Figure 3. Stable knockdown of β4-integrin in SW620 cells reduced cell migration, invasion, and tumorigenicity.

(A) Stable β4-integrin knockdown clones were generated from SW620 cells, using β4-integrin-pBabe retrovirus and selected in 1μg/ml of puromycin. Expression of β4-integrin in SW620 stable clones was verified by western blotting with β-actin as loading control. (B) Migration assay using SW620 cells, two vector control clones, and three β4-integrin knockdown clones was performed as described earlier. Data are presented as mean ±SD from three independent wells. ^***p<0.001 compared to control. (C) Invasion assay through Matrigel was performed using above cells as described in Materials and Methods. Data are presented as the mean ±SD from three independent wells. ^***p<0.001 compared to control. (D and E) Decrease in anchorage-independent growth of β4-knockdown clones. Soft agar assays were performed in 35-mm dishes and colonies were allowed to grow for 14 days. Total number of colonies grown on soft agar was counted and shown. Each data point is the average of three values determined from three independent plates. Pictures were taken with a magnification of 200X. These experiments were performed four times in triplicate with similar results.