Fig. 8. Morphologically altered epilysin-expressing A549 cells and MT1-MMP transfected A549 cells have an increased ability to invade type I collagen. Type I collagen gels were made into cell culture plate inserts. (A) Stable A549 cell pools and (B) A549 cells transiently transfected with epilysin and MT1-MMP were seeded to the upper chamber as indicated and medium containing HGF (10 ng/ml) as a chemoattractant was added to the lower chamber. The epilysin-induced morphological changes were not affected by the neutralizing anti-HGF antibodies in the EMT assay (Fig. 3B). The MMP-inhibitor GM6001 (10 µM) was added to both chambers as indicated. The cells were incubated on the collagen gels for 8 days changing the medium every third day. The gels were finally fixed with 3% PFA, dehydrated and embedded in paraffin. Sections were then cut and stained with hematoxylin and eosin. Cells that had invaded into the collagen gel were counted under a light microscope. The asterisks denote statistically significant variation as compared with the control (Student's t-test, P<0.05).