Circular RNA_0076977 contributes to oral squamous cell carcinoma progression through mediating microRNA-802 axis

The study aims to explore the role and the mechanism of circ_0076977 regulating oral squamous cell carcinoma progression (OSCC) progression.

Reverse transcription-quantitative polymerase chain reaction and western blot assays were conducted to analyze RNA and protein expression. Cell proliferation was analyzed by 5-ethynyl-2'-deoxyuridine incorporation and colony formation assays. Cell apoptosis was measured by flow cytometry. Tube formation assay was conducted to analyze cell angiogenesis ability. Transwell assays were performed to detect cell migration and invasion abilities. Dual-luciferase reporter assay was implemented to verify the target relationship.

Circular (circ)_0076977 was abnormally up-regulated in OSCC tissues and cell lines. Circ_0076977 absence inhibited the proliferation, angiogenesis, migration, and invasion and induced the apoptosis of oral squamous cell carcinoma (OSCC) cells. Circ_0076977 knockdown blocked xenograft tumor growth. miR-802 was a direct target of circ_0076977, and circ_0076977 knockdown restrained OSCC progression largely by up-regulating miR-802. miR-802 directly interacted with myosin VI (MYO6) mRNA, and MYO6 was negatively modulated by miR-802 in OSCC cells. miR-802 overexpression reduced the malignant potential of OSCC cells largely by down-regulating MYO6. Circ_0076977 could up-regulate MYO6 expression by absorbing miR-802 in OSCC cells.

Circ_0076977 was up-regulated in OSCC tissues and cell lines, and high circ_0076977 expression contributed to OSCC progression by targeting miR-802/MYO6 axis.