Objective: To detect the effect of vascular endothelial growth factor (VEGF) on dendritic cells (DC) in patients with non-small cell lung cancer (NSCLC).
Methods: The measurement of DC in the peripheral blood was performed by a novel flow cytometric assay in 85 patients with NSCLC and 14 healthy volunteers. Enzyme-linked immunosorbent assay (ELISA) was used to measure the concentration of VEGF(165) in the plasma. CD(14)(+) peripheral blood mononuclear cells (PBMC) were cultured to obtain DC in vitro with cytokines. VEGF(165) was added to evaluate its effect on DC differentiation and survival. The phenotypes and apoptosis of cultured cells were detected by flow cytometry.
Results: In comparison with healthy volunteers, the level of VEGF(165) was significantly increased (P < 0.05), while that of DC was significantly decreased (P < 0.01) in patients with NSCLC. No significant correlation was noted between the concentration of VEGF(165) and age, gender, differentiation and histological types in patients with NSCLC, neither was found in the level of DC (P > 0.05). The concentration of VEGF(165) was closely associated with TNM stage and distal metastasis (P < 0.05), while no correlation was found between the concentration of VEGF(165) and lymph node metastasis (P > 0.05). Significant correlations were noted between the level of DC in patients with NSCLC and TNM stage, lymph node metastasis and distal metastasis (P < 0.05). There was a negative correlation between the concentration of VEGF(165) and the level of DC (P < 0.05). Patients with abnormally elevated VEGF(165) showed significantly fewer DC. Cells cultured in vitro in the presence of VEGF(165) exhibited higher expression of CD(+)(14)(P = 0.000) and increased ratio of apoptic cells (P < 0.01), but decreased expression of CD(40), CD(86) and HLA-DR (P < 0.01), as compared to cells cultured without VEGF(165).
Conclusions: The level of DC and the concentration of VEGF in the peripheral blood can reflect the malignancy of NSCLC. NSCLC can over-express VEGF to inhibit DC differentiation and maturation to evade host immune surveillance.