Figure 4. Cell proliferation, proteins and mRNAs regulated by knockdown of STAT3. (A) STAT3 mRNA expression was decreased by more than 80% after STAT3 knockdown with siRNA on OE33 and FLO1 cells measured by qRT-PCR. (B) WST-1 assays were used to determine the cell viability for STAT3 siRNA transfecting OE33 and FLO1 cells. Values represented the mean ± s.d. from three independent experiments. (C) Protein levels of t-STAT3 and p-FAK were regulated by STAT3 siRNA in OE33 and FLO cells, and c-Myc was also changed in FLO1 cells by Western blotting. PARP cleavage was also induced by STAT3 siRNA in OE33 cells. GAPDH was used as a protein loading control. (D) qRT-PCR showing the mRNA expression of c-MYC and FAK in OE33 and FLO1 cells. GAPDH was used as control. Values represented the mean ± s.d. from three independent experiments. *P < 0.05, **P < 0.01.