P55PIK promotes angiogenesis of HT29 through upregulating vascular endothelial growth factor

Abstract

Objective To study the effect of p55PIK on colon tumor cells (HT29) secreting vascular endothelial growth factor (VEGF) and tumorgenesis,and the relationship between p55PIK and angiogenesis in tumors.Methods The tumor cells were infected by adenovirus coding p55PIK-GFP,and the mRNA and protein expression level of VEGF in blank control group,empty vector group and p55PIK vector group was detected by using real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting respectively.In animal study,nude mice xenograft model was made by injecting HT29 cells infected by adenovirus carrying control vector or p55PIK vector respectively.The effect of p55PIK on tumorgenesis was observed,and the expression of p55PIK,VEGF and CD31 in the xenograft of mice was detected by using immunohistochemitry.Results The mRNA level of VEGF in p55PIK vector group was 2.7 times higher in blank control group and empty control group,so was the protein level (P ＜ 0.01).Meanwhile,the tumorigenic ability and growth speed of the xenograft were increased.The average tumor weight in blank control group,empty vector group and p55 PIK vector group was (0.057 ± 0.040) g,(0.060 ±0.030) g and (0.225 ±0.070) g respectively (P ＜0.01).The expression of VEGF and CD31 in xenograft of mice was significantly increased in p55PIK-overexpression group.Conclusion Overexpressing p55PIK promotes angiogenesis by enhancing VEGF expression in tumor cells,which increases tumorigenesis eventually. Key words: p55PIK; Vascular endothelial growth factor; Angiogenesis ; Colon cancer