Effects of VPA or β-catenin on EGFR, β-catenin, and Ras regulation. (A-B) NPCs grown in 10 ng/ml bFGF were treated with 1 mM VPA for 48 h or different periods of time. (C-D) NPCs were transfected with pcDNA3.0 or Flag-β-catenin-pcDNA3.0 and grown in the presence of 10 ng/ml bFGF. (A-C) Whole-cell lysates were then subjected to immunoblotting for detection of p-GSK3β (Ser-9), β-catenin, Pan-Ras, p-ERK, p21Cip/WAF1, Tuj1, EGFR, or β-actin. (D) Immunofluorescent labeling was performed for Flag or BrdU. Nuclei were counterstained with DAPI.