Linc00662 sponges miR-15b-5p to promote hypopharyngeal squamous cell carcinoma progression by facilitating cancer stem cell-like phenotypes

Abstract

Background: Long non-coding RNAs (lncRNAs) are associated with multiple head and neck tumors and play important roles in cancer. This study explored the molecular mechanism of Linc00662 in hypopharyngeal squamous cell carcinoma (HSCC). Methods: Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect gene expression in HSCC tissues. The viability and proliferation of tumor cells were measured using CCK-8 assays. HSCC cell apoptosis was measured using flow cytometry and western blotting. Cell stemness was examined using the sphere formation assay. A xenograft tumor model was established to investigate the role of Linc00662 in vivo. Results: The expression level of Linc00662 in HSCC tissues was significantly higher than that in adjacent normal tissues. The expression of Linc00662 had no significant relationship with the tumor stage. Patients with high Linc00662 expression were found to have shorter overall survival than those with low Linc00662 expression. Linc00662 over-expression promoted cell viability and inhibited apoptosis. Using online databases and a dual luciferase reporter, miR-15b-5p was confirmed as a potential downstream sponge of Linc00662. Moreover, Linc00662 was negatively associated with miR-15b-5p in HSCC cells. Depletion of miR-15b-5p can reverse the function of Linc00662 in vivo and in vitro. Furthermore, Linc00662 promotes tumor growth, which was abolished by miR-15b-5p mimics. Importantly, the stemness of cancer stem cells was mediated by the Linc00662/miR-15b-5p axis. Conclusion: Patients with HSCC with high Linc00662 showed poor prognosis and high Linc00662 induced stemness of tumor cells by targeting miR-15b-5p. Linc00662 may serve as a novel diagnostic and target marker for head and neck squamous cell carcinoma.