Kobe0065 is a novel and effective small-molecule compound that inhibits the Ras-Raf interaction by structure-based drug design (SBDD); it displays potent activity, competitively inhibiting the binding of H-Ras·GTP to c-Raf-1 RBD with a Ki value of 46 ± 13 μM.

C-Raf1 RBD:46 ± 13 μM(ki)

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].

Kobe0065 has antitumor activity. The compound-treated tumors show a prominent increase of apoptotic cells without any significant body weight loss[1].

Determination of lipase activity: For determination of lipase activity, lysates are incubated with a substrate containing radiolabeled [9,10-3H(N)]-triolein. Subsequently, FA are extracted and quantitated by liquid scintilation counting. Data are presented as mean S.D. of triplicate determinations and representative for at least three independent experiments.

NIH 3T3 cells are transfected with pEF-BOS-HA-H-Ras(G12V) or an empty vector and treated with the 2 and 20 μM compound or the vehicle (DMSO) in the presence of 2% FBS for 1 h. Cell lysate is subjected to detection of c-Raf-1 coimmunoprecipitated with an anti-H-Ras antibody and total c-Raf-1 by Western blotting with an anti-c-Raf-1 antibody. Immunoprecipitated H-Ras(G12V) are detected by an anti-HA antibody.(Only for Reference)