Cell migration and invasion assay

The effect of veratramine on HepG2 cell migration and invasion was assessed using a wound healing assay and Transwell assay, respectively. For the wound healing assay, HepG2 cells were seeded in 6 well plates and cultured to 90% confluence. The cell monolayer was scratched using a 10-µl pipette tip. Subsequently, the cells were treated with veratramine (40 µM) for 48 h. After drug treatment, the cells were observed through an inverted microscope (Olympus Corporation), and the width of the scratch was measured.

For the Transwell assay, Transwell culture inserts were placed into the wells of 6-well plates and coated with a layer of Matrigel™. Subsequently, RPMI-1640 medium containing 10% FBS was added to the lower chamber and HepG2 cells were seeded in the upper chamber. After veratramine (40 µM) treatment for 48 h, the invaded cells in the lower chamber were fixed with 1% formaldehyde for 10 min at 25°C and stained with 0.5% crystal violet for another 5 min. Finally, the cells were observed under an inverted microscope (magnification, ×200).