LncRNA NOP14-AS1 Promotes Tongue Squamous Cell Carcinoma Progression by Targeting MicroRNA-665/HMGB3 Axis

PURPOSE: The expression profile, clinical effects, and detailed roles of NOP14 antisense RNA 1 (NOP14-AS1) in tongue squamous cell carcinoma (TSCC) remain ambiguous and need to be further explored. Thus, this work was initiated to offer further solid evidence regarding the expression and roles of NOP14-AS1 in TSCC. Furthermore, additional efforts were exerted to reveal the molecular events by which NOP14-AS1 affects the malignant behaviours of TSCC. METHODS: NOP14-AS1 expression was detected in TSCC tissues and cell lines using quantitative reverse transcription-polymerase chain reaction. Cell Counting Kit-8 assay, flow cytometric analysis, Transwell migration and invasion assays, and xenograft tumor model analysis were performed to assess the malignant biological behaviors of TSCC cells after NOP14-AS1 depletion. Mechanistic studies were performed using bioinformatics analysis, luciferase reporter assay, RNA immunoprecipitation, and rescue experiments. RESULTS: NOP14-AS1 upregulation was identified in TSCC tissues and cell lines. Patients with TSCC exhibiting a high NOP14-AS1 expression faced shorter overall survival than those with a low NOP14-AS1 expression. Functionally, NOP14-AS1 depletion facilitated apoptosis and impeded cell proliferation, migration, and invasion in TSCC. In vivo, the growth of TSCC cells was hindered by NOP14-AS1 depletion. Mechanically, NOP14-AS1 functioned as a competing endogenous RNA by sponging microRNA-665 (miR-665), thereby overexpressing the target high mobility group box 3 (HMGB3) of miR-665. Lastly, rescue experiments confirmed that the introduction of HMGB3 overexpression plasmid or miR-665 inhibitor could abrogate the inhibition of aggressive phenotypes triggered by NOP14-AS1 knockdown. CONCLUSION: NOP14-AS1 executed pro-oncogenic activities in TSCC cells by targeting the miR-665/HMGB3 axis. The NOP14-AS1/miR-665/HMGB pathway may be a valuable prognostic indicator and therapeutic target for preventing TSCC.