FNDC5 affects invasion and migration of oral cancer by inhibiting PI3K/Akt/Snail signaling pathway

This study first investigated how FNDC5 affected the development of oral cancer and revealed the role of FNDC5 in the migration and invasion of oral cancer. The present work evaluated differential FNDC5 expression within oral cancer samples versus matched non-carcinoma samples based on GEO database analysis and immunohistochemistry. We then generated oral cancer cell lines with FNDC5 overexpression and knockdown to determine the role of altered FNDC5 expression in the migration and invasion of oral cancer. PI3K inhibitor was used for investigating the possible mechanism underlying FNDC5 during EMT of oral cancer. Finally, these in-vitro results were validated using the lung metastatic nude mouse model. According to our results, FNDC5 level markedly decreased within oral cancer compared with adjacent samples and FNDC5 overexpression inhibited migration, invasion as well as EMT of oral cancer, while FNDC5 knockdown promoted oral cancer cell EMT. In addition, PI3K inhibitors blocked the induction of oral cancer cells EMT by FNDC5 knockdown. In vivo experiments further demonstrated the above results. This work is the first to illustrate the impact of FNDC5 on inhibiting migration and invasion of oral cancer, and our results suggest that FNDC5 affects EMT of oral cancer via the inhibition of PI3K/Akt/Snail pathway.