Figure 6

Invasive and Metastatic Potential of MCF-7 and MCF-7CLU. Panel A: In vitro invasive potential was analysed using a Boyden chamber Matrigel™ invasion assay. Cells that invaded through the 8 micron Matrigel™ membrane and attached to the bottom of the well were fixed with 1% gluteraldehyde, stained with crystal violet, allowed to dry and counted using a light microscope. Data represent the mean ± SEM of 3 independent experiments performed in quadruplicate for each cell line. SUM-159PT cells are shown as a positive control. *P < 0.05; MCF-7 vs MCF-7CLU and SUM-159PT. Panel B: Representative lung tissue sections from mice inoculated orthotopically with MCF-7 or MCF-7CLU were formalin fixed, paraffin embedded, sectioned and stained with hematoxylin and eosin. Incidence of metastatic lung deposits was monitored in animals 10 weeks after implantation. Arrow indicates MCF-7CLU metastatic foci to the lung. Lung sections from mice inoculated with the metastatic SUM-159PT are shown as positive controls. Bar: 100 microns.