Expression of HOTAIR in cisplatin-resistant A549/DDP cells is significantly upregulated compared with that in parental A549 cells.

<p>(<b>A</b>) Morphologies of A549 and A549/DDP cells. Cells were grown to 70% confluency and then photographe under 40× magnification. (<b>B</b>) The IC₅₀ value of cisplatin to A549/DDP cells was significantly higher than that to A549 cells. (<b>C</b>) Flow cytometric analysis of cell cycle distribution in A549 and A549/DDP cells. (<b>D</b>) The colony formation of A549 and A549/DDP cells treated with various concentrations of cisplatin (0.5, 1.0, 1.5 and 2.0 μg/L). (<b>E</b>) qRT-PCR analysis of HOTAIR expression in A549/DDP and A549 cells. (<b>F</b>) A549 cells were cultured in the presence of various concentrations of cisplatin (0.0, 0.5, 1.0, 1.5 or 2.0 μg/L) for 24h. qRT-PCR assay was performed to detect HOTAIR expression. GAPDH was used as an internal control. 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.