Sant7 treatment of INA-6 cells leads to a reduced STAT3 DNA-binding activity.

INA-6 cells were cultivated without IL-6 (lane 1), with 2 ng/mL IL-6 (lanes 2, 3, and 6-8), or with BMSCs (lanes 4 and 5), and treated with Sant7 (50 μg/mL; lanes 3 and 5) for 12 hours. EMSA with double-stranded ³²P-labeled oligonucleotide probe (which contains a consensus-binding site for STAT3) were performed to show DNA-binding activity of STAT3. Preincubation with an anti-STAT3 antibody inhibits the binding of STAT3 protein to the SIE probe (lane 7). To control binding specificity of the ³²P-labeled SIE probe, a competition with a 50-fold excess of unlabeled probe was performed (lane 9). A probe for the transcription factor Oct-1 served as a control.