HoxB9 promotes the migration and invasion via TGF-β1/Smad2/Slug signaling pathway in oral squamous cell carcinoma.

HoxB9, as a HOX family member, is known to play important roles in embryonic development. Recent studies have shown that HoxB9 is involved in cancer progression. However, little is known about the role of HoxB9 and the underlying mechanisms that suppress oral squamous cell carcinoma (OSCC) progression. In the present study, we used immunohistochemical staining to demonstrate that HoxB9 is over-expressed in OSCC cells and found that high levels of HoxB9 were significantly associated with shorter overall survival in patients with OSCC. Functional studies revealed that knocking down HoxB9 in OSCC cells using RNA interference decreased the migration and invasion of OSCC cells in vitro. Our mechanistic studies suggested that HoxB9 could stimulate the migration and invasion of OSCC cells by targeting EMT via the TGF-β1/Smad2/Slug signaling pathway. Collectively, these findings suggest the vital roles of HoxB9 in OSCC progression through its effects in promoting EMT.