Figure 2
High-MMP cells exhibit increased migration and invasion. (a) The time course of changes in the MMP of A549 cells was investigated by JC-1 (5,5′,6,6′-tetrachloro-1,1′,3′,3′-tetraethyl benzimidazolyl carbocyanine iodide) staining and real-time fluorescence microscopy using IncuCyte ZOOM (Essen BioScience). Cells were imaged at 2-h intervals for 24 h; a representative image is shown. Images of the entire time course are shown in Supplementary Movie 1. Red, high-MMP cells; green; low-MMP cells; black arrow, MMP-unchanged cells; white arrow, MMP-changed cells. (b) The change in MMP over 24 h was quantified. (c) A549 and H1650 cells stained with JC-1 were sorted according to their MMP level by flow cytometry using a FACSort flow cytometer (BD Biosciences). Cells in the highest and lowest 20% MMP categories were labelled high- and low-MMP cells, respectively. (d) The proliferation rates of high- and low-MMP cells were determined by sulforhodamine B (SRB) assay. (e, f) High-MMP cells exhibited increased migration and invasion. Migration and invasion of high- and low-MMP cells were assessed by Transwell migration and invasion assays. Data are representative of at least three independent experiments. *P<0.05, **P<0.01, ***P<0.001 relative to high-MMP cells.
