Effect of BIO on viability of INA6 MM cells in vitro. Viability of INA6-WT (A) and INA6-10.13 (B) cells exposed to increasing concentrations of BIO (0-1600nM) for 72 hours with or without addition of 10% MSC-conditioned medium as determined by trypan blue exclusion. Mean (± SD) for n = 6-9 samples is shown. ANOVA was performed after arcsine transformation of proportions. Asterisk indicates cut-off dose of BIO causing statistically significant reduction of viability (*P < .05). There were 2 to 3 sets of independent triplicates analyzed. (C) Western blot for cleaved caspase-3 showing induction of apoptosis in INA6-WT and INA6-10.13 cells by BIO after 18 hours exposure. Note the initial rescuing effect of MSC-conditioned medium, which is overcome by higher concentrations of BIO (1000nM). Membranes were cut and exposed with different sensitivity using an automated imaging system. To ensure comparability, INA6-WT or INA6-10.13 cells were run on the same gel, respectively, and lanes were spliced together for presentation purposes. Experiment was performed twice independently.