Objective: To explore the effect of Nordy, a synthesized lipoxygenase Inhibitor, on the expression of formylpeptide receptor (FPR) and its functional activities after activation in human malignant glioma cells.
Methods: Human malignant glioma cells of the line U87 were cultured and divided into 3 groups: N-formyl-methionyl-leucyl-phenylalanine (fMLF) group, added with 100 nmol/L fMLF; Nordy group, added with 100 micromol/L Nordy for 12 h and then added with 100 nmol/L fMLF; and control group. The expression of FPR I the U87 cells was detected with indirect immunofluorescence staining and confocal laser scanning microscopy. The effect of Nordy on the U87 cell proliferation induced by fMLF was assayed by MTT method. RT-PCR was used to detect the mRNA expression of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) in the U87 cells. ELISA was used to detect protein secretion of VEGF and IL-8 in the supernatant.
Results: FPR was expressed on the cytoplasmic membrane of U87 cells. The mean FPR absorbance of the Nordy group was significantly lower than that of the fMLF group. The U87 cell proliferation of the Nordy group was significantly inhibited in comparison with the other 2 groups. The mRNA expression of VEGF and mRNA expression of IL-8 in the U87 cells activated by fMLF were significantly higher than those of the control group (both P<0.05), and Nordy significantly attenuated the mRNA expression of VEGF and IL-8 at different time points (all P<0.05). ELISA showed that the VEGF and IL-8 protein levels in the supernatant were 4.14 ng/ml+/-0.28 ng/ml and 4.03 ng/ml+/-0.59 ng/ml respectively, and increased to 6.46 ng/ml+/-0.33 ng/ml and 7.54 ng/ml+/-0.73 ng/ml respectively after stimulation of fMLF, however, the VEGF and IL-8 protein levels in the supernatant of the Nordy group were 3.59 ng/ml+/-0.33 ng/ml and 3.13 ng/ml+/-0.48 ng/ml respectively.
Conclusion: Nordy inhibits the FPR expression and the effects in promoting the cell proliferation and mRNA expression and protein secretion of VEGF and IL-8 after the activation of FPR in malignant human glioma cells, showing that Nordy has the effects of inhibition of tumor growth and angiogenesis.