Exosome-delivered TRPP2 siRNA inhibits the epithelial-mesenchymal transition of FaDu cells.

The prognosis for patients with head and neck cancer (HNC) remains poor, owing to uncontrolled tumor invasion and metastasis. Epithelial-mesenchymal transition (EMT) serves an important role in this invasion and metastasis, and transient receptor potential polycystic 2 (TRPP2) enhances metastasis and invasion by regulating EMT in human laryngeal squamous cell carcinoma. The present study examined whether exosomes/TRPP2 small interfering RNA (siRNA) complexes were able to reduce EMT by suppressing TRPP2 expression in FaDu cells, a cell line of human pharyngeal squamous cell carcinoma. Using agarose gel electrophoresis, it was determined that exosome/TRPP2 siRNA complexes were stable in the presence of nucleases and serum. A fluorescence assay and western blotting analysis was performed, and it was reported that the FaDu cells took up exosomes, the exosomes effectively delivered TRPP2 siRNA into FaDu cells and that exosome/TRPP2 siRNA complexes significantly suppressed TRPP2 protein expression levels in FaDu cells. Furthermore, expression levels of E-cadherin were significantly increased, whereas expression levels of N-cadherin and vimentin were significantly decreased in FaDu cells transfected with TRPP2 siRNA. Thus, exosome/TRPP2 siRNA complexes markedly suppressed TRPP2 expression and EMT in FaDu cells. These results suggested that further development of exosome/TRPP2 siRNA complexes for use as an RNA-based gene therapy in the treatment of HNC is warranted.