Fig. 3

Effect of zinc on lung cancer cell migration and invasion. Cells were pre-treated with zinc (0–50 µM) for 24 h. The treated cells were subjected to migration and invasion assays. a For wound healing assay, the confluent monolayers of the cells were wounded by using a 1 mm-wide tip and cultured with the medium containing indicated treatments. After 24 h of incubation, wound spaces were analyzed and represented as a relative migration level. b The relative migration level was determined by comparing the relative change of zinc-treated cells to untreated control cells. Values are means of independent triplicate experiments ± SD. *p < 0.05 versus untreated control. c For transwell migration assay, migratory cells were stained with Hoechst 33342 for 30 min, determined under a fluorescence microscope and represented as average number of migratory cells in each field relatively to control cells. d Cell invasion was evaluated using a transwell coated with matrigel as described under “Methods” section. After 24 h, the cells that invaded across the membrane were stained with Hoechst 33342 for 30 min and visualized under a fluorescence microscope. Value was represented as average number of invaded cells in each field relatively to control. Values are means of independent triplicate experiments ± SD. *p < 0.05 versus untreated control. e The expression levels of motility-regulatory proteins were determined by western blotting. The blots were re-probed with β-actin to confirm equal loading of the samples. f The blots were quantified by densitometry and mean data from three independent experiments were normalized to the results. The bars are the mean ± SD of independent triplicate experiments. *p < 0.05 versus untreated control