BACKGROUND: Circular RNAs (circRNAs) are frequently aberrantly expressed in non-small cell lung cancer (NSCLC) and are considered to exert a pivotal role in the occurrence and development of NSCLC via targeting and negatively regulating microRNAs (miRNAs). We aimed to investigate the role of hsa_circ_0109320 in the proliferation, invasion and apoptosis of NSCLC, and explore its underlying molecular mechanism.

MATERIAL AND METHODS: Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis was performed to determine the circ_0109320 and miR-595 expression in tissues or cells. Western blot analysis was conducted to examine the cleaved caspase-3, Bax, Bcl-2, and E2F7 protein expression. Transwell detection was used to evaluate the invasion level of NSCLC cell lines.

RESULTS: The results of present study indicated that circ_0109320 expression in NSCLC patients was upregulated significantly in tumor tissues compared with tissues adjacent to carcinoma. Upregulated circ_0109320 level was significantly associated with TNM stages as well as lymph node metastasis of NSCLC. Moreover, downregulation of circ_0109320 attenuated proliferation and invasion while promoting apoptosis in NSCLC cells. We further confirmed that circ_0109320 could sponge miR-595 to upregulate E2F7 expression. Silencing of miR-595 or overexpression of E2F2 could partially reversed the inhibitory role of circ_0109320 knockdown in NSCLC cells. These data provided evidence that the suppression of circ_0109320 attenuates NSCLC cell proliferation and invasion and enhances apoptosis through the miR-595/E2F7 pathway.

CONCLUSIONS: Circ_0109320/miR-595/E2F2 axis may exert a pivotal role in the pathological mechanism of NSCLC progression, and it has potential application in the future treatment of NSCLC.

Keywords: E2F2 Transcription Factor, RNA, Untranslated, Aged, 80 and over, Apoptosis Regulatory Proteins, RNA, RNA, Circular, Real-Time Polymerase Chain Reaction