miR-124 介导外泌体的释放调控非小细胞肺癌侵袭转移的机制研究

Non-small cell lung cancer (NSCLC) is a serious malignant tumor with dismal prognosis. Invasion and metastasis are the leading reason for the resultant mortality of patients with NSCLC. Exosomes in tumor microenvironment is one of the most important factor to influence the invasion and metastasis of tumor cells. Our previous study confirmed that the number of exosomes in serum of NSCLC patients and supernatants of tumor cell was significantly higher than that of normal controls, and significantly positive relevant with clinical stage and metastasis in NSCLC patients. MiRNA sequencing for patient tissue and cell line revealed that some of the miRNA molecules were significantly associated with the release of exosomes and the prognosis of metastasis. Further study found that low levels of miR-124 in NSCLC cells significantly improved the secretion of exosomes; overexpression of miR-124 significantly reduced the release of exosomes and inhibited the expression of Rab27a protein obviously. This study intends to use the regulation of Rab27a by miR-124 as a breaking point, studying the intermediate process for the secretion of exosomes and the upstream regulatory molecules for miR-124, to clarify the molecular mechanisms of highly secretion of exosomes by NSCLC cells. This study will not only help further expand the knowledge field of invasion and metastasis regulation in NSCLC, and also may provide important clues and new perspective for the development of new target and prognosis indicators in NSCLC.

非小细胞肺癌(NSCLC)危害严重，侵袭转移是影响预后的关键原因。外泌体是肿瘤微环境中影响肿瘤细胞侵袭转移的一个重要因素，我们前期研究证实NSCLC患者血清和肿瘤细胞株上清中外泌体数量显著高于正常对照，且与患者的临床分期和转移呈正相关关系；患者组织及细胞株miRNA测序发现部分miRNA分子与外泌体释放及患者的转移预后显著相关；进一步功能研究发现NSCLC细胞中低水平的miR-124极显著的提高了外泌体的分泌，过表达miR-124可显著降低外泌体的释放，抑制Rab27a的蛋白水平。本课题拟从miR-124调节Rab27a水平为切入点，研究miR-124调控外泌体分泌的中间过程并挖掘miR-124的上游调控分子，最终阐明NSCLC肿瘤细胞外泌体释放调控的关键分子机制。本课题不仅有助于拓展NSCLC侵袭转移调控的知识领域，并为开发新的肺癌转移治疗靶点和转移预后判断指标提供重要线索和新的视角。

非小细胞肺癌(NSCLC)危害严重，侵袭转移是影响预后的关键原因。先前研究提示外泌体参与非小细胞肺癌的癌症进展、转移和治疗效果。本研究探索外泌体在NSCLC 侵袭转移中的作用以及外泌体分泌调控的分子机制。研究通过采集不同分期的NSCLC患者血清标本，发现晚期肺癌患者（n=24）血清中外泌体含量显着高于早期肺癌患者（n=30）。在细胞水平研究中，外泌体的释放促进NSCLC 细胞系 A549的迁移和侵袭；研究进一步发现LINC00511与非小细胞肺癌的外泌体分泌有关，将LINC00511转染到A549中促进了细胞的迁移和侵袭。萤光素酶报告基因显示miR-124是LINC00511的靶基因，并进一步靶向 RAS 基因家族成员 Rab27a，miR-124 的 3'-UTR 中含有LINC00511和Rab27a结合位点；在将 Rab27a 转染到 A549 中促进了外泌体的释放并促进肿瘤细胞的迁移和侵袭。高表达miR-124 在小鼠 NSCLC 异种移植模型中可抑制肿瘤生长和肺转移，LINC00511/miR-124/Rab27a 轴在肺癌进展中起重要作用。本研究阐明NSCLC肿瘤细胞外泌体释放调控的关键分子机制。本课题不仅有助于拓展NSCLC侵袭转移调控的知识领域，并为开发新的肺癌转移治疗靶点和转移预后判断指标提供重要线索和新的视角。