Mnk抑制剂靶向Mnk-eIF4E/β-catenin轴治疗非小细胞肺癌的分子机制研究

The incidence rate of non-small cell lung cancer (NSCLC) has the most rapidly increasing in the people of our city. Activation of the MAP kinase-interacting kinases (Mnk) and phosphorylation of eukaryotic translation initiation factor 4E (eIF4E) catalyzed by Mnk play vital roles in tumor progression. In our preliminary experiment, we found that Mnk inhibitor CGP57380 reversed RAD001-induced eIF4E phosphorylation and inhibited the Akt activation in the NSCLC cell lines in vitro and in vivo. Our results also showed that CGP57380 increased expression of E-cadherin, decreased Vimentin expression and inhibited the nuclear translocation of β-catenin protein in the NSCLC cell lines. Furthermore, Mnk inhibitor suppressed cell proliferation and induced cell apoptosis of NSCLC cells. Basing on the results above, we put forward the hypothesis that the activation of Mnk-eIF4E/β-catenin axis promotes the NSCLC progression; targeted inhibition of Mnk-eIF4E/β-catenin axis could regulate the distribution of β-catenin protein and expressions of its downstream genes via Akt-dependent manner, abrogate epithelial-mesenchymal transition, and inhibit the cell proliferation, aggression and metastasis of NSCLC through inducing cell apoptosis. In the project, we will plan to confirm the scientific hypothesis and investigate its specific molecular mechanisms through a series of combination experiments with four factors and three levels from the clinical specimens of human non-small cell lung cancer, cell lines and animal models. The completion of this project will lay the profound experimental foundations for targeted treatment basing on Mnk-eIF4E/β-catenin axis in NSCLC, which is of both significances on theoretical and clinical therapy.

非小细胞肺癌（NSCLC）发病率日趋增加。MAPK相互作用激酶（Mnk）和依赖其磷酸化的真核细胞翻译起始因子-4E（eIF4E）的激活在肿瘤进展中起重要作用。我们前期发现Mnk抑制剂逆转RAD001治疗NSCLC诱导的eIF4E磷酸化和Akt活化；增加E-cad、下调Vim表达，抑制β-catenin核转位，抑制细胞增殖，诱导凋亡。据此提出如下科学假说：Mnk-eIF4E/β-catenin轴的激活导致NSCLC进展；靶向抑制Mnk-eIF4E/β-catenin轴，可能经Akt依赖方式调控NSCLC细胞内β-catenin的分布及其下游基因的表达，逆转上皮间质转化，诱导凋亡，抑制细胞增殖、侵袭和转移。拟从临床肺癌标本、细胞和动物模型三个层面阐明这一假说的具体机制。本项目的实施为基于靶向抑制Mnk-eIF4E/β-catenin轴治疗NSCLC提供实验依据，具有重要理论意义和临床应用价值。

中文摘要：.项目背景：Mnk抑制剂逆转RAD001(Everolimus)治疗NSCLC所诱导的eIF4E磷酸化和Akt活化；增加E-cad表达并下调Vimentin，阻止β-catenin核转位，抑制NSCLC细胞增殖，诱导凋亡。本项目旨在阐明靶向Mnk-eIF4E/β-catenin信号轴，经何种具体机制发挥抗肿瘤作用。.项目主要包括四个方面的研究：.① 明确激活的Mnk-eIF4E轴是否调控Wnt/β-catenin通路关键分子的表达。.② 研究靶向Mnk-eIF4E/β-catenin轴，经何途径发挥抗肿瘤作用。.③ 阐明增效RAD001(Everolimus)/CGP57380治疗NSCLC的具体分子机制。.④ 分析Akt/mTOR、Mnk/eIF4E、凋亡等通路关键因子和YTHDF1与NSCLC临床病理和预后相关性。.项目取得八个方面的重要研究成果：.①肺腺癌存在EGFR的高突变，EGFR-TKI治疗是EGFR基因突变患者的独立预后预测因子。.②联合miR-4634和RAD001(Everolimus)发挥协同抗肿瘤疗效，miR-4634是NSCLC靶向治疗的潜在分子。.③首次阐明RAD001(Everolimus)以Rab27A和Rab27B依赖方式从NSCLC细胞中释放载 miR-7-5p 外泌体，导致Everolimus治疗耐药。miR-7-5p联合Everolimus靶向抑制Mnk/eIF4E轴和mTOR，增强Everolimus疗效。.④β-catenin 蛋白调控浸润性免疫细胞，β-catenin 在NSCLC免疫和肿瘤微环境中发挥重要作用。.⑤过表达P4HA1的NSCLC患者预后差，P4HA1促进NSCLC增殖、转移和顺铂耐药，P4HA1可作为NSCLC新靶点。.⑥PD-L1阳性表达为肺腺癌患者预后差的独立分子标志；USP22调控PD-L1稳定性和蛋白水平，PD-L1介导免疫逃逸起重要作用。.⑦Akt/mTOR、Mnk/eIF4E和凋亡通路关键分子，热休克蛋白与NSCLC临床病理特征相关，可作为NSCLC诊断、预测预后和治疗的靶标。.⑧YTHDF1缺失抑制肺腺癌进展和对顺铂耐药。YTHDF1高表达患者预后好，YTHDF1在缺氧适应和NSCLC致病过程中起关键作用。.本项目的完成为NSCLC靶向治疗提供新的理论依据，具有重要临床转化应用前景。