Integrin beta1 mediates hepatocellular carcinoma cells chemotaxis to laminin

OBJECTIVE: To study the effects of integrin beta1 on the chemotaxis of hepatocellular carcinoma (HCC) cells to laminin (LN). METHODS: A micropipette technique was adopted to investigate the effect of integrin beta1 blockade on pseudopod protrusion of HCC cells in response to LN stimulation. Chemotactic pseudopod protrusion of a HCC cell was evaluated using a dual-pipette set-up, in which two pipettes filled with LN solution were positional in close contact with the same cell, and pseudopod protrusion into each pipette was viewed dynamically and recorded with a tape recorder. The lengths of pseudopods were measured, then plotted against time to obtain a pseudopod growth curve. The integrin beta1 subunit on the surfaces of HCC cells was analyzed by flow cytometry. RESULTS: In dual pipette chemotaxis experiment, when the two pipettes were filled with LN (50microg/ml, 200microg/ml), pseudopods extended from the HCC cells into each of the pipettes nearly symmetrically. Upon addition of anti-CD29 (20microg/ml) to one of the pipettes, the pseudopod protrusion was blocked almost completely, while the pseudopod protrusion into the opposite pipette became more evidently, with larger maximum length. The expression rate of integrin beta1 on the cells was up to 95.78%. CONCLUSION: Integrin beta1 subunit is the important receptor for mediating HCC cells chemotaxis to laminin.