Suppression of endothelial cell migration by tumor associated macrophage-derived exosomes is reversed by epithelial ovarian cancer exosomal lncRNA

Quanfeng Wu,Qinyi Zhu,Xin Chen,Xiaoli Wu,Lu Jiang,Xipeng Wang,Xinjing Wang,Xiang Ying,Yueqian Wu

doi:10.1186/s12935-017-0430-x

Quanfeng Wu, Qinyi Zhu + Show 7 more

Open Access

https://doi.org/10.1186/s12935-017-0430-x

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Abstract

ObjectiveTo study the mechanism by which epithelial ovarian cancer (EOC)-derived exosomes restore the migration of endothelial cells that is suppressed by TAM-derived exosomes.MethodsExosomes were isolated from TAMs in the ascites of patients with EOC. The effect of exosomes on the expression of endothelial cell miRNA was monitored by PCR. The miRNA mimics were transfected to explore their effects. Microarray data and literature searches were used to predict target genes and the impact of target gene pathways, and small interfering RNA was used to target these genes. We used migration assays to determine whether ovarian cancer cell-derived exosomes participate in the regulation of TAMs and endothelial cells. We used microarray data to identify the target lncRNA, and we constructed target lncRNA expression plasmids to validate targets by Western blotting.ResultsWe separated TAMs from the ascites of patients with EOC and isolated exosomes from TAM supernatants. After co-culture with HUVECs, these exosomes were efficiently incorporated into HUVECs. The migration of HUVECs was suppressed significantly in the exosome group compared with blank controls (P < 0.05).The miRNA mimic transfection and target gene prediction found that TAM-derived exosomes targeted the miR-146b-5p/TRAF6/NF-κB/MMP2 pathway to suppress endothelial cell migration; this result was supported by PCR and Western blotting analyses. The expression of exosomal miR-146b-5p isolated from serum in the EOC group was significantly increased compared to healthy individuals. Finally, TAM-derived exosomes and EOC SKOV3-derived exosomes in combination stimulated HUVEC cells and overcame the inhibition of endothelial cell migration caused by TAM-derived exosomes. Two lncRNAs that were carried by SKOV3-derived exosomes were identified as NF-κB pathway-associated genes by Western blotting.ConclusionTAM-derived exosomes can inhibit the migration of endothelial cells by targeting the miR-146b-5p/TRAF6/NF-kB/MMP2 pathway. However, EOC-derived exosomes can transfer lncRNAs to remotely reverse this effect of TAMs on endothelial cells.

Highlights

Epithelial ovarian cancer (EOC) is considered the most malignant gynecological tumor; its mortality rate is the highest of all gynecological malignancies
We obtained the same results as with exosome incubation. These findings indicate that exosomal miR-146b-5p can suppress the migration of Human umbilical vein endothelial cells (HUVECs) via Tumor necrosis factor receptor-associated factor 6 (TRAF6)/nuclear factor-κB (NF-κB)/ Matrix metalloproteinase-2 (MMP2)
We found that tumor-associated macrophages (TAMs)-derived exosomes targeted the miR-146b-5p/TRAF6/NF-kB/MMP2 pathway to suppress endothelial cell migration (Fig. 5e)

Summary

Introduction

Epithelial ovarian cancer (EOC) is considered the most malignant gynecological tumor; its mortality rate is the highest of all gynecological malignancies. The overall 5-year survival rate is approximately 30% [1]. A remarkable feature of advanced EOC is the presence of widespread peritoneal metastases at the time of initial diagnosis. The mechanisms of peritoneal seeding, spreading, and progression remain elusive. Our previous studies suggested that various stromal cells, including activated endothelial cells, tumor-associated macrophages (TAMs), fibroblasts, and bone marrow-derived cells infiltrated the EOC peritoneum [2, 3]. More than 75% of the mononuclear immune cells in the peritoneum near a tumor implant were TAMs, which mimic chronic inflammation [2] and associated with tumor progression

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