Knockdown of circXPO1 inhibits the development of oral squamous cell carcinoma cells.

Background: Circular RNAs (circRNAs) have emerged as pivotal regulators of cellular processes in human malignancies, including oral squamous cell carcinoma (OSCC).

Methods: Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect RNA expression levels of circXPO1, miR-524-5p and cyclin D1 (CCND1). Colony formation assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay were performed to analyze cell proliferation, while transwell assay was carried out to investigate the cell migration and invasion. Cell apoptosis was assessed by flow cytometry. Protein expression analysis was implemented by Western blot assay. Additionally, lactate production and glucose consumption were investigated using a lactate assay kit and glucose assay kit, respectively. The in vivo tumorigenic potential of circXPO1 was evaluated using a xenograft mouse model assay.

Results: Elevated levels of circXPO1 and CCND1, alongside reduced miR-524-5p expression were decreased in OSCC tissues and cells. Knockdown of circXPO1 in OSCC cells inhibited their proliferative, migratory and invasive capacities, as well as glycolysis, prompting apoptosis. Moreover, circXPO1 silencing hindered tumor growth in vivo. MiR-524-5p could be sequestered by circXPO1, and its inhibition could counteract the beneficial effects of circXPO1 knockdown on OSCC progression.

Conclusion: Knockdown of circXPO1 inhibited OSCC progression by up-regulating miR-524-5p and down-regulating CCND1 expression, which might provide potential targets for OSCC treatment.