Hsa_circ_001569 is an unfavorable prognostic factor and promotes cell proliferation and metastasis by modulating PI3K-AKT pathway in breast cancer

Circular RNAs (circRNAs) have gained attention for their involvement in carcinogenesis, but its functional effects in breast cancer (BC) remains largely unclear. In this study, we aimed to explore the expressing pattern, clinical significance and potential function of a newly identified circRNA, hsa_circ_001569, in BC. RT-PCR was performed to detect the expression of hsa_circ_001569 in both BC tissues and cell lines. The associations between hsa_circ_001569 expression and clinicopathological features and prognosis in BC patients were statistically analyzed. Next, we investigated the effects of hsa_circ_001569 on the proliferation, apoptosis, migration and invasion in BC cells lines. The effects of abnormal hsa_circ_001569 expression on EMT pathway and PI3K/AKT pathway were determined using Western blot. We found that hsa_circ_001569 expression was significantly up-regulated in both BC tissues and cell lines. Overexpression of hsa_circ_001569 was associated with Lymph node metastasis, advanced clinical stage and shorter overall survival. Multivariate assay confirmed that hsa_circ_001569 expression was an independent prognostic factor for 5-year overall survival. Furthermore, functional investigations revealed that knockdown of hsa_circ_001569 significantly suppressed the growth and metastatic potentials of BC cells. Besides, molecular mechanistic study revealed that depression of hsa_circ_001569 impeded the activation of PI3K-AKT signaling in BC cells. Our results indicated that hsa_circ_001569 upregulation was associated with BC lymph-node metastasis, clinical stage, and poor prognosis. Hsa_circ_001569 might contribute to progression of BC by modulating PI3K-AKT pathway.