LB-100 inhibits STAT3 activation in vitro. (A) Activation of STAT3 was quantified by phosphorylation level of STAT3(Y705) levels using enzyme-linked immunosorbent assay. IOMM-LEE, GAR and CH-157 cells were treated with LB-100 for 24 hours. Data represents the mean ± SEM from two independent experiments. *P < 0.05, **P < 0.01< ***P<0.001 and ****P < 0.0001. One way ANOVA with Tukey's multiple comparison test. (B) LB-100 down-regulates expression of STAT3 target genes. Western blot analysis of IOMM-LEE, GAR and CH-157 cells treated with increasing LB100 concentration demonstrates dose-dependent decrease in STAT3 target genes, including mcl-1, c-myc, and cyclin D.