PCI-32765 potently down-regulates cytokines/chemokine in supernatants from human OC and BMSC cultures from normal donors and MM patients. Supernatants collected at day 14 of human OC cultures treated with PCI-32765 starting on day 1 and day 5 were subjected to ELISA and Multiplex Luminex Assay (A-E). Many MM- and OC-related cytokines and chemokines were decreased (ED₅₀ = 0.1-0.48nM). TRAP5b, a mature OC-specific marker, was also inhibited (ED₅₀ = 17nM; F). (G) Survival of CD138-negative BMSCs from MM patients with active disease was measured by MTT assay, and supernatants assayed for secretion of cytokine/chemokines (H). (I) TRAP staining was performed at day 21 culture, visualized, and further measured using a spectrophotometer.