TGF-b Inhibition in Myeloma Figure 4. Terminally differentiated OBs suppress MM cell growth. A. MC3T3-E1 cells and primary bone marrow stromal cells isolated from a patient with MM were cultured in 24-well culture plates in a-MEM containing 10% FBS with or without b-glycerophosphate, ascorbic acid and 50 ng/ mL rhBMP-2 as described in ‘‘Materials and methods’’. After forming mineralized nodules in the osteogenic cultures with rhBMP-2, the cells were washed to remove rhBMP-2. MM cell lines, 5TGM1, RPMI8226, U266 and KMS-12 at 56104/mL, were cultured alone as a control or cocultured in quadruplicate with thus treated MC3T3-E1 cells or primary bone marrow stromal cells with or without inducing terminal OB differentiation. After culturing for 3 days, MM cells were harvested, and viable MM cell numbers were counted. Percent changes from the control are shown. Results are PLoS ONE | www.plosone.org 6 March 2010 | Volume 5 | Issue 3 | e9870