Shining a Light on the Effects of the Combination of (-)-Epigallocatechin-3-gallate and Tapentadol on the Growth of Human Triple-negative Breast Cancer Cells.

Breast cancer is characterized by a high rate of mortality and is considered one of the deadliest types of cancer. It is of note that (-)-epigallocatechin-3-gallate (EGCG), the principal catechin of green tea, is able to hinder the growth of MDA-MB-231 breast cancer cells by influencing different signaling pathways, including apoptosis. Furthermore, EGCG is also used in the treatment of bone cancer pain. Tapentadol, an opioid drug acting at the level of noradrenaline (norepinephrine) reuptake inhibition and μ-opioid receptor, is able to modulate bone cancer pain and influence cancer cell viability by regulating apoptosis.In vitro assays were performed on triple-negative MDA-MB-231 cells treated with tapentadol (1, 5, 10, 20, 40 and 80 μg/ml) and EGCG (1, 10, 20, 40, 80, 160 μmol/l), alone and in combination. The effects of EGCG and TAP on viability were determined by wound-healing and MTT assays, while cell migration was assessed by transwell migration.Cell proliferation, viability and apoptosis of MDA-MB-231 cells were impaired by the combination of EGCG and tapentadol. Specifically, our data show that EGCG and TAP reduced the proliferation of MDA-MB-231 cells by impairing cell-cycle progression (p<0.05). These findings suggest that the combination of these substances may represent a new strategy for the treatment of patients suffering from triple-negative breast cancer.