Abstract:

Objective To investigate the effect of poiaic acid （PA） on the migration， invasion， and epithelial-mesenchymal transition（EMT） of the pancreatic cancer PANC-1 cells by up regulating the expressions of activating transcription factor 3 （ATF3） and heat shock protein family A member 6（HSPA6），and to clarify its possible mechanism. Methods The pancreatic cancer PANC-1 cells were divided into blank control group and different concentrations （2，5，10，20，30，40， and 50 μmol·L^－1）of PA groups，and the activities of the PANC-1 cells in various groups were detected by CCK-8 method. The PANC-1 cells were treated with different concentrations （0， 10， 30， and 50 μmol·L^－1） of PA， and the migration and invasion abilities of the PANC-1 cells were detected by Transwell chamber experiment， and the expression level of EMT-related proteins in the PANC-1 cells were detected by Western blotting method. A total of 10 BALB/c nude mice were randomly divided into control group and PA group， and there were 5 mice in each group. The PANC-1 cells were subcutaneously injected into the nude mice. When the tumor volume reached 60 mm³， the nude mice in PA group were intraperitoneally injected with 25 mg·kg^－1 PA， and the nude mice in control group were injected with the same volume of normal saline， the tumor volume and tumor weight of the mice in various groups were measured， and the expressions of Ki-67 in xenografted tissue of the mice in various groups were detected by immunohistochemistry. The differentially expressed genes of the PA-treated and PA-untreated pancreatic cancer cells in the GSE64111 Dataset were analyzed by GEO2R software. The PANC-1 cells were treated with different concentrations（0 and 30 μmol·L^－1） of PA， and the expression levels of HSPA6 and ATF3 proteins in the PANC-1 cells were detected by Western blotting method. The PANC-1 cells treated with 30 μmol·L^－1 PA were randomly divided into si-NC group and si-ATF3 group， and the cells were transfected with control siRNA and ATF3 siRNA， respectively. The expression levels of HSPA6 and ATF3 proteins and EMT-related proteins in the PANC-1 cells in various groups were detected by Western blotting method， and the migration and invasion abilities of the cells were detected by Transwell chamber experiment. Results The CCK-8 experiment results showed that compared with blank control group， the activities of the PANC-1 cells in different concentrations of PA groups were significantly decreased （P<0.05）.The results of Transwell chamber experiment showed that compared with blank control group， the migration and invasion abilities of the PANC-1 cells in different concentrations of PA groups were significantly decreased （P<0.05），and showed a concentration depent manner. The Western blotting results showed that compared with blank control group， the expression levels of E-cadherin protein in the PANC-1 cells in different concentrations of PA groups were significantly increased （P<0.05）， while the expression levels of N-cadherin and Vimentin proteins were significantly decreased （P<0.05）.The results of tumor formation in the nude mice showed that compared with control group， the volume and weight of the xenografted of the mice in PA group were significantly decreased （P<0.05）；the immunohistochemistry results showed that the Ki-67 staining in xeografted was shallow； the GEO2R software analysis and Western blotting results showed that compared with blank control group， the expression levels of HSPA6 and ATF3 proteins in the PANC-1 cells in PA group were significantly increased （P<0.05）. The Western blotting results showed that compared with si-NC group， the expression levels of ATF3， HSPA6， and E-cadherin proteins in the PANC-1 cells in si-ATF3 group were significantly decreased （P<0.05）， while the expression levels of N-cadherin and Vimentin proteins were significantly increased （P<0.05）.The Transwell chamber experiment results showed that compared with si-NC group， the migration and invasion abilities of the PANC-1 cells in si-ATF3 group were significantly increased （P<0.05）. Conclusion PA inhibits the migration， invasion， and EMT of the pancreatic cancer cells by up-regulating the expressions of HSPA6 and ATF3， thus play an anti-pancreatic cancer effect.

Key words: Pachymic acid, Pancreatic neoplasm, PANC-1 cells, Epithelial-mesenchymal transition, Cell migration, Cell invasion, Activating transcription factor 3, Heat shock protein family A member 6