LiCl induced MM cell apoptosis. A, B. After treatment with LiCl for 48 h, RPMI-8226 cells were analyzed using an Annexin V-FITC/PI double staining detection kit. C. Western blot analyses of apoptosis-related proteins caspase-9, caspase-3, PARP1, and corresponding cleaved forms, β-actin was used as internal reference. D, E. Flow cytometry analyses of U266 cell apoptosis following treatment with different concentrations (5 mM, 10 mM, 20 mM, and 40 mM) of LiCl for 48 h, with 40 mM NaCl used as a negative control. F. Assessment of caspase-9, caspase-3, PARP1, and corresponding cleaved forms in U266 cells treated by 40 mM LiCl for 48 h. All experiments were repeated three times. Error bars, mean ± SD. *, P < 0.05; **, P < 0.01.