Cell migration, apoptosis and proliferation
Cell proliferation was performed by seeding NPC cells into 6-well plates at the density of 1,000 cells/well, culturing for 7 days in the presence or absence of different concentrations of IDX with/without cisplatin, fixing in 4 % paraformaldehyde and staining with 1 % crystal violet. For the migration assay, NPC cell lines were seeded on the upper chambers of 24-well Transwell inserts (BD Biosciences) and allowed to migrate with/without combined drugs in the bottom well. Migrated cells were fixed and stained as described above. For the apoptosis assay, the apoptotic cells were quantified (percentage) using an Annexin V-FITC/propidium iodide (PI) apoptosis detection kit (BD Biosciences). Cells were seeded at a density of 2 x 105 cells per well in 6-well plates. After treatment, cells were harvested and Annexin-V-FITC/PI labeling was performed according to the manufacturer’s instructions. The stained cells were analyzed on a NovoCyte Quanteon flow cytometer (Acea Biosciences).