circFIG 4 drives the carcinogenesis and metastasis of esophagus cancer via the miR-493-5p/E2F3 axis

Background Esophageal cancer (EC) is a highly malignant tumor of the digestive tract. Circular RNAs (circRNAs) have been verified to play a regulatory role in the occurrence and progression of different cancers, including EC. This research aimed to investigate the role and molecular mechanism of circFIG 4 in EC progression. Methods The analyses of circFIG 4, miR-493-5p, and neuro-oncological ventral antigen 2 levels were administrated by quantitative real-time polymerase chain reaction. The characteristics of circFIG 4 were determined by Ribonuclease R assay and Actinomycin D assay. Cell proliferation was assessed via colony formation assay and 5-ethynyl-2'-deoxyuridine incorporation assay. Cell cycle distribution and apoptosis were evaluated by flow cytometry. Western blot was performed to assess protein expression. The targeted interaction among circFIG 4, miR-493-5p, and E2F transcription factor 3 (E2F3) were validated using dual-luciferase reporter or RNA immunoprecipitation assays. Results circFIG 4 was overtly upregulated in EC and was relatively stable in EC cells. circFIG 4 knockdown impeded proliferation, migration, and invasion and expedited apoptosis in EC cells. circFIG 4 served as a miR-493-5p sponge to act in the development of EC. Furthermore, circFIG 4 modulated EC progression via targeting miR-493-5p and miR-493-5p suppressed EC progression via targeting E2F3. circFIG 4 modulated E2F3 expression through acting as a sponge of miR-493-5p. Moreover, circFIG 4 knockdown inhibited EC tumorigenesis by targeting miR-493-5p/E2F3 axis tumor growth in vivo. Conclusion circFIG 4 silence mitigated EC malignant progression at least partly by mediating the miR-493-5p/E2F3 pathway, highlighting new biomarkers and therapeutic targets for EC treatment.