MicroRNA-520a-3p inhibits cell growth and metastasis of non-small cell lung cancer through PI3K/AKT/mTOR signaling pathway.

Objective: MicroRNAs are a class of small non-coding RNAs that be involved in the pathogenesis of non-small cell lung cancer (NSCLC). The purpose of this study was to evaluate the effects of miR-520a-3p in cell growth and metastasis. Materials and

Methods: The mimics and inhibitor of miR-520a-3p were used to identify the effects of miR-520a-3p on cell proliferation and apoptosis using methylthiazol tetrazolium (MTT) assay and flow-cytometric method, respectively. Transwell assay was used to evaluate the cell migration and invasion. The protein expression levels related PI3K/AKT/mTOR signaling pathways were measured by Western blot.

Results: The results showed that miR-520a-3p overexpression could significantly inhibit cell proliferation and induce apoptosis, suppress cell migration and invasion. MiR-520a-3p overexpression could markedly reduce the ratio of p-AKT/AKT, p-PI3K/PI3K and Bcl-2/Bax, the levels of mTOR, matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) compared with control. However, miR-520a-3p overexpression could increase caspase-3 expression compared with control group. After inhibited the expression of miR-520a-3p, the capacity of cell proliferation, migration and invasion were increased, cell apoptosis was inhibited compared with control group. The ratio of p-AKT/AKT, p-PI3K/PI3K and Bcl-2/Bax, the levels of mTOR, MMP-2 and MMP-9 were increased compared with control group.

Conclusions: Our study suggested that miR-520a-3p could suppress the NSCLC proliferation, migration and invasion through PI3K/AKT/mTOR signaling pathway.