CircRNA circFNDC3B promotes esophageal cancer progression via cell proliferation, apoptosis, and migration regulation

Background: Esophageal cancer is one of the most common malignant tumors threatening human health worldwide. Circular RNAs (circRNAs) are a large group of covalently closed continuous loops that are prevalently expressed in human cells and might be applied as novel esophageal cancer biomarkers. Purpose: To investigate the expression of a novel circular RNA, circFNDC3B, in esophageal cancer, as well as determine its function in the regulation of esophageal cell proliferation, apoptosis, migration, and invasion. Methods: Quantitative RT-PCR using circular RNA-specific primers was performed to analyze the existence and expressional change of circFNDC3B in esophageal cancer tissues. The esophageal cancer cell lines ECA109 and KYSE150 with inhibited circFNDC3B expression by gene silencing were subjected to proliferation analysis with the MTS method, FITC Annexin V apoptosis detection, and a proliferation and invasion evaluation using a transwell system. Results: circFNDC3B was specifically up-regulated in esophageal cancer tissues. Esophageal cancer cell lines ECA109 and KYSE150 with decreased circFNDC3B expression by gene silencing showed inhibited proliferation, increased apoptosis, and weakened migration and invasion abilities. Conclusion: The circFNDC3B encoded by two FNDC3B gene exons is an important regulator of esophageal cancer progression.