Knockdown of circMYOF inhibits cell growth, metastasis, and glycolysis through miR-145-5p/OTX1 regulatory axis in laryngeal squamous cell carcinoma.

ABSTRACT

New evidence suggests that abnormal expression of circular RNA (circRNA) is associated with the development of human cancers. This study aims to reveal circMYOF roles in the malignant phenotype of laryngeal squamous cell carcinoma (LSCC). The expression of circMYOF, microRNA (miR)-145-5p, and orthodenticle homeobox 1 (OTX1) was detected by quantitative real-time PCR. Cell proliferation, migration, invasion, and apoptosis were determined using colony formation assay and EdU assay, wound healing assay, transwell assay, and flow cytometry, respectively. Protein expression was examined by western blot analysis. Cell glycolysis was assessed by detecting glucose consumption and lactate production. Mice xenograft models were constructed to evaluate the regulation of circMYOF on LSCC tumorigenesis. The regulatory relationships among circMYOF, miR-145-5p, and OTX1 were identified using dual-luciferase reporter assay and RIP assay. Serum exosomes were isolated to confirm the existence of circMYOF in LSCC patients. CircMYOF was upregulated in LSCC tissues and cells, and its knockdown suppressed LSCC cell growth, metastasis, and glycolysis, as well as inhibited LSCC tumor growth. MiR-145-5p had decreased expression in LSCC, and it could be sponged by circMYOF. The inhibition effect of circMYOF lentivirus short hairpin RNA (sh-circMYOF) on LSCC progression was restored by the inhibitor of miR-145-5p (in-miR-145-5p). Also, OTX1 was targeted by miR-145-5p and was positively regulated by circMYOF. MiR-145-5p could repress LSCC progression, and OTX1 overexpression also eliminated this effect. In addition, we found that circMYOF was significantly overexpressed in the serum exosomes of LSCC patients. Our data revealed that circMYOF contributed to LSCC progression by promoting cell growth, metastasis, and glycolysis through miR-145-5p/OTX1 axis.