Inhibition of proliferation and induction of apoptosis by EGCG in human osteogenic sarcoma (HOS) cells.

EGCG [(-)-epigallocatechin-3-gallate], a major component of green tea has been considered as a major antioxidant constituent. In addition to having been considered for cancer treatment as a chemopreventive and chemotherapeutic agent, EGCG has recently been attributed an anti-proliferative effect. We re-examined the latter finding in this study and added specific focus on the ability of EGCG to induce apoptosis in human osteogenic sarcoma (HOS) cells. Antiproliferative action of EGCG (IC50 = 35.3 +/- 6.0 microg/mL) appeared to be linked to apoptotic cell death based on morphological changes, chromosomal DNA degradation, and an increase in the sub-G1 apoptotic cell population. Treatment of HOS cells with EGCG gradually activated caspase-3, an established inducer of apoptotic cell death.