Kobe0065

Kobe0065 is a novel and effective inhibitor of Ras-Raf interaction, competitively inhibiting the binding of H-Ras·GTP to c-Raf-1 RBD with a K_i value of 46±13 μM. In Vitro: Kobe0065-family compounds bind to Ras?GTP and exhibit antiproliferative activity toward cancer cells carrying the activated ras oncogenes. The compounds efficiently inhibit the interaction of Ras?GTP with their multiple effectors including Raf, PI3K, and RalGDS and a regulator/effector Sos and show rather broad binding specificity toward various Ras family small GTPases, which may account for their higher potency at the cellular level compared with that of the in vitro binding inhibition^[1]. The phosphorylation of downstream kinases MEK and ERK is effectively attenuated by 20 μM Kobe0065 and Kobe2602 in NIH3T3 cells transiently expressing H-RasG12V^[2]. In Vivo: Kobe0065 and Kobe2602 exhibit antitumor activity on a xenograft of human colon carcinoma SW480 cells carrying the K-ras(G12V) gene by oral administration^[1].