巨噬细胞外泌体源miR-223促进胃癌细胞对奥沙利铂的耐药研究

背景与目的：化疗耐药是导致胃癌患者预后不良的重要因素,阐明胃癌细胞化疗耐药的机制有助于为临床治疗提供新思路,具有重要的现实意义。探讨巨噬细胞外泌体源miR-223对胃癌细胞奥沙利铂化疗敏感性的影响及作用机制。方法：将购自中国科学院典型培养物保藏委员会细胞库/中国科学院上海生命科学研究院细胞资源中心的胃癌细胞与巨噬细胞及其来源外泌体共培养,检测miR-223的表达水平并观察其对奥沙利铂的化疗敏感性。采用荧光显微镜观察巨噬细胞是否通过外泌体传递miR-223至胃癌细胞。采用细胞计数试剂盒-8（cell counting kit-8,CCK-8）、细胞凋亡实验观察巨噬细胞外泌体源miR-223对胃癌细胞奥沙利铂化疗敏感性的影响。采用实时荧光定量聚合酶链反应（real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR）检测胃癌患者外周血外泌体源miR-223的表达水平,分析其与奥沙利铂耐药的关系。结果：巨噬细胞及其外泌体与胃癌细胞共培养后,胃癌细胞对奥沙利铂化疗的敏感性降低,半数抑制浓度（half inhibition concentration,IC ₅₀ ）明显升高;同时miR-223相对表达量明显增加。采用荧光显微镜观察发现,巨噬细胞通过外泌体传递miR-223至胃癌细胞。巨噬细胞外泌体源miR-223通过调控FBXW7增强胃癌细胞抗凋亡能力,促进其对奥沙利铂的耐药。奥沙利铂耐药胃癌患者外周血外泌体miR-223的表达水平显著升高。结论：巨噬细胞通过外泌体传递miR-223增强胃癌细胞对奥沙利铂的耐药,外周血外泌体源miR-223有望成为胃癌患者化疗耐药的监测指标。

Exosomal transfer of macrophage-derived miR-223 confers oxaliplatin resistance in gastric cancer

Background and purpose: Chemotherapy resistance is an important factor resulting in poor prognosis of gastric cancer patients. The elucidation of molecular mechanisms underlying chemoresistance is helpful to provide new therapeutic strategy, which has important practical significance. This study aimed to investigate the effect ofexosomal miR-223 derived from macrophage on oxaliplatin chemosensitivity of gastric cancer cells and its mechanism. Methods: Gastric cancer cells purchased from National Collection of Authenticated Cell Cultures were co-cultured with macrophages or macrophage-derived exosomes. The miR-223 expression was detected by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR). The transfer of miR-223 through internalization of exosomes was observed by immunofluorescence. Macrophages were transfected with a miR-223 inhibitor or negative control. Cell counting kit-8 (CCK-8) and apoptosis assay were employed to explore the effect of macrophage-derived exosomes on the oxaliplatin chemosensitivity of gastric cancer cells. The clinical relationship between the expression of exosomal miR-223 in plasma and oxaliplatin resistance in gastric cancer patients was also explored. Results: The chemosensitivity of gastric cancer cells to oxaliplatindecreased, while half inhibition concentration (IC ₅₀ ) increased significantly when co-cultured with macrophages or macrophage-derived exosomes. The expression level of miR-223 was significantly increased, and exosomal transfer of miR-223 was observed by immunofluorescence. Functional studies revealed that exosomal miR-223 derived from macrophages promoted oxaliplatin resistance in gastric cancer cells by inhibiting FBXW7. Clinically, the high expression of plasma exosomal miR-223 was highly linked with oxaliplatin resistance in gastric cancer patients. Conclusion: The exosomal transfer of macrophage-derived miR-223 conferred oxaliplatin resistance in gastric cancer cells, and these results indicated that circulating exosomal miR-223 may be a useful monitoring indicator for oxaliplatin resistance in gastric cancer treatment.