Figure 3

Modulation of integrin expression inhibits cell proliferation, migration and invasion. A. Cell proliferation of 4T1 cells. 4T1 control, 4T1-GFP, 4T1-α5, and 4T1-α6-shRNA1 cells were seeded and MTT assays done at 24-hr intervals. MTT data were plotted based on the average absorbance value and standard deviation. The Y axis presents the absorbance at 572 nm; the X axis represents incubation time. Black curve: 4T1 control; red curve: 4T1-GFP cells; green curve: 4T1-α5 cells; blue curve: 4T1-α6-shRNA1 cells. ** p < 0.01 (as compared to GFP-4T1). We found that the in-vitro proliferation ability of 4T1 cells is inhibited by overexpression of integrin α5 and knockdown of integrin α6. B. A transwell migration assay was done for 4T1 (control), GFP-4T1, 4T1-α5, and 4T1-α6-shRNA1 cells. The number of cells that migrated to the lower surface of the filter membrane was counted in 5 random fields under a light microscope (×200). The ability of 4T1 cells to migrate was significantly diminished by overexpression of integrin α5 (p < 0.01) and knockdown of 4T1-α6-shRNA1 (p < 0.05). C. Representatives of cell migration figures for each cell type. D. A cell invasion assay was done for 4T1, 4T1-GFP, 4T1-α5, and 4T1-α6-shRNA1 cells. 0.1% crystal violet solution was used to stain the lower chamber of transwell. The number of cells that invaded the Matrigel and penetrated the transwell pore to the lower surface was counted in 5 random fields under a light microscope (×200). Overexpression of integrin α5 and knockdown of α6 inhibited the ability of 4T1 cells to invade (p < 0.01).