长链非编码RNA-LINC01140抑制NONO蛋白泛素化降解促进胃癌侵袭转移的作用及机制研究

It is of great significance for gastric cancer targeted therapy to find novel molecules that are related to invasion and metastasis, and to uncover their underlying mechanism, for the reason that invasion and metastasis predominantly contribute to the poor prognosis in gastric cancer patients. Our preliminary data showed that LINC01140, a new type of long noncoding RNA (lncRNA), was overexpressed in gastric cancer with promoted cancer cells ability of migration and invasion. However, the underlying mechanism was still elusive. We further indicated that LINC01140 was physically interacted with NONO protein, which would up-regulate NONO protein level through inhibiting NONO protein ubiquitination and degradation. Moreover, LINC01140 could activate ERK1/2 signaling pathway. NONO protein has been proved to facilitate tumor progression, and its ubiquitination was directly mediated by ubiquitin-ligase enzyme FBW7. Based on these data, we speculate that LINC01140 physically interacts with NONO protein, inhibits NONO protein ubiquitination and degradation which are mediated by FBW7, then up-regulates NONO protein level, follows with activating ERK1/2 signaling pathway, to promote gastric cancer invasion and metastasis. We will validate the role of LINC01140 and its related mechanism at levels of cell lines, animal model and clinical specimens, which would favor the early diagnosis, prognosis prediction and treatment of gastric cancer.

侵袭转移是胃癌预后不良的主要原因，寻找新的侵袭转移相关分子并阐明其作用机制对于胃癌的靶向治疗有重要意义。我们前期发现一种新的长链非编码RNA-LINC01140在胃癌中高表达，并可促进癌细胞侵袭转移，但机制不明。进一步研究发现LINC01140与NONO蛋白结合，抑制NONO蛋白泛素化降解，并可活化ERK1/2通路。己知NONO可促进多种肿瘤进展，其泛素化降解受泛素连接酶FBW7的直接介导。结合前期结果，我们提出科学假说：LINC01140与NONO蛋白结合，通过抑制FBW7介导的NONO蛋白泛素化降解，上调其蛋白水平，激活下游ERK1/2通路，促进胃癌侵袭转移。本课题拟通过基因转染、Co-IP、RNA pull down等实验在细胞、动物、临床标本三个层次深入研究LINC01140抑制NONO蛋白泛素化降解促进胃癌侵袭转移的作用机制，有望为将其应用于胃癌转移预判及靶向治疗提供理论依据。

侵袭和转移是胃癌治疗预后不佳的主要原因，寻找和研究与胃癌侵袭转移有关分子的功能及作用机制，在分子水平上找到可预测胃癌转移和预后的标志物，有助于预警高危个体，并为针对该分子的靶向治疗提供理论依据。我们前期在胃癌芯片中筛选出一个高表达的新的长链非编码RNA-LINC01140，其功能研究较少，且其在胃癌发生发展中的作用不清楚。本项目发现LINC01140在胃癌中高表达，并与淋巴结转移、差的预后密切相关，并通过体内、外实验证实LINC01140可促进胃癌侵袭转移。进一步我们对LINC01140的作用机制进行了探讨，发现：(1)LINC01140可与NONO蛋白直接结合，并上调NONO蛋白表达，激活下游ERK1/2通路；(2)LINC01140可抑制NONO蛋白的泛素化从而上调其表达；(4)NONO蛋白在胃癌中高表达并具有促进胃癌侵袭转移的作用；(5)NONO介导了LINC01140促进胃癌侵袭转移的作用。这些结果揭示了LINC01140促进胃癌侵袭转移的作用及下游分子机制，有望为LINC01140应用于胃癌分子靶向治疗提供理论基础。本项目之外，我们还对LINC01140的上游调控机制进行了探讨，发现LINC01140存在较多m6A修饰，初步实验显示IGF2BP2可通过m6A依赖的方式上调LINC01140的表达，此部分实验正在开展中，我们拟整合后续结果及本项目结果撰写一篇高质量论文，完整阐述LINC01140在胃癌中功能及上游和下游作用机制。