Abstract
PURPOSE: Previous studies have shown the antitumor activity of melatonin against a wide range of human cancers; however, the impact of melatonin on gastric cancer growth remains to be illustrated. This study aimed to investigate the activity of melatonin against gastric cancer growth in a chick embryo tumor xenograft model and explore the possible mechanisms. MATERIALS AND METHODS: The growth of gastric cancer SGC-7901 cells was measured using MTT assay, and a chick embryo tumor xenograft model was generated to observe the effect of melatonin on gastric cancer growth in vivo. In addition, the VEGF and angiogenin secretion was measured in the supernatant of chick embryo tumor xenograft models with ELISA. RESULTS: MLT treatment inhibited the growth of SGC-7901 cells at a concentration-dependent manner, and treatment with MLT at 1 mM was found to markedly reduce the volume and weight of tumors bearing the allantois of chicken embryos. ELISA showed that MLT at concentrations of 0.0041, 0.012, 0.037 and 0.11 had no remarkable impact on VEGF and angiopoietin secretion, while MLT at 1 mM significantly suppressed VEGF and angiopoietin production in chick embryo tumor xenograft models with SGC-7901 cells (P = 0.023). CONCLUSION: Our data demonstrate that MLT inhibits gastric cancer growth in vitro at a concentration-dependent manner, and suppresses angiogenesis of the chick embryo tumor xenograft model with SGC-7901 cells through inhibiting VEGF and angiogenin secretion. Further studies are needed to investigate the therapeutic potential of MLT for gastric cancer as compared to drugs clinically approved.