Circular RNA hsa_circ_0006522 correlates with unfavorable prognosis and promotes the proliferative, migrative, and invasive abilities of breast cancer cells.

Background: Breast cancer persists as a predominant oncology burden impacting women globally. It is of utmost importance to explore new therapeutic targets that can boost recovery rates and enhance the long-term survival of breast cancer patients. Recently, emerging evidence substantiates circular RNAs as pivotal mediators orchestrating breast carcinogenesis. We aimed to evaluate the role of circular RNA hsa_circ_0006522 on breast cancer behavior Methods: In this study, we utilized fluorescence in situ hybridization (FISH) and tissue microarray techniques to examine the expression of hsa_circ_0006522 in breast cancer tissues. Subsequently, we carried out a comprehensive analysis of the correlation between the expression level of hsa_circ_0006522 in breast cancer patients and clinical characteristics. To assess the proliferative capacity of breast cancer cells, we employed the cell counting kit-8 and the colony formation assay. Meanwhile, wound healing assay and transwell migration and invasion assays were performed to explore the metastatic and invasive abilities of breast cancer cells. Finally, we further predicted the biological functions of this molecule by bioinformatics analysis. Results: Through FISH, we verified that hsa_circ_0006522 was mainly located in the cytoplasm of breast cancer cells. Further investigations revealed that high expression of hsa_circ_0006522 was notably associated with multiple unfavorable clinical indicators. These included an elevated risk of lymphatic metastasis, a worse clinical stage, and a reduced overall survival time for patients. Cox regression analysis showed that the expression level of hsa_circ_0006522 can serve as an independent prognostic factor for breast cancer. Moreover, functional experiments demonstrated that the overexpression of hsa_circ_0006522 could significantly stimulate the proliferation, migration, and invasion of breast cancer cells. Conversely, knocking down hsa_circ_0006522 could yield the opposite outcome. Bioinformatics analysis showed that hsa_circ_0006522 harbored hsa-miR-217, hsa-miR-548b-3p and hsa-miR-769-3p seed sequences to regulate these three miRNAs and downstream target genes and exerted its various biological functions in the progression of breast cancer. Conclusions: An elevation in the expression level of hsa_circ_0006522 was significantly associated with a decline in the survival rate of breast cancer patients. Furthermore, our data suggest that hsa_circ_0006522 expression levels could independently predict breast cancer prognosis. Specifically, hsa_circ_0006522 could notably enhance the proliferation, migration, and invasion of breast cancer cells. Based on these findings, we hypothesized that hsa_circ_0006522 is highly probable to be a vital biomarker in breast cancer progression.