MiR-212-5p regulates the proliferation and apoptosis of AML cells through targeting FZD5.

OBJECTIVE: To explore the effects of microRNA-212-5p (miR-212-5p) on biological functions of acute myeloid leukemia (AML) and to find the potential molecular mechanism.

PATIENTS AND METHODS: We measured the expression level of miR-212-5p in 35 AML patients and 20 patients with idiopathic thrombocytopenic purpura (ITP) as control cases. Besides, the miR-212-5p expression at cellular level was checked as well. In order to screen the functional targets of miR-212-5p, online prediction software was used and gene frizzled class receptor 5 (FZD5) attracted our attention. The effects of miR-212-5p on biological functions of AML cell line (Kasumi-1) were analyzed by subsequent experiments. The mRNA and protein expressions of FZD5 were detected by quantitative Real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB) analysis, respectively. Cell proliferation was tested by cell counting kit-8 (CCK-8) assay. Cell cycle and apoptosis were measured by flow cytometry. Finally, protein expression of β-catenin was analyzed by WB assay.

RESULTS: In AML cases and cells, miR-212-5p was found to be lowly expressed. The potential target of miR-212-5p was predicated in three public databases. Through a series of experiments including qRT-PCR, WB and luciferase assay, we identified FZD5 as a functional target of miR-212-5p. In further cellular functional experiments on Kasumi-1, we found overexpression of miR-212-5p in Kasumi-1 cells greatly inhibited the cell viability and proliferation. The ratio of cells in G0/G1 phase and the proportion of apoptotic cells increased after miR-212-5p overexpression. Furthermore, Wnt/β-catenin signal pathway was the most apparent pathway that was regulated by miR-212-5p according to WB results. However, the effects of miR-212-5p were suppressed after restoring the expression of FZD5.

CONCLUSIONS: Expression of miR-212-5p was significantly lower in AML patients and cell lines, indicating that miR-212-5p served as a tumor-suppressor gene in AML. According to our in vitro experiments, miR-212-5p/FZD5 was likely to become a new therapeutic target for AML.