Supplementary Figure 1.

Initial administration of bortezomib induces drug resistance in MM-bearing mice.

Tumor burden of mice with established MM tumors was determined by BLI and shown as a region of interest (ROI) normalized to tumor size before pretreatment. MM-bearing mice were pretreated with vehicle (n = 8) or bortezomib (n = 8; 1.0 mg/kg) administered IP twice a week (BIW) for 2 weeks. A treatment with bortezomib showed initial response in the first week and then relapse in week 2.