| BackgroundDiabetes is a group of metabolic diseases characterized by hyperglycemia.It can cause many complications,among which vascular complication is the leading cause of death.Endothelial cell injury is the first pathological phenomenon in the process of diabetic vascular injury.In diabetes,long-term hyperglycemia results in oxidative stress and induces vascular endothelial cell injury.When the body is subject to harmful stimulation,the oxidation and anti-oxidation system become imbalance,causing tissue and cells oxidative damage.Studies found that,in the diabetic state,ROS production increases and causes cardiovascular damage.There are also many antioxidant enzymes in the body,such as catalase(CAT),glutathione(GPX)and superoxide dismutase(SOD).They constitute an antioxidant system that maintains a dynamic equilibrium of oxidation and anti-oxidation.Glucagon-like peptide 1(GLP-1)is a novel drug for diabetes treatment.It not only reduces blood sugar,but also inhibits oxidative stress-induced damage to vascular endothelial cells,but the mechanism of its antioxidant stress injury has not yet been elucidated.In addition,activation of the GLP-1 receptor directly promotes cell proliferation and increases cell viability,such as islet beta cells,neurons,fibroblasts and cardiomyocytes.Therefore,does GLP-1 also have similar proliferative effects on tumor cells?Does long-term GLP-1 administration be at risk of carcinogenesis?There is no definite conclusion yet.Furthermore,oxidative stress has been shown to induce epithelial-mesenchymal transition(EMT)in tumor cells.Whether the antioxidant function of GLP-1 will affect the EMT transformation of tumor cells has not been reported.Objective1.To investigate the protective effect of GLP-1 on endothelial cell oxidative damage induced by hydrogen peroxide.2.To investigate the effect of GLP-1 on proliferation and EMT of PANC-1 cell.Methods1.Human umbilical vein endothelial cells(HUVEC)were randomized into six groups including Control,H2O2,GLP-1,H2O2+10nmol/L GLP-1,H2O2+100nmol/L GLP-1 and H2O2+1000nmol/L GLP-1 groups.Cell F-actin,intracellular ROS and the protein of CAT and GPX1 were measured by immunofluorescence microscopy.Cell apoptosis was evaluated by flow cytometry.The p-mTOR,CAT,GPX1 protein expression level was tested by Western Blotting.The gene expression of CAT,SOD2 and GPX1 were tested by Quantitative Real-time PCR.2.The proliferation of pancreatic cancer cells(PANC-1)was detected by CCK8 kit.The migration of PANC-1 cells was detected by cell scratch test and transwell assay.Real-time fluorescence quantitative polymerase chain reaction(QPCR)was used to detect epithelial-mesenchymal transition(EMT)-related gene expression of E-cadherin and N-cadherin.Results1.Hydrogen peroxide(H2O2)induced cell F-actin damage,ROS production and apoptosis in HUVEC cells.GLP-1 rescued the cell damage,decreased the ROS and apoptosis.GLP-1 reversed the down-regulation of p-mTOR protein induced by H2O2,whereas exenatide(9-36),a GLP-1 receptor antagonist,abolished this effect.Moreover,Real-time PCR showed that GLP-1 up-regulated gene expression of CAT,SOD2 and GPX1.Furthermore,Western Blot showed that GLP-1 up-regulated protein expression of CAT and GPX1.2.GLP-1 had no significant effect on PANC-1 cells proliferation,but inhibited the migration of PANC-1 cells.H2O2 induced EMT by down-regulating E-cadherin gene expression and up-regulation of N-cadherin gene expression.GLP-1 inhibits EMT in PANC-1 cell by increasing the expression of E-cadherin and decreasing the expression of N-cadherin.Conclusions1.GLP-1 may play a protective role by increasing the expression of p-mTOR protein and activating the mTOR pathway.In addition,GLP-1 up-regulated expression of CAT,SOD2 and GPX1,inhibit production of ROS and protect endothelial cells against oxidative stress injury.2.GLP-1 had no effect on PANC-1 cells proliferation,but inhibited the migration of PANC-1 cells.3.GLP-1 inhibits EMT induced by H2O2 in pancreatic cancer(PANC-1)cells... |
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