OBJECTIVE To explore the effects of breast cancer (BC)-derived exosomes on invasion and migration of BC cells. METHODS Exosomes (Exo-MA, Exo-M7, Exo-M1) were extracted from normal breast epithelial cells (MCF-10A), BC cells (MCF-7/MDA-MB-231) and BC cells with miR-146a overexpression or knockdown using multi-step differential centrifugation. Morphologies and sizes of exosomes were observed by transmission electron microscope (TEM) and particle size analysis respectively. BC mouse models were injected with DIR labeled Exo-MA, Exo-M7 or Exo-M1. The epithelial-mesenchymal transition (EMT) in BC cells was determined by PCR and Western blot. PKH67 labeled Exo-MA, Exo-M7 and Exo-M1 were incubated with NFs or MCF-7 to measure the activation of CAFs. Cell invasion and migration abilities were determined by scratch test and Transwell assay. RESULTS Exo-MA, Exo-M7, Exo-M1 were successfully extracted with positive expressions of Alix, CD63 and TSG101. Contents of Ki67, N-cadherin, Vimentin and Snail-1 were increased but E-cadherin was decreased, compared to Exo-MA group. Exo-M7 or Exo-M1 could increase BC cell proliferation and enhance EMT in nude mouse. Exo-M7 and Exo-M1 could accelerate the transformation of NFs into CAFs and promote the recruitment of CAFs in MCF-7. Transfection of miR-146a could promote the transformation of NFs into CAFs and promote cell invasion and migration of MCF-7 cells. As a target gene of miR-146a, TXNIP could inhibit the activation of CAFs. miR-146a overexpression or TXNIP silence enhance the activation of Wnt signal pathway. CONCLUSION BC-derived exosomes promote the activation of CAFs through miR-146a/TXNIP axis to activate Wnt pathway, which in turn enhances invasion and metastasis of BC cells.

中文翻译：

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乳腺癌来源的外来体通过miR-146a调节乳腺癌细胞的侵袭和转移，从而激活肿瘤微环境中与癌症相关的成纤维细胞。

目的探讨乳腺癌（BC）来源的外泌体对BC细胞侵袭和迁移的影响。方法从正常乳腺上皮细胞（MCF-10A），BC细胞（MCF-7 / MDA-MB-231）和miR-146a过表达或表达过高的BC细胞中提取外泌体（Exo-MA，Exo-M7，Exo-M1）使用多步差速离心法进行组合。分别通过透射电子显微镜（TEM）和粒度分析来观察外泌体的形态和大小。BC小鼠模型注射了DIR标记的Exo-MA，Exo-M7或Exo-M1。通过PCR和蛋白质印迹法测定BC细胞中的上皮-间质转化（EMT）。将标记有Exo-MA，Exo-M7和Exo-M1的PKH67与NF或MCF-7孵育，以测量CAF的激活。通过划痕试验和Transwell测定法测定细胞的侵袭和迁移能力。结果成功提取了Exo-MA，Exo-M7，Exo-M1，并带有Alix，CD63和TSG101阳性表达。与Exo-MA组相比，Ki67，N-钙黏着蛋白，波形蛋白和Snail-1的含量增加，而E-钙黏着蛋白减少。Exo-M7或Exo-M1可以增加裸鼠的BC细胞增殖并增强EMT。Exo-M7和Exo-M1可以加速NFs向CAF的转化，并促进MCF-7中CAF的募集。miR-146a的转染可以促进NFs向CAF的转化，并促进MCF-7细胞的侵袭和迁移。作为miR-146a的靶基因，TXNIP可以抑制CAF的激活。miR-146a过表达或TXNIP沉默增强Wnt信号通路的激活。结论BC来源的外来体通过miR-146a / TXNIP轴促进CAF的激活以激活Wnt途径，