Down-regulation of C/EBPβ by various anti-MM agents is associated with inhibition of proliferation. MM.1S MM cells were incubated with various anti-MM agents such as pomalidomide, thalidomide, dexamethasone, PD 98059, LY 294002, and melphalan for 48 hours. DMSO 0.1% was used as control treatment. (A) Whole-cell extracts were analyzed for C/EBPβ expression by Western blotting using anti-C/EBPβ antibody. β-Actin was used as a loading control. (B) DNA synthesis was measured by ³H-thymidine incorporation and results are presented as the mean from triplicates. Error bars indicate SD.