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Opposing action of curcumin and green tea polyphenol in human keratinocytes
Author(s) -
Eckert Richard L.,
Crish James F.,
Efimova Tatiana,
Balasubramanian Sivaprakasam
Publication year - 2006
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200500125
Subject(s) - curcumin , involucrin , transcription factor , ap 1 transcription factor , keratinocyte , biology , tumor promotion , microbiology and biotechnology , enhancer , biochemistry , chemistry , carcinogenesis , in vitro , gene
Persistent environmental insult can convert a normal cell into a cancer cell. However, various natural chemopreventive agents called antioxidants can retard this progression. We have recently explored the effects of several chemopreventive agents, including green tea polyphenol and curcumin, on normal human keratinocyte function. Our findings suggest that a bioactive polyphenol from green tea, (–)‐epigallocatechin‐3‐gallate (EGCG), acts to increase involucrin gene expression, suggesting that EGCG treatment enhances normal human keratinocyte differentiation. Mechanistic studies indicate that EGCG alters mitogen‐activated protein kinase cascade function to activate involucrin gene transcription via a Ras, MEKK1, MEK3, ERK1/2–p38δ cascade that targets AP1 and CAATT enhancer binding protein transcription factors. These findings suggest that EGCG may inhibit disease progression by promoting keratinocyte differentiation. Parallel studies indicate that not all antioxidants produce a similar response. Curcumin, an antioxidant derived from the turmeric, antagonizes the EGCG‐dependent response by interfering in this signaling pathway. These studies suggest that different antioxidant may produce antagonistic effects in tissues.