Ro 5126766 (CH5126766) is a first-in-class dual MEK/RAF inhibitor that allosterically inhibits BRAF, CRAF, MEK, and BRAF (IC50: 8.2, 56, 160 nM, and 190 nM, respectively).
IC50&Target
MEK
160 nM (IC50)
BRaf
8.2 nM (IC50)
Braf
190 nM (IC50)
CRAF
56 nM (IC50)
体外研究
Ro 5126766 (RO5126766) is an allosteric inhibitor that binds directly to MEK and prevents its phosphorylation by RAF through the formation of a stable RAF-MEK complex. Ro 5126766 inhibits both the phosphorylation of MEK by RAF and the activation of ERK by MEK. In cell-free MEK and RAF kinase assays, Ro 5126766 effectively inhibits activation of ERK2 by MEK1 with an IC50 of 160 nM (SD=±0.043) and inhibits the phosphorylation of MEK1 protein by BRAF (IC50=190 nM, SD=±0.003), BRAF (IC50=8.2 nM, SD=±0.0015), and CRAF (IC50=56 nM, SD=±0.016). Ro 5126766 effectively inhibits both MEK and ERK phosphorylation in a panel of human tumor cell lines including KRAS/HRAS and BRAF mutant cell lines and KRAS/HRAS and BRAF wild-type cells. In order to investigate whether the mevalonate pathway affects the sensitivity to MEK inhibitors, human breast cancer MDA-MB-231 cells harboring KRAS and BRAF mutations are treated Ro 5126766 (CH5126766), with or without statins, which inhibits HMG-CoA reductase, the rate-limiting enzyme in the mevalonate pathway. The combined treatment of Ro 5126766 with XU 62-320 demonstrates more significant reduction in cell growth in a dose-dependent manner than the single treatment of Ro 5126766. The marked combined effects of Ro 5126766 at 40 nM and XU 62-320 at 0.3 μM is also confirmed on the suppression of the colony formation of the cells.
体内研究
In KRAS-mutant xenograft models, Ro 5126766 (RO5126766) inhibits growth and causes tumor regressions more effectively than another allosteric MEK inhibitor, PD0325901. Preclinical data from a series of human tumor mouse xenograft models indicates an ED50 for Ro 5126766 of 0.03 to 0.23 mg/kg and an ED90 of 0.15 to 1.56 mg/kg. These effective doses are associated with target trough concentrations of 17 to 133 ng/L and 87 to 901 ng/mL, respectively. . In this experiment, Ro 5126766 (CH5126766) or PD0325901 is administrated at their maximum tolerated dose (MTD) in the HCT116 model (1.5 and 25 mg/kg, respectively). These doses inhibit pERK and ERK signaling output at similar degrees in the tumors from the drug-treated mice at 4 hours from the first drug administration. Moreover, in HCT116 models, the ED50 for Ro 5126766 and PD0325901 are 0.056 and 0.80 mg/kg, respectively. Therefore, the doses used for this experiment are 26.8- and 31.3-fold higher doses than the 50% effective doses, respectively. Daily oral administration of either drug causes significant tumor regression of each these tumors. However, whereas inhibition of tumor growth is maintained for the entire 28-day treatment period in Ro 5126766-treated mice, tumor models receiving PD0325901 become refractory after 10 days of treatment.
分子式
C21H18N5O5FS
分子量
471.46
CAS号
946128-88-7
运输条件
Room temperature in continental US; may vary elsewhere.