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

Abstract

Zheng Wang,1,* Xiaoxi Wang,2,* Fei Cheng,2 Xue Wen,2 Shi Feng,2 Fang Yu,2 Hui Tang,2 Zhengjin Liu,3 Xiaodong Teng2 1Department of Neurology, Hangzhou Seventh People’s Hospital, Hangzhou, People’s Republic of China; 2Department of Pathology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 3Department of Pathology, Zhongshan Hospital, Xiamen University, Xiamen, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zhengjin LiuDepartment of Pathology, Zhongshan Hospital, Xiamen University, 201 Hubin South Road, Xiamen, Fujian, 361004, People’s Republic of ChinaEmail [email protected] TengDepartment of Pathology, The First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79 Qingchun Road, Hangzhou, 310000, People’s Republic of ChinaEmail [email protected]: 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

Keywords

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