SDX-101 and SDX-308 inhibit growth of MM cell lines. (A-C) MM cell lines MM.1S (6 × 10⁴/well), OPM2 (3 × 10⁴/well), and RPMI-8226 (3 × 10⁴/well) were incubated in 96-well culture plates in the presence of RPMI-1640 medium containing 10% FCS and SDX-101 (10, 100 μM, and 1 mM), SDX-308 (1, 10, and 100 μM), or control (DMSO 0.1%) for 48 hours at 37°C with 5% CO₂. DNA synthesis was measured by ³H-thymidine incorporation. All experiments were performed in triplicate. Results are shown as mean ± SD. Asterisks indicate significant difference from control (P < .05).