LncRNA LINC01436作为ceRNA竞争结合miR-30a-3p在肺腺癌中的作用和机制研究

By using lncRNA microarray, bioinformatics analysis and preliminary experiments, we found a key lncRNA-LINC01436 which was up-regulated in lung adenocarcinoma tissues, and its higher expression was significantly associated with poor outcome in patients with lung adenocarcinoma. Knockdown of LINC01436 inhibited proliferation, migration and invasion of lung cancer cell line in vitro. Based on the result of miRNA microarray analysis, we also found a significant negative correlation between LINC01436 and miR-30a-3p, and miR-30a-3p was predicted to target binding to LINC01436. LINC01436 knockdown resulted in increased level of miR-30a-3p and decreased level of its targeted gene EPAS1 in lung adenocarcinoma cells. Based on these lines of evidence, we hypothesize that LINC01436 may act as competing endogenous RNA (ceRNA) by competitively binding to miR-30a-3p to regulate the expression of EPAS1 and EPAS1-related signaling pathways, and thus, promotes lung adenocarcinoma tumorigenesis and progression. To verify this hypothesis, this project is designed to study the role of LINC01436 in lung adenocarcinoma and its potential mechanisms from different perspectives, i.e. clinical study, animal and cell model studies. Our findings will provide a new theoretical basis for further understanding of the molecular basis of lung cancer pathogenesis, and also provide new ideas for the prevention and treatment of lung cancer.

我们前期通过lncRNA表达谱芯片、生物信息分析和预实验，发现lncRNA LINC01436在肺腺癌中显著上调，其高表达与较差的肺腺癌预后相关；干扰LINC01436可抑制肺腺癌细胞的增殖、侵袭和迁移；进而结合miRNA表达谱芯片发现miR-30a-3p与LINC01436的表达呈负相关，且miR-30a-3p与LINC01436具有靶向结合位点；干扰LINC01436可上调miR-30a-3p，并下调miR-30a-3p潜在靶基因EPAS1的表达。由此推测：LINC01436可能作为竞争性内源性RNA（ceRNA)，竞争结合miR-30a-3p，解除对EPAS1表达抑制，进而调节EPAS1相关信号通路，促进肺腺癌的发生发展。为验证此假说，本项目拟从人群、动物、细胞多个层次，明确LINC01436在肺腺癌发生发展中的作用和分子机制，有助于深入认识肺癌的分子基础，为肺癌的防治提供新的思路。

肺癌是我国乃至全世界发病率和死亡率最高的恶性肿瘤之一。非小细胞肺癌(NSCLC)在所有肺癌中的比例约为85%，且肺腺癌是所占比例最高的病理类型。尽管目前已经发现了一些肺癌相关的促癌基因和抑癌基因，对肺癌的早期诊断和治疗起到了一些作用，但是，非小细胞肺癌患者的5年生存率仍然不足20%。因此，进一步深入研究肺癌发生和进展的分子机制，并在此基础上寻找新的早期诊断、预后预测的分子标志物，探索有效的分子治疗靶标，是提高肺癌预防和治疗效果的当务之急。长链非编码RNA（lncRNAs）的失调已经涉及到许多人类疾病，包括肺癌。然而，大多数lncRNAs的确切生物学功能和分子机制仍有待阐明。我们在NSCLC中发现了一种新的上调的lncRNA LINC01436。LINC01436高表达与NSCLC患者较差的预后显著相关。从细胞增殖、集落形成、细胞迁移和细胞侵袭等方面研究了LINC01436功能的获得和丧失，结果表明LINC01436在体外通过促进肺癌细胞的生长、迁移和侵袭而发挥原癌基因的作用。裸鼠移植瘤实验证实LINC01436在体内促进肿瘤生长和转移。在机制上，LINC01436通过作为miR-30a-3p海绵调控其靶基因EPAS1的表达发挥生物学功能。LINC01436还是一种新的缺氧敏感性lncRNA，在非小细胞肺癌中具有致癌性作用，提示LINC01436可能是一种潜在的预后和治疗靶点的候选生物标志物。本课题探索新的lncRNA-LINC01436在非小细胞肺癌发生发展中的作用和预后意义，有助于深入认识肺癌的分子基础，为寻找新的生物标记物和治疗靶点提供理论依据，为深入了解缺氧相关的lncRNA在肺癌中的作用提供了新的依据。