c-MET-PI3K-AKT通路对厄洛替尼辐射增敏调控作用研究

The optimization of administration c-Method for the radiosensitivity of the tyrosine kinase inhibitor is a significant proposition of the TKI combined with radiotherapy. And our previous study confirmed that the TKI radiosensitive effect changed greatly with different administration schedules. Further, both TKI and radiation are closely related to c-MET-PI3K-AKT-mTOR pathway, and the effect of radiation to c-MET-PI3K-AKT-mTOR pathway is time dependent. Therefore, the c-MET-PI3K-AKT-mTOR pathway may have close relationship with the TKI radiosensitive effect of different administration schedules, and may play an important regulatory role on it. However，the relations and the regulation effects between the c-MET-PI3K-AKT-mTOR pathway and TKI radiosensitive effect of different administration schedules have not been reported. Therefore, this study will use lung adenocarcinoma cells and xenograft in nude mice to investigate the relationship between the c-MET-PI3K-AKT-mTOR pathway and the TKI radiosensitive effect of different administration time, focus on expression change of c-MET-PI3K-AKT-mTOR pathway and the regulatory effect of c-MET-PI3K-AKT-mTOR pathway blocking on the TKI radiosensitive effect of different dosing schedules at animal, cellular and molecular levels，to make up the differences in radiosensitive effect of different TKI administration schedules , and to improve the effect of the TKI radiosensitive effect further. This study will provide experimental basis for the optimization of the administration c-Method and new targets for improving the effect of TKI combined with radiotherapy.

我们前期研究证实TKI辐射增敏效应随不同给药时间变化而呈明显差异，而TKI和辐射均与c-MET-PI3K-AKT-mTOR通路密切相关，且辐射对c-MET-PI3K-AKT-mTOR通路的影响亦呈时间依赖性，由此，c-MET-PI3K-AKT-mTOR通路可能与TKI不同给药时间辐射增敏效应关系密切且对其发挥重要调控作用。而c-MET-PI3K-AKT-mTOR通路与TKI不同给药时间辐射增敏效应的关系及其调控作用未见报道。本课题以TKI不同给药时间辐射增敏效应差异为出发点，以c-MET-PI3K-AKT-mTOR通路为主线，从动物，细胞和分子水平观察TKI联合辐射不同给药时间条件下c-MET-PI3K-AKT-mTOR通路的表达变化，同时研究阻断通路对TKI不同给药时间辐射增敏效应的调控作用，为临床TKI联合放疗给药方式的优化和疗效提高提供实验依据。

TKI和辐射均与c-MET-PI3K-AKT-mTOR通路密切相关，由此，c-MET-PI3K-AKT-mTOR通路可能与TKI辐射增敏效应关系密切且对其发挥重要调控作用。而c-MET-PI3K-AKT-mTOR通路与TKI辐射增敏效应的关系及其调控作用未见报道。.本课题采用肺腺癌细胞系体外培养和裸鼠移植瘤模型, 通过凋亡检测,体外存活曲线和体内生长曲线观察辐射联合厄洛替尼作用下肿瘤抑制作用及耐药; 通过western检测AKT, p-AKT, P70, p-P70等基因的改变观察肿瘤耐药与c-MET-PI3K-AKT-mTOR通路的关系；应用依维莫司阻断mTOR, 观察阻断后AKT, p-AKT, P70, p-P70等基因的改变，同时进一步观察阻断前后肿瘤凋亡，体外存活曲线和体内生长曲线的变化，确定阻断MTOR抑制剂对辐射联合TKI后肺腺癌耐药逆转作用。 实验结果显示辐射联合厄洛替尼在体外和体内辐射增敏效应明确，但仍存在较多肿瘤细胞产生耐药。 同时辐射联合厄洛替尼可以明显提高p-AKT, p-P70等基因的表达，依维莫司阻断mTOR后肿瘤凋亡进一步增加，存活分数较阻断前明显下降，体内生长曲线在阻断后明显逆转。可见，辐射联合TKI后肺腺癌耐药与PI3K-AKT-mTOR通路活性提高相关，阻断mTOR可以逆转辐射联合TKI后肺腺癌耐药，进一步提高TKI辐射增敏效应。.本课题通过探讨辐射联合TKI后PI3K-AKT-MTOR通路表达变化，并通过阻断通路逆转耐药，为放疗联合TKI临床耐药解决提供潜在靶点和思路。