pcDNA/p21 or siRNA/p21 could mimic the effects of siRNA/HOTAIR1 or pcDNA/HOTAIR on the sensitivity of LAD cells to cisplatin.

<p>(<b>A</b>) Western blot analysis of the effect of HOTAIR on p21 protein expression in pcDNA/HOTAIR (or pcDNA/control) or siRNA/HOTAIR1 (or siRNA/control)-transfected A549 or A549/DDP cells. GAPDH was used as an internal control. (<b>B</b>) MTT analysis of the IC₅₀ values of cisplatin to pcDNA/control or pcDNA/p21-transfected A549/DDP cells and siRNA/control or siRNA/p21-transfected A549 cells. (<b>C</b>) Flow cytometry analysis of apoptosis in pcDNA/control or pcDNA/p21-transfected A549/DDP cells combined with various concentrations of cisplatin (0.0, 1.0 or 2.0 μg/L). (<b>D</b>) Flow cytometry analysis of apoptosis in siRNA/control or siRNA/p21-transfected A549 cells combined with various concentrations of cisplatin (0.0, 1.0 or 1.5 μg/L). (<b>E</b>) Flow cytometry analysis of cell cycle distribution in pcDNA/control or pcDNA/p21-transfected A549/DDP cells combined with various concentrations of cisplatin (0.0, 1.0 or 2.0 μg/L). (<b>F</b>) Flow cytometry analysis of cell cycle distribution in siRNA/control or siRNA/p21-transfected A549 cells combined with various concentrations of cisplatin (0.0, 1.0 or 1.5 μg/L). Results represent the average of three independent experiments (mean±SD). <i>N.S</i> indicates <i>P</i>>0.05 and * or ** indicates <i>P</i><0.05 or <0.01, respectively.