MicroRNA-223 decreases cell proliferation, migration, invasion, and enhances cell apoptosis in childhood acute lymphoblastic leukemia via targeting Forkhead box O 1

Objective: Acute lymphoblastic leukemia (ALL) is a frequent malignancy in childhood. The present study was aimed to investigate the effect of miR-223 in ALL and its underlying molecular mechanisms. Methods: The mRNA expression of miR-223 and FOXO1 was detected by qRT-RCR in ALL children. The correlation between miR-223 and clinical indexes of ALL was determined. CCRF-CEM and NALM-6 cells were transfected with miR-223 mimic and miR-223 inhibitor, respectively. The proliferation, apoptosis, invasion and migration of CCRF-CEM and NALM-6 cells were measured by MTT, flow cytometry and transwell assay. The protein expression of FOXO1 was detected by Western blot. Additionally, dual-luciferase reporter and RNA pull-down assay were performed to investigate the target gene of miR-223 and validate their targeting relationship. Results: The mRNA expression of miR-223 was markedly down-regulated in ALL, but FOXO1 was up-regulated. The protein expression of FOXO1 was highly expressed in CCRF-CEM and NALM-6 cells. The expression of miR-223 was related to WBC, PLT, RBC and risk stratification. Overexpression of miR-223 not only inhibited cell proliferation, migration and invasion, but also induced cell apoptosis. Importantly, FOXO1 was a target gene of miR-223 in ALL cells. Silencing of FOXO1 reversed the effects of miR-223 inhibitor on cell proliferation, migration, invasion and apoptosis in ALL. Conclusions: miR-223 could inhibit cell proliferation, migration and invasion, and promote apoptosis by targeting FOXO1 in ALL.