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

Abstract

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.