7-Epitaxol Induces Apoptosis and Autophagy in Head and Neck Squamous Cell Carcinoma through Inhibition of the ERK Pathway.

As the main derivative of paclitaxel, 7-Epitaxol is known to a have higher stability and cytotoxicity. However, the anticancer effect of 7-Epitaxol is still unclear. The purpose of this study was to explore the anticancer effects of 7-Epitaxol in squamous cell carcinoma of the head and neck (HNSCC). Our study findings revealed that 7-Epitaxol potently suppressed cell viability in SCC-9 and SCC-47 cells by inducing cell cycle arrest. Flow cytometry and DAPI staining demonstrated that 7-Epitaxol treatment induced cell death, mitochondrial membrane potential and chromatin condensation in OSCC cell lines. The compound regulated the proteins of extrinsic and intrinsic pathways at the highest concentration, and also increased the activation of caspases 3, 8, 9, and PARP in OSCC cell lines. Interestingly, a 7-Epitaxol-mediated induction of LC3-I/II expression and suppression of p62 expression were observed in OSCC cells lines. Furthermore, the MAPK inhibitors indicated that 7-Epitaxol induces apoptosis and autophagy marker proteins (cleaved-PARP and LC3-I/II) by reducing the phosphorylation of ERK1/2. In conclusion, these findings indicate the involvement of 7-Epitaxol in inducing apoptosis and autophagy through ERK1/2 signaling pathway, which identify 7-Epitaxol as a potent cytotoxic agent in HNSCC.