| Background Laryngeal squamous cell carcinoma（LSCC）is the second most frequently diagnosed malignancy.The critical regulatory role of circular RNAs（circRNAs）in malignant tumor progression has been demonstrated.The aim of our study was to explore the functional role and underlying action mechanism of circular RNA cyclin D1（circ-CCND1）in LSCC progression.MethodsQuantitative real-time polymerase chain reaction（qRT-PCR）assay was performed to detect the expression of circ＿CCND1,CCND1,microRNA-136-5p（miR-136-5p）and ubiquitin-specific protease 7（USP7）mRNA.RNase R assay and Actinomycin D assay were conducted to determine the characteristics of circ＿CCND1.Cell colony formation assay,Edu incorporation assay and 3-（4,5-Dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide（MTT）assay were employed to evaluate cell colony formation ability,proliferation and cell vitality,respectively.Western blot assay or Immunohistochemistry（IHC）assay was utilized to examine protein levels.Cell migration and invasion were tested via transwell assay.Flow cytometry analysis was conducted to measure cell apoptosis.Dual-luciferase reporter assay was utilized to confirm the putative interactions between miR-136-5p and circ＿CCND1 or USP7.Tumor xenograft assay was conducted to explore the effect of circ＿CCND1 on LSCC progression in vivo.ResultsCirc＿CCND1 level was increased in LSCC tissues and cells.Circ＿CCND1 was a stable circRNA,mainly located in cytoplasm.Depletion of circ＿CCND1 suppressed cell proliferation,metastasis and induced apoptosis in LSCC cells in vitro and blocked tumor growth in vivo.Circ＿CCND1 sponged miR-136-5p to positively regulate USP7 expression.Inhibition of miR-136-5p counteracted the inhibitory effect of circ＿CCND1knockdown on LSCC cell progression.Mi R-136-5p overexpression relieved the malignant phenotypes of LSCC cells by targeting USP7.ConclusionOur study manifested that circ＿CCND1 contributed to LSCC progression at least partially through modulating miR-136-5p/USP7 axis. |
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