RKI 1447 dihydrochloride is an effective and selective ROCK inhibitor (ROCK1 IC50=14.5 nM, ROCK2 IC50=6.2 nM). RKI 1447 dihydrochloride can inhibit the growth of colorectal cancer cells and promote cell apoptosis.

RKI 1447 suppresses phosphorylation of the ROCK substrates MLC-2 and MYPT-1 in human cancer cells, but has no effect on the phosphorylation levels of the AKT, MEK, and S6 kinase at concentrations as high as 10 μM [1]. RKI 1447 (0.003-10 μM) is potent at inhibiting the phosphorylation of the ROCK substrates MLC-2 and MYPT-1 in human cancer cells [1]. RKI 1447 exhibits effective anticancer activity in colorectal carcinoma (CRC). RKI 1447 (10-320 μM; 24 hours) drastically suppresses HCT-8 and HCT-116 cell growth [2]. RKI 1447 (20-80 μM; 24 hours) induces apoptosis in a dose-dependent manner [2]. Cell Viability Assay [2] Cell Line: CRC cell lines HCT-8 and HCT-116 cells Concentration: 0, 10, 20, 40, 80, 160, 320 μM Incubation Time: 24 hours Result: HCT-8 and HCT-116 viability was drastically decreased in a dose-dependent manner. Apoptosis Analysis [2] Cell Line: CRC cell lines HCT-8 and HCT-116 cells Concentration: 0, 20, 40, 80 μM Incubation Time: 24 hours Result: Treatment promoted apoptosis. Western Blot Analysis [1] Cell Line: MDA-MB-231 human breast cancer cells Concentration: 0.003, 0.01, 0.03, 0.1, 0.3, 1, 3,10 μM Incubation Time: Result: Decreased the levels of P-MLC-2, but not total MLC-2, in a concentration-dependent manner with significant effects starting at 100 nM.

RKI 1447 (200 mg/kg; i.p. daily for 14 days) inhibits mammary tumor growth in vivo [1]. RKI 1447 (100 mg/kg; i.p.; once every 3 days; for 14 days) exerts antitumor activity on CRC in vivo. RKI 1447 does not exert physiological toxicity on the mice [2]. Animal Model: MMTV/neu transgenic mice [FVB/N-Tg (MMTVneu) 202 Mul/J] [1] Dosage: 200 mg/kg Administration: Treated i.p. daily for 14 days Result: Tumors from mice treated with vehicle increased in size with an average percent change in tumor volume of 68.3%. In contrast, tumors from mice treated with the RKI-1447 increased in size with an average percent change in tumor volume of only 8.8%. Thus, RKI-1447 inhibited mammary tumor growth by 87%. Animal Model: 5-week-old Male BALB/C nude mice [2] Dosage: 100 mg/kg Administration: Intraperitoneally injected; once every 3 days; for 14 days Result: Efficiently blocked CRC tumor growth in vivo.