Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan.
Biomaterials. 2011 Oct;32(30):7633-40. doi: 10.1016/j.biomaterials.2011.06.073. Epub 2011 Jul 22.
(--)-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.
（--）-表没食子儿茶素没食子酸酯（EGCG）是绿茶中的一种有效成分，能有效抑制肿瘤的形成和发展。然而，过量摄取 EGCG 也会导致正常细胞的细胞毒性。在这项研究中，通过扫描电子显微镜证实了纳米金颗粒（pNG）表面物理附着的 EGCG。用 MBT-2 鼠膀胱肿瘤细胞皮下植入 C3H/HeN 小鼠，研究 EGCG 吸附的 pNG 的抗癌活性。EGCG-pNG 通过细胞凋亡证实能抑制肿瘤细胞生长。通过线粒体途径中的 Bcl 家族蛋白激活胱天蛋白酶级联反应，揭示了 EGCG-pNG 介导肿瘤凋亡的机制。此外，通过向肿瘤部位直接注射 EGCG-pNG 抑制肿瘤的机制被确定为通过下调 VEGF，而通过口服 EGCG 则是通过逆转癌症进展过程中的免疫抑制。在这项评估中，证实制备的 EGCG-pNG 比游离 EGCG 更能有效地抑制模型小鼠的膀胱癌。
