I. Naasani et al., TELOMERASE INHIBITION, TELOMERASE SHORTENING, AND SENESCENCE OF CANCER-CELLS BY TEA CATECHINS, Biochemical and biophysical research communications (Print), 249(2), 1998, pp. 391-396
Animal in vivo studies and human epidemiological observations indicate
d potent anticancer effects for tea. Here we demonstrate that epigallo
catechin gallate (EGCG), a major tea catechin, strongly and directly i
nhibits telomerase, an enzyme essential for unlocking the proliferativ
e capacity of cancer cells by maintaining the tips of their chromosome
s. Telomerase inhibition was elaborated in a cell-free system (cell ex
tract) as well as in living cells. In addition, the continued growth o
f two representative human cancer cell lines, U937 monoblastoid leukem
ia cells and HT29 colon adenocarcinoma cells, in the presence of nonto
xic concentrations of EGCG showed life span limitations accompanied wi
th telomere shortening, chromosomal abnormalities, and expression of t
he senescence-associated beta-galactosidase. It is suggested that telo
merase inhibition could be one of the major mechanisms underlying the
anticancer effects of tea. (C) 1998 Academic Press.