MicroRNA-125a regulates proliferation and apoptosis of acute myeloid leukemia through targeting NF-κB pathway.

OBJECTIVE: To elucidate the influence of microRNA-125a on the biological behaviors of acute myeloid leukemia (AML) cells. MATERIALS AND METHODS: MicroRNA-125a mimic and negative control (NC) were constructed and transfected into AML cell line HL60, respectively. Cell viability of HL60 cells transfected with microRNA-125a mimic or NC was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Regulatory effects of microRNA-125a on enzyme activities of B-cell lymphoma-2 (Bcl-2), Bcl-xl, caspase-3, and caspase-9 in HL60 cells were quantified by a spectrophotometry. Changes in apoptosis and invasion of HL60 cells overexpressing microRNA-125a were detected by flow cytometry and transwell assay, respectively. Protein levels of cell cycle genes (cyclin B, cdc-2, mdm-2), pro-apoptotic gene p53 and anti-apoptotic gene Bcl-2 in HL60 cells transfected with microRNA-125a mimic or NC were assessed by Western blot. Finally, the mRNA levels of Bax, caspase-8, nuclear factor-κB (NF-κB), and c-myc in HL60 cells with microRNA-125a overexpression were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). RESULTS: MicroRNA-125a expression remarkably increased by transfection of microRNA-125a mimic into HL60 cells, suggesting its sufficient transfection efficacy. MTT assay revealed an inhibited viability after microRNA-125a overexpression. Transfection of microRNA-125a mimic markedly enhanced enzyme activities of caspase-3 and caspase-9, but reduced activities of Bcl-2 and Bcl-xl in HL60 cells than controls (p<0.05). Moreover, microRNA-125a overexpression elevated apoptotic rate as FCM data indicated. Transwell assay demonstrated a decrease in the invasive rate of HL60 cells overexpressing microRNA-125a. Western blot analyses revealed that cell cycle genes all downregulated by transfection of microRNA-125a mimic in HL60 cells. The protein level of p53 upregulated and Bcl-2 downregulated in HL60 cells overexpressing microRNA-125a (p<0.05). Furthermore, mRNA levels of pro-apoptotic genes Bax and caspase-8 were enhanced after microRNA-125a overexpression, while mRNA levels of NF-κB and c-myc were reduced (p<0.05). CONCLUSIONS: MicroRNA-125a inhibits proliferative and invasive potentials, arrests the cell cycle in the G2/M phase of AML cells by regulating the NF-κB pathway.