Total RNA (A) or protein (B) was extracted from A549 cells stably transfected with either control shRNA or 2 distinct STAT3 shRNA constructs and used to determine levels of STAT3 mRNA by quantitative RT-PCR (A) or levels of pSTAT3, total STAT3 and GAPDH protein using Luminex beads (B); mean ± SD of 3 separate determinations are shown; *, p<0.003 for each. C) Cell proliferation in A549 cells stably transfected with either control shRNA or 2 distinct STAT3 shRNA constructs was determined by MTT assay using either anchorage-dependent (left panel) and anchorage- independent (right panel) conditions. Data shown are mean ± SD of 3 determinations; *, p<0.0001 for each. D) Levels of four STAT3 downstream gene targets were determined in total RNA of A549 cells stably transfected with either control shRNA or 2 distinct STAT3 shRNA constructs using quantitative RT-PCR. Data shown are mean ± SD of 3 determinations; *, p<0.02, p<0.04, p<0.03 and p<0.02, as shown.