Potential molecular targets of tea polyphenols in human tumor cells: significance in cancer prevention.
Next to water, tea is the most popular beverage in the world, and the cancer-preventive effects of this beverage have been suggested. Epidemiological studies have shown decreased cancer occurrence in those individuals who drink green tea regularly. A wealth of research suggests numerous mechanisms of action to explain these observations. The most abundant and popular compound studied in tea research is (-)-epigallocatechin-3-gallate (EGCG), which acts as a powerful antioxidant and can inhibit a number of tumor cell proliferation- and survival-related proteins. Tea polyphenols are known to inhibit the large multi-catalytic protease (the proteasome) and metaloproteionases, involved in tumor survival and metastasis, respectively. Additionally, tea polyphenols inhibit the activities of many tumor-associated protein kinases, including epidermal growth factor receptor, vascular endothelial growth factor receptor, platelet-derived growth factor receptor, mitogen-activated protein kinase, and IkB kinase. Tea polyphenols have also been found to inhibit some cancer-related proteins that regulate DNA replication and transformation. At present, it is not known which of these activities of tea polyphenols are required for its cancer-preventive effects. However, by understanding the in vivo concentrations of tea polyphenols required to inhibit each of these activities, we may start to sort out in the future the mechanisms responsible for the cancer-preventive effects of tea.
Kazi
Aslamuzzaman
A
Drug Discovery Program, H. Lee Moffitt Cancer Center & Research Institute, Departments of Interdisciplinary Oncology and Biochemistry & Molecular Biology, College of Medicine, University of South Florida, Tampa, FL 33612, USA.
Smith
David M
DM
Daniel
Kenyon
K
Zhong
Sherry
S
Gupta
Puja
P
Bosley
Marie E
ME
Dou
Q Ping
QP
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology* / Q000627:therapeutic use; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D018890:Chemoprevention; D003546:Cysteine Endopeptidases / Q000187:drug effects / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids; D006801:Humans; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000235:genetics; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000235:genetics; D009369:Neoplasms / Q000201:enzymology / Q000235:genetics / Q000517:prevention & control*; D010636:Phenols / Q000494:pharmacology* / Q000627:therapeutic use; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D011108:Polymers / Q000494:pharmacology* / Q000627:therapeutic use; D046988:Proteasome Endopeptidase Complex; D013662:Tea / Q000737:chemistry
D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D005419:Flavonoids; D009097:Multienzyme Complexes; D010636:Phenols; D010936:Plant Extracts; D011108:Polymers; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; D003546:Cysteine Endopeptidases; D008666:Metalloendopeptidases; D046988:Proteasome Endopeptidase Complex