BACKGROUND: Chemotaxis is an important step during the invasion of carcinoma cells. And integrins are most important receptors mediating interaction between cells and extracellular matrix (ECM). This study was designed to study integrin beta1 mediating chemotaxis of hepatocellular carcinoma (HCC) cells to laminin(LN).
METHODS: A micropipette technique was adopted to investigate the effect of blockade of integrin beta1 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 positioned 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 and plotted against time to obtain a pseudopod growth curve. The integrin beta1 subunit on the surfaces of HCC cells were analyzed by flow cytometry.
RESULTS: In dual pipette chemotaxis experiment, when the two pipettes were filled with LN（50 μg/ml, 200 μg/ml), pseudopods extended from the HCC cell into each of the pipettes nearly symmetrically, ie, with nearly identical maximum pseudopod length and similar pseudopod growth curves. Upon addition of anti-CD29 （20 μg/ml） to one of the pipettes, pseudopod protrusion was blocked nearly completely while protrusion into the opposite pipette became more evidently, with a larger maximum length.  Expression of integrin beta1 was up to 95.78% to cells chosen in the experiment.
CONCLUSION: Integrin beta1 subunit was an important constituent receptor subunit for mediating chemotactic pseudopod protrusion of HCC cell to LN.