Expression of Circular RNA ciRS-7 and Its Effect on Invasion and Migration of Triple-negative Breast Cancer Cells

Objective To investigate the expression of circular RNA ciRS-7 in triple-negative breast cancer (TNBC) and its effect on invasion and migration. Methods The expression levels of ciRS-7 in TNBC tissues and cells were detected by qRT-PCR, and its relationship with clinicopathological parameters of breast cancer patients was further analyzed. Scratch and Transwell assays were used to detect the migration and invasion of MDA-MB-231 and BT-549 cells after silencing ciRS-7. Animal experiment was performed to verify the above findings in vivo. Results The relative expression of ciRS-7 in TNBC tissues was (6.52±0.38), significantly higher than Luminal type (1.56±0.17) (P < 0.001), HER2 overexpressing breast cancer tissues (2.27±0.66) (P < 0.001) and normal adjacent tissues (0.83 ± 0.09) (P < 0.001). Clinical data analysis showed that ciRS-7 expression was significantly associated with molecular typing, tumor invasion and lymph node metastasis (all P < 0.05), not associated with patients' age, tumor diameter or pathological grade (all P > 0.05). After silencing ciRS-7, the migration and invasion of MDA-MB-231 and BT-549 cells were significantly reduced (all P < 0.05). The number of lung metastasis clones was significantly reduced in ciRS-7 knockdown group (P < 0.05). Conclusion ciRS-7 is highly expressed in TNBC and may enhance the invasion and migration of TNBC cells.