Effect of LBW242 on normal lymphocytes and MM patient BMSCs. (A) Lymphocytes from 4 healthy donors were treated with indicated concentrations of LBW242 and then analyzed for viability. Data are means ± SD of 3 independent experiments (P = .25 from J-T test for trend). (B) BMSCs from 4 patients with MM were treated with indicated concentrations of LBW242 for 48 hours and analyzed for apoptosis by DNA fragmentation assays. Data are means ± SD of 3 independent experiments (P < .005). As a positive control, MM cell lines (A, MM.1S; B, MM.1R) were treated with LBW242 and similarly analyzed for apoptosis. Inset shows total protein extracts from untreated and LBW242-treated BMSCs or patient MM cells when subjected to immunoblotting with anti-PARP Abs.