研发双重抑制EGFR和mTOR用于胶质母细胞瘤的分子靶向治疗是急待解决的任务。我们发现上调胶质母细胞瘤细胞系U87中Rab5的GTP活性可下调细胞增殖能力、加速EGFR降解并抑制mTOR下游靶蛋白S6K1磷酸化。因此我们推测Rab5双重抑制EGFR/mTOR是通过①加速初级包涵体融合促使EGFR向溶酶体转运降解②改变mTOR复合体（mTORC）形成、胞内分布及靶蛋白磷酸化实现的。本项目拟在明确人胶质瘤组织中GTP-Rab5与EGFR/mTOR关系的基础上，在U87及U87ΔEGFR细胞中双向调控Rab5的GTP活性并结合特异性抑制剂，用免疫荧光、GST pulldown、CoIP等观察其对EGFR转运和mTOR胞内分布及复合体形成的调控，以EGFR/mTOR下游标志性蛋白磷酸化改变观察其信号转导改变，以细胞增殖、侵袭和裸鼠模型研究Rab5双重抑制EGFR/mTOR活性对肿瘤恶性演进的影响。

It is an urgent task to develop new molecular therapeutic approaches for glioblastoma via duel inhibition on EGFR/mTOR. In our preliminary study, we found that upregulation of the GTP activity of Rab5 in glioblastoma cell line U87 can inhibit cell proliferation, accelerate the degradation of EGFR and attenuate the phosphorylation of mTOR downstream effector, S6K1. Accordingly, we hypothesize that upregulating Rab5 GTP activity can simultaneously inhibit EGFR/mTOR, which is accomplished by two ways: 1) accelerating early endosome fusion and promoting EGFR transportation to lysosome for degradation; 2)disturbing the subcellular localization and complex formation of mTOR complex, especially mTORC1, and attenuating the phosphorylation of downstream effectors. To test the hypothesis, we will identify the relationship between GTP-Rab5 and EGFR/mTOR in human glioma and normal brain tissues; In U87MG and U87MGΔEGFR cells, by adopting EGFR/mTOR specific inhibitors, immunofluorescence, GST-pulldown and co-immunoprecipitation, we will bidirectionally regulate Rab5 activity and detect its effect on EGFR transportation and degradation, the change of mTOR subcellular distribution and complex formation. The phosphorylation of downstream effectors will also been tested to determine the effect of Rab5 activity on EGFR/mTOR signal transduction. Moreover, we will study the regulation by Rab5 on the cellular proliferation， invasion and tumor growth in the nude mouse model.