Effect of the EGFR inhibitors, gefitinib and erlotinib, on HNSCC cell invasion.

<p>(<b>A</b>) OSC19 cells were treated with the indicated concentrations of erlotinib, a small molecule inhibitor of EGFR, for 48 h and the effects on invasion assessed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031093#pone-0031093-g001" target="_blank">Figure 1</a>. Crystal violet staining of the membrane shows that erlotinib inhibited invasion of OSC19 cells in a concentration-dependent manner. (<b>B</b>) The invasive cells were counted and the results expressed as the mean number of invasive cells±SD/microscopic field, magnification: ×10. (<b>C</b>) Similarly, treatment of OSC19 cells with the indicated concentrations of gefitinib, a small molecule inhibitor of tyrosine kinase activity and, thus, of EGFR, inhibited cell invasion in a dose-dependent manner as indicated by crystal violet staining of the membrane. (<b>D</b>) The invasive cells from the experiment described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031093#pone-0031093-g003" target="_blank">Figure 3C</a> were counted and the results expressed as the mean number of invasive cells±SD/microscopic field, magnification: ×10. Significant reduction of cell invasion versus untreated control cells, ^¶<i>P</i><0.05, ^*<i>P</i><0.001.