The green tea polyphenol (-)-epigallocatechin-3-gallate blocks nuclear factor-κB activation by inhibiting IκB kinase activity in the intestinal epithelial cell line IEC-6

Fajun Yang, Helieh S. Oz, Shirish Barve, Willem J S De Villiers, Craig J. McClain, Gary W. Varilek

Research output: Contribution to journalArticle

314 Citations (Scopus)

Abstract

The IκB kinase complex (IKK) mediates activation of the transcription factor nuclear factor-κB (NF-κB). We previously showed that green tea polyphenols inhibited endotoxin-mediated tumor necrosis factor-α (TNFα) production by blocking NF-κB activation. In this study, we evaluated whether green tea polyphenols inhibit NF-κB by blocking IKK activity. We assessed IKK activity by detecting changes in phosphorylation of an IκBα-glutathione S-transferase (GST) fusion protein. IEC-6 cells pretreated with an extract of green tea polyphenols (GrTPs; 0-0.4 mg/ml) had diminished TNFα-induced IKK and NF-κB activity. Of the various GrTPs, (-)-epigallocatechin-3-gallate (EGCG) was the most potent inhibitor. We next examined whether EGCG inhibited activated IKK. In cytosolic extracts of TNFα-stimulated cells, EGCG inhibited phosphorylation of IκBα-GST (IC50 > 18 μM) consistent with inhibition of IKK activity. Using other polyphenols, we showed that the gallate group was essential for inhibition, and antioxidants were ineffective in blocking activated IKK. Importantly, EGCG decreased IKK activity in cytosolic extracts of NIK transiently transfected cells. This latter finding showed that our findings were not related to nonspecific kinase activity. In conclusion, EGCG is an effective inhibitor of IKK activity. This may explain, at least in part, some of the reported anti-inflammatory and anticancer effects of green tea.

Original languageEnglish (US)
Pages (from-to)528-533
Number of pages6
JournalMolecular Pharmacology
Volume60
Issue number3
StatePublished - 2001
Externally publishedYes

Fingerprint

Polyphenols
Tea
Phosphotransferases
Epithelial Cells
Cell Line
Tumor Necrosis Factor-alpha
Glutathione Transferase
Phosphorylation
Endotoxins
Inhibitory Concentration 50
Anti-Inflammatory Agents
Transcription Factors
Antioxidants
epigallocatechin gallate
Proteins

ASJC Scopus subject areas

  • Pharmacology

Cite this

The green tea polyphenol (-)-epigallocatechin-3-gallate blocks nuclear factor-κB activation by inhibiting IκB kinase activity in the intestinal epithelial cell line IEC-6. / Yang, Fajun; Oz, Helieh S.; Barve, Shirish; De Villiers, Willem J S; McClain, Craig J.; Varilek, Gary W.

In: Molecular Pharmacology, Vol. 60, No. 3, 2001, p. 528-533.

Research output: Contribution to journalArticle

Yang, Fajun ; Oz, Helieh S. ; Barve, Shirish ; De Villiers, Willem J S ; McClain, Craig J. ; Varilek, Gary W. / The green tea polyphenol (-)-epigallocatechin-3-gallate blocks nuclear factor-κB activation by inhibiting IκB kinase activity in the intestinal epithelial cell line IEC-6. In: Molecular Pharmacology. 2001 ; Vol. 60, No. 3. pp. 528-533.
@article{c494c1af17094c3c9a1e5a57ff65f53c,
title = "The green tea polyphenol (-)-epigallocatechin-3-gallate blocks nuclear factor-κB activation by inhibiting IκB kinase activity in the intestinal epithelial cell line IEC-6",
abstract = "The IκB kinase complex (IKK) mediates activation of the transcription factor nuclear factor-κB (NF-κB). We previously showed that green tea polyphenols inhibited endotoxin-mediated tumor necrosis factor-α (TNFα) production by blocking NF-κB activation. In this study, we evaluated whether green tea polyphenols inhibit NF-κB by blocking IKK activity. We assessed IKK activity by detecting changes in phosphorylation of an IκBα-glutathione S-transferase (GST) fusion protein. IEC-6 cells pretreated with an extract of green tea polyphenols (GrTPs; 0-0.4 mg/ml) had diminished TNFα-induced IKK and NF-κB activity. Of the various GrTPs, (-)-epigallocatechin-3-gallate (EGCG) was the most potent inhibitor. We next examined whether EGCG inhibited activated IKK. In cytosolic extracts of TNFα-stimulated cells, EGCG inhibited phosphorylation of IκBα-GST (IC50 > 18 μM) consistent with inhibition of IKK activity. Using other polyphenols, we showed that the gallate group was essential for inhibition, and antioxidants were ineffective in blocking activated IKK. Importantly, EGCG decreased IKK activity in cytosolic extracts of NIK transiently transfected cells. This latter finding showed that our findings were not related to nonspecific kinase activity. In conclusion, EGCG is an effective inhibitor of IKK activity. This may explain, at least in part, some of the reported anti-inflammatory and anticancer effects of green tea.",
author = "Fajun Yang and Oz, {Helieh S.} and Shirish Barve and {De Villiers}, {Willem J S} and McClain, {Craig J.} and Varilek, {Gary W.}",
year = "2001",
language = "English (US)",
volume = "60",
pages = "528--533",
journal = "Molecular Pharmacology",
issn = "0026-895X",
publisher = "American Society for Pharmacology and Experimental Therapeutics",
number = "3",

}

TY - JOUR

T1 - The green tea polyphenol (-)-epigallocatechin-3-gallate blocks nuclear factor-κB activation by inhibiting IκB kinase activity in the intestinal epithelial cell line IEC-6

AU - Yang, Fajun

AU - Oz, Helieh S.

AU - Barve, Shirish

AU - De Villiers, Willem J S

AU - McClain, Craig J.

AU - Varilek, Gary W.

PY - 2001

Y1 - 2001

N2 - The IκB kinase complex (IKK) mediates activation of the transcription factor nuclear factor-κB (NF-κB). We previously showed that green tea polyphenols inhibited endotoxin-mediated tumor necrosis factor-α (TNFα) production by blocking NF-κB activation. In this study, we evaluated whether green tea polyphenols inhibit NF-κB by blocking IKK activity. We assessed IKK activity by detecting changes in phosphorylation of an IκBα-glutathione S-transferase (GST) fusion protein. IEC-6 cells pretreated with an extract of green tea polyphenols (GrTPs; 0-0.4 mg/ml) had diminished TNFα-induced IKK and NF-κB activity. Of the various GrTPs, (-)-epigallocatechin-3-gallate (EGCG) was the most potent inhibitor. We next examined whether EGCG inhibited activated IKK. In cytosolic extracts of TNFα-stimulated cells, EGCG inhibited phosphorylation of IκBα-GST (IC50 > 18 μM) consistent with inhibition of IKK activity. Using other polyphenols, we showed that the gallate group was essential for inhibition, and antioxidants were ineffective in blocking activated IKK. Importantly, EGCG decreased IKK activity in cytosolic extracts of NIK transiently transfected cells. This latter finding showed that our findings were not related to nonspecific kinase activity. In conclusion, EGCG is an effective inhibitor of IKK activity. This may explain, at least in part, some of the reported anti-inflammatory and anticancer effects of green tea.

AB - The IκB kinase complex (IKK) mediates activation of the transcription factor nuclear factor-κB (NF-κB). We previously showed that green tea polyphenols inhibited endotoxin-mediated tumor necrosis factor-α (TNFα) production by blocking NF-κB activation. In this study, we evaluated whether green tea polyphenols inhibit NF-κB by blocking IKK activity. We assessed IKK activity by detecting changes in phosphorylation of an IκBα-glutathione S-transferase (GST) fusion protein. IEC-6 cells pretreated with an extract of green tea polyphenols (GrTPs; 0-0.4 mg/ml) had diminished TNFα-induced IKK and NF-κB activity. Of the various GrTPs, (-)-epigallocatechin-3-gallate (EGCG) was the most potent inhibitor. We next examined whether EGCG inhibited activated IKK. In cytosolic extracts of TNFα-stimulated cells, EGCG inhibited phosphorylation of IκBα-GST (IC50 > 18 μM) consistent with inhibition of IKK activity. Using other polyphenols, we showed that the gallate group was essential for inhibition, and antioxidants were ineffective in blocking activated IKK. Importantly, EGCG decreased IKK activity in cytosolic extracts of NIK transiently transfected cells. This latter finding showed that our findings were not related to nonspecific kinase activity. In conclusion, EGCG is an effective inhibitor of IKK activity. This may explain, at least in part, some of the reported anti-inflammatory and anticancer effects of green tea.

UR - http://www.scopus.com/inward/record.url?scp=0034859081&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034859081&partnerID=8YFLogxK

M3 - Article

C2 - 11502884

AN - SCOPUS:0034859081

VL - 60

SP - 528

EP - 533

JO - Molecular Pharmacology

JF - Molecular Pharmacology

SN - 0026-895X

IS - 3

ER -