Circ_0001387 regulates SKA2 to accelerate breast cancer progression through miR‐136‐5p

BACKGROUND: Growing evidence has revealed the critical regulatory role for circular RNAs (circRNAs) in cancer. This study aimed to explore the function of circ_0001387 in breast cancer (BC). METHODS: Circ_0001387, miR‐136‐5p, and spindle and kinetochore‐associated protein 2 (SKA2) levels were analyzed by quantitative real‐time polymerase chain reaction. Clone formation and 5‐ethynyl‐2′‐deoxyuridine assays were used to analyze cell proliferation. Cell apoptosis and cell migration and invasion abilities were analyzed using flow cytometry or transwell assay. Mechanism assay was used to confirm the association between miR‐136‐5p and circ_0001387 or SKA2. The effect of circ_0001387 on tumor growth in vivo was analyzed by the xenograft mice model. RESULTS: Circ_0001387 and SKA2 were expressed at high levels, whereas miR‐136‐5p was lowly expressed in BC tissues and cells. Meanwhile, the downregulation of circ_0001387 restrained BC cell progression in vitro and in vivo. Circ_0001387 competitively bound to miR‐136‐5p to regulate BC cell malignant behaviors. SKA2 was targeted by miR‐136‐5p, and SKA2 reinstated the suppressive effect of miR‐136‐5p upregulation in BC cells. CONCLUSION: Our study indicated that circ_0001387 contributed to BC cell progression through miR‐136‐5p/SKA2 axis.