Circ_0000005 Facilitates Proliferation, Apoptosis, Migration and Invasion of Acute Myeloid Leukemia Cells via Modulating miR-139-5p/Tspan3 Axis

Abstract Background: Accumulating circular RNAs (circRNAs) are reported to be abnormally expressed in diverse cancers, hematologic malignancies included. This study aimed to investigate the biological function and underlying mechanisms of circ_0000005 in acute myeloid leukemia (AML).Materials and methods: Bone marrow samples were enrolled from AML patients with normal samples as controls. Circ_0000005, miR-139-5p and tetraspanin 3 (Tspan3) were detected by qRT-PCR and Western blot, respectively. AML cell lines (KG1 and HL60) were used as cell models. CCK-8, Transwell and flow cytometry assays were adopted to study the biological functions of circ_0000005 on AML cells in vitro. The interrelation between circ_0000005 and miR-139-5p was detected by bioinformatics, qRT-PCR, luciferase reporter gene assay, RNA pull-down assay, and RNA-binding protein immunoprecipitation (RIP) assays. Ultimately, Western blot, qRT-PCR, luciferase reporter gene assay were adopted to corroborate the interrelation between miR-139-5p and its target Tspan3. Results: Circ_0000005 was demonstrably elevated in both AML clinical samples and cell lines. Circ_0000005 overexpression promoted the viability, migration and invasion of AML cells, and repressed the apoptosis of AML cells, while silencing circ_0000005 showed opposite biological effects. Circ_0000005 interacted with miR-139-5p and repressed its expression, and Tspan3 was proved to be negatively regulated by miR-139-5p. Circ_0000005 could promote the expression of Tspan3 via repressing miR-139-5p, and the oncogenic functions of circ_0000005 were dependent on its regulatory function on miR-139-5p/Tspan3 axis.Conclusion: Circ_0000005 facilitates the malignant phenotypes of AML cells via miR-139-5p/Tspan3 axis. Circ_0000005 may serve as a potential therapeutic target in AML.