Fig. 5.

Acetaminophen (AAP) binds to STAT3 with high specificity relative to STAT1. Spectrofluorimetry experiments were used to determine the binding affinity of AAP and C 188-9 to STAT3 (A, C) and STAT1 (B, D). (E) H460 NSCLC cells were grown in CSC medium and treated for 4 h with vehicle, AAP (1 mM) or C188-9 (10 μM). The cells were then collected and subjected to immune-blotting analysis. The blots were quantified using Image J software, and the pSTAT3/pSTAT1 ratio of 2 independent experiments was graphed, as shown in (F).