Epirubicin Stimulates Gastric Cancer Cells Migration And Invasion And Its Underlying Mechanisms

Background and ObjectiveMigration and invasion are two common manifestations of patients with terminal cancer,which will contribute to tumor-related death in the end.Our previous data have showed that,activation of PI3K/Akt pathway is closely related to the epithelial-mesenchymal transition(EMT)process in gastric cancer cells.The expression of the epithelial cell marker E-cadherin,is decreased,while the mesenchymal cell marker N-cadherin,is increased during EMT.In addition,EMT promotes gastric cancer cell migration and invasion.Recently,we have noted that sometimes chemotherapy may accelerate the progression of tumor.It has been reported that,chemotherapy could promote cancer cell migration through impairing vascular endothelial and immune system in animal models.Besides,it was reported that Oxaliplatin induces EMT in colorectal cancer cell lines and increase its migration and invasion.However,it is still unclear about the effects of chemotherapy on migration and invasion in gastric cancer cells.In this study,we will investigate the effects of epirubicin on metastatic potentials in BGC823(poor differentiated cell line)and SGC7901(moderate differentiated cell line)gastric cancer cells,as well as its underlying molecular mechanisms.Materials and methods 1.Gastric cancer cell lines BGC823(poor differentiated)and SGC7901(moderate differentiated)were provided by the Department of Histology and Embryology of Zhengzhou University.2.The cytotoxic effects of epirubicin on gastric cancer cells were detected by MTT.3.The changes in cell morphology were observed using inverted light microscope.4.Explored the effect of epirubicin on the biological behaviors in gastric cancer cells.(1)The changes of cell migration ability after treatment with epirubicin were detected by wound healing assay.(2)The migration and invasion-associated proteins(MMP-2,MMP-9 and VEGF)were detected by Western blotting.5.Explored the mechanisms of epirubicin promoting migration and invasion.The EMT-associated protein levels(E-cadherin,N-cadherin)and the Phosphorylation levels of Akt were all detected by Western blottingting,with or without PI3K/Akt inhibitor Wortmannin(1?mol/L)or Ly294002(25?mol/L).Results: 1.The cytotoxic effects of epirubicin on cancer cells are dose-and-time dependent.MTT data shows that,cell mortality rate was positively correlated with drug concentration and treatment period.2.Cell morphologies were changed after the treatment of epirubicin.Compared to the control group,the morphologies of the epirubicin treated-gastric cancer cells changed a lot,including the lose of cell polarity,and the weakened intercellular connection.Besides,most cells were in spindle shape,the typical morphology of mesenchymal cells.3.Epirubicin promoted gastric cancer cell migration and invasion.Wound healing assay and Western blotting data shows that,epirubicin-treated cells migrated faster than control group,and the expression of MMP-9(related with cell migration and invasion)increased,so did the angiogenesis-associated protein VEGF.(P < 0.05)4.Epirubicin induced EMT in gastric cancer cells to promote migration and invasion.Western blotting data shows that,the protein expression of N-cadherin was markedly increased,while E-cadherin was reduced,compared with those in control group,(P < 0.05),indicating that epirubicin induced EMT in gastric cancer cells.5.Epirubicin activated PI3K/AKT pathway to induce EMT in gastric cancer cells.Western blotting data shows that,epirubicin increased the phosphorylation of Akt.And PI3K/Akt inhibitor(Wortmannin or Ly294002)could reduce the phosphorylation of Akt and the expressions of MMP-9,VEGF and N-cadherin,while increase the expression of E-cadherin.(P < 0.05)ConclusionsChemotherapeutic drug epirubicin can induce epithelial-mesenchymal transition,and promote migration and invasion via PI3K/Akt pathway in gastric cancer cells.