The effect of induced FAK and FAK-CD in MCF-7-Tet-ON cell line on cell growth, rounding, adhesion and soft agar colony formation in vitro. A, FAK-CD induction with doxycycline causes increased rounding of MCF-7-Tet-ON cells. The ratio of rounded cells cultivated either with doxycycline 2 μg/ml for 6 days or without doxycycline treatment (Dox+/Dox- ratio) is shown. Bars show average of three independent field counts ± standard deviations. *, p < 0.05, Student's t-test. B, Cells with doxycycline-induced FAK had increased cell growth in vitro, while cells with doxycycline-induced FAK-CD expressed decreased cell growth. MCF-7-Tet-ON-TRE-2 control, -FAK or -FAK-CD cells were grown without and with doxycycline for 1–8 days and the cell number of viable cells detected with trypan blue dye is plotted on the graph. *, p < 0.05, Student's t-test. Bars show average ± standard deviations of three independent experiments. C, Cells with doxycycline-induced FAK expressed increased cell adhesion on collagen, while cells with induced FAK-CD had decreased adhesion. The doxycycline-induced adhesion is expressed relative to the adhesion of cells without doxycycline. Bars show average ± standard deviations of three independent experiments. *, p < 0.05, Student's t-test. D, Cells with doxycycline-induced FAK had increased soft agar colony formation, while cells with FAK-CD overexpression had decreased colony formation. The number of soft agar colonies on plates with doxycycline is expressed relative to the number of colonies on plates without doxycycline *, p < 0.05, Student's t-test.