In vitro anticancer effect of epigallocatechin gallate nano-emulsion on head and neck cancers

Head and neck cancer, as one of the most common cancers, causes the death of many people worldwide every year. The current approaches to treat this cancer have not been successful, and recurrence, drug-resistance development, side effects, and high treatment costs are important problems necessitating the need for more effective drugs and treatment approaches. Epigallocatechin gallate (EGCG) is the most plentiful and biological-active catechin in green tea with proved anticancer effect. However, the stability, low bioavailability, and short half-life, limits its clinical use. Nanocarrier development may overcome these deficiencies by improving pharmacokinetics and pharmacodynamics. Therefore, this study aimed to examine the nano-emulsion containing EGCG for their anticancer activity. First, EGCG nano-emulsion was prepared, which was then characterized by dynamic light scattering (DLS), zeta potential, and Fourier transform infrared spectroscopy (FTIR). The toxicity of the nano-emulsion on the TSCC-1 cancer cell line was assessed by MTT and LDH assays. Cell migration rate, colony-formation ability, the apoptosis rate, and the expression level of BAX, BCL2, and VEGF genes after treatment of cancer cells were assessed. Moreover, the effect of EGCG nano-emulsion on the spheroid growth of TSCC-1 cells in three-dimensional (3D) culture was investigated. The FTIR results demonstrated the presence of EGCG in the nano-emulsion. The size and zeta potential of the nano-emulsion with and without EGCG were 17.53 ± 1.62 nm and - 0.166 ± 0.169 mV, and 14.0 ± 2.3 nm and - 0.266 ± 0.169 mV, respectively. The sustained drug release was observed. Moreover, the MTT assay exhibited that the cytotoxicity of the nano-emulsion was significant at a concentration of 80 µg/mL on TSCC-1 cells. The colony-formation assay revealed no colonies in the groups treated with nano-emulsion containing EGCG compared to the control group. The scratch test also showed the ability of nano-emulsion to inhibit cell migration. Furthermore, the induction of delayed apoptosis by 88.3 ± 3.18% was observed in the group treated with EGCG nano-emulsion at a concentration of 80 µg/mL. The expression of BCL2 and VEGF genes significantly decreased, while that of BAX gene increased. Moreover, the 3D culture showed a decrease in the size and growth of spheroids in the EGCG nano-emulsion-treated group compared to the control group. The results showed that the nano-emulsion containing EGCG has significant anticancer activity (TSCC-1) and may be a suitable treatment option for the management of squamous cell carcinoma of the head and neck.