Circular RNA SMARCA5 may serve as a tumor suppressor in non‐small cell lung cancer

BACKGROUND: This study aimed to investigate the correlation of circular RNA SMARCA5 (circ‐SMARCA5) expression with clinicopathological characteristics and survival profiles, furthermore, to explore the function of circ‐SMARCA5 on regulating cell proliferation and chemotherapy sensitivity in non‐small cell lung cancer (NSCLC). METHODS: A total of 460 NSCLC patients were retrospectively reviewed, and circ‐SMARCA5 expressions in tumor tissue and adjacent tissue were detected by RT‐qPCR. Clinical characteristics were collected. Disease‐free survival (DFS) and overall survival (OS) were calculated. In vitro, circ‐SMARCA5 overexpression and control overexpression plasmids were transfected into NCI‐H1437 as well as NCI‐H1299 cells, which were further treated with different concentrations of cisplatin and gemcitabine. RESULTS: Circ‐SMARCA5 expression was decreased in tumor tissues compared to adjacent tissues. Moreover, circ‐SMARCA5 expression negatively correlated with tumor size, lymph node metastasis, and TNM stage, but positively correlated with DFS and OS. Subsequent analysis displayed that circ‐SMARCA5 high expression independently predicted prolonged DFS and OS. In vitro, circ‐SMARCA5 expression was reduced in NSCLC cell lines (NCI‐H650, NCI‐H1299, NCI‐H1437, and A549) compared to human normal lung bronchus epithelial cell line (BEAS‐2B). In NCI‐H1437 and NCI‐H1299 cells, cell proliferation was decreased by circ‐SMARCA5 overexpression, furthermore, chemosensitivity to cisplatin and gemcitabine were enhanced in circ‐SMARCA5 overexpression treated cells compared to the control cells. CONCLUSION: Circ‐SMARCA5 may serve as a tumor suppressor in NSCLC, which provides insight to the exploration of novel strategies in NSCLC management.