Naasani I, Seimiya H, Tsuruo T
Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Kami-Ikebukuro, Tokyo, Toshima-ku, 170-8455, Japan.
Biochem Biophys Res Commun. 1998 Aug 19;249(2):391-6. doi: 10.1006/bbrc.1998.9075.
Animal in vivo studies and human epidemiological observations indicated potent anticancer effects for tea. Here we demonstrate that epigallocatechin gallate (EGCG), a major tea catechin, strongly and directly inhibits telomerase, an enzyme essential for unlocking the proliferative capacity of cancer cells by maintaining the tips of their chromosomes. Telomerase inhibition was elaborated in a cell-free system (cell extract) as well as in living cells. In addition, the continued growth of two representative human cancer cell lines, U937 monoblastoid leukemia cells and HT29 colon adenocarcinoma cells, in the presence of nontoxic concentrations of EGCG showed life span limitations accompanied with telomere shortening, chromosomal abnormalities, and expression of the senescence-associated beta-galactosidase. It is suggested that telomerase inhibition could be one of the major mechanisms underlying the anticancer effects of tea.
动物体内研究和人类流行病学观察表明茶具有强大的抗癌作用。在此我们证明，表没食子儿茶素没食子酸酯（EGCG），一种主要的茶儿茶素，能强烈且直接地抑制端粒酶，端粒酶是一种通过维持癌细胞染色体末端来开启其增殖能力所必需的酶。端粒酶抑制作用在无细胞体系（细胞提取物）以及活细胞中均得到证实。此外，在无毒浓度的EGCG存在下，两种代表性人类癌细胞系，U937单核细胞样白血病细胞和HT29结肠腺癌细胞的持续生长显示出寿命受限，并伴有端粒缩短、染色体异常以及衰老相关β-半乳糖苷酶的表达。提示端粒酶抑制可能是茶抗癌作用的主要机制之一。
