Black Tea Suppresses Invasiveness and Reverses TNF‐α‐Induced Invasiveness and Cell Stemness in Human Malignant Melanoma Cells

Invasiveness and epithelial–mesenchymal transition (EMT) are main patterns of metastatic disease, which is the major cause cancer‐related mortality in human malignant melanoma cells. Tea and its consumption extract are associated with a lower risk of several types of cancer and have anti‐inflammatory and antioxidative biological effects. However, the anti‐EMT and anti‐cancer stemness effect of black tea ethanol extracts (BTEE) in human melanoma remain poorly understood. In this study, the effects of BTEE‐reduced invasiveness, EMT, and cancer stemness were evaluated in human A 375 and A2058 melanoma cells. BTEE inhibited the activity of u‐PA, migration, and invasiveness by repressing p‐FAK signaling pathway. BTEE affected the EMT by downregulating the expression of β ‐catenin, N ‐cadherin, fibronectin, vimentin, and Twist‐1. BTEE also reduced tumor necrosis factor‐alpha (TNF‐α)‐induced invasiveness and cancer stemness characteristics in vitro. The growth of melanoma in nude mice xenograft model showed that BTEE suppressed A 375 tumor growth in vivo.