L-779450

L-779450 is a potent and selective B-Raf kinase inhibitor with a K_d of 2.4 nM. In Vitro: L-779450 (L-779,450) shows a high degree of specificity towards Raf. The only other tested kinase inhibited is p38MAPK, which has a kinase domain structurally related to Raf. L-779450 inhibits anchorage-independent growth of human tumor lines at doses ranging from 0.3 to 2?μM^[2]. The effects of L-779450 (L-779,450) on TRAIL sensitivity are investigated here in melanoma cell lines with high TRAIL sensitivity (A-375 and SK-Mel-147), moderate sensitivity (Mel-HO, SK-Mel-13, and SK-Mel-28), and permanent resistance (MeWo, Mel-2a, and SK-Mel-103), as well as in TRAIL-selected cell lines with acquired resistance (A-375-TS and Mel-HO-TS). Despite only moderate direct effects of L-779450 on apoptosis, it strongly enhances TRAIL-induced apoptosis in sensitive melanoma cells and overrules TRAIL resistance in Mel-2a, SK-Mel-103, A-375-TS, and Mel-HO-TS. At 24?hours, 16-35% apoptosis induction is obtained^[3].