Figure 4.

Panel a. c-Src, STAT3, and survivin siRNA reduce the levels of their target proteins. The (−) column indicates non-target siRNA, while the (+) column indicates specific siRNA as labeled. The siRNA to c-Src, STAT3 and survivin reduced the level of the corresponding protein in all three lines. For quantitation of the Western blots see Table S4b.

Panel b. siRNA targeting c-Src, STAT3, and survivin reduces growth of the lung adenocarcinoma lines A549 and H522. Cells treated with siRNA targeting c-Src, STAT3, and survivin exhibited reduced growth when compared to cells treated with non-targeting siRNA. P value of <0.05 is indicated with an asterisk.

Panel c. siRNA targeting c-Src or STAT3 do not reduce ritonavir IC₅₀ for the lung adenocarcinoma lines A549 and H522. A549 and H522 cells transfected with siRNA targeting c-Src, STAT3, survivin, or non-targeting siRNA were grown in the presence of increasing concentrations of ritonavir. Silencing of survivin mRNA expression increased the cell sensitivity to ritonavir, reducing its IC₅₀ to 25μM for the A459 line and 27μM for the H522 line.

Panel d. siRNA targeting survivin increases the sensitivity to ritonavir of the lung adenocarcinoma lines A549 and H522. A549 and H522 cells transfected with siRNA targeting survivin were treated with ritonavir at the appropriate IC₅₀. Survivin siRNA and ritonavir acted together to reduce cell growth in both lines. P value of <0.05 is indicated with an asterisk.