Inhibition of activator protein 1 activity and cell growth by purified green tea and black tea polyphenols in H-ras-transformed cells

Structure- activity relationship and mechanisms involved

Jee Y. Chung, Chuanshu Huang, Xiaofeng Meng, Zigang Dong, Chung Yang

Research output: Contribution to journalArticle

229 Citations (Scopus)

Abstract

ras gene mutation, which perpetually turns on the growth signal transduction pathway, occurs frequently in many cancer types. The mouse epidermal JB6 cell line has been transfected with a mutant H-ras gene to mimic carcinogenesis in vitro. These transformed cells (30.7b Ras 12) are able to grow in soft agar, exhibiting anchorage independence and high endogenous activator protein 1 (AP-1) activity, which can be detected by a stable AP-1 luciferase reporter. The present study investigated the ability of different pure green and black tea polyphenols to inhibit this ras signaling pathway. The major green tea polyphenols (catechins), (-)- epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin, (-)-epicatechin-3- gallate, (-)-epicatechin, and their epimers, and black tea polyphenols, theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate, and theaflavin-3,3'- digallate (TFdiG), were compared with respect to their ability to inhibit the growth of 30.7b Ras 12 cells and AP-1 activity. All of the tea polyphenols except (-)-epicatechin showed strong inhibition of cell growth and AP-1 activity. Among the catechins, both the galloyl structure on the B ring and the gallate moiety contributed to the growth inhibition and AP-1 activity; the galloyl structure appeared to have a stronger effect on the inhibitory action than the gallate moiety. The epimers of the catechins showed similar inhibitory effects on AP-1 activity. The addition of catalase to the incubation of the cells with EGCG or TFdiG did not prevent the inhibitory effect on AP-1 activity, suggesting that H2O2 does not play a significant role in the inhibition by tea polyphenols. Both EGCG and TFdiG inhibited the phosphorylation of p44/42 (extracellular signal-regulated kinase 1 and 2) and c-jun without affecting the levels of phosphorylated-c-jun-NH2-terminal kinase. TFdiG inhibited the phosphorylation of p38, but EGCG did not. EGCG lowered the level of c-jun, whereas TFdiG decreased the level of fra-1. These results suggest that tea polyphenols inhibited AP-1 activity and the mitogen- activated protein kinase pathway, which contributed to the growth inhibition; however, different mechanisms may be involved in the inhibition by catechins and theaflavins.

Original languageEnglish (US)
Pages (from-to)4610-4617
Number of pages8
JournalCancer Research
Volume59
Issue number18
StatePublished - Sep 15 1999

Fingerprint

Transcription Factor AP-1
Polyphenols
Tea
Structure-Activity Relationship
Catechin
Growth
ras Genes
Phosphorylation
Mitogen-Activated Protein Kinase 3
JNK Mitogen-Activated Protein Kinases
Mitogen-Activated Protein Kinase 1
Mitogen-Activated Protein Kinases
Luciferases
Catalase
Agar
epigallocatechin gallate
Signal Transduction
Carcinogenesis
theaflavin-3,3'-digallate
Cell Line

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

Cite this

@article{eada4e5783a14fcb8be7c6b98e93ef21,
title = "Inhibition of activator protein 1 activity and cell growth by purified green tea and black tea polyphenols in H-ras-transformed cells: Structure- activity relationship and mechanisms involved",
abstract = "ras gene mutation, which perpetually turns on the growth signal transduction pathway, occurs frequently in many cancer types. The mouse epidermal JB6 cell line has been transfected with a mutant H-ras gene to mimic carcinogenesis in vitro. These transformed cells (30.7b Ras 12) are able to grow in soft agar, exhibiting anchorage independence and high endogenous activator protein 1 (AP-1) activity, which can be detected by a stable AP-1 luciferase reporter. The present study investigated the ability of different pure green and black tea polyphenols to inhibit this ras signaling pathway. The major green tea polyphenols (catechins), (-)- epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin, (-)-epicatechin-3- gallate, (-)-epicatechin, and their epimers, and black tea polyphenols, theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate, and theaflavin-3,3'- digallate (TFdiG), were compared with respect to their ability to inhibit the growth of 30.7b Ras 12 cells and AP-1 activity. All of the tea polyphenols except (-)-epicatechin showed strong inhibition of cell growth and AP-1 activity. Among the catechins, both the galloyl structure on the B ring and the gallate moiety contributed to the growth inhibition and AP-1 activity; the galloyl structure appeared to have a stronger effect on the inhibitory action than the gallate moiety. The epimers of the catechins showed similar inhibitory effects on AP-1 activity. The addition of catalase to the incubation of the cells with EGCG or TFdiG did not prevent the inhibitory effect on AP-1 activity, suggesting that H2O2 does not play a significant role in the inhibition by tea polyphenols. Both EGCG and TFdiG inhibited the phosphorylation of p44/42 (extracellular signal-regulated kinase 1 and 2) and c-jun without affecting the levels of phosphorylated-c-jun-NH2-terminal kinase. TFdiG inhibited the phosphorylation of p38, but EGCG did not. EGCG lowered the level of c-jun, whereas TFdiG decreased the level of fra-1. These results suggest that tea polyphenols inhibited AP-1 activity and the mitogen- activated protein kinase pathway, which contributed to the growth inhibition; however, different mechanisms may be involved in the inhibition by catechins and theaflavins.",
author = "Chung, {Jee Y.} and Chuanshu Huang and Xiaofeng Meng and Zigang Dong and Chung Yang",
year = "1999",
month = "9",
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volume = "59",
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Inhibition of activator protein 1 activity and cell growth by purified green tea and black tea polyphenols in H-ras-transformed cells : Structure- activity relationship and mechanisms involved. / Chung, Jee Y.; Huang, Chuanshu; Meng, Xiaofeng; Dong, Zigang; Yang, Chung.

In: Cancer Research, Vol. 59, No. 18, 15.09.1999, p. 4610-4617.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Inhibition of activator protein 1 activity and cell growth by purified green tea and black tea polyphenols in H-ras-transformed cells

T2 - Structure- activity relationship and mechanisms involved

AU - Chung, Jee Y.

AU - Huang, Chuanshu

AU - Meng, Xiaofeng

AU - Dong, Zigang

AU - Yang, Chung

PY - 1999/9/15

Y1 - 1999/9/15

N2 - ras gene mutation, which perpetually turns on the growth signal transduction pathway, occurs frequently in many cancer types. The mouse epidermal JB6 cell line has been transfected with a mutant H-ras gene to mimic carcinogenesis in vitro. These transformed cells (30.7b Ras 12) are able to grow in soft agar, exhibiting anchorage independence and high endogenous activator protein 1 (AP-1) activity, which can be detected by a stable AP-1 luciferase reporter. The present study investigated the ability of different pure green and black tea polyphenols to inhibit this ras signaling pathway. The major green tea polyphenols (catechins), (-)- epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin, (-)-epicatechin-3- gallate, (-)-epicatechin, and their epimers, and black tea polyphenols, theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate, and theaflavin-3,3'- digallate (TFdiG), were compared with respect to their ability to inhibit the growth of 30.7b Ras 12 cells and AP-1 activity. All of the tea polyphenols except (-)-epicatechin showed strong inhibition of cell growth and AP-1 activity. Among the catechins, both the galloyl structure on the B ring and the gallate moiety contributed to the growth inhibition and AP-1 activity; the galloyl structure appeared to have a stronger effect on the inhibitory action than the gallate moiety. The epimers of the catechins showed similar inhibitory effects on AP-1 activity. The addition of catalase to the incubation of the cells with EGCG or TFdiG did not prevent the inhibitory effect on AP-1 activity, suggesting that H2O2 does not play a significant role in the inhibition by tea polyphenols. Both EGCG and TFdiG inhibited the phosphorylation of p44/42 (extracellular signal-regulated kinase 1 and 2) and c-jun without affecting the levels of phosphorylated-c-jun-NH2-terminal kinase. TFdiG inhibited the phosphorylation of p38, but EGCG did not. EGCG lowered the level of c-jun, whereas TFdiG decreased the level of fra-1. These results suggest that tea polyphenols inhibited AP-1 activity and the mitogen- activated protein kinase pathway, which contributed to the growth inhibition; however, different mechanisms may be involved in the inhibition by catechins and theaflavins.

AB - ras gene mutation, which perpetually turns on the growth signal transduction pathway, occurs frequently in many cancer types. The mouse epidermal JB6 cell line has been transfected with a mutant H-ras gene to mimic carcinogenesis in vitro. These transformed cells (30.7b Ras 12) are able to grow in soft agar, exhibiting anchorage independence and high endogenous activator protein 1 (AP-1) activity, which can be detected by a stable AP-1 luciferase reporter. The present study investigated the ability of different pure green and black tea polyphenols to inhibit this ras signaling pathway. The major green tea polyphenols (catechins), (-)- epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin, (-)-epicatechin-3- gallate, (-)-epicatechin, and their epimers, and black tea polyphenols, theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate, and theaflavin-3,3'- digallate (TFdiG), were compared with respect to their ability to inhibit the growth of 30.7b Ras 12 cells and AP-1 activity. All of the tea polyphenols except (-)-epicatechin showed strong inhibition of cell growth and AP-1 activity. Among the catechins, both the galloyl structure on the B ring and the gallate moiety contributed to the growth inhibition and AP-1 activity; the galloyl structure appeared to have a stronger effect on the inhibitory action than the gallate moiety. The epimers of the catechins showed similar inhibitory effects on AP-1 activity. The addition of catalase to the incubation of the cells with EGCG or TFdiG did not prevent the inhibitory effect on AP-1 activity, suggesting that H2O2 does not play a significant role in the inhibition by tea polyphenols. Both EGCG and TFdiG inhibited the phosphorylation of p44/42 (extracellular signal-regulated kinase 1 and 2) and c-jun without affecting the levels of phosphorylated-c-jun-NH2-terminal kinase. TFdiG inhibited the phosphorylation of p38, but EGCG did not. EGCG lowered the level of c-jun, whereas TFdiG decreased the level of fra-1. These results suggest that tea polyphenols inhibited AP-1 activity and the mitogen- activated protein kinase pathway, which contributed to the growth inhibition; however, different mechanisms may be involved in the inhibition by catechins and theaflavins.

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