Western blot analysis of STAT3 activation: A, A549 and A549/B cells were treated with DMSO and BHS-1 (15μM) for 24 h and expression and phosphorylation of STAT3 was determined by Western blot analysis; B, protein expressions of p-STAT3/STAT3 from 3 different experiments. Columns not sharing the same superscript letter differ significantly (P<0.05).