uPA-uPAR系统对骨巨细胞瘤细胞p44(MAPK)信号转导的影响

目的研究uPA／uPAR系统对骨巨细胞瘤细胞MAPK信号转导的影响。方法分离并培养骨巨细胞瘤细胞，用免疫组化检测骨巨细胞瘤组织中uPAR的表达水平，用免疫共沉淀方法检测外源激活或阻断uPA—uPAR对骨巨细胞瘤细胞信号转导通路的p44（MAPK）蛋白磷酸化水平的影响。结果仅有单核基质细胞可以在体外培养中长期生存；在骨巨细胞瘤组织中uPAR主要表达在部分单核基质细胞和一些多核巨细胞的胞膜上；将uPA—ATF加入培养的骨巨细胞瘤细胞后，细胞信号通路上的p44蛋白磷酸化水平明显增高。用uPAR抗体处理后，细胞p44蛋白磷酸化水平明显降低。说明uPA—ATF具有细胞信号转导活性，该活性受uPAR拮抗剂的影响。结论本实验检测到uPA—uPAR系统是通过p44（MAPK）信号转导通路转导信息，从而调节骨巨细胞瘤细胞增殖、分化及其他生物学行为。

Effect of uPA- uPA system on p44 (MAPK) signal transduction in human giant cell tumor of bone(四)

Objective ] To study the effect of urokinase-type plasminogen activator (uPA)and its receptor(uPAR) system on p44(MAPK) signal transduction in giant cell tumor of bone (GCT). Methods] Expressions of uPAR in GCT tissue was detected by immunohistochemistry. Phosphorylation level of mitogen-activate protein kinase (P44) in uPA/uPAR signal pathway in cultured GCT cells was detected by immunoprecipetation. Results] Only the mononuclear stromal cells can survive through in vitro; 2)Urokinase-type plasminogen activator receptor (uPAR) is positive on the cell membrane and in cytoplasm of some mononuclear stromal cells (MSCs) and multinucleated giant cells (MGCs); 3) After treatment by uPA-ATF, the phosphorylation level of P44 in GCT cultured cells is much higher than the control. Addition of anti-uPAR antibody in the cells remarkably down-regulated the phosphorylation level of P44 as compared with the control group, suggesting that uPA-ATF participates cell signal transduction and this reaction can be inhibited by anti-uPAR antibody. Conclusion] The study demonstrates that uPA-uPAR system directly regulates the phosphorylation level of P44(MAPK) pathway