Exosomal miR-3682-3p Suppresses Angiogenesis by Targeting ANGPT1 via the RAS-MEK1/2-ERK1/2 Pathway in Hepatocellular Carcinoma.

Shuang-Shuang Dong,Yan Zhao,Gui-Qi Zhu,Dong-Mei Gao,Bin-Bin Liu,Jie Chen,Zhang-Fu Yang,Dan-Dan Dong

doi:10.3389/fcell.2021.633358

Abstract

BackgroundAngiogenesis is a crucial process in tumorigenesis and development. The role of exosomes derived from hepatocellular carcinoma (HCC) cells in angiogenesis has not been clearly elucidated.Methods and ResultsExosomes were isolated from HCC cell lines (HCCLM3, MHCC97L, and PLC/RFP/5) by ultracentrifugation and identified by nano transmission electron microscopy (TEM), NanoSight analysis and western blotting, respectively. In vitro and in vivo analyses showed that exosomes isolated from highly metastatic HCC cells enhanced the migration, invasion and tube formation of human umbilical vein endothelial cells (HUVECs) compared to exosomes derived from poorly metastatic HCC cells. In addition, microarray analysis of HCC-Exos was conducted to identify potential functional molecules, and miR-3682-3p expression was found to be significantly downregulated in exosomes isolated from highly metastatic HCC cells. By in vitro gain-of-function experiments, we found that HCC cells secreted exosomal miR-3682-3p, which negatively regulates angiopoietin-1 (ANGPT1), and this led to inhibition of RAS-MEK1/2-ERK1/2 signaling in endothelial cells and eventually impaired angiogenesis.ConclusionOur study elucidates that exosomal miR-3682-3p attenuates angiogenesis by targeting ANGPT1 through RAS-MEK1/2-ERK1/2 signaling and provides novel potential targets for liver cancer therapy.

Highlights

Liver cancer is one of the most common malignancies, ranking sixth globally in incidence and fourth in mortality (Bray et al, 2018)
We found that miR-3682-3p could suppress human umbilical vein endothelial cells (HUVECs) angiogenesis, migration, and invasion by targeting ANGPT1 through the RAS-MEK1/2-ERK1/2 pathway
Nanoparticle tracking analysis (NTA) was performed to analyze the size and distribution of particles obtained from HCCLM3, MHCC97L, and PLC/RFP/5 cells, and the results indicated that the mean diameter of the derived particles were 129, 154, and 139 nm, respectively (Figure 1C)

Summary

Introduction

Liver cancer is one of the most common malignancies, ranking sixth globally in incidence and fourth in mortality (Bray et al, 2018). Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, accounting for approximately 750,000 deaths worldwide each year, and more than 50% of the cases occur in China (Siegel et al, 2018). Specific proteins are highly expressed in Exos, such as Alix, CD9, CD81, and TSG101, which are usually used as markers for the identification of exosomes (Pfeffer, 2010). Increasing evidence has demonstrated that exosomes play important roles in the regulation of the tumor microenvironment via the promotion of angiogenesis, signaling pathway activation, tumorigenesis, and metastasis (Taylor and Gercel-Taylor, 2011). Exosomes contain many functional molecules, such as proteins, DNA, RNA, and lipids, and play important roles in intercellular material and information transmission. The role of exosomes derived from hepatocellular carcinoma (HCC) cells in angiogenesis has not been clearly elucidated

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