High hsa_circ_0081621 expression indicates a poor prognosis of laryngeal squamous cell carcinoma: A bioinformatics analysis and retrospective clinical study.

Laryngeal squamous cell carcinoma (LSCC) is the second most common malignant tumour of the head and neck with a low 5-year survival rate. There is need to identify novel biomarkers for diagnosis and treatment of LSCC. The present study identified differentially expressed circular RNAs (circRNAs/circs) in LSCC and larynx adjacent non-carcinoma epithelial specimens by analysing the circRNA microarray dataset GSE117001. hsa_circ_0081621 had highest expression among three circRNAs (hsa_circ_0015211, hsa_circ_0023326 and hsa_circ_0081621) in LSCC specimens by reverse transcription-quantitative PCR. The expression levels of hsa_circ_0081621 in 67 LSCC specimens were detected by fluorescence in situ hybridization (FISH). Expression levels of hsa_circ_0081621 were analysed in relation to clinicopathological parameters and prognosis of patients with LSCC. According to FISH results, 59.7% of LSCC specimens exhibited high hsa_circ_0081621 expression. In LSCC specimens, hsa_circ_0081621 high expression was associated with lymph node metastasis and high clinical stage. High expression levels of hsa_circ_0081621 were associated with a poor 5-year overall survival rate in patients with LSCC. In addition, high hsa_circ_0081621 expression was an independent prognostic factor for patients with LSCC. hsa_circ_0081621 may participate in malignant progression of LSCC, and its high expression could be used for prognostic assessment of patients with LSCC.

FOXP4 promotes laryngeal squamous cell carcinoma progression through directly targeting LEF­1.

Forkhead box (FOX) proteins are multifaceted transcription factors that have been shown to be involved in cell cycle progression, proliferation and metastasis. FOXP4, a member of the FOX family, has been implicated in diverse biological processes in tumor initiation and progression. However, the molecular mechanisms of FOXP4 in laryngeal squamous cell carcinoma (LSCC) remain unknown. In the present study, differentially expressed transcripts in transforming growth factor­ß­treated TU177 cells were screened using microarrays and it was found that FOXP4 was significantly upregulated. The high expression of FOXP4 was detected in LSCC tissues and cells, and predicted poor prognosis. The role of FOXP4 in laryngeal cancer cell proliferation, migration and invasion was determined by gain­ and loss­of­function assays. Besides, FOXP4 was demonstrated to participate in the epithelial­mesenchymal transition process at the mRNA and protein levels. Mechanically, FOXP4 directly bound to the promoter of lymphoid enhancer­binding factor 1 and activated Wnt signaling pathway, which was confirmed via chromatin immunoprecipitation and luciferase reporter assays. Consequently, these findings provided novel mechanisms of FOXP4 in LSCC progression, which may be considered as potential therapeutic and prognostic targets for LSCC.