Figure 4. siRNA knockdown of regulatory targets of miR-337-3p sensitizes NCI-H1155 cells to paclitaxel.

(A) Effect of knockdown of RAP1A and STAT3 expression by siRNA on cell viability in the presence and absence of paclitaxel. Shown in red is cell viability in 16 nM paclitaxel normalized to viability in carrier as a function of increasing concentrations of siRNAs against RAP1A or STAT3. Shown in black is cell viability in the absence of paclitaxel. (B) Effect of combined knockdown of RAP1A and STAT3 on paclitaxel sensitivity. Shown is the relative cell viability in the presence 16 nM paclitaxel normalized to control oligos. (C) Knockdown of STAT3 and RAP1A enhances paclitaxel-induced G₂/M arrest as measured by flow cytometry. The ratio (R) of the G₂ to G₁ fractions induced by paclitaxel treatment was determined as above. (D) Cell viability as a function of oligo concentration (miR-337-3p mimic or negative control mimic) in the presence of cucurbitacin. *, p<0.05.