长非编码RNA-ATB在环境污染物镍促进肺癌进展中的作用及机制研究

Nickel is a common environmental carcinogen, but whether it can promote the progress of lung cancer still has not been elucidated. Our recently studies indicated that nickel treatment can induce epithelial-mesenchymal transition (EMT) and promote the invasion and migration of lung cancer cell in vitro. Moreover, nickel treatment can also induce the expression of the LncRNA-activated by TGF-β (ATB), which present with dose and time dependent manner. Therefore, we hypothesized that nickel promote the invasion and migration of lung cancer cell via activating the signal pathway of TGF-β by ATB, which act as a ceRNA targeting miR-200s and/or miR-425 and inducing EMT. In order to validate this hypothesis, we plan to evaluate the invasion and migration of lung cancer cell lines, which knockdown ATB by shRNA and then treatment with nickel for different time in vitro. We also plan to detect the main molecules of TGF-β signal pathway and biomarks of EMT in lung cancer cell lines, which overexpression miR-200s and/or miR-425 by transfect plasmid and then treatment with nickel for different time in vitro. Moreover, we also plan to test the interaction of ATB with miR-200s and miR-425 by RNA immunoprecipitation in overexpression of wildtype and mutation ATB. Furthermore, we also detect the content of nickel and ATB expression in plasma and lung tissues, and then analysis those correlation with the progress of lung cancer in clinical patients. This project not only can clarify the role and mechanisms of nickel promote lung cancer progress, but also can provide novel highlight for the prevention and control of lung cancer progress.

镍是一种常见的环境致癌物，然而对其是否促进肺癌进展及机制尚不完全清楚。课题组前期研究发现镍可诱导肺癌细胞发生EMT并且促进细胞侵袭迁移，同时可诱导细胞中长非编码RNA-ATB基因表达水平上调。因此，课题组假设：镍可能通过ATB竞争结合miRNAs使TGF-β介导的信号通路活化，进而诱导细胞发生EMT促进肺癌细胞侵袭迁移。为证实以上假设，本项目拟通过体外实验探讨敲减ATB对镍促进肺癌细胞侵袭迁移能力影响；通过研究miR-200s和miR-425过表达探讨其对TGF-β介导的信号通路和EMT影响；通过RNA免疫沉淀研究ATB与miRNAs结合作用；同时在人群当中验证镍含量与ATB表达水平和肺癌进展关系。本研究对阐明镍促进肺癌进展具有重要意义，也为防控肺癌进展提供了新的思路。

近年来研究显示长链非编码RNA-ATB参与调节肿瘤进展，然而关于ATB在镍化合物促进肺癌进展中的作用尚不清楚。本项目通过人群研究发现原发性非小细胞肺癌患者外周血清中镍含量明显高于对照人群，并且原发性非小细胞肺癌患者外周血清中镍含量与ATB表达水平呈明显的正相关关系，通过meta分析发现ATB表达水平升高是肿瘤患者生存期缩短的风险因素，并且ATB表达水平升高促进肿瘤转移，以上研究提示ATB可能参与镍促进原发性非小细胞肺癌患者进展。通过体外研究发现氯化镍处理可促进非小细胞肺癌细胞系A549细胞中ATB表达水平升高，敲低ATB表达水平可抑制氯化镍促进A549细胞的侵袭和迁移，而过表达ATB表达水平则加强氯化镍促进A549细胞的侵袭和迁移。进一步机制研究发现ATB可能通过吸附miR-200a/b，上调转录因子ZEB1和ZNF217表达，促进TGF-β1基因转录，正反馈TGF-β1/Smad2/3信号通路，从而加强氯化镍诱导A549细胞发生EMT过程。该研究提示ATB可能是镍化合物促进肺癌进展的早期生物标志物，并且ATB/miR-200a/b/ZEB1和ATB/miR-200a/b/ZNF217轴可能是TGF-β1信号通路正反馈的启动因素之一，为分子干预提供了新的靶标。