Basic Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 14, 2019; 25(22): 2752-2762
Published online Jun 14, 2019. doi: 10.3748/wjg.v25.i22.2752
MiR-34a overexpression enhances the inhibitory effect of doxorubicin on HepG2 cells
Shun-Zhen Zheng, Ping Sun, Jian-Ping Wang, Yong Liu, Wei Gong, Jun Liu
Shun-Zhen Zheng, Jian-Ping Wang, Yong Liu, Wei Gong, Jun Liu, Department of Liver Transplantation and Hepatobiliary Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, Shandong Province, China
Ping Sun, Department of Clinical Laboratory, Blood Station of Jinan, Jinan 250021, Shandong Province, China
Author contributions: Zheng SZ and Li J designed the research; Zheng SZ, Sun P, Wang JP, Liu Y, and Gong W performed the research; Sun P and Wang JP analyzed the data; Zheng SZ wrote the paper.
Supported by: the National Natural Science Foundation of China, No. 81302124, Shandong Key R and D Program No. 2017GSF218038 and Shandong Provincial Natural Science Foundation, No. ZR2014HP065.
Institutional review board statement: This study was reviewed and approved by the Medical Ethics Committee of Shandong Provincial Hospital Affiliated to Shandong University.
Institutional animal care and use committee statement: No animal models were used in this study.
Conflict-of-interest statement: None of the authors has any conflicts of interest to declare.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: No animal models were used in this study.
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 Non Commercial (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: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Jun Liu, MD, Professor, Surgeon, Department of Liver Transplantation and Hepatobiliary Surgery, Shandong Provincial Hospital Affiliated to Shandong University, No. 324 Jingwu Road, Jinan 250021, Shandong Province, China. dr_liujun1967@126.com
Telephone: +86-531-68776932 Fax: +86-531-87925615
Received: March 14, 2019
Peer-review started: March 14, 2019
First decision: April 4, 2019
Revised: April 13, 2019
Accepted: April 29, 2019
Article in press: April 29, 2019
Published online: June 14, 2019
ARTICLE HIGHLIGHTS
Research background

Hepatocellular carcinoma (HCC) is the third leading cause of death from malignant tumors worldwide. Surgery is still the preferred treatment, however nearly 80% of patients have lost their chance of surgery by the time that they are diagnosed. Like other malignant tumors, multidisciplinary treatment has become the primary means of HCC treatment, with chemotherapy being the most important alternative to surgery. Nevertheless, drug resistance is the most important reason for the insensitivity of HCC to chemotherapy. Therefore, the mechanism of chemotherapy resistance in HCC requires more research.

Research motivation

Chemotherapy resistance is the most important reason for the poor outcome of HCC. Previous studies have shown that increasing expression of miR-34a in tumor cells can increase the sensitivity of tumor cells to chemotherapeutic drugs. In addition, chemotherapeutic drugs can exert an antitumor effect by causing p53-dependent DNA damage. We were interested in the relationship between the expression of miR-34a and the chemosensitivity in HCC cell lines.

Research objectives

The aim of this study was to investigate the effect of miR-34a over-expression on the growth inhibition of HepG2 HCC cells by doxorubicin.

Research methods

A recombinant lentiviral vector containing miR-34a was constructed and transfected into HepG2 cells to upregulate expression of miR-34a. Cells were exposed to doxorubicin after miR-34a over-expression. To evaluate the effect of miR-34a over-expression, cell viability, cell cycle and apoptosis were detected by MTT and flow cytometry. Expression levels of phospho (p)-p53, sirtuin (SIRT) 1, cyclin D1, cyclin-dependent kinase (CDK) 4, CDK6, BCL-2, multidrug resistance protein (MDR)1/P glycoprotein (P-gp), and AXL were detected by Western blotting.

Research results

The expression of miR-34a in HepG2 cells was significantly upregulated. Growth of HepG2 cells was inhibited after upregulation of miR-34a, and viability was significantly decreased after combination with doxorubicin. The number of HepG2 cells in G1 phase increased, and G1 phase arrest was more obvious after upregulation of miR-34a. The apoptosis rate of HepG2 cells was increased after upregulation of miR-34a, and became more obvious after intervention with doxorubicin. Western blotting showed that upregulation of miR-34a combined with doxorubicin treatment caused significant changes in the expression levels of p-p53, SIRT1, cyclin D1, CDK4, CDK6, BCL-2, MDR1/P-gp and AXL proteins.

Research conclusions

Over-expression of miR-34a can significantly enhance the inhibitory effect of doxorubicin on HepG2 cells. miR-34a may enhance the killing effect of doxorubicin by down-regulating MDR1/P-gp and AXL, which may be related to p53 expression.

Research perspectives

Over-expression of miR-34a can reduce the malignant biological behavior of HCC cells and enhance the chemosensitivity of HCC cells to doxorubicin. miR-34a is worth studying in the reversal of HCC resistance to chemotherapy.