CBS9106-induced CRM1 protein reduction depends on ubiquitin/proteasome. (A) MM.1S and RPMI-8226 cells were treated with vehicle or CBS9106 (13, 50, or 200nM) for 5 hours, and the changes of CRM1 mRNA and protein were determined by RT-PCR and immunoblotting, respectively. (B) MM.1S and RPMI-8226 cells were treated with vehicle, LMB (2nM), and CBS9106 (200nM) in the presence or absence of bortezomib (10nM) for 8 hours, and the whole-cell lysates were analyzed by immunoblotting.