Bortezomib decreases the expression of complement inhibitors (CD46, CD55, CD59) at the transcriptional level in Raji cells. (A) Raji cells were incubated with either diluent or bortezomib (10-50nM) for 12, 24, or 48 hours. Then, cells at a density of 105/100 μL were incubated with saturating amounts of FITC-conjugated mAb against CD55 and CD59 or with unconjugated mAb against CD46 for 30 minutes on ice in the dark. Then, cells incubated with anti-CD46 were washed twice with PBS and incubated with PE-conjugated goat anti–mouse IgG for another 30 minutes on ice in the dark. Subsequently, cells were washed twice with PBS and analyzed in a FACSCalibur using CellQuest Pro Software Version 5.2. The mean fluorescence intensity (MFI) serves as a measure for mAb binding on a per-cell basis. *P < .05 (Student t test). (B) CD46, CD55, and CD59 mRNA levels in Raji cells incubated with either diluent or bortezomib for 12, 24, or 48 hours were assayed with RT-PCR.
