Circ_0005033 is an oncogene in laryngeal squamous cell carcinoma and regulates cell progression and Cisplatin sensitivity via miR-107/IGF1R axis

Transcriptome expression profiles of laryngeal squamous cell carcinoma (LSCC) are altered, and we aimed to investigate expression and role of hsa_circ_0005033 (circ_0005033), microRNA (miR)-107 and insulin-like growth factor 1 receptor (IGF1R) in LSCC. Real-time PCR, western blotting and immunohistochemistry detected RNA and protein expression levels. Functional assays were performed using MTT assay, EdU assay, apoptosis assay, flow cytometry, Transwell assay, and xenograft tumor model. Direct interaction was predicted by Starbase algorithm and validated by dual-luciferase reporter assay and RNA immunoprecipitation. Expression of circ_0005033 was substantially upregulated in LSCC tissues and cells, and allied with miR-107 downregulation and IGF1R upregulation. Circ_0005033 showed a closed-loop structure and long half-life. Essentially, circ_0005033 and IGF1R were competing endogenous RNAs for miR-107 via target binding. Silencing circ_0005033 facilitated apoptosis rate and lowered cell viability, proliferation, migration and invasion of LSCC cells, as well as delayed xenograft tumor growth. Allied with that, cleaved-caspase 3/8/9 expression was elevated via death receptor-mediated and mitochondrial pathways, and expression of matrix metalloproteinase-2 (MMP2), MMP9, cyclin D1 and proliferating cell nuclear antigen was decreased. Moreover, Cisplatin-induced inhibition of cell viability was exacerbated by inhibiting circ_0005033. These functional effects of circ_0005033 depression were consistent with those of miR-107 overexpression. Furthermore, depleting miR-107 and restoring IGF1R abated the effects of circ_0005033 knockdown and miR-107 overexpression, respectively. Circ_0005033 was oncogenic in LSCC by regulating cell progression and Cisplatin sensitivity at least via miR-107/IGF1R axis.