ABSTRACT
BACKGROUND: Existing evidence has shown that that the effect of NGF/TrkA signaling pathway on proliferation and differentiation of tumor cells is closely related to PI3 K/AKT signaling pathway in human benign and malignant tumors. However, there is little information on the NGF/TrkA signaling pathway in pathogenesis of intraspinal schwannomas. OBJECTIVE: To investigate the effect of nerve growth factor-beta on the proliferation of interspinal schwannoma cells and to explore on the pathogenesis of NGF/TrkA signaling pathway in interspinal schwannoma. METHODS: Tumor samples were collected and digested to obtain high purity tumor cells as experimental cells. Then the cells were given different concentrations of nerve growth factor-beta (15, 30, 60, 120 and 240 μg/L), K252 a (100, 200, 300, 400, 500 and 600 nmol/L), LY294002 (10, 20, 30, 40, 50 and 60 μmol/L), nerve growth factor-beta (120 μg/L) plus K252 a (TrkA inhibitor, 400 nmol/L), and nerve growth factor-beta (120 μg/L) plus LY294002 (P13 K inhibitor, 50 μmol/L), respectively, for a certain time. The cell proliferation was detected by MTT assay. TrkA, AKT, p-AKT (Ther308), p-GSK-3 beta protein expression was detected by western blot assay. TrkA and AKT mRNA expression was detected by RT-PCR. RESULTS AND CONCLUSION: (1) Compared with the control group, the absorbance value of cells in the nerve growth factor-beta groups was increased in a concentration-dependent manner (P ＜ 0.05), and increased obviously at the concentration of 120 μg/L (P ＜ 0.001). The absorbance value of cells in the K252 a and LY294002 groups was decreased continuously (P ＜ 0.05), and decreased obviously at the concentration of 400 nmol/L and 50 μmol/L, respectively (P＜ 0.001). (2) The expression levels of TrkA, p-AKT (Ther308), and p-GSK-3 beta protein were upregulated in the nerve growth factor-beta group (P ＜ 0.05), and the expression level of TrkA mRNA was upregulated (P ＜ 0.05). (3) In the nerve growth factor-beta (120 μg/L) plus K252 a (400 nmol/L) group, the absorbance value of cells decreased (P ＜ 0.001). The expression levels of TrkA, p-AKT (Ther308), and p-GSK-3 beta protein downregulated (P ＜ 0.05), and the expression level of TrkA mRNA downregulated (P ＜ 0.05). (4) In the nerve growth factor-beta (120 μg/L) plus LY294002 (50 μmol/L) group, the absorbance value of cells decreased (P ＜ 0.01), and the expression levels of p-AKT (Ther308), and p-GSK-3 beta protein downregulated (P ＜ 0.05). (5) There was no significant change in AKT protein and mRNA in each group (P＞ 0.05). (6) These results suggest that nerve growth factor-beta can promote interspinal schwannoma cell proliferation, which may be related to the expression of TrkA, p-AKT (Ther308) and p-GSK-3 beta protein in NGF/TrkA signaling pathway.