miRNA-203/Snail轴调控巨噬细胞与胃癌细胞交互作用对肿瘤侵袭转移的影响及其机制研究

Epithelial-mesenchymal transition (EMT) is a key step for cancer cells to obtain metastatic ability. The macrophages in the tumor microenvironment play a significant role in promoting the occurrence of EMT, while cancer cells with EMT can recruit and activate macrophages. Both promoting each other to form a vicious cycle that lead to cancer cells invasion and metastasis. Currently, the molecular mechanism of the cross-talk between cancer cells and macrophages is not clear. The latest research shows that microRNA can not only control EMT behavior of cancer cells, but also closely relate to the generation and polarization of macrophages. Our preliminary data showed that miR-203 could inhibit gastric cancer cells EMT behavior and invasive potential, the macrophages in tumor microenvironment may down-regulate expression of miR-203 in gastric cancer cells; at the same time, we found that EMT mediated the core transcription factor Snail, which is a target gene of miR-203. Thus we speculate that the miR-203/Snail axis may play a crucial role in mutual interactions between macrophages and gastric cancer cells. Using protein microarray, ChIP assays and miR-203 knockout mice model and etc, we plan to investigate the role and mechanism of miRNA-203/Snail axis that involved in the mutual interactions and find potential intervention targets to break the vicious circle. The results of the present study may provide new clues in the design of new anti-tumor invasion and metastasis on theoretical and experimental basis.

上皮间质转化(EMT)是癌细胞获得转移能力的关键步骤。肿瘤微环境中的巨噬细胞对癌细胞EMT的发生具有明显促进作用，而癌细胞发生EMT后也可募集并活化巨噬细胞。两者互相促进形成恶性循环并导致癌细胞不断侵袭转移。目前介导癌细胞与巨噬细胞相互作用的机制尚不明确。最新研究显示microRNA不仅能调控癌细胞的EMT行为，还与巨噬细胞极化密切相关。我课题组前期发现miR-203能明显抑制胃癌细胞EMT行为及侵袭潜能，肿瘤微环境中巨噬细胞对胃癌细胞miR-203的表达可能具有下调作用；同时，我们发现介导EMT的核心转录因子Snail是miR-203的靶基因。由此推测miR-203/Snail轴可能为两者相互作用的核心。本项目拟采用蛋白芯片和ChIP等技术及miR-203敲除的小鼠模型，探讨该轴介导两者相互作用的机制及其在胃癌转移中的作用，并寻求可干预的靶点以打破恶性循环，为抗肿瘤转移治疗提供新思路。

上皮间质转化(EMT)是癌细胞获得转移能力的关键步骤。肿瘤微环境中的巨噬细胞对癌细胞EMT的发生具有明显促进作用，而癌细胞发生EMT后也可募集并活化巨噬细胞。两者互相促进形成恶性循环并导致癌细胞不断侵袭转移。目前介导癌细胞与巨噬细胞相互作用的机制尚不明确。最新研究显示microRNA不仅能调控癌细胞的EMT行为，还与巨噬细胞极化密切相关。本项目采用蛋白芯片和ChIP等技术及miR-203敲除的小鼠模型，发现miR-203能明显抑制胃癌细胞EMT行为及侵袭潜能，肿瘤微环境中巨噬细胞对胃癌细胞miR-203的表达具有下调作用肿瘤相关巨噬细胞与肿瘤的侵袭性相关，是胃癌预后差独立预测因子。靶向肿瘤相关巨噬细胞的研究可能是胃癌治疗的重要内容。肿瘤细胞与巨噬细胞共培养，定量RT-PCR检测巨噬细胞外泌体中microRNAs含量，结果显示miR-155、miR-21、miR-23a含量较高。miR-203较低。定量RT-PCR检测胃癌细胞外泌体中microRNAs含量，结果显示miR-155、miR-21、miR-23a含量较高。miR-203较低。Transwell实验显示M2型巨噬细胞来源的exosome对胃癌迁移起到促进作用，并且呈现剂量相关性。发现胃癌细胞及巨噬细胞外泌体中miR-203、miR-155这两种 miRNAs变化最为显著，发挥着巨大的作用。M2型巨噬细胞来源的exosome对肿瘤迁移起到促进作用，并且呈现剂量相关性。miR-203/Snail轴为两者相互作用的核心。CD163高表达的肿瘤相关巨噬细胞多见于病理特征显示出高侵袭性的特点，特别多见于肿瘤复发的患者。胃癌组织中CD163表达与胃癌干细胞标志物表达具有很好的一致性。CD163高表达、复发与患者预后不良密切相关。同时，我们发现介导EMT的核心转录因子Snail是miR-203的靶基因。该轴介导两者相互作用的机制及其在胃癌转移中的作用，并寻求可干预的靶点以打破恶性循环，为抗肿瘤转移治疗提供新思路。