Figure 5. Newer allosteric MEK inhibitors inhibit ERK phosphorylation better than PD0325901.
(A) A panel of BRAFV600E (n, 15) and KRAS mutant (n, 50) tumor cell lines were subjected to proliferation assays with the indicated drugs. Cells were treated for three days with increasing amounts of the indicated compounds, in order to determine their respective IC50s. The mean (line) and range of IC50s across cell lines (n of 3 for each cell line) is shown.
(B) KRAS mutant A549 cells were treated with increasing concentrations of PD0325901, trametinib or CH5126766 for 48 hr. Lysates were evaluated by immunoblotting to determine the level of ERK phosphorylation. A representative of two independent experiments is shown.
(C, D) KRPC cells expressing dox-inducible CRAF shRNAs were treated with dox alone (no drug) or in combination with trametinib (C) or PD0325901 (D) at the indicated concentrations. The data were normalized to the number of shRNA expressing cells in the dox only controls. A representative of two independent experiments with at least two different shRNAs targeting CRAF is shown.
(E) KRAS mutant A549 cells were treated with 100 nM PD0325901, 2 μM AZ628, or 100 nM trametinib as indicated. The fold increase in viable cell number over time is shown. Means +/- SEM from a representative of two independent experiments, each performed in triplicate, are shown.
See also Figure S5