Ethyl Acetate Extract of Oratosquilla Inhibits the Growth of Nasopharyngeal Carcinoma through the Hippo Pathway

The Hippo pathway and its transcription co-activator YAP play a critical role in the regulation of cell proliferation, apoptosis and the control of organ size. In the past several years, YAP has been found to be expressed in various human cancers, however, its expression in Nasopharyngeal Carcinoma (NPC) remains unstudied. In this report, we found that YAP was overexpressed in human NPC tissues, and its expression was also significantly higher in five NPC cell lines when compared with the nasopharyngeal epithelial cell line NP69 (P < 0.01). CNE1 and CNE1-GL cells treated with EOS had an enhanced expression level of phosphorylated YAP and downregulated expression of survivin, which inhibits the proliferation of CNE1 and CNE1-GL cells. These results highlight an important role of hippo pathway in the growth of nasopharyngeal carcinoma and implicate a potential mechanism of ethyl acetate extract of oratosquilla (EOS) preventing the proliferation of nasopharyngeal carcinoma.