MicroRNA-29a functions as a tumor suppressor through targeting STAT3 in laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma (LSCC) is a common head and neck cancer with high mortality in developing countries. A comprehensive understanding of the molecular mechanisms of tumor progression in laryngeal cancer is needed for new treatment strategies. MicroRNA-29a has been emerged as a critical miRNA in various cancers, and shown to regulate multiple oncogenic processes. In this study, we investigated the tumor suppressive role of miRNA-29a in laryngeal squamous cell carcinoma. We performed cell-based functional analysis after overexpression of miR-29a in AMC-HN-8 and HEP2 cells in vitro. It turned out that ectopic expression of miR-29a significantly inhibited cell proliferation, invasion, and migration in two LSCC cell lines (AMC-HN-8 and Hep2) in vitro. Further downstream target analysis by western blotting and luciferease reporter assay showed that overexpression of miR-29a significantly downregulated expression of STAT3, and STAT3 is a putative direct target of miR-29a in LSCC. In addition, the tumor suppressive function of miR-29a can be abrogated by forced expression of STAT3. Taken together, our data suggest that miR-29a functions as a tumor suppressor through targeting STAT3 in laryngeal squamous cell carcinoma.