Bortezomib downregulates the expression and production of chemokine (CXC motif) ligand 12 (CXCL12) in MS-5 cells. MS-5 cells were incubated without or with bortezomib (5-500 nM) in X-VIVO medium for 24 hr prior to reverse transcription-PCR (A), real-time quantitative reverse transcription-PCR (B), and western blotting for CXCL12 (C). GAPDH, glyceraldehyde 3-phosphate dehydrogenase. (D) Concentrations of CXCL12α in 3-day MS-5 culture supernatants were measured by ELISA. Data are mean±SD of 3 independent experiments. ^a)P<0.05, compared with the control (no bortezomib).