The Effect Of Theanine On Angiogenesis In Lung Cancer

Background and Objective:Angiogenesis is a key step in the growth, invasion,and metastasis of most solid tumours,new vessels can provid nutrient and oxygen to the malignant cells,it can also deliver tumor cells to other sites and continue to grow with inducing more new vessels, leading to tumor migrate.So targeted to neovascularization, inhibition of tumor angiogenesis is of great significance in inhibition of tumor growth and metastasis.The main procedure of angiogenesis include:matrix degradation and remodeling, endothelial cells proliferation and migration,lumen formation.So endothelial cells is an important target in anti-angiogenesis.Theanine, a characteristic nonprotein amino acid of tea,is found can anti-tumor in several processes and improve the sensitivity of some chemotherapy drugs,while reduce the side effects.In recent years,we also found theanine can decrease VEGF exprssion in tumor of nude mice,however, the number of such reports is still very limited. So there is need to futher investigate wether theanine affect endothial cells and lung cancer.In this study,we first investigate whether theanine affect human umbilical vein endothelial cells (HUVECs) proliferation and apoptosis,then investigate whether it affect angiogenesis in vitro3-D model,finally,we construct lung adenocarcinoma Xenografts in nude mice model to investigate whether it affect lung cancer angiogenesis in nude mice.Methods:The study include two part:in vitro and in vivo.In vitro part,we used six concentrations of theanine to culture HUVECs,then use MTT to reflect the effect of theanine in endothial cells;use flow cytometry to analyse cell apoptosis; use in vitro three-dimensional(3-D) model to analyse angiogenesis in vitro.In vivo part,the nude mice is divided in two groups:the theanine group,given theanine via intraperitoneal injection;the control group,given the same vulume of normal saline(NS)in the same way.Then count the MVD of tumor to analyse the effect of theanine in angiogenesis at heterotopic lung cancer.Results:1)Effect of theanine on the proliferation of endothelial cells:Compared with the control group, after different concentrations of theanine on HUVECs, cell survival rate reduced,inhibition rate increased.As the processing time and the concentration increase, HUVECs growth inhibition rate increased gradually.compare between groups, the difference statistically significant (P<0.001).2)Effect of theanine on apoptosis of endothelial cells:after different concentrations of theanine on HUVECs, results show that with increasing concentration of theanine, apoptosis of HUVECs increase gradually.the difference statistically significant (P<0.001).3)Effect of theanine on angiogenesis in vitro3-D model:compare between groups,MVD in theannie treatment group declined, theanine dose-dependent suppresse MVD(P<0.001).4)Effect of theanine on nude mice transplantation tumor MVD:Compared with the control group,nude mice transplantation tumor MVD of theanine group decreased markedly(P<0.05).Conclusion:(1)theanine can concentration-dependent inhibit endothelial cell proliferation,induce endothelial cell apoptosis.(2)Theanine can concentration-dependent inhibit angiogenesis in vitro3-D model.(3)Theanine can inhibite nude mice transplanted tumor to form neovascularization.