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Differential prooxidative effects of the green tea polyphenol, (–)‐epigallocatechin‐3‐gallate, in normal and oral cancer cells are related to differences in sirtuin 3 signaling
Author(s) -
Tao Ling,
Park JongYung,
Lambert Joshua D.
Publication year - 2015
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.201400485
Subject(s) - sirt3 , sirtuin , cancer cell , chemistry , reactive oxygen species , cancer research , oxidative stress , cancer , biology , microbiology and biotechnology , biochemistry , medicine , acetylation , gene
Scope We have previously reported that the green tea catechin, (–)‐epigallocatechin‐3‐gallate (EGCG), can induce oxidative stress in oral cancer cells but exerts antioxidant effects in normal cells. Here, we report that these differential prooxidative effects are associated with sirtuin 3 (SIRT3), an important mitochondrial redox modulator. Methods and results EGCG rapidly induced mitochondria‐localized reactive oxygen species in human oral squamous carcinoma cells (SCC‐25, SCC‐9) and premalignant leukoplakia cells (MSK‐Leuk1), but not in normal human gingival fibroblast cells (HGF‐1). EGCG suppressed SIRT3 mRNA and protein expression, as well as, SIRT3 activity in SCC‐25 cells, whereas it increased SIRT3 activity in HGF‐1 cells. EGCG selectively decreased the nuclear localization of the estrogen‐related receptor α (ERRα), the transcription factor regulating SIRT3 expression, in SCC‐25 cells. This indicates that EGCG may regulate SIRT3 transcription in oral cancer cells via ERRα. EGCG also differentially modulated the mRNA expressions of SIRT3‐associated downstream targets including glutathione peroxidase 1 and superoxide dismutase 2 in normal and oral cancer cells. Conclusion SIRT3 represents a novel potential target through which EGCG exerts differential prooxidant effects in cancer and normal cells. Our results provide new biomarkers to be further explored in animal studies.