中文摘要：

目的探讨TAG-1对U251细胞的生长活力和粉样前体蛋白胞内段（AICD）,p53和表皮生长因子受体（EGFR）~因表达变化的影响。方法以MTT法检测不同浓度TAG．1（0、5、10、20μg／mL）对U251细胞活力影响；免疫荧光细胞化学法观察U251细胞8淀粉样前体蛋白（APP）的表达；TUNEL法检测TAG-1对U251细胞凋亡形态学变化的影响：Real-time PCR检测TAG-1对U251细胞AICD,p53和EGFR基因表达的调控。结果TAG．1没有抑制U251细胞的生长．相反表现出一定的促生长效应；APP广泛表达于U251细胞膜；在TAG．1浓度为10μg/mL时，U251细胞形态学检测没有发现明显的凋亡细胞，但AICD,p53和EGFR基因表达增加。结论TAG-1在胶质瘤的增殖中发挥重要作用，但未发现其能通过TAG-1／APP／AICD／p53或TAG-1／APP，AJCD／EGFR信号途径促进U251细胞凋亡。

英文摘要：

Objective To investigate the effects of transient axonal glycoprotein-1 （TAG-1） on activity ofU251 cells and expressions ofAIC, D, p53 and EGFR genes in the cells. Methods The viability of U251 cells was tested by MTT assay at 48 h following the addition of various concentrations of TAG-1 （0, 5, 10 and 20 μg/mL）. The expression of amyloid precursor protein （APP） was detected by immunofluorescent staining. The apoptotic cells were examined by TUNEL. Real-time PCR was employed to detect the influence of TAG-1 on the expressions of AICD, p53 and EGFR genes in U251 / cells. Results TAG-1 did not play an inhibitory effect on the proliferation of the U251 cells. APP was abundantly expressed on membrane of the U251 cells. U251 cells did not show apoptotic cells but increased expressions of AICD, p53 and EGFR genes were noted when U251 cells were exposed at 10 μg/mL of TAG-1. Coneluslon TAG-1 plays an important role in regulating the proliferation of glioma and may not induce the apoptosis of U251 cells through the signal pathway of TAG-1/APP/AICD/p53 or TAG- 1/APP/AICD/EGFR.