RKI-1447

RKI-1447 is a potent and selective ROCK inhibitor with significant anti-invasive and antitumor activities. RKI-1447 binds the ATP binding site through interactions with the hinge region and the DFG motif. RKI-1447 inhibited migration, invasion and anchorage-independent tumor growth of breast cancer cells. RKI-1447 was also highly selective at inhibiting ROCK-mediated cytoskeleton re-organization (actin stress fiber formation) following LPA stimulation, but does not affect PAK-meditated lamellipodia and filopodia formation following PDGF and Bradykinin stimulation, respectively. RKI-1447 suppressed phosphorylation of the ROCK substrates MLC-2 and MYPT-1 in human cancer cells, but had no effect on the phosphorylation levels of the AKT, MEK and S6 kinase at concentrations as high as 10 μmol/L. Finally, RKI-1447 was highly effective at inhibiting the outgrowth of mammary tumors in a transgenic mouse model.