Abstract: Objective To investigate the impact of puerarin on the proliferation, migration, invasion, and epithelial⁃mesenchymal transition (EMT) in nasopharyngeal carcinoma cells, as well as to elucidate its potential mechanism. Methods Nasopharyngeal carcinoma 5⁃8F and HK⁃1 cells were exposed to varying concentrations of puerarin to identify the optimal concentration for intervention using the CCK⁃8 assay. The cells were divided into the negative control group and the puerarin group, receiving their respective treatments. Cycle progression was assessed by flow cytometry, cell migration was assessed via a scratch assay, and cell invasion was evaluated using a Transwell assay. Western blot and immunofluorescence assays were conducted to quantify the expression of proteins associated with the EMT process and the PI3K/AKT/mTOR signaling pathway. Furthermore, 5⁃8F and HK⁃1 cells were co⁃treated with the PI3K activator 740Y⁃P and puerarin, followed by Western blot analysis to detect the expression of proteins related to the PI3K/AKT/mTOR signaling pathway. The effects of puerarin on tumour cell proliferation were validated via CCK⁃8 assays, and clonogenic assays. Results The viability of nasopharyngeal carcinoma 5⁃8F and HK⁃1 cells was significantly reduced (all P<0.0001) upon exposure to varying concentrations (200-1,600 μmol/L) of puerarin, exhibiting a dose⁃dependent effect. Compared with the control group, puerarin at concentrations of 800 μmol/L and 1,200 μmol/L significantly suppressed the proliferation, migration, and invasion capabilities of nasopharyngeal carcinoma 5⁃8F and HK⁃1 cells (all P<0.001). Additionally, puerarin treatment resulted in cell cycle at the G0/G1 phase (all P<0.05), enhanced the protein expression levels of the epithelial marker E⁃cadherin, and reduced the protein expression levels of the mesenchymal markers N⁃cadherin and vimentin. Puerarin downregulated the expression of PI3K, AKT, mTOR and their phosphorylated forms, whereas the PI3K activator 740Y⁃P reversed the puerarin⁃induced changes in phosphorylation levels of PI3K, AKT and mTOR, and attenuated  the inhibitory effect of puerarin on nasopharyngeal carcinoma cell proliferation (all P<0.01).  Conclusions Puerarin inhibits the proliferation, migration, invasion, and EMT in nasopharyngeal carcinoma 5⁃8F and HK⁃1 cell lines, possibly by modulating the PI3K/AKT/mTOR signaling pathway. 

Key words: Nasopharyngeal carcinoma, Puerarin, Invasion, Migration, Epithelial? mesenchymal transition