Hsa_circ_0109320 Serves as a Novel Circular RNA Biomarker in Non-small Cell Lung Cancer by Promoting Metastasis

Non-small cell lung cancer (NSCLC), including squamous cell carcinoma and adenocarcinoma, ranks among the top 10 cancers worldwide in terms of prevalence and mortality. NSCLC, a highly malignant tumor, exhibits distant invasion and migration as well as an unfavorable prognosis. As an innovative circular RNA, hsa _circ_0109320 (circ_0109320) has been recognized as a promising cancer modulator. However, our understanding of the influence of circ_0109320 in NSCLC remains insufficient. Our research explored the clinical significance and effects of circ_0109320 on oncogenic non-small cell lung cancer (NSCLC) phenotypes. Microarray analysis and qPCR indicated that circ_0109320 expression in NSCLC specimens increased relative to that in adjacent normal tissues and was further elevated in metastatic lymph nodes. The specimens acquired from 25 patients confirmed these findings. Additionally, circ_0109320 indicated a good score (AUC = 0.688, P = 0.013) on the ROC curves, which suggests its suitability as a promising biomarker for lung cancer. Meanwhile, circ_0109320 was noticeably upregulated in lung cancer (LC) cell lines compared to human bronchial epithelial cells. Next, we performed loss- and gain-of-function experiments to examine the role of circ_0109320 in the tumor phenotypes of the cell lines. We observed that depletion or overexpression of circ_0109320 did not alter cell viability. However, the ectopic removal of circ_0109320 repressed the migration and invasion of A549 and SK-MES-1 cells, whereas circ_0109320 overexpression promoted cell migration and invasion. Furthermore, the examination of epithelial-mesenchymal transition (EMT) markers indicated that circ_0109320 elevates cell EMT activity. In conclusion, circ_0109320 level was highly associated with increased tumor cell proliferation and metastasis. circ_0109320 could be a promising predictor of clinical outcomes and a reliable target to treat NSCLC by inhibiting metastasis.