Objective      To determine the effects of theanine on the proliferation

apoptosis

and tubule formation of human umbilical vein endothelial cells (HUVECs)

and on tumor angiogenesis of lung cancer heterotopic xenograft.       Methods      HUVECs were treated with theanine at 6 different concentrations (0

25

50

100

200 and 400 mmol/L). MTT assay was used to measure cell viability. Flow cytometry was applied to analyze cell apoptosis. In vitro three-dimensional (3-D) model was employed for analyzing tube formation in vitro. Heterotopic lung adenocarcinoma xenograft of A549 cells was established in nude mice

and then these mice were divided into 2 groups (n=6). In theanine group

theanine was given at 100 mg/(kg·d) via intraperitoneal injection for 14 d

while the control group was given the same volume of normal saline. All mice were sacrificed at the end of treatment

and tumor masses were resected for the size. The expression of VEGF in the tumor and tumor microvessel density (MVD) were measured with immunohistochemical assays.       Results      Theanine treatment resulted in a decrease of cell proliferation

an increase in cell apoptosis and tubule formation of HUVECs in a dose-dependent manner (P0.01). Theanine also made a decrease in VEGF expression and MVD in the xenograft (P0.05).       Conclusion      Theanine suppresses the proliferation

induces cell apoptosis and reduces tube formation in a 3-D in vitro model in a dose-dependent fashion

and also

inhibits the angiogenesis in lung adenocarcinoma xenograft in nude mice.