胃癌组织VEGF表达及血清VEGF浓度与DCs浸润及其活性的关联分析

Relationship of VEGF expression level on gastric cancer cells and serum VEGF level with density and activity of tumor-infiltrating dendritic cells

目的:观察胃癌患者肿瘤组织VEGF表达和血清VEGF水平与肿瘤浸润DCs密度的关联,胃癌组织VEGF阳性DCs频率与临床病期的关联,以及胃癌患者外周血单核细胞来源DCs表面HLA-DR和CD86表达情况。方法:首先利用免疫荧光法检测胃癌组织和癌旁组织内CD11c和VEGF的表达,以及酶联免疫吸附实验测定血清VEGF的浓度。其次分离胃癌患者和健康个体外周血单个核细胞,利用GM-CSF和IL-4体外诱导为DCs,流式细胞仪检测DCs表面HLA-DR和CD86的表达。最后用重组VEGF蛋白体外刺激DCs,观察VEGF对DCs表达CD86的影响。结果:胃癌细胞VEGF表达强度与肿瘤内DCs浸润密度呈负相关,血清VEGF浓度与肿瘤内DCs浸润密度无关,胃癌组织内VEGF阳性DCs频率与胃癌进展正相关,胃癌患者外周血单核细胞诱导DCs表达HLA-DR和CD86降低,VEGF可降低DCs表面CD86的表达。结论:胃癌组织可通过分泌VEGF抑制DCs活性而介导免疫逃逸,胃癌组织内浸润的DCs可分泌VEGF参与病情进展。

Objective：To investigate whether VEGF expression level on cancer cells and serum VEGF level in gastric cancer patients correlate with density of tumor-infiltrating DCs,and whether frequency of VEGF positive DCs infiltrated in gastric cancer is associated with clinic stages,and to analyze expression of HLA-DR and CD86 on peripheral blood monocyte-derived DCs.Methods： At first sections of gastric cancer tissues were double stained with CD11c and VEGF antibodies and corresponding secondary antibodies,and sections were observed under fluorescent microscopy.Concentration of serum VEGF was measured by an ELISA assay.Peripheral blood mononuclear cells（PBMCs） were isolated from both gastric cancer patients and healthy controls,and stimulated with GM-CSF and IL-4 to induce DCs.HLA-DR and CD86 expression was detected by flow cytometry.Finally recombinant VEGF protein was added into DCs cultures to see how VEGF affected CD86 expression.Results： Expression level of VEGF on gastric cancer cells was inversely correlated with density of tumor-infiltrating DCs,but there was no association of serum VEGF level with density of tumor-infiltrating DCs.Frequency of VEGF positive DCs was positively correlated with stages of gastric cancer.Peripheral blood monocyte-derived DCs from gastric cancer patients decreased expression of HLA-DR and CD86 compared with those from healthy controls.Recombinant VEGF inhibited CD86 expression on DCs directly.Conclusion： VEGF secretion from gastric cancer cells would down-regulate activities of DCs and thus mediate immune evasion.In addition,DCs infiltrated in gastric cancer may produce VEGF to worsen disease.