RKI-1447 is an inhibitor of the Rho-associated kinases ROCK-I and II (IC50s = 14.5 and 6.2 nM, respectively) that functions by binding to the ATP binding site of the kinase. In cancer cells, RKI-1447 at a concentration of 100 nM has been found to suppress the activation of ROCK substrates myosin light chain (MLC)-2 and the MLC phosphatase PP1 regulatory subunit MYPT1 without effect on the phosphorylation of Akt, MEK, or S6 kinase. Furthermore, it can prevent ROCK-mediated migration, invasion, and anchorage-independent growth of MDA-MB-231 breast cancer cells (IC50 = 709 nM).
