Circular RNA circ_0103552 forecasts dismal prognosis and promotes breast cancer cell proliferation and invasion by sponging miR-1236.

Breast cancer (BC) is a fatal malignancy, which has a high incidence and mortality across the world. Circular RNAs (circRNAs) have crucial roles in tumor initiation and progression. In this project, a newly found circRNA, circ_0103552 was explored. Quantitative real-time polymerase chain reaction was applied to measure its expression in the patients' tissue specimens and cells. In addition, Fisher's exact test, Kaplan-Meier curves and Cox regression model were conducted to discover the clinical significance of circ_0103552. Cell viability, clone-forming ability, apoptosis, and metastatic properties of BC cells were evaluated by gain/loss-of-function assays. Dual luciferase reporter assay was applied to illuminate its mechanisms. As data indicated, circ_0103552 was significantly elevated in BC tissue samples and cells. In addition, its expression correlates with clinical severity and dismal prognosis. Furthermore, circ_0103552 could facilitate cell growth, clone-forming ability, migration and invasion, and decrease apoptotic cells. For the mechanism exploration, circ_0103552 could directly sponge miR-1236 to execute oncogenic activities in BC cells. In summary, this study provides a novel circRNA in tumorigeneis and progression of BC and may help to develop effective therapeutic target for this devastating disease.