Alphastatin Inhibits Tumor Angiogenesis In Nude Mice Bearing Human Gastric Cancer Cells

AbstractGastric cancer is one of the most common disease of malignant tumors which are harmful to health.Surgical resection and postoperative chemotherapy are the main methods to treat this disease for decades.Previous studies proved that angiogenesis play important role in gastric cancer development and metastasis.Recently, angiogenesis inhibitors have become the focus of tumor treatment,and some agents are in clinical trial.Alphastatin is a potent agent inhibit endothelial cells tubular formation and murine CT26 tumor growth.On the base of this,we treated gastric cancer with alphastatin in nude mice xenografts model.The aims of this study was to find out the feasibility and efficiency of alphastatin in the treatment of malignant tumors,and furthermore investigate the mechanisms involved in these process.All of these were to provide experiment data to explain the biological functions of alphastatin.Human endothelial cells were isolated using standard method.We observed the effects of alphastatin on HUVECs migration,proliferation, and tubular formation respectively.In;vitro results showed alphastatin had no significant effects on endothelial cells proliferation and cytotoxicity.But it markedly inhibited HUVECs migration induced by HGF and Matrigel tubular formation in a dose-dependent manner.Then we investigated the effect of alphastatin on Matrigel Plug angiogenesis and nude mice tumor growth bearing human gastric cancer cells.BGC823 cells were injected subcutaneously into the hind limb and animal tumor models were established.2 weeks after treatment,tumor size,weight and microvessel density were analysedJn vivo results showed that alphastatin significantly inhibited nude mice tumor volume and weight in a dose-dependent manner.Histopathology results proved that microvessel density in alphastatin treated group was less than PBS group.On the base of in vitro and in vivo assay,we investigated the cellular ormolecular mechanisms that alphastatin showed biological functions. In view of the theory that sphingolipid factor play important role in angiogenesis.We detected endothelial cells derived from tumor tissue SPK activity. Results showed that alphastatin could downregulate endothelial cells SPK activity,reducing intracellular SIP production in a concentration-dependent manner.Conclusions:(l).Alphastatin may affect some angiogenic factors ,rather than HUVECs themselves.(2).Alphastatin markedly reduce nude mice bearing human gastric cancer growth and tumor angiogenesis,thus poss the potency to become new potent anti-tumor agents. (3).Downregulating tumor tissue endothelial cells SPK activity is one of the important mechanisms involved in the process of angiogenesis inhibition.