b-AP15 reduces tumor burden and prolongs survival in disseminated KMS-11 MM xenograft model. b-AP15 was dissolved in Cremophor EL/polyethylene glycol 400 (1:1) to a stock concentration of 8 mg/mL, which was diluted in saline immediately before injection. KMS-11-LUC2 cells (5 × 10⁶) were injected intravenously in female SCID mice. After being injected for 7 days, mice were randomized into control and b-AP15 treatment groups (8 mice per group). Mice were treated with vehicle or b-AP15 (4 mg/kg) for 10 consecutive days. (A) The representative imaging was taken at day 32 by using a charge-coupled device (CCD camera, Xenogen IVIS Lumina System). (B) The bioluminescence in the animal was measured at days 16, 24, and 32 of tumor cell injection. Signal intensity was quantified by using IGOR Pro version 4.09A Software (WaveMetrics, Inc., Lake Oswego, OR). The effect of the treatments was expressed as percentage of radiance inhibition with respect to control group values (P < .001). (C) Mice were sacrificed when paralysis was observed, and the number of days of survival is shown in a Kaplan-Meier plot (P < .001). (D) Tumor sections from control and b-AP15–treated mice were immunostained with anti–Ub-K48 antibody. Scale bar = 50 μM.