Effects of Pyk2-siRNA on BDNF-induced cell invasion. Pyk2 knockdown cells had TrkB expression unaffected, while the activation of ERK promoted by BDNF treatment was largely reduced (A). In addition, the invasive number of Pyk2-siRNA transfected A549 cells was significantly decreased and less than those non-silencing and control cells (B). Original magnification, all ×400. The data are representative of three replicates.