S109 induces proteasomal degradation of CRM1 protein. (A and B) HCT-15 and HT-29 cells were treated with S109 at the indicated concentrations for 24 h, and then subjected to Western blot analyses using anti-CRM1 antibody. (C) HCT-15 cells were treated with LMB at the indicated concentrations for 24 h, and then subjected to Western blot analyses using anti-CRM1 antibody. (D) HCT-15 cells were treated with S109 (2 μM) for the indicated time, and then subjected to Western blot analyses. (E and F) HCT-15 and HT-29 cells were treated with S109 (2 μM) alone, in combination with the proteasomal inhibitor MG132 (10 μM), or with MG132 (10 μM) alone for 12 h and then subjected to Western blot analyses.