Dabrafenib Mesylate (GSK2118436) is the mesylate salt form of dabrafenib, an orally bioavailable inhibitor of B-raf (BRAF) protein with IC50s of 0.7 nM, 5.2 nM and 6.3 nM for B-Raf (V600E), B-Raf (WT) and C-Raf, respectively.[1-2]
Dabrafenib displayed compelling inhibitory activity in enzyme and cellular mechanistic assays, and in cell proliferation assays in B-RafV600E-driven melanoma lines, SKMEL28 and A375P F11 (IC50 = 3 and 8 nM, respectively), and colorectal carcinoma line Colo205 (IC50 = 7 nM). Dabrafenib has a minimal effect in vitro on cells with wild-type B-Raf (HFF IC50 = 3.0 μM) and in tumor cells not harboring the activating B-RafV600E mutation. It is highly selective, exhibiting >500-fold selectivity for B-RafV600E compared to most kinases screened. Significant activity (<100-fold selectivity) was observed for a single kinase in the panel, alk5. gsk2118436 is significantly less effective at inhibiting smad2>
In Vivo
In a BRAFV600E-containing xenograft model of human melanoma, orally administered dabrafenib inhibited ERK activation, downregulated Ki67, and upregulated p27, leading to tumor growth inhibition. Dabrafenib is orally bioavailable, doesn’t significantly accumulate after multiple dosing, and causes a reduction of pERK that is sustained for up to 18 h post-dosing after 7 and 14 days of dosing[2].
A375P cells were transfected with the indicated siRNA for 72 h and treated with 8 nM dabrafenib (+) or DMSO control (?) for 1 h. Lysates were immunoblotted.[2]
数据来源文献
[1] Rheault TR, et al. ACS Med Chem Lett. 2013, 4(3):358-62. [2] Alastair J. King, et al. PLoS One. 2013, 8(7): e67583.