LY294002 (LY) enhances the therapeutic efficacy of mifepristone (MF) as shown by comparative dose-response curves. In (A and B) cells were treated with various concentrations of MF in the presence or absence of 10 μM LY294002, and cell growth was calculated considering controls as 100%. In (C and D) normalized isobolograms depict the pharmacological interaction between MF and LY as calculated from the comparative dose-responses curves using CalcuSyn software. The depicted CIs in the isobolograms were calculated using the following combined concentrations: in (C), (1) 20 μM MF with 40 μM LY, (2) 5 μM MF with 20 μM LY, (3) 10 μM MF with 20 μM LY, and (4) 1.25 μM MF with 2.5 μM LY. For (D), (1) 10 μM MF with 50 μM LY, (2) 15 μM MF with 7.5 μM LY, and (3) 30 μM MF with 15 μM LY.