Vav3 is linked to poor prognosis of pancreatic cancers and promotes the motility and invasiveness of pancreatic cancer cells

Background/objectives: The aim of this study was to investigate the role of the guanine nucleotide exchange factor Vav3 in the motility and invasiveness of pancreatic ductal adenocarcinoma (PDAC) cells. Methods: Immunohistochemistry was used to determine whether high Vav3 expression in human PDAC tissues is correlated with poor prognosis. Immunocytochemistry was used to determine the association and intracellular distribution of Vav3, Rac1 and Akt in PDAC cells. Phosphoprotein array analysis was performed to determine the Vav3-associated intracellular signaling pathways. Immunocytochemistry and Matrigel invasion assays were used to examine the effects of Vav3 on the formation of cell protrusions and PDAC cell invasion. Results: Expression of Vav3 in PDAC tissue was significantly correlated with overall survival. Vav3 was localized in cell protrusions of migrating PDAC cells. Knockdown of Vav3 inhibited the motility and invasiveness of PDAC cells through a decrease in cell protrusions. The levels of active Rac1 or active Akt were not associated with the concentration of Vav3 in cell protrusions. The Vav3-dependent promotion of motility and invasiveness was not modulated by Rac1 or Akt. Additionally, knockdown of Vav3 increased phosphorylated WNK1 in PDAC cells, and knockdown of WNK1 inhibited the motility and invasiveness. This study suggests that Vav3 can be a useful marker for predicting the outcome of patients with PDAC and that Vav3 can promote PDAC cell motility and invasion through association with dephosphorylation of WNK1. Conclusions: Vav3 was accumulated in cell protrusions, contributed to the formation of membrane protrusions, and thereby increased the motility and invasiveness of PDAC cells. (C) 2016 IAP and EPC. Published by Elsevier B.V. All rights reserved.