SU6668 is a cell-permeable indolinone compound that acts as a potent ATP-competitive inhibitor against RTKs (receptor tyrosine kinases) Kit, PDGFRβ, VEGFR2 (Flk-1/KDR), FGFR1 activity in vitro (IC50 = 0.01, 0.1, 3.9, and 3.8 µM, respectively) and PDGF/VEGF/bFGF-mediated angiogenesis and tumor development. Although initially characterized as an RTK inhibitor, SU6668 is now also known to target ser/thr kinases Aurora A, Aurora B, TBK1 (NAK/T2K), and AMPK (IC50 = 0.85, 0.047, 1.4, and 1.8 µM, respectively), as well as non-receptor TKs Lyn and Yes (IC50 = 4.3 and 5.8 µM, respectively).