In vitro activity: MLN2480 (also known as BIIB-024, TAK-580 and AMG 2112819) is an orally bioactive, potent and selective pan-Raf kinase inhibitor that is under in clinical investigation. MLN2480 inhibits MAPK pathway signaling in BRAF mutant and some RAS mutant preclinical cancer models at concentrations that are tolerated in vivo. It is found to activate phosphorylated MEK at very low concentrations, but inhibits this same activity at higher concentrations. The inhibitory effects of MLN-2480 are found to vary across models and genetic contexts. The Raf kinases (A-Raf, B-Raf and C-Raf) are key regulators of cell proliferation and survival within the mitogen-activated protein kinase (MAPK) pathway. The MAPK pathway is frequently disregulated in human cancers, often via activating mutations of Ras or Raf. MLN2480 inhibits MAPK pathway signaling in BRAF mutant and some RAS mutant preclinical cancer models at concentrations that are tolerated in vivo. It is found to activate phosphorylated MEK at very low concentrations, but inhibits this same activity at higher concentrations. The inhibitory effects of MLN-2480 are found to vary across models and genetic contexts. In vitro analysis of this drug combination of MLN2480 and TAK-733(an investigational allosteric MEK kinase inhibitor) in cell proliferation assays demonstrates synergistic activity .In addition, western blot analysis demonstrates the effect of MLN2480 in reversing feedback activation of MEK in response to TAK-733, leading to more concerted MAPK pathway inhibition.MLN-2480 only modestly inhibits PRAK.

Kinase Assay: MLN2480 (also known as BIIB-024, TAK-580 and AMG 2112819) is an orally bioactive, potent and selective pan-Raf kinase inhibitor that is under in clinical investigation. MLN2480 inhibits MAPK pathway signaling in BRAF mutant and some RAS mutant preclinical cancer models at concentrations that are tolerated in vivo.

Cell Assay: MLN-2480 is active against wild-type B-raf and B-raf Val600Glu in vitro. MLN-2480 is found to activate phosphorylated MEK at very low concentrations, but at higher concentrations MLN-2480 inhibits this same activity. MLN-2480 inhibits signaling pathway at high concentrations in the human malignant melanoma A-375 mutant B-raf Val600Glu cell line. The inhibitory effects of MLN-2480 are found to vary across models and genetic contexts; MLN-2480 only modestly inhibits PRAK. MLN-2480 in combination with TAK-733 demonstrates synergy in NRAS mutant human malignant melanoma cell lines (SK-MEL-2), with high levels of apoptotic biomarkers observed.