Inhibition of MEK1/2 increases sensitivity to prednisolone. Western blots for pERK, ERK, and p53 in Reh (A), RS4;11 (B), UOCB1 (C), and 697 cells (D) treated with 0.01 μM, 0.1 μM, or 1.0 μM trametinib for 48 hours. Cell viability was measured in Reh (E), RS4;11 (F), UOCB1 (G), and 697 cells (H) treated with the indicated concentration of trametinib, increasing concentrations of prednisolone (pred), or a combination of trametinib and prednisolone (combo) for 48 hours. (I) Percentage of apoptotic 697 cells grown alone or cocultured with HS-5 BMSCs upon treatment with prednisolone (pred), 0.1 μM trametinib, or a combination of prednisolone and 0.1 μM trametinib (combo).