title: Green tea constituent (--)-epigallocatechin-3-gallate inhibits topoisomerase I activity in human colon carcinoma cells.
abstract: DNA topoisomerases I and II are essential for cell survival and play critical roles in DNA metabolism and structure. Inhibitors of topoisomerase constitute a novel family of antitumor agents with demonstrated clinical activity in human malignancies. The clinical use of these agents is limited due to severe toxic effects on normal cells. Therefore, there is a need to develop novel, nontoxic topoisomerase inhibitors that have the ability to spare normal cells. Recent studies have shown that green tea and its major polyphenolic constituent, epigallocatechin-3-gallate (EGCG), impart growth inhibitory responses to cancer cells but not to normal cells. Based on the knowledge that EGCG induces DNA damage, cell cycle arrest, and apoptosis, we considered the possibility of the involvement of topoisomerase in the antiproliferative response of EGCG. Here, for the first time, we show that EGCG inhibits topoisomerase I, but not topoisomerase II in several human colon carcinoma cell lines. Based on this study it is tempting to suggest that combination of EGCG with other conventional topoisomerase inhibitors could be an improved strategy for treatment of colon cancer. The possible role of EGCG as a chemotherapeutic agent needs to be investigated.
authors.affiliation: Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. sjb4@po.cwru.edu
authors.forename: S J
authors.initials: SJ
authors.lastname: Berger
authors.forename: S
authors.initials: S
authors.lastname: Gupta
authors.forename: C A
authors.initials: CA
authors.lastname: Belfi
authors.forename: D M
authors.initials: DM
authors.lastname: Gosky
authors.forename: H
authors.initials: H
authors.lastname: Mukhtar
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D002277:Carcinoma / Q000201:enzymology* / Q000473:pathology; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D013662:Tea / Q000737:chemistry; D059004:Topoisomerase I Inhibitors; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D013662:Tea; D059004:Topoisomerase I Inhibitors; D002392:Catechin; C045651:epigallocatechin gallate; D004250:DNA Topoisomerases, Type II