Circ_0001667 accelerates breast cancer proliferation and angiogenesis through regulating CXCL10 expression by sponging miR‐6838‐5p

BACKGROUND: An increasing number of circular RNAs (circRNAs) have been shown to play an important role in the tumorigenesis of breast cancer. The aim of this study was to investigate the expression and function of circ_0001667 and its potential molecular mechanisms in breast cancer. METHODS: The expression levels of circ_0001667, miR‐6838‐5p and CXC chemokine ligand 10 (CXCL10) in breast cancer tissues and cells were detected by quantitative real‐time PCR. Cell counting kit‐8 assay, EdU assay, flow cytometry, colony formation and tube formation assays were used to detect cell proliferation and angiogenesis. The binding relationship between miR‐6838‐5p and circ_0001667 or CXCL10 was predicted using the starBase3.0 database and verified by dual‐luciferase reporter gene assay, RIP and RNA pulldown. Animal experiments were performed to assess the function of circ_0001667 knockdown on breast cancer tumor growth. RESULTS: Circ_0001667 was highly expressed in breast cancer tissues and cells, and its knockdown inhibited proliferation and angiogenesis of breast cancer cells. Circ_0001667 sponged miR‐6838‐5p, and inhibition of miR‐6838‐5p reversed the inhibitory effect of silencing circ_0001667 on proliferation and angiogenesis of breast cancer cells. MiR‐6838‐5p targeted CXCL10, and overexpression of CXCL10 reverses the effect of miR‐6838‐5p overexpression on breast cancer cell proliferation and angiogenesis. In addition, circ_0001667 interference also reduced breast cancer tumor growth in vivo. CONCLUSION: Circ_0001667 is involved in breast cancer cell proliferation and angiogenesis through regulation of the miR‐6838‐5p/CXCL10 axis.