Inhibition of STAT3 by shRNA sensitizes PDAC cells to Gemcitabine in vitro . PDAC cells and their respective STAT3-shRNA clone cells were treated with indicated concentrations of gemcitabine for 96 h and MTT assays were performed to measure the rate of growth. Data are presented as % growth of control. Bars represent SD of eight replicates, repeated three times. (*) = significant growth inhibition (p < 0.001) starts from this dose point and remains significant at higher dose levels. Insets: Western blots showing differences in the expression of STAT3 in control and shSTAT3 clone cells. As a loading control, β-actin levels are shown.