BI 847325 is a dual inhibitor of Ras-mitogen-activated protein kinase kinases (MEK) and Aurora kinases [1,2]. BI 847325 inhibits MEK1 and MEK2 with IC50 values of 25 and 4 nM, respectively. For inhibiting the activity of Aurora A, B and C, IC50 values are 3, 25 and 15 nM, respectively [1].
The RAS-dependent MAP kinase signaling pathway is important in the regulation of cell survival and proliferation. It is hard to design direct inhibitors of RAS proteins. MEK is a downstream kinase of MAP kinase [1]. MEK is a ERK kinase [3].
In cells treated with BI 847325, based on levels of phospho-histone H3 (pHH3) and phospho-ERK (pERK), EC50 values were determined. To KRAS-and-PI3Kα-mutant NCI-H460 cells, the EC50 value was 44 nM. To BRAF-mutant A375 cells, the EC50 value was 37 nM. In a panel of 240 cell lines from diverse tissues with diverse genetic background, BI 847325 produced a potent inhibition of cell proliferation with a gm GI50 value of 28 nM. In a subset of cell lines, BI 847325 induced cell death. These in vitro potency correlated with mutations in BRAF or RAS, significantly [1].
In nude mouse xenograft models of cutaneous melanoma (A375, mutant BRAF) and NSCLC (Calu-6, mutant KRAS), BI 847325 at a daily oral dose of 10 mg/kg produced complete inhibition of tumor growth. In animals with A375 tumors, treatment with BI 847325 significantly reduced levels of both pHH3 and pERK in the tumors compared to controls [1].
References:
[1]. Sini P, Gürtler U, Zahn SK, et al. Pharmacological characterization of BI 847325, a dual inhibitor of MEK and Aurora kinases. Cancer Research, 2012, 72(8 Supplement): 1919-1919.
[2]. Hideshima T, Chauhan D, Richardson P, et al. NF-κB as a therapeutic target in multiple myeloma. Journal of Biological Chemistry, 2002, 277(19): 16639-16647.
[3]. Rommel C, Clarke BA, Zimmermann S, et al. Differentiation stage-specific inhibition of the Raf-MEK-ERK pathway by Akt. Science, 1999, 286(5445): 1738-1741..