miR-587在非小细胞肺癌内持续性激活NF-κB信号通路的正反馈网络调控机制及生物学功能

The NF-κB pathway, serving as one key oncogenic signaling pathway in cancer invasion and metastasis, is constitutively activated in various types of cancers. The strength and duration of NF-κB signaling are tightly controlled by multiple positive and negative feedback mechanisms. However, in cancer cells, these feedback loops underlying mechanisms to sustain activation of NF-κB signaling still unclear. The results obtained from published Non-small-cell lung cancer (NSCLC) high-throughput microarray dataset (NCBI/GEO/GSE15008) and our recent preliminary data on the alteration of miRNAs in human NSCLC identify miR-587 as one of the substantially overexpressed miRNAs in NSCLC. Significantly, miR-587 directly suppresses NF-κB negative regulators ITCH, consequently resulting in activation of NF-κB signaling and promotion of NSCLC invasion and metastasis. Furthermore, analysis of the miR-587 promoter region using the CONSITE program predictes 2 typical NF-κB-responsive elements, and miR-587 is up-regulated in cells after TNF-α treatment. Collectively, all these data suggest that miR-587 is able to sustain NF-κB constitutive activation via a positive feedback loop, leading to increased NSCLC invasion and metastasis. In the current study, using in vivo and in vitro systems, and combined with clinical samples, we aim to further investigate the distinct mechanism by which miR-587 enhances the strength and prolongs the duration of NF-κB signaling through a positive feedback loop, and reveal the biological effect of miR-587 on invasion and metastasis of NSCLC cells. Our research will uncover a novel mechanism for sustained NF-κB activation and may suggest miR-587 as a new target for clinical intervention in human NSCLC.

NF-κB信号通路是肿瘤细胞内持续性激活的关键信号通路，促进肿瘤的侵袭和转移等生物学过程。但肿瘤细胞内NF-κB信号通路持续性激活的网络调控机制仍不清楚，需进一步研究。公共数据分析和预实验结果表明miR-587在非小细胞肺癌中高表达，具有促进细胞侵袭转移的生物学功能，并可抑制ITCH的蛋白表达，激活NF-κB信号通路。同时，TNF-a处理细胞激活NF-κB后诱导miR-587的表达增加。这些研究结果提示miR-587和NF-κB信号通路可能形成正反馈网络调控机制，从而促进肿瘤的侵袭和转移。在此基础上，本项目将深入探讨非小细胞肺癌内miR-587和NF-κB信号通路的相互作用机制，体内体外实验确定miR-587具有促进非小细胞肺癌细胞侵袭转移的生物学功能，为miR-587持续性激活NF-κB信号通路而促进非小细胞肺癌细胞侵袭转移的假设提供客观证据，为非小细胞肺癌的治疗提供新的潜在分子靶点。

肺癌的侵袭转移是肺癌的恶性标志和特征之一, 也是导致肺癌复发和和患者死亡的主要原因。80%-90%的肺癌患者死亡是由肺癌的侵袭转移引起的。本项目的主要内容是研究促进肿瘤侵袭转移的分子机制，研究诱导NF-B信号通路持续性激活的起正反馈调控作用的非编码小分子RNA（miroRNA），并阐明 miRNA在肿瘤侵袭转移过程中的生物学功能和分子机制。. 本研究主要发现：转录因子NF-kB结合在非编码小分子RNA miR-616的启动子上，上调miR-616的表达； miR-616抑制NF-kB信号通路负性调控因子PTEN和TRAF3的表达，形成正反馈调控网络从而诱导NF-kB信号通路的持续性激活进而促进肿瘤的发生发展。.同时，在本项目的资助下，本课题组发现在转录调控中起“开关”作用的蛋白TBLRXR1通过与VEGF-C的启动子结合而诱导VEGF-C的表达，促进肿瘤的淋巴管生成及淋巴转移。并且发现癌基因GABRA3在肺腺癌中高表达，与肺腺癌的临床病理分级、患者生存预后相关；GABRA3通过激活JNK/AP-1信号通路上调金属蛋白酶MM2和MMP9的表达，促进肺癌的淋巴结转移。. 在本项目的资助下，本课题组深入研究在肿瘤侵袭转移过程中起重要作用的基因和非编码RNA，研究NF-kB信号通路在肿瘤中持续性激活的调控机制，为非小细胞肺癌的预后的预测和治疗提供可能的潜在分子靶点。. 在本项目的资助下，发表SCI论文2篇和培养博士研究生1名，硕士研究生1名。.