Effects of glycogen synthase kinase-3β knock-down on growth and angiogenensis of human pancreatic cancer xenografts in nude mice

Abstract

Objective To study the effects of glycogen synthase kinase-3β (GSK-3β) knock-down on the growth and the angiogenesis of human pancreatic cancer xenografts in nude mice.Methods Panc-1 cells were inoculated subcutaneously in athymic nude mice to establish xenograft models.The mice were divided into negative control group,vector control group and experimental group (n =8 each).After 8 weeks,the mice were killed.Tumor volume and weight were measured in nude mice beating xenografts.The inhibitory rate was calculated according to the weights of xenografts.The expression of proliferating cell nuclear antigen (PCNA) and CD31 proteins was assessed by using immunohistochemitry.Proliferation index (SPF) and microvessel density (MVD) were respectively counted according to PCNA and CD31 staining.The expression level of vascular endothelial growth factor (VEGF) was detected by using real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting.Results As compared with control group,the growth rate of human pancreatic cancer xenografts of nude mice in experimental group was decreased notably (P ＜0.05) and the inhibitory rate was 35.17％.In experimental group,the SPF index [(69.55 ± 2.64) ％] was significantly higher than in the negative control group [(83.26 ±2.83) ％] and the vector control group [(83.65 ± 2.65) ％] (P ＜ 0.05).In experimental group,the MVD index [(17.2 ± 2.9)] was higher than in the negative control group [(27.2 ± 3.1)] and the vector control group [(27.2 ± 3.1)] (P ＜ 0.05).The expression levels of VEGF mRNA and protein [(0.089 38 ±0.008 84 and 0.450 6 ±0.014 6) respectively] were significandy higher in xenografts tissues than in the negative control group (0.139 06 ± 0.003 35 and 0.675 8 ± 0.026 2 respectively) and the vector control group (0.138 89 ± 0.001 75 and 0.664 5 ± 0.010 5 respectively),but there was no significant difference between the negative control group and the vector control group (P ＞ 0.05).Conclusion In vivo GSK-3β knock-down can inhibit the growth and the angiogenesis of human pancreatic cancer xenografts in nude mice,which may be related to the down-regulation of VEGF. Key words: Pancreatic cancer; Glycogen synthase kinase-3β ; Microvessel density ; Vascular endothelial growth factor