Involvement of platelet-derived growth factor (PDGF)-Rβ in the regulation of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3K)/Akt cell signaling pathways. (A) Whole cell lysates from A172 cells transfected with either nonsense (Non) or PDGF-Rβ short interfering (si)RNAs were subjected to immunoblot analysis using antibodies specific for MAPKs and PI3K/Akt signaling. PDGF-Rβ siRNA, but not Non siRNA inhibited PDGF-BB-mediated phosphorylation of extracellular-signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38 and Akt pathways. All the data are presented as mean ± SD of three individual experiments. **P <0.01, ***P <0.001 versus control group, ##P <0.01, ###P <0.001 versus PDGF-BB-treated group.