Abstract: [Abstract] Objective: To investigate the influence of miR-7704 expression on the biological behavior of head and neck squamous cell carcinoma (HNSCC) cells. Methods: The discrepant expression levels of miR-7704 were detected by real-time quantitative RT-PCR (qRT-PCR) among human oral epithelial cell line HOK and HNSCC cell lines, HN6, HN13, HN4 and CAL27. The expression level of miR-7704 was confirmed by qRT-PCR when HN6 and CAL27 was transfected with miR-7704 mimic and mimic NC. And, the effects of miR-7704 overexpression on the proliferation, migration and invasion of HNSCC cells were investigated by using CCK8, plate colony formation, wound healing experiment and Transwell invasion experiment. At the same time, total cell proteins were extracted, and the expression levels of EMT related indicators and threonine kinase (AKT) signaling pathway were detected by Western blot after the increase of miR-7704 expression. Results: Compared with HOK cell line, the expression levels of miR-7704 in all HNSCC cell lines were significantly up-regulated. After transfection of HNSCC cells with an overexpressed plasmid miR-7704 mimic, the expression level of miR-7704 was increased. Meanwhile, the cell proliferation, migration and invasion ability were enhanced. Western blot results showed that the expression levels of e-cadherin and beta-catenin in HNSCC cells were decreased after the overexpression of miR-7704, when the up-regulated expression of vimentin, Snail and Slug protein was observed. Levels of threonine kinase (AKT) and phosphorylated threonine kinase (p-akt) were significantly elevated. Conclusion: miR-7704 may act as a pro-oncogenic factor and induce EMT by regulating the AKT signaling pathway to promote the biological behavior of HNSCC cells.

Key words: miR-7704, Head and neck squamous cell carcinoma, Epithelial-mesenchymal transformation, AKT signaling pathway