Figure 4: STAT3 knockdown sensitizes H1581-V561M cells to AZD4547 treatment.

A H1581-WT and H1581-V561M cells were infected with virus containing shRNA targeting STAT3 or a non-targeting scrambled control. Lysates were harvested and immunoblots of two replicate lysates were performed as described in 2A. B STAT3 expression levels were quantified using ImageJ and normalized to a GAPDH loading control and plotted using GraphPad Prism. C 5×10⁴ cells were plated in full growth media containing 250 nM AZD4547 or a DMSO control and incubated for 72 h. Cells were imaged using a Nikon Eclipse Ti-S fluorescence microscope. Scale bars correspond to 100 μm. Cells were then trypsinized and quantified using the Countess automated cell counter. D Data were plotted using GraphPad Prism. E, F IC₅₀ curves for AZD4547 treatment of H1581-WT and H1581-V561M cells treated with scrambled control or STAT3 targeting shRNA were generated as described for Figure 1. Significance values: *<0.05; **<0.01, ***<0.001.