Catechin, a green tea component, rapidly induces apoptosis of myeloid leukemic cells via modulation of reactive oxygen species production in vitro and inhibits tumor growth in vivo.

BACKGROUND AND OBJECTIVES: The aim of this study was to investigate the possibility of green tea polyphenol, (-)-epigallocatechin-3-gallate (EGCG) as a novel therapeutic agent for the patients with myeloid leukemia. DESIGN AND METHODS: We investigated the effects of EGCG on the induction of apoptosis in leukemic cells in vitro and in vivo. We further examined the molecular mechanisms of EGCG-induced apoptosis in myeloid leukemic cells.
RESULTS: EGCG rapidly induced apoptotic cell death in retinoic acid (RA)-resistant acute promyelocytic leukemia (APL), UF-1 cells within 3 h. EGCG induced apoptosis in UF-1 cells was in association with the loss of mitochondrial transmembrane potentials (Deltapsim) and activation of caspase-3 and -9. Elevation of intracellular reactive oxygen species (ROS) production was also demonstrated during EGCG-induced apoptosis of UF-1 as well as fresh myeloid leukemic cells. In NOD/SCID mice transplanted with UF-1 cells, EGCG effectively inhibited tumor growth in vivo, and the number of mitoses among the cells significantly decreased in comparison to that of control mouse cells. INTERPRETATION AND
CONCLUSIONS: In summary, EGCG has potential as a novel therapeutic agent for myeloid leukemia via induction of apoptosis mediated by modification of the redox system.