Abstract: Objective To explore the effect of breast tumor deriving vascular endothelial growth factor(VEGF)on the immune functions of vascular endothelial cells(VEC). Methods Human umbilical vein endothelial cells(HUVEC)were divided into 4 groups: Media group, T-sup group, VEGF group and SU5416 group. The levels of VEGF, PGE₂, IL-6 and IL-12 in 24 h conditioned cultural supernatants were assayed by ELISA. Experiments of CCK-8, ELISPOT and flow cytometry were processed on peripheral blood T cells after treatment with the 24 h conditioned cultural supernatants. Results The levels of VEGF, PGE₂ and IL-6 were increased in the T-sup group, compared with those in Media group(P<0.05), and the level of IL-12 was decreased in the T-sup group(P<0.05). Compared with Media group, the conditioned media in T-sup group promoted the apoptosis of T-lymphocytes, suppressed the expression of IFN-γ, and reduced the production of IFN-γ in CD8⁺ T cells. The levels of VEGF, PGE₂ and IL-6 were increased and the level of IL-12 was decreased in the VEGF group, compared with those in Media group. But there were no statistically significant differences after the treatment of SU5416, a VEGF receptor antagonist. Conclusion Breast tumor cells suppress the immune fuctions of VEC, which is closely related with the high expression of VEGF.

Key words: Breast cancer, Vascular endothelial cells, Immune suppression, Vascular endothelial growth factor