The treatment of bladder cancer in a mouse model by epigallocatechin-3-gallate-gold nanoparticles

(--)-Epigallocatechin-3-gallate (EGCG), an active ingredient in green tea, was known to effectively inhibit formation and development of tumors. However, excessive uptake of EGCG was also known to cause cytotoxicity to normal cells. In this study, EGCGs that were physically attached onto the surface of nanogold particles (pNG) was confirmed by scanning electron microscopy. The anticancer activity of the EGCG-adsorbed pNG was investigated in C3H/HeN mice subcutaneously implanted with MBT-2 murine bladder tumor cells. EGCG-pNG was confirmed to inhibit tumor cell growing by means of cell apoptosis. The mechanism that EGCG-pNG mediates tumor apoptosis was uncovered to activate the caspase cascade through the Bcl-family proteins in the mitochondrial pathway. Additionally, the mechanism that tumors were suppressed by injecting EGCG-pNG directly into the tumor site was determined to be through downregulation of VEGF, whereas that by oral administration of EGCG was through reversing immune suppression upon cancer progression. In this assessment, the prepared EGCG-pNG was confirmed to be more effective than free EGCG in inhibiting bladder tumor in model mice.