Kobe0065 is a small-molecule inhibitor of Ras with Ki value of 46 μM for the binding of H-Ras.GTP to c-Raf-1 [1].

Kobe0065 is a compound screened out by an in silico screen method as a potent inhibitor of the Ras–Raf interaction. It showed favorite efficacy to inhibit the binding of M-Ras.GTP and H-Ras.GTP to the Ras-binding domain of c-Raf-1. Kobe0065 also dose-dependently inhibited the binding of H-RasG12V to c-Raf-1 in NIH 3T3 cells with a rough IC50 value of 10 μM. Besides that, 20 μM of Kobe0065 effectively suppressed the phosphorylation of down-stream kinases of Raf, including MEK and ERK. In NIH 3T3 cells transfected with H-rasG12V, Kobe0065 inhibited the colony formation with IC50 value of 0.5 μM. Kobe0065 also showed effect on other cancer cells carrying activated ras oncogenes, such as PANC-1(K-rasG12V), HT1080 (N-rasQ61L) and HCT116 (H-rasG13D). Moreover, in mice bearing SW480 xenografts, administration of Kobe0065 resulted in 40-50% inhibition of the tumor growth at dose of 80 mg/kg. This effect turned to be more distinct when the dose was up to 160 mg/kg [1].