Circular RNA circPRMT5 is upregulated in breast cancer and is required for cell proliferation and migration

BACKGROUND/AIM: To evaluate the role of cyclic protein arginine methyltransferase 5 (circPRMT5) in the occurrence and development of breast cancer (BC). MATERIALS AND METHODS: A total of 90 BC patients who underwent radical mastectomy and 40 age-matched healthy female controls were recruited in the Second People’s Hospital of China Three Gorges University, Yichang Second People’s Hospital from 2017 to 2020. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to detect the expression levels of circPRMT5 in BC tissues, serum, normal breast cell line (MCF-10A), and BC cell line (T47D, MCF-7, BT549, Hs-578T, and MDA-MB-231, MDA-MB-468). The associations between circPRMT5 expression level and age, tumor size, degree of differentiation, TNM stage, distant metastasis, estrogen receptor (ER) or progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status were analyzed. BC cell lines with circPRMT5 knockdown or overexpression were subject to CCK-8 cell proliferation assay, and transwell cell invasion/migration assay. RESULTS: CircPRMT5 expression in BC tissue was higher than that in adjacent normal breast tissue. Consistently, the expression level of circPRMT5 was also elevated in serum samples collected from BC patients when compared with healthy controls. And in multiple breast cancer cell lines, circPRMT5 was upregulated as compared to normal breast epithelial MCF-10A cells. CircPRMT5 expression level was correlated with tumor size, TNM stage, lymph node metastasis distant metastasis, but no correlation was observed with ER, PR, HER2 status. Overexpression of circPRMT5 promoted the proliferation, invasion, and migration of MCF7 cells; while the knockdown of circPRMT5 inhibited cell proliferation, invasion, and migration. CONCLUSION: CircPRMT5 seems to act as an oncogene in the progression of BC. Our data suggest that CircPRMT5 may be used as a biomarker for the diagnosis, prognosis evaluation, and targeted therapy of breast cancer.