Objective:To figure out the effect of somatostatin analogue Octreotide on proliferation and invasion of human hepatocellular carcinoma cell MHCC97-H and the underlying mechanism in vitro and in vivo.Methods:MHCC97-H cells were treated with Octreotide at the concentration of 0.2 ug/mL in vitro,proliferation related to time was evaluated.After treated with Octreotide at the concentration of 0.2 ug/mL for 48 h,MHCC97-H cells were observed by transmission electron microscope.Cell proliferation was detected by MTT assay after MHCC97-H cells were treated with Octreotide at different concentrations including 0.05,0.1,0.2,0.4,0.6 and 0.8 ug/mL for 36 h in vitro.27 nude mice,in which MHCC97-H tumor mass was planted orthotopically,were divided into 3 groups randomly including control group (intraperitoneal injection with equal volume normal saline; n=8),low dose treated group (intraperitoneal injection with Octreotide at 50 ug/kg.d; n=9) and large dose treated group (intraperitoneal injection with Octreotide at 200 ug/kg·d; n=10).All mice were raised for 35 d and sacrificed.The information about survival time,the weight at death point and the pathology change of liver and lung was collected.The expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases-2 (MMP-2) in mouse HCC tissues were detected by immunohistochemistry finally.Results:MTT assays showed that Octreotide inhibited the proliferation of MHCC97-H cells significantly.Apoptosis cells were found by transmission electron microscope after treatment with Octreotide at 0.2 ug/mL for 48 h in vitro.The proliferation was inhibited significantly by Octreotide in a dose-dependant manner (r=0.86,P＜0.01).Compared with control group,the treated group had the heavier weight at death point and lower intrahepatic metastasis ratio (P＜0.05),meanwhile,there was not significant difference in treated groups (P＞0.05).The positive expression ratios of VEGF and MMP-2 in treated groups were lower than those in control group (P＜0.05),while there was no apparent difference in treated groups (P＞0.05).Conclusion:Octreotide could inhibit the proliferation of MHCC97-H cells in vitro via inducing apoptosis and the inhibitory function acts in a dose-dependant manner.Octreotide could improve survival of mice with MHCC97-H cells and inhibit the metastasis of MHCC97-H cells in vivo.Regulation of VEGF and MMP-2 expression by Octreotide would be involved in its inhibition in vivo.