Role of Curcumin and (−)-Epigallocatechin-3-O-Gallate in Bladder Cancer Treatment: A Review

The incidence of bladder cancer (BC) is increasing, and although current therapeutic approaches are effective in many cases, recurrence of BC is common. Therefore, it seems necessary to search not only for novel therapeutic approaches, but also for new therapeutic agents. Natural polyphenols, such as curcumin (CUR) and epigallocatechin gallate (EGCG), possess remarkable antitumor activity. Their biochemical mechanisms of action include regulation of signaling pathways, modeling of proteins involved in apoptosis and cell cycle inhibition, angiogenesis, and the proliferation, migration and adhesion of tumor cells. Both compounds also present antioxidant, anti-inflammatory, antibacterial and antiviral properties. CUR has been considered a promising candidate for the treatment of cystic fibrosis, Alzheimer’s disease or malaria, whereas EGCG can play a supportive role in the treatment of obesity, metabolic and neurodegenerative diseases. The review summarizes the latest research on the role of CUR and EGCG in the treatment of BC. In particular, the effects of CUR and EGCG, and their prospects for use in BC therapy, their inhibition of cancer development and their prevention of multidrug resistance, are described. The literature’s data indicate the possibility of achieving the effect of synergism of both polyphenols in BC therapy, which has been observed so far in the treatment of ovarian, breast and prostate cancer.