Clinical significance of miR-138 in patients with malignant melanoma through targeting of PDK1 in the PI3K/AKT autophagy signaling pathway

The present study investigated the clinical significance of miR-138 in patients with malignant melanoma ( MM), which has previously been associated with tumor growth. In patients with MM, we found that the expression of miR-138 was significantly downregulated when compared with healthy control subjects. Overexpression of miR-138 in the human melanoma cell line A2058 inhibited cell proliferation and induced cell apoptosis, and increased caspase-3 and Bax protein expression when compared with a negative control group. Meanwhile, miR-138 overexpression promoted cell autophagy, induced LC3 protein expression, and suppressed the PI3K/AKT/mTOR signaling pathway and PDK1 protein expression in A2058 cells. LY294002, an inhibitor of PI3K, suppressed PI3K/AKT/mTOR signaling, induced apoptosis, inhibited cell proliferation, increased caspase-3 and Bax protein expression, and decreased PDK1 protein expression in A2058 cells following miR-138 overexpression. Collectively, our findings indicate the clinical significance of miR-138 in patients with MM through its targeting of PDK1 expression in the PI3K/AKT/mTOR autophagy signaling pathway.