Quantifying Cell Invasion via Matrigel Chambers

Cells were seeded in 6-well plates and transfected with 10 nM of htRNA^Leu/miR-34a-5p, htRNA^Leu/miR-124-3p or htRNA^Leu. After 48 h, survived cells were harvested and seeded onto the upper inserts of the 24-well Corning BioCoat Matrigel Invasion Chambers (Corning, Bedford, MA) at 6 × 10⁴ cells/well with 500 μL serum-free RPMI 1640 medium where the lower chamber was supplied with 750 μL of serum-containing culture medium (10% FBS). 20 h later, the invaded cells were fixed with 500 μL of 10% formaldehyde, stained with 500 μL 0.1% crystal violet, and imaged with an Olympus IX2-UCB microscope. The number of invaded cells was acquired by counting five fields per insert (100 × magnification), and then compared between different treatments as we described recently 31 (link).