Long noncoding RNA NEAT1 changes exosome secretion and microRNA expression carried by exosomes in hepatocellular carcinoma cells

Shengning Zhang; Yuanyi Mang; Li Li; Jianghua Ran; Yingpeng Zhao; Laibang Li; Yang Gao; Wang Li; Guoyu Chen; Jun Ma

doi:10.21037/jgo-21-729

Long noncoding RNA NEAT1 changes exosome secretion and microRNA expression carried by exosomes in hepatocellular carcinoma cells

J Gastrointest Oncol. 2021 Dec;12(6):3033-3049. doi: 10.21037/jgo-21-729.

Authors

Shengning Zhang¹, Yuanyi Mang¹, Li Li¹, Jianghua Ran¹, Yingpeng Zhao¹, Laibang Li¹, Yang Gao¹, Wang Li¹, Guoyu Chen¹, Jun Ma¹

Affiliation

¹ Department of Hepato-Biliary-Pancreatic Surgery and Liver Transplantation Center, the Calmette Affiliated Hospital of Kunming Medical University, the First People's Hospital of Kunming, Clinical Medical Center for Organ Transplantation of Yunnan Province, Kunming, China.

Abstract

Background: This study aimed to investigate the roles and functions of nuclear-enriched abundant transcript 1 (NEAT1) in exosome secretion and exosomal microRNA (miRNA) changes in hepatocellular carcinoma (HCC) cells.

Methods: HepG2 and HuH-7 cells were divided into two groups: Lv-control (which were infected with lentivirus without NEAT1 expression) and Lv-NEAT1 (which were infected with lentivirus with NEAT1 overexpression). Each group was used to study cell function (proliferation, invasion, and apoptosis) and exosome secretion by nanoparticle tracking analysis (NTA), electron microscopy, and nanoflow cytometry (nanoFCM). Different levels of messenger RNA (mRNA), miRNA, and exosomal miRNA were detected by RNA sequencing. Next, potential target RNAs were verified by reverse transcription polymerase chain reaction (RT-PCR). Changed exosomal miRNAs were found and miRNA mimics were used to study cell function in NEAT1-overexpression and NEAT1-knockdown HCC cells.

Results: The data showed that NEAT1-overexpression promoted exosome secretion. The overexpression of NEAT1 altered global genes, including exosome-related genes. Compared with the control group, we observed that several miRNAs changed in the exosomes secreted by NEAT1-overexpressing cells. Our study found that these changed exosomal miRNAs played a suppressor role in HCC. Transfection of miR-634, miR-638, and miR-3960 reversed the enhanced invasion and proliferation in HCC cells with a high level of NEAT1 expression.

Conclusions: These results suggested that NEAT1 regulates exosome-related genes, which might be associated with increasing exosome secretion by NEAT1-overexpressing cells. Furthermore, NEAT1 promotes cell invasion and proliferation via downregulation of miR-634, miR-638, and miR-3960 in exosomes. This study may provide potential targets for exosome-mediated miRNA transfer in HCCs with a high level of NEAT1 expression therapy.

Keywords: Long noncoding RNA (lncRNA); exosome; hepatocellular carcinoma (HCC); microRNA (miRNA); nuclear-enriched abundant transcript 1 (NEAT1).