Rapamycin Inhibits Glioma Cells Growth and Promotes Autophagy by miR-26a-5p/DAPK1 Axis

Abstract

Background

Glioma is a common intracranial malignant tumor with high rates of invasiveness and mortality. This study aimed to investigate the mechanism of rapamycin in glioma.

Methods

U118-MG cells were treated with and without rapamycin in vivo and then collected for RNA sequencing. Differentially expressed miRNAs (DEMs) were screened and verified. MiR-26a-5p was selected for functional verification, and the target gene of miR-26a-5p was identified. The effects of miR-26a-5p on cell proliferation, cell cycle, apoptosis, and autophagy were also investigated.

Results

In total, 58 up-regulated and 41 down-regulated DEMs were identified between rapamycin-treated and untreated U118-MG cells. MiR-26-5p levels were up-regulated in U118-MG cells treated with 12.5 μM rapamycin, and death-associated protein kinase 1 (DAPK1) expression, a direct miR-26a-5p target gene, was down-regulated. Rapamycin substantially inhibited cell proliferation and cell percentage in the S phase and promoted cell apoptosis; miR-26a-5p inhibitor increased cell proliferation and cell cycle and decreased cell apoptosis; DAPK1 overexpression further induced cell proliferation, increased the cell number in the S phase, and inhibited apoptosis in glioma cells. Notably, rapamycin increased the autophagy-related Beclin1 protein expression levels and the LC3 II/I ratio.

Conclusion

Rapamycin exerts anti-tumor effects by promoting autophagy in glioma cells, which was dependent on the miR-26a-5p/DAPK1 pathway activation by rapamycin.

Keywords:

• rapamycin
• autophagy
• RNA sequencing
• glioma cells
• miR-26a-5p
• death-associated protein kinase 1

Abbreviations

DEMs, expressed miRNAs; mTOR, mammalian target of rapamycin; DAPK1, death associated protein kinase 1; pc-DAPK1, DAPK1 overexpression vector; PI, propidium iodide; HCAECs, human coronary artery endothelial cells; HDMECs, human skin microvascular endothelial cells.

Data Sharing Statement

All data generated or analyzed during this study is included in this published article.

Consent for Publication

All of the authors have agreed to publish this article in your journal if it is accepted.

Author Contributions

All authors have read and approved the manuscript. All authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

Zheng Wang and Xiaoxi Wang are co-first authors for this study. The authors declare that they have no competing interests.