circHIPK2 promotes malignant progression of laryngeal squamous cell carcinoma through the miR-889-3p/MCTS1/IL-6 axis

Laryngeal squamous cell carcinoma (LSCC) is a common malignant tumor of the head and neck with a poor prognosis. The role of circRNAs in LSCC remains largely unknown. In this study, quantitative real-time PCR (qRT-PCR), Sanger sequencing and fluorescence in situ hybridization were undertaken to detect the expression, localization, and clinical significance of circHIPK2 in LSCC tissues and TU686 and TU212 cells. The functions of circHIPK2 in LSCC were explored through proliferation analysis, EdU staining, colony formation assay, wound healing assay, and Transwell assay. The regulatory mechanisms underpinning circHIPK2, miR-889-3p, and MCTS1 were investigated using luciferase assay, Western blotting, and qRT-PCR. We found that LSCC tissues and cells demonstrated high expression of circHIPK2 that was closely associated with the malignant progression and poor prognosis of LSCC. Knockdown of circHIPK2 inhibited the proliferation and migration of LSCC cells in vitro. Mechanistic studies showed that circHIPK2 competitively bound to miR-889-3p, elevated MCTS1 level, promoted IL-6 secretion, and ultimately accelerated the malignant progression of LSCC. In conclusion, an axis involving circHIPK2, miR-889-3p, MCTS1 and IL-6 regulates the malignant progression of LSCC. circHIPK2 expression may serve as a novel diagnostic and prognostic biomarker for LSCC.