(A) Structures of KPT-8752 and KPT-9274. (B) Western blot analysis of SUM159 cells treated with either KPT-8752, KPT-9274, or compound 17 (72 hr). Western blots were probed with anti PAK4 and anti PAK1 antibodies, and with antibodies against the PAK4 pathway targets β-catenin and Cofilin. β-actin was used as a loading control. (C) The intensity of the bands in the western blot in panel B were quantitated using Image J software, and the bands were normalized to the β-actin control. Results are plotted as a percent of control, where the control represents the band intensity for DMSO, and set as 100% for each protein (PAK4, PAK1, Phospho-Cofilin, Cofilin, Phospho-β-Catenin and β-Catenin). This data was from a single experiment, where multiple doses of the inhibitor are represented. (D) Western blot analysis of PAK4 levels in MDA-MB-231 cells and MDA-MB-468 cells treated with KPT-9274. (The membranes were cut prior to exposure so that only the portion of gel containing bands in the size range of proteins under investigation would be detected, as described in materials and methods. In the top panel of (B) an upper band that represents a non-specific band that reacts with the PAK4 antibody, is spliced out of the figure, in order to focus on the PAK4 band).