulation of phosphorylated ERKs in human umbilical vein endothelial cells and in human aortic endothelial cells in a manner that is dependent on the functioning of the upstream components of the MAPK pathway, B-Raf, and MEK kinases. The enhanced accumulation of phospho-ERKs is observed only in cells that have been stimulated with sphingosine 1-phosphate or protein growth factors; SU1498 by itself is ineffective^[2]. SU1498 blocks signal transduction from VEGFR2 in MS1 VEGF cells.In the presence of SU1498, levels of Ets-1 are decreased, suggesting that VEGF-VEGFR-2 interactions contributed to baseline levels of Ets-1 expression, and interruption of this autocrine interaction with SU1498 led to decreased expression of Ets-1^[3]. SU1498 treatment significantly impacts U87 cell proliferation and apoptosis. SU1498 induces a marked increase in lipids and a decrease in glycerophosphocholine. Accordingly, accumulation of lipid droplets is seen in the cytoplasm of SU1498-treated U87 cells^[4].