migration < invasion??? - More cells migrating through matrigel than through control inserts (Mar/22/2010 )

When I first observed that fewer BEAS2B lung epithelial cells had migrated through the BD 8 micron control transwell inserts less than through the BD BioCoat Growth Factor Reduced Matrigel Invasion Chambers, I thought that I had somehow seeded the wells wrong. However, after several repeats I'm consistently observing higher invasion than migration rates. For seeding the inserts, I'm using 25K cells in Lonza BEGM media without growth factor supplements but with .1% BSA to promote cell adhesion. The wells contain Lonza BEGM media with growth factors added as the chemoattractant.

It occurs to me that the cells may be adhering to the matrigel more readily than to the control inserts and thus we are observing an artificially high invasion rate. Has anyone observed similar results?

http://www.nature.com/nprot/journal/v2/n3/...t.2006.466.html

This paper answered my question and provided a great deal of useful information on the inv/mig assay.