Intracellular signaling network as a prime chemopreventive target of (-)-epigallocatechin gallate

Chemoprevention is an attempt to use either naturally occurring or synthetic substances or their mixtures to intervene in the progress of carcinogenesis. Recently, it has been shown that some edible phytochemicals alter gene expression, directly or indirectly, thereby regulating the carcinogenic processes. (-)-Epigallocatechin gallate (EGCG), a principal antioxidant derived from green tea, is one of the most extensively investigated chemopreventive phytochemicals. EGCG has been known to block each stage of carcinogenesis by modulating signal transduction pathways involved in cell proliferation, transformation, inflammation, apoptosis, metastasis and invasion. This review addresses the molecular target-based chemoprevention with EGCG by focusing on the common events mediated by transcription factors, such as NF-kappa B, activator protein-1 and nuclear factor erythroid 2 p45-related factor, and upstream kinases involved in the cellular signaling network.