Hsa_circRNA_0000518 facilitates breast cancer development via regulation of the miR‐326/FGFR1 axis

BACKGROUND: Breast cancer (BC) is a heterogeneous malignant tumor that threatens the health of women worldwide. Hsa_circRNA_0000518 (circ_0000518) has been revealed to be upregulated in BC tissues. However, the role and mechanism of circ_0000518 in BC are indistinct. METHODS: Quantitative real‐time polymerase chain reaction (qRT‐PCR) was implemented to detect the levels of circ_0000518, microRNA (miR)‐326, and fibroblast growth factor receptor 1 (FGFR1) mRNA in BC tissues and cells. Cell counting kit‐8 (CCK‐8), colony formation, flow cytometry, and transwell assays were executed to estimate BC cell proliferation, cell cycle progression, apoptosis, migration, and invasion. The relationship between circ_0000518 or FGFR1 and miR‐326 was verified by dual‐luciferase reporter and/or RNA immunoprecipitation (RIP) assays. The role of circ_0000518 in vivo was confirmed by xenograft assay. RESULTS: Circ_0000518 and FGFR1 were upregulated while miR‐326 was downregulated in BC tissues and cells. Circ_0000518 silencing impeded tumor growth in vivo and induced cell cycle arrest, apoptosis, cured proliferation, colony formation, migration, and invasion of BC cells in vitro. Circ_0000518 regulated FGFR1 expression via competitively binding to miR‐326 in BC cells. MiR‐326 inhibitor reversed the inhibitory influence of circ_0000518 knockdown on the malignant behaviors of BC cells. FGFR1 overexpression abolished miR‐326 mimic‐mediated influence on the malignant behaviors of BC cells. CONCLUSIONS: Circ_0000518 facilitated BC development via regulation of the miR‐326/FGFR1 axis, suggesting that circ_0000518 might be a promising target for BC treatment.