MiR-20a suppresses proliferation and facilitates apoptosis of breast cancer cells via the MTOR signaling pathway

K.-Y. Shi, L.-Y. Fan, D. Xu, L.-P. Ren, L.-P. Wang, L.-Y. Chen, L.-J. Wang

Department of Ultrasound, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Zhejiang, China. wanglj@zjcc.org.cn

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• Oncology

OBJECTIVE: The paper aimed to explore the role of micro ribonucleic acid (miR)-20a in regulating the proliferation and apoptosis of breast cancer cells.

MATERIALS AND METHODS: The expression of miR-20a in breast cancer cells was analyzed via quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) assay. Cell Counting Kit-8 (CCK-8) assay, colony formation assay, and flow cytometry were employed to analyze the proliferation and apoptosis of cells. Thereafter, the target proteins of miR-20a were predicted using TargetScan, a website for miRNA target gene prediction, and the interaction between miR-20a and the target genes was detected through the Luciferase reporter gene assay, qRT-PCR assay, and Western blotting. Finally, the miR-20a inhibitor and target gene expression plasmids were co-transfected for rescue experiment to study whether the target genes participate in the inhibitory effect of miR-20a on the proliferation of breast cancer cells.

RESULTS: It was found that the expression of miR-20a was upregulated in breast cancer cell lines. Silencing miR-20a expression inhibited the proliferation and promoted the apoptosis of breast cancer cell. Besides, it was demonstrated that late endosomal/lysosomal adaptor, mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR) activator 3 (LAMTOR3) were a direct target of miR-20a. The knockdown of LAMTOR3 expression repressed the influence of miR-20a on the proliferation of breast cancer cells.

CONCLUSIONS: MiR-20a targets LAMTOR3 gene to regulate the mTOR signaling pathway, thereby suppressing the proliferation and facilitating the apoptosis of breast cancer cells. It suggests that miR-20a exerts a carcinogenic effect in breast cancer, which may be a potential target for the treatment of breast cancer.

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