Jing-Si herbal tea attenuates oral cancer cell viability, migration, and invasion by regulating epithelial-to-mesenchymal transition and reactive oxygen species accumulation

Oral cancer is the sixth most common cancer worldwide and can be life-threatening if not diagnosed and treated in its early stages. Jing-Si Herbal Tea (JSHT), containing eight traditional Chinese medicine-based herbs, is known to suppress the malignancy, growth, and metastasis of several tumor cells, including breast, lung, and colon cancer cells. However, the pharmacological effect of JSHT on oral cancer progression is still unclear. In this study, we evaluated the potential of JSHT to arrest the development of oral cancer via induction of cell death by reactive oxygen species (ROS) accumulation and inhibition of migration, invasion, and epithelial-to-mesenchymal transition (EMT). For this purpose, we employed the human tongue squamous cell carcinoma SAS cell line, which we treated with different JSHT concentrations for 24 h, and assessed cell viability, migration, and wound healing capabilities, together with western blotting for measuring expression levels of EMT markers. Survival, migration/invasion ability, EMT, and ROS production in the SAS human tongue squamous carcinoma and FaDu human pharynx squamous cell carcinoma cell line were decreased by JSHT treatment via Lon protease-independent mechanisms. This study demonstrates that JSHT could be regarded as a candidate new supplement to existing anticancer therapies and an alternative, orally administered healthcare product for treating oral squamous cell carcinoma.