Up-regulation of SOCS3 by 5-aza-2'-deoxycytidine treatment inhibited cell migration and associated PYK2 expression, Tyr402 and ERK1/2 phosphorylations. (a) Decreased PYK2 expression, Tyr402 and ERK1/2 activations and migration of A549 cells were observed by SOCS3 up-regulation. A549 cells were treated with 5-aza-2'-deoxycytidine for 6 d, and cell lysates were analysed by western blot using the indicated antibodies. Elevated PYK2 expression, Tyr402 and ERK1/2 phosphorylations were found by the pretreatment of β-lactacystin. (b) PYK2 mRNA levels remained invariable regardless of treatment or not. The amplified PYK2 products were 629 bp in length. β-actin amplification demonstrated the consistency of PT-PCR. (c) Cell migration was suppressed by SOCS3 restoration, and the β-lactacystin pretreatment facilitated cell migration to some extent. The values are means of three replicates.