NF-κB通路调节蛋白α-catenin对非小细胞肺癌上皮间质转化及肿瘤干细胞标志物的调控作用及其分子机制的研究

Cancer stem cell(CSC) and epithelial to mesenchymal transion(EMT) are key inducers of cancer metastasis, while their mechanism, especially the related regulation and signaling events remain elusive, making additional work valuable to conquer metastasis and improve the prognosis. Our preliminary data indicated that α-catenin, a member of the cadherin-catenin complex, can inhibit the EMT of colorectal cancer (CRC) cells and its expression was negatively related with the metastatic ratio of CRC patients. Further work unveiled the roll of NF-κB in enhancing the mobility of the CRC cells via down regulating their expression of α-catenin. Moreover, our recent data showed that α-catenin expression was almost abolished in poorly differentiated NSCLC tissues, which exhibited a mesenchymal appearance, accompanied by enhanced p65 and the CSC markers: SOX2 and OCT4 expression，suggesting possible relationship between them. Here we plan to utilize shRNA to knockdown α-catenin expression in highly or poorly differentiated NSCLC cell lines, investigating its mechanism in NF-κB regulation and further influence on cancer invasion, EMT and CSC marker expression. Our work will be valuable to develop pluripotent molecular drugs which are able to block both EMT and CSC generation of NSCLC.

肿瘤干细胞(CSC)和肿瘤上皮间质转化(EMT)是肿瘤转移的重要原因，但两者之原理，尤其是调控机制及相关信号转导尚不清楚。对此开展研究对抑制肿瘤转移、改善预后具有重要意义。我们前期研究发现cadherin-catenin连接复合物成员α-catenin可抑制结直肠癌(CRC)细胞发生EMT，且其表达与CRC病人肿瘤转移负相关；而NF-κB通路可下调α-catenin表达而增强CRC细胞迁移能力；并观察到在低分化非小细胞肺癌(NSCLC)组织中α-catenin分子的表达显著下降，及NF-κB转录因子p65的上调，并可见CSC标志物SOX2及OCT4的表达，提示三者间可能存在某种联系。本课题拟用高、低分化NSCLC细胞系，通过siRNA及免疫共沉淀，分析α-catenin对NF-κB通路的调控机制及对侵袭力、EMT、CSC标志物表达的影响，为开发联合抗EMT及CSC的分子药物作有益探索。

肺腺癌是一类异质性显著的恶性肿瘤，其中分化程度不同者在预后及生存率上存在显著差异。我们初期的研究发现低分化肺腺癌具有显著的上皮-间质转化（EMT）特征，但其相关分子机制不明。本次研究首先着眼于低分化肺腺癌内cadherin-catenin复合物的功能改变，研究其调控的分子机制，阐明了该复合物分解与经典WNT/β-catenin通路在促进肿瘤EMT与生长、转移力增强之间的关系。其次，我们通过TCGA数据库发现NF-KB通路相关分子TRIM8的功能与肿瘤血管生成负相关，从而调节非小细胞肺癌的血管生成能力，我们的结果证实低分化肺腺癌中TRIM8表达减弱，而同时血管内皮生长因子3/4（VEGFR 3/4）的表达增强，这表明低分化肺腺癌中NF-KB通路的功能与肿瘤血管生成有关。最后，我们通过低覆盖度全基因组测序技术（LPWGS）测定了低分化肺腺癌的染色体不稳定程度（CIN），发现其显著高于高分化肺腺癌，并且这一过程可能与前者TP53基因拷贝缺失有关。以上工作利用低分化肺腺癌样本，研究了其EMT相关肿瘤侵袭的分子机制，并揭示了其NF-KB通路与肿瘤的血管生成有关，最后对低分化腺癌的染色体不稳定性进行了分析，并提示其潜在的分子机制为TP53缺失。