Rab27A调控Stat3信号通路促进非小细胞肺癌转移的机制研究

Metastasis of non-small cell lung cancer(NSCLC) is the main characteristic of pulmonary malignant, and it is the leading cause of poor prognosis and cancer death. The transport and exocytosis of vesicular play pivotal role in the metastasis of tumor and is the focus of research in recent years. As the key protein of vesicle transport, Rab27A can regulate the formation of exosome and mediate the metastasis and invasion of tumor. Our preliminary experimental results showed that Rab27A was upregulated in NSCLC tissues and positively correlated with NSCLC metastasis. Importantly, knockdown of Rab27A could suppress the EMT, migration and invasion of NSCLC cell lines, especially inhibit Stat3 signaling pathway. Therefor, we put forward the scientific hypothesis that Rab27A can promote the formation of exosome and release cytokines，which can bind to receptors on the cell membrane to activate the Stat3 signaling pathway, thereby promoting the metastasis of NSCLC. To text this hypothesis, immunohistochemistry, establishment of stable cell lines, vivo model of metastasis and exosome related experiments were performed to investigate the mechanism of Rab27A in NSCLC metastasis. Taken together, our research will provide new molecular targets and theoretical basis for the treatment and prognosis of NSCLC.

非小细胞肺癌转移和侵袭是其预后不良的征兆，也是导致晚期癌症患者死亡的主要因素。囊泡运输以及胞吐作用在肿瘤转移发生过程中扮演着重要角色，是近年来的研究热点。Rab27A作为囊泡运输关键蛋白，能够调控外泌体形成，且可以介导肿瘤的转移和侵袭。我们前期预实验显示Rab27A在非小细胞肺癌组织样本中高表达并与其恶性转移程度相关，敲弱Rab27A后可抑制非小细胞肺癌细胞发生EMT，迁移和侵袭，同时抑制Stat3信号通路。因此，我们提出科学假说：Rab27A可将外泌体运输至细胞膜外，释放细胞因子与膜上受体结合激活Stat3信号通路，增强其下游基因转录调控，进而促进非小细胞肺癌发生转移。为了验证该假说，我们利用免疫组化、稳转细胞株构建，裸鼠移植瘤模型和外泌体相关实验手段等从体内外揭示Rab27A促进非小细胞肺癌转移的分子机制，为肺癌的治疗与预后提供新的分子靶标和理论基础。

囊泡运输以及胞吐作用在肿瘤发生和发展过程中扮演着重要角色，是近年来的研究热点。Rab27A作为囊泡运输关键蛋白，能够调控外泌体形成，且可以介导肿瘤的转移和侵袭。虽然Rab27A曾被报道在非小细胞肺癌中高表达，但是其作用以及机制仍然不明。我们研究发现miR-124可以通过与Rab27A的3‘-UTR结合来抑制其表达，阐明了Rab27A在NSCLC组织和细胞株中的高表达状态可能与miR-124的低表达相关。随后，我们构建了稳定高表达和敲低Rab27A的A549和H1299细胞株，从体外细胞水平和体内动物水平上证明了Rab27A可以影响NSCLC细胞的增殖、转移和侵袭。此外，我们还通过蛋白芯片技术揭示了Rab27A影响NSCLC细胞的功能主要与JAK/STAT信号通路相关。最终我们阐明了Rab27A可以通过外泌体的方式促进IFNα的分泌，进一步与受体结合增强TYK2（tyr1054）磷酸化蛋白的表达激活下游STAT信号来发挥促癌作用的具体分子机制，为非小细胞肺癌的治疗与预后提供新的分子靶标和理论基础。