Basic Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Stem Cells. Jul 26, 2022; 14(7): 539-555
Published online Jul 26, 2022. doi: 10.4252/wjsc.v14.i7.539
miR-3682-3p directly targets FOXO3 and stimulates tumor stemness in hepatocellular carcinoma via a positive feedback loop involving FOXO3/PI3K/AKT/c-Myc
Qian Chen, Si-Bo Yang, Ye-Wei Zhang, Si-Yuan Han, Lei Jia, Bo Li, Yi Zhang, Shi Zuo
Qian Chen, Ye-Wei Zhang, Bo Li, Shi Zuo, Department of Hepatobiliary Surgery, Affiliated Hospital of Guizhou Medical University, Guiyang 550000, Guizhou Province, China
Si-Bo Yang, Department of Clinical Medicine, Guizhou Medical University, Guiyang 550000, Guizhou Province, China
Si-Yuan Han, Department of Infectious Diseases, SSL Central Hospital of Dongguan, Dongguan 523000, Guangdong Province, China
Lei Jia, Department of Organ Transplantation, Affiliated Hospital of Guizhou Medical University, Guiyang 550000, Guizhou Province, China
Yi Zhang, Department of Hepatobiliary Surgery, Guizhou Provincial People's Hospital, Guiyang 550000, Guizhou Province, China
Author contributions: Zuo S designed the experiments and reviewed the manuscript; Chen Q, Yang SB and Li B performed the experiments and wrote the manuscript; Zhang YW, Han SY, Zhang Y and Jia L performed the statistical analysis; all authors checked the final manuscript.
Supported by the 12th Special Fund for Young Scientists and Technicians in Guizhou Province, No. (2019) 5647; the Science and Technology Fund of Guizhou Provincial Health and Health Commission, No. gzwjkj2020-1-101; the National Natural Science Foundation Training Program of Guizhou Medical University, No. 19NSP055; and Dongguan Science and Technology of Social Development Program, No. 201950715024201.
Institutional review board statement: The study was reviewed and approved by the Affiliated Hospital of Guizhou Medical University Institutional Review Board (Approval No. 2021039).
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of the Guizhou Medical University [IACUC protocol number: (Protocol No. 2100555)].
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.
ARRIVE guidelines statement: The authors have read the ARRIVE Guidelines, and the manuscript was prepared and revised according to the ARRIVE Guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Shi Zuo, PhD, Chief Doctor, Department of Hepatobiliary Surgery, Affiliated Hospital of Guizhou Medical University, No. 28 Gui Medical Street, Beijing Road, Yunyan District, Guiyang 550000, Guizhou Province, China. 1056659393@qq.com
Received: March 6, 2022
Peer-review started: March 6, 2022
First decision: April 19, 2022
Revised: April 24, 2022
Accepted: June 22, 2022
Article in press: June 22, 2022
Published online: July 26, 2022
Processing time: 141 Days and 20.7 Hours
Abstract
BACKGROUND

Cancer stem cells (CSCs) have been implicated in tumorigenesis and tumor recurrence and metastasis are key therapeutic targets in cancer treatment. MicroRNAs display therapeutic potential by controlling the properties of CSCs; however, whether an association exists between miR-3682-3p and CSCs is unknown.

AIM

To investigate the mechanism by which miR-3682-3p promotes stemness maintenance in hepatocellular carcinoma (HCC).

METHODS

MiR-3682-3p expression in HCC cell lines and 34 pairs of normal and HCC specimens was assayed by quantitative polymerase chain reaction. The functional role of miR-3682-3p was investigated in vitro and in vivo. Dual-luciferase reporter and chromatin immunoprecipitation assays were performed for target assessment, and western blotting was utilized to confirm miR-3682-3p/target relationships.

RESULTS

We found that miR-3682-3p plays a key role in HCC pathogenesis by promoting HCC cell stemness. The upregulation of miR-3682-3p enhanced CSC spheroid-forming ability, side population cell fractions, and the expression of CSC factors in HCC cells in vitro and the tumorigenicity of transplanted HCC cells in vivo. Furthermore, silencing miR-3682-3p prolonged the survival of HCC-bearing mice. Mechanistically, we found that miR-3682-3p targets FOXO3 and enables FOXO3/β-catenin interaction, which promotes c-Myc expression through PI3K/AKT; c-Myc, in turn, activates miR-3682-3p, forming a positive feedback loop. Intriguingly, miR-3682-3p expression was induced by hepatitis B virus X protein (HBx) and was involved in HBx-induced tumor stemness-related pathogenesis.

CONCLUSION

Our findings reveal a novel mechanism by which miR-3682-3p promotes stemness in HCC stem cells. Silencing miR-3682-3p may represent a novel therapeutic strategy for HCC.

Keywords: miR-3682-3p; FOXO3; Cancer stem cells; Hepatocellular carcinoma

Core Tip: In this work, we identified miR-3682-3p as a key inducer of cancer stem cell properties, thereby promoting the pathogenesis of hepatocellular carcinoma (HCC). In brief, we found that the upregulation of miR-3682-3p enhanced the spheroid forming ability, the fraction of side population cells, and the expression of cancer stem cell factors in HCC cells in vitro as well as the tumorigenicity of transplanted HCC cells in vivo; furthermore, silencing miR-3682-3p significantly prolonged the survival time of HCC-bearing mice. Mechanistically, we found that miR-3682-3p targets FOXO3 and enables FOXO3/β-catenin interaction, which promotes c-Myc expression through PI3K/AKT; c-Myc, in turn, activates miR-3682-3p, resulting in the formation of a positive feedback loop. Taken together, we identified a novel positive feedback regulatory loop involving HBx, miR-3682-3p, FOXO3, β-catenin, and c-Myc that plays a pivotal role in the stemness of HCC. Our findings revealed a novel mechanism by which miR-3682-3p promotes stem cell maintenance in HCC, and silencing miR-3682-3p may represent a novel therapeutic strategy for the treatment of this cancer.