Tumor suppressor miR-520a inhibits cell growth by negatively regulating PI3K/AKT signaling pathway in acute myeloid leukemia.

Background: Short regulatory RNAs, called microRNAs (miRNAs), have been found to possess regulatory functions in cancer and, as such, have recently been evaluated for their therapeutic role against various human malignancies.

Objectives: The present work aimed to investigate whether miR-520a can play a therapeutic role in the treatment of human acute myeloid leukemia.

Material and methods: Human myeloid leukemia cell lines (Kasumi-1, Kasumi-3, Kasumi-6, BDCM, and K562) and a normal myeloid cell line (NCI-H5N6) were used for the study. Cell lines were subjected to real-time quantitative polymerase chain reaction (RT-qPCR), evaluation of cell viability and proliferation by MTT assay and colony formation assays. Dual acridine orange (AO)/ethidium bromide (EB) staining was applied for transfected K562 cells with miR-negative control (NC) or miR-520a mimics, and annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) dual staining and flow cytometry were performed to analyze cancer cell apoptosis followed by western blot.

Results: Cancerous cell lines exhibited lower gene expression of miR-520a, and its overexpression significantly reduced (p < 0.05) the proliferation and viability of cancer cells. Cancer cells demonstrated the induction of Bax/Bcl-2-mediated apoptosis following miR-520a overexpression. The miR-520a was shown to target the PI3K/AKT signaling pathway in human acute myeloid leukemia to exercise its regulatory role in cancer.

Conclusions: The study showed that miR-520a actively regulated cell proliferation in acute myeloid leukemia and illustrated the mechanism by which it exerts its regulatory role, emphasizing the possibility of targeting miR-520a as an efficient therapeutic strategy against human acute myeloid leukemia.