Department of Biology, Faculty of Science, Islamic Azad University, Science and Research Branch, Tehran, Iran.
Faculty of Veterinary Medicine, Kazerun Branch, Islamic Azad University, Kazerun, Iran.
Environ Res. 2023 Aug 15;231(Pt 1):116115. doi: 10.1016/j.envres.2023.116115. Epub 2023 May 12.
Exosomes are small extracellular vesicles that can be derived from human cells such as mesenchymal stem cells (MSCs). The size of exosomes is at nano-scale range and owing to their biocompatibility and other characteristics, they have been promising candidates for delivery of bioactive compounds and genetic materials in disease therapy, especially cancer therapy. Gastric cancer (GC) is a leading cause of death among patients and this malignant disease affects gastrointestinal tract that its invasiveness and abnormal migration mediate poor prognosis of patients. Metastasis is an increasing challenge in GC and microRNAs (miRNAs) are potential regulators of metastasis and related molecular pathways, especially epithelial-to-mesenchymal transition (EMT). In the present study, our aim was to explore role of exosomes in miR-200a delivery for suppressing EMT-mediated GC metastasis. Exosomes were isolated from MSCs via size exclusion chromatography. The synthetic miR-200a mimics were transfected into exosomes via electroporation. AGS cell line exposed to TGF-β for EMT induction and then, these cells cultured with miR-200a-loaded exosomes. The transwell assays performed to evaluate GC migration and expression levels of ZEB1, Snail1 and vimentin measured. Exosomes demonstrated loading efficiency of 5.92 ± 4.6%. The TGF-β treatment transformed AGS cells into fibroblast-like cells expressing two stemness markers, CD44 (45.28%) and CD133 (50.79%) and stimulated EMT. Exosomes induced a 14.89-fold increase in miR-200a expression in AGS cells. Mechanistically, miR-200a enhances E-cadherin levels (P < 0.01), while it decreases expression levels of β-catenin (P < 0.05), vimentin (P < 0.01), ZEB1 (P < 0.0001) and Snail1 (P < 0.01), leading to EMT inhibition in GC cells. This pre-clinical experiment introduces a new strategy for miR-200a delivery that is of importance for preventing migration and invasion of GC cells.
外泌体是一种可以从间质干细胞（MSCs）等人类细胞中衍生出来的小细胞外囊泡。外泌体的大小在纳米范围内，由于其生物相容性和其他特性，它们已成为在疾病治疗中递送生物活性化合物和遗传物质的有前途的候选物，特别是在癌症治疗中。胃癌（GC）是导致患者死亡的主要原因，这种恶性疾病影响胃肠道，其侵袭性和异常迁移导致患者预后不良。转移是 GC 面临的一个日益严峻的挑战，microRNAs（miRNAs）是转移和相关分子途径的潜在调节剂，特别是上皮-间充质转化（EMT）。在本研究中，我们的目的是探索外泌体在 miR-200a 递送中的作用，以抑制 EMT 介导的 GC 转移。通过分子筛色谱法从 MSC 中分离出外泌体。通过电穿孔将合成的 miR-200a 模拟物转染到外泌体中。AGS 细胞系暴露于 TGF-β 诱导 EMT，然后用负载 miR-200a 的外泌体培养这些细胞。进行 Transwell 测定以评估 GC 迁移，测量 ZEB1、Snail1 和波形蛋白的表达水平。外泌体的负载效率为 5.92±4.6%。TGF-β 处理将 AGS 细胞转化为表达两种干细胞标志物 CD44（45.28%）和 CD133（50.79%）的成纤维细胞样细胞，并刺激 EMT。外泌体使 AGS 细胞中 miR-200a 的表达增加了 14.89 倍。从机制上讲，miR-200a 增加 E-钙粘蛋白水平（P<0.01），同时降低 β-连环蛋白（P<0.05）、波形蛋白（P<0.01）、ZEB1（P<0.0001）和 Snail1（P<0.01）的表达水平，从而抑制 GC 细胞的 EMT。这项临床前实验为 miR-200a 的递呈提出了一种新策略，对于防止 GC 细胞的迁移和侵袭具有重要意义。
