Circular RNA ciRS-7 correlates with advance disease and poor prognosis, and its down-regulation inhibits cells proliferation while induces cells apoptosis in non-small cell lung cancer.

OBJECTIVE: This study aimed to assess the association of circular RNA (circRNA) ciRS-7 expression with clinicopathological characteristics and prognosis of non-small cell lung cancer (NSCLC) patients, and to investigate its effect on cells proliferation as well as apoptosis in NSCLC. PATIENTS AND METHODS: 132 patients with primary NSCLC who received surgical resection were recruited in this retrospective study. All patients' tumor tissue and paired adjacent tissue were collected for circRNA ciRS-7 expression detection by RT-qPCR. Disease-free survival (DFS) and overall survival (OS) were calculated. CCK-8 and Annexin-V/propidium iodide (AV/PI) assays were performed to detect cells proliferation and apoptosis in A549 cells after circRNA ciRS-7 inhibition plasmid transfection. RESULTS: CircRNA ciRS-7 expression in tumor tissue was elevated compared to paired adjacent tissue, and positively correlated with tumor size, lymph node metastasis and tumor node metastasis (TNM) stages. K-M curves illustrated that circRNA ciRS-7 high expression was correlated with both shorter DFS and OS, and multivariate Cox's proportional hazards regression analysis showed that circRNA ciRS-7 high expression was an independent factor for predicting unfavorable DFS and OS. Cells methods revealed that circRNA ciRS-7 expression was elevated in NSCLC cell lines (A549, PC9, NCI-H1299 and NCI-H1650) compared to normal lung epithelial cells (DEAS-2B), and the inhibition of circRNA ciRS-7 expression reduced cells proliferation and promoted cells apoptosis in A549 cells. CONCLUSIONS: CircRNA ciRS-7 overexpression is associated with advanced disease and poor prognosis in NSCLC patients, and the down-regulation of circRNA ciRS-7 inhibits tumor cells proliferation as well as improves cells apoptosis.