DADS Inhibit EMT In Gastric Cancer MGC803 Cells Through Downregulation Of TGF-β1

Purpose: On the basis of before researches, this project will further explore DADS inhibits human gastric carcinoma cells EMT through downregulation of TGF-β1 and its molecular mechanism through TGF-β1-mediated Wnt/β-catenin pathway. The research may lay the theoretical foundation for the targets of DADS’ inhibiting migration and invasion of gastric cancer cell.Methods: Human gastric carcinoma cells MGC803 were divided into untreated group, DADS-treated group, the exogenous TGF-β1-treated group, the TGF-β1-and TGF-β1-inhibitor SB431542-treated group, the TGF-β1-and-DADS-treated group, the TGF-β1-and-Rac-1-inhibitor NSC23766-treated group. RT-PCR and Western blot were used respectively to detect the expressions of TGF-β1 、 β-catenin 、 Rac-1 、E-cadherin、Vimentin of each group. Nude mice tumorigenicity experiment observed growths of transplanted tumors of each group and immunohistochemistry detected the expressions of Ki-67, CD34, E-cadherin and Vimentin of tumor tissues.Results: RT-PCR and Western blot showed that DADS can time-dependently down-regulate the expressions of TGF-β1、Rac-1、β-catenin、Vimentin m RNA and protein and time-dependently up-regulate the expressions of E-cadherin m RNA and protein with 48h-treated one showing the best effect(P < 0.05). Treated by exogenous TGF-β1, TGF-β1、Rac-1、β-catenin、Vimentin m RNA and protein of Cell MGC803up-regulated significantly while the E-cadherin m RNA and protein down-regulated significantly(P<0.05). On the contrary, treated by DADS, SB431542 and NSC23766 respectively, the expressions of TGF-β1 、 Rac-1 、 β-catenin 、 Vimentin m RNA and protein down-regulated significantly while E-cadherin m RNA and protein up-regulated significantly(P < 0.05). The nude mice tumorigenicity experiment showed that compared with the untreated group, the growth rate and volume of transplanted tumors of DADS-treated group were obviously reduced(P < 0.05), while the growth rate and volume of transplanted tumors of TGF-β1-treated group increased significantly(P<0.05). Besides, the respective addition of DADS, SB431542 and NSC23766 can inhibit TGF-β1’s promotion on the growth rate and volume of transplanted tumors(P<0.05). Immunohistochemical assay revealed that compared with untreated group, Ki-67, CD34 and Vimentin positive protein of DADS-treated group reduced significantly, while E-cadherin positive protein increased significantly.Instead, Ki-67, CD34 and Vimentin positive protein of TGF-β1-treated group enhanced obviously, while E-cadherin protein positive expression decreased obviously.Compared with TGF-β1-treated group, Ki-67, CD34, Vimentin positive protein of TGF-β1 and SB431542 treated group, TGF-β1 and DADS treated group, TGF-β1 and NSC23766 treated group reduced obviously while E-cadherin protein increased significantly.Conclusion:1. TGF-β1 can promote the growth of Cell MGC803 and transplanted tumors.2. DADS can down-regulate the TGF-β1and inhibit the growth of Cell MGC803 and transplanted tumors.3. SB431542 and NSC23766 can weaken the growth of TGF-β1’s promotion on Cell MGC803 EMT and transplanted tumors.