Fig. 5

Effect of the five anti-EGFR sdAbs on inhibiting cell migration and invasion by the transwell assay. a–f The inhibition of cancer cell migration by anti-EGFR sdAbs was shown. Cells in the medium containing 1% FBS and the five purified anti-EGFR sdAbs (aEG1B4, aEG2C7, aEG2E12, aEG4D9 and aEG6B2) at different concentrations (0, 25, 50 or 100 µg/ml) were seeded into the upper chambers of transwells. Two sdAbs (aVE201 and aHer2-13C1) were included as negative controls. After 24 h of incubation, cells which migrated to the bottom chamber membrane were stained with 0.1% crystal violet. Images were photographed. Crystal violet on the bottom chamber membrane was dissolved in 33% acetic acid solution, and absorbance at 570 nm was measured. a, b A549 cells; c, d MCF-7 cells; e, f DU145 cells. Detecting cell invasion (g–l) was performed as described above except each upper chamber of transwells was coated with 60 μl of diluted matrix gel overnight at 37 °C before cells and sdAbs were added into transwells. g, h A549 cells; i, j MCF-7 cells; k, l DU145 cells. Data are shown as mean ± S.D. (n = 5). *P < 0.05 and **P < 0.01 vs. the respective control (0 µg/ml)