BACKGROUND: Although there are many studies on the mechanism of chemoresistance in cancers, studies on the relations between WNT5 A and chemoresistance in pancreatic cancer are rare. The present study was to examine the role of WNT5 A in the regulation of cell cycle progression and in chemoresistance in pancreatic cancer tissues and cell lines.METHODS: Fresh pancreatic cancer and paracarcinoma tissues were obtained from 32 patients. The expressions of WNT5 A,AKT/p-AKT and Cyclin D1 were detected by immunohistochemistry,and the correlation between WNT5 A expression and clinicopathological characteristics was analyzed. The relationship between WNT5 A expression and gemcitabine resistance was studied in PANC-1 and MIAPaCa2 cell lines. The effect of WNT5 A on the regulation of cell cycle and gemcitabine cytotoxicity were investigated. The associations among the expressions of p-AKT,Cyclin D1 and WNT5 A were also analyzed in cell lines and the effect of WNT5 A on restriction-point(R-point) progression was evaluated.RESULTS: WNT5 A, p-AKT and Cyclin D1 were highly expressed in pancreatic cancer tissues, and the WNT5 A expression was correlated with the TNM stages. In vitroWNT5 A expression was associated with gemcitabine chemoresistance. The percentage of cells was increased in G0/G1 phase and decreased in S phase after knockdown of WNT5 A in PANC-1. WNT5 A promoted Cyclin D1 expression through phosphorylation of AKT which consequently enhanced G1-S transition and gemcitabine resistance. Furthermore, WNT5 A enhanced the cell cycle progression toward R-point through regulation ofretinoblastoma protein(pRb) and pRb-E2 F complex formation.CONCLUSIONS: WNT5 A induced chemoresistance by regulation of G1-S transition in pancreatic cancer cells. WNT5 A might serve as a predictor of gemcitabine response and as a potential target for tumor chemotherapy. BACKGROUND: Although there are many studies on the mechanism of chemoresistance in cancers, studies on the relations between WNT5 A and chemoresistance in pancreatic cancer are rare. The present study was to examine the role of WNT5 A in the regulation of cell cycle progression and in chemoresistance in pancreatic cancer tissues and cell lines. METHODS: Fresh pancreatic cancer and paracarcinoma tissues were obtained from 32 patients. The expressions of WNT5 A, AKT / p-AKT and Cyclin D1 were detected by immunohistochemistry, and the correlation between WNT5 A expression and The relationship between WNT5 A expression and gemcitabine resistance was studied in PANC-1 and MIAPaCa2 cell lines. The effect of WNT5 A on the regulation of cell cycle and gemcitabine cytotoxicity were investigated. The associations among the expressions of p- AKT, Cyclin D1 and WNT5 A were also analyzed in cell lines and the effect of WNT5 A on restriction-point (R-point) progression was evaluated.RESULTS: WNT5 A, p-AKT and Cyclin D1 were highly expressed in pancreatic cancer tissues, and the WNT5 A expression was correlated with the TNM stages. In vitro WNT5 A expression was associated with gemcitabine chemoresistance. The percentage of cells was increased in G0 / G1 phase and decreased in S phase after knockdown of WNT5 A in PANC-1. WNT5 A promoted Cyclin D1 expression through phosphorylation of AKT which was enhanced in G1-S transition and gemcitabine resistance. progression toward R-point through regulation ofretinoblastoma protein (pRb) and pRb-E2 F complex formation. CONCLUSIONS: WNT5 A induced chemoresistance by regulation of G1-S transition in pancreatic cancer cells. WNT5 A might serve as a predictor of gemcitabine response and as a potential target for tumor chemotherapy.