01A significantly decreases many APRIL-induced target genes and blocks MM cell growth in a SCID-hu mouse model of human MM. (A) MM1S and H929 MM cells were incubated overnight with (+) or without (−) APRIL in the presence (+) or absence (−) of 01A. Levels of downstream target genes were assayed using real-time qRT-PCR, normalized to 18S or GAPDH internal controls. Fold changes to control media are shown. Two-way ANOVA test (Tukey’s multiple comparison) was done for all genes except BIRC3 and IL-8 (1-way ANOVA). Fold changes are significantly higher on APRIL induction in H929 vs MM1S cells for BIRC3 (24-fold vs 2-fold) and IL-8 (8-fold vs 1.3-fold). *P < .05; **P < .01; ***P < .001; ***P < .0001. (B) INA-6 MM cells were injected into the implanted human bone chips in SCID-hu mice. Two days later, mice were treated (5 days/week) with 01A (20 mg/kg, n = 4) or isotype IgG control (n = 4); tumor growth was then monitored by measuring shuIL-6R in mouse serum samples weekly. Two-way ANOVA test (Tukey’s multiple comparison) determined P < .0001 at day 32.