外泌体H3F3A调控巨噬细胞VEGFC表达重塑淋巴网络在胃癌淋巴结转移中的机制研究

The incidence and mortality of gastric cancer are at the forefront of malignant tumours. Lymph node metastasis is the most critical factor affecting the prognosis of gastric cancer. Lymphatic network remodelling is an essential basis for the premetastatic niche before lymph node metastasis. We have reported that exosome IRF-2 promotes the expression of VEGFC by macrophages through transcriptional levels, thereby promoting lymphangiogenesis and increasing lymph node metastasis. However, the effect of exosomes on post-transcriptional levels of VEGFC in macrophages is still unclear. We found that exosome H3F3A from the serum of gastric cancer patients was significantly increased by exoRBase database RNA-seq analysis and Q-PCR detection. Exosome H3F3A can promote the secretion of VEGFC by macrophages and encourage the formation of tubules. H3F3A mRNA promotes macrophage VEGFC expression by competitively binding to miR-3163. Therefore, we speculate that the gastric cancer exosome H3F3A promotes lymphatic network remodelling by competitively binding to macrophage miR-3163, promoting macrophage VEGFC expression. This project intends to further elucidate the role of exosome H3F3A in lymphangiogenesis through in vivo and in vitro experiments, providing new clues for therapeutic intervention for distant metastasis.

胃癌发病率和死亡率均位居恶性肿瘤前列，淋巴结转移是影响胃癌预后的最主要因素。淋巴网络重塑是淋巴结转移前微环境的重要基础。我们前期报道肿瘤外泌体IRF-2通过转录水平促进巨噬细胞表达VEGFC，从而促进淋巴管新生，增加淋巴结转移。然而，外泌体对巨噬细胞VEGFC转录后水平的影响尚不明确。我们通过exoRBae数据库RNA-seq分析和Q-PCR验证发现胃癌患者血清外泌体H3F3A表达显著增高。外泌体H3F3A促进巨噬细胞分泌VEGFC，加速小管形成。H3F3A mRNA通过与VEGFC竞争性结合miR-3163，促进巨噬细胞VEGFC表达。因此，我们推测胃癌外泌体H3F3A通过竞争性结合巨噬细胞miR-3163，促进VEGFC表达，推动淋巴网络重塑。本项目拟采用体内体外实验进一步阐述外泌体H3F3A mRNA在淋巴网络重塑中的作用，为寻找胃癌远处转移的干预靶点提供新线索。

胃癌发病率和死亡率均位居恶性肿瘤前列，淋巴结转移是影响胃癌预后的最主要因素，淋巴网络重塑是淋巴结转移前微环境的重要基础。我们通过构建胃癌外泌体小鼠教育模型揭示胃癌外泌体增加淋巴结内淋巴内皮细胞增殖；通过构建胃癌原位模型发现外泌体教育增加胃癌淋巴结转移。通过exoRBae数据库RNA-seq分析和Q-PCR验证发现胃癌患者血清外泌体H3F3A表达显著增高，H3F3A mRNA与胃癌总生存期显著相关。VEGFC是淋巴网络生成的主要调节者，与胃癌淋巴结转移密切相关。我们采用shH3F3A转染胃癌细胞以敲减外泌体内H3F3A mRNA；巨噬细胞教育模型发现外泌体H3F3A mRNA促进巨噬细胞VEGFC表达，影响小管形成。进一步的研究结果显示，外泌体H3F3A mRNA抑制miR-3163的表达；miR-3163过表达抑制VEGFC mRNA和蛋白水平表达；荧光素酶实验显示miR-3163能显著抑制VEGFC和H3F3A质粒载体的荧光素酶活性。本项目揭示外泌体H3F3A mRNA通过竞争性吸附巨噬细胞miR-3163，转录后水平促进VEGFC表达，促进淋巴网络重塑的分子机制，揭示外泌体促进淋巴结转移的调控通路，为理解胃癌淋巴结转移的生物学行为提供新视角。胃癌血清外泌体H3F3A mRNA显示良好的诊断价值及预后预测价值，具有潜在的临床应用价值。