Abstract
Induction of apoptosis by green tea polyphenols has been observed in various tumor cell systems, but whether green tea polyphenol-induced apoptosis requires caspase 3 for execution has not been confirmed. We previously reported that green tea polyphenol-induced apoptosis involved Apaf-1 accumulation and caspase 3 activation in the cytosol. In the current study, tumor cells either with deleted caspase 3 gene or expressing wild-type caspase 3 were treated with increasing concentrations of green tea polyphenol(s), followed by morphological analysis and caspase 3 activity assay. The caspase 3 null parental cell line was further examined in comparison with a well-characterized, caspase 3 wild type oral carcinoma cell line by MTT assay and BrdU incorporation assay. The results demonstrated that, while the mitochondrial function gradually declined to insignificant levels, caspase 3 null cells did not undergo apoptosis, which suggested that green tea polyphenol-induced apoptosis is a mitochondria-targeted, caspase 3-executed mechanism.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenocarcinoma / enzymology
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Adenocarcinoma / pathology
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Apoptosis / drug effects*
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Apoptotic Protease-Activating Factor 1
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Bone Neoplasms / enzymology
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Bone Neoplasms / pathology
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Breast Neoplasms / enzymology
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Breast Neoplasms / pathology
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Carcinoma, Squamous Cell / pathology
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Carcinoma, Squamous Cell / secondary
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Caspase 3
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Caspases / deficiency
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Caspases / genetics
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Caspases / physiology*
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Catechin / analogs & derivatives*
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Catechin / pharmacology
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DNA Replication / drug effects
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Female
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Flavonoids*
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Gene Deletion
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Gingival Neoplasms / pathology
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Humans
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Keratinocytes / cytology
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Lymphatic Metastasis
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Mitochondria / drug effects*
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Mouth Neoplasms / pathology
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Neoplasm Proteins / deficiency
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology*
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Osteosarcoma / enzymology
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Osteosarcoma / pathology
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Phenols / pharmacology*
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Plant Extracts / pharmacology*
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Polymers / pharmacology*
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Proteins / metabolism
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Tea / chemistry*
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Tumor Cells, Cultured / drug effects
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Tumor Cells, Cultured / enzymology
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Tumor Cells, Cultured / pathology
Substances
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APAF1 protein, human
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Apoptotic Protease-Activating Factor 1
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Flavonoids
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Neoplasm Proteins
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Phenols
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Plant Extracts
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Polymers
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Proteins
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Tea
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Catechin
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epicatechin gallate
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epigallocatechin gallate
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CASP3 protein, human
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Caspase 3
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Caspases
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gallocatechol