| Glioma, which is the most common primary intracranial tumors in adults, performances the characteristics of invasive growth, high degree of malignancy, poor prognosis and easy to relapse, so it becomes a difficult problem of treatment in central nervous system tumors. At present, the main treatment of glioma is surgical resection, supplemented by radiotherapy, chemotherapy, gene therapy, immune therapy treatment, et al. Although medium-term survival has been improved, glioma still can not be completely cured, and there are many reasons affect the effectiveness of treatment, for example, the drugs cannot infiltration blood brain barrier, tumor cells have a strong ability of migration and invasion and resistence to radiation and chemotherapy. Glioma is a kind of solid tumors rich in blood vessels, rich vascular system can further promote tumor growth and metastasis, therefore, finding new therapeutic targets and drugs of the inhibiting angiogenesis becomes one of the hot research spots.Serine/arginine protein kinase 1 (SRPK1) can phosphorylate specific proteins rich in serine/arginine repeats, regulates a variety of cell physiological functions. It has been reported that SRPK1, which is abnormal expression in many tumors, can regulate the growth, apoptosis of tumor cell and control tumor angiogenesis by adjusted splicing factor. So it becomes a new target for therapy of tumor angiogenesis. However SRPK1 is not expressed in normal glial cells and there is no report on the role of SRPK1 in glioma. Thus we assume SRPK1 can affect the growth, apoptosis and angiogenesis of glioma cell, if this assumption is valid, we can provide a new theoretical basis and experimental foundation for glioma treatment.First of all, we identified SRPK1 is abnormal high expressed in glioma cells by immuno-fluorescence staining. Then we respectively studied the growth, apoptosis, invasion and migration, angiogenesis of glioma both in vivo and vitro, through siRNA transfection to inhibit SRPKl expression. Second, to evaluate whether siRNA SRPK1 affects the growth and apoptosis of U251 and U87 cells, we detected the cells growth cycle and apoptosis by flow cytometry. The experimental results showed that the transfection group was significantly inhibited the glioma cells growth and promoted early cells apoptosis compared with control group, and it was showed the same results in vitro study. Next, we explored the function of SRPK1 on the invasion and migration of glioma through Transwell invasion and migration experiments, detected the expression of MMP2 and MMP9 by RT-PCR and Western blot, the whole results showed that SRPKl inhibition could reduce the expression of MMP2 and MMP9 and inhibit invasion and migration ability of glioma cell. Then to test the role of SRPK1 in glioma angiogenesis through in vivo small animal imaging, we used immuneofluo-rescence staining experiment to detect the expression of EGF and VEGF, the results indicated that knockdown of SRPK1 can significantly reduce the expression of EGF and VEGF in glioma, suggested that angiogenesis in transfection group was obviously reduced when compared with control group. Finally, to discuss the possible mechanism controlled by SRPK1 in apoptosis, migration and angiogenesis of glioma cells, we detected the expression of Akt, eIF4E, p-Akt, p-eIF4E and HIF-la by Western blot and immunohistochemical staining, it turned out that siRNA SRPK1 can reduce the expression of p-Akt, p-eIF4E and HIF-1α under the normoxia condition, but there was no significant influence on SRPK1 expression when inhibition of HIF-1α under the normoxia condition. In a word, SRPKl can affect the growth, apoptosis, invasion, migration and angiogenesis of glioma through Akt/eIF4E/HIF-1α pathway. |
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