Green tea epigallocatechin gallate shows a pronounced growth inhibitory effect on cancerous cells but not on their normal counterparts

doi:10.1016/S0304-3835(98)00108-6

Cancer Letters

Volume 129, Issue 2, 19 June 1998, Pages 173-179

https://doi.org/10.1016/S0304-3835(98)00108-6 Get rights and content

Abstract

(−)-Epigallocatechin gallate (EGCG), a catechin polyphenol compound, represents the main ingredient of green tea extract. Although EGCG has been shown to be growth inhibitory in a number of tumor cell lines, it is not clear whether the effect is cancer-specific. In this study we compared the effect of EGCG on the growth of SV40 virally transformed WI38 human fibroblasts (WI38VA) with that of normal WI38 cells. The IC₅₀ value of EGCG was estimated to be 120 and 10 μM for WI38 and WI38VA cells, respectively. Thus, EGCG at 40 μM completely inhibited the growth of WI38VA cells, but had little or no inhibitory effect on the growth of WI38 cells. Similar differential growth inhibition was also observed between a human colorectal cancer cell line (Caco-2), a breast cancer cell line (Hs578T) and their respective normal counterparts. EGCG at a concentration range of 40–200 μM induced a significant amount of apoptosis in WI38VA cultures, but not in WI38 cultures, as determined by terminal deoxynucleotidyl transferase assay. After exposure to EGCG at 200 μM for 8 h, more than 50% of WI38VA cells in a confluent culture became apoptotic. In contrast, less than 1% of WI38 cells displayed apoptotic labeling under the same condition. EGCG did not affect the serum-induced expression of c-fos and c-myc genes in normal WI38 cells. However, it significantly enhanced their expression in transformed WI38VA cells. It is possible that differential modulation of certain genes, such as c-fos and c-myc, may cause differential effects of EGCG on the growth and death of cancer cells.

Introduction

Epidemiological studies, though inconclusive, suggest a protective effect of tea consumption on certain human cancers 1, 2. Animal studies show that green tea polyphenols inhibit carcinogen-induced skin, lung, forestomach, esophagus, duodenum and colon tumors in rodents and inhibit TPA-induced skin tumor promotion in mice 3, 4, 5, 6. The green tea polyphenols have also been shown to inhibit the proliferation of cultured mammalian cells, including colon carcinoma, lung carcinoma, breast carcinoma, melanoma and leukemic cells 7, 8, 9, 10. Six polyphenol compounds, (+)-gallocatechin (GC), (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin gallate (EGCG) and caffeine, have been isolated and purified from green tea [11]. Of these, the most active is (−)-epigallocatechin-3-gallate (EGCG), the major constituent in green tea extracts. One major goal in developing effective cancer chemotherapy is to search for specific anticancer agents. Previous work 1, 2, 3, 4, 5, 6, 7, 8, 9, 10has suggested that EGCG may have the potential to be developed into a new class of chemotherapeutic agents. In light of this possibility, we have initiated systematic studies to determine whether the effects of EGCG on cell proliferation and gene expression are cancer cell-specific. We report here that EGCG inhibited cell growth, induced apoptosis and modulated gene expression differently in transformed cells as compared to their normal counterparts.

Section snippets

Materials

Dulbecco's modified Eagle's medium and fetal bovine serum were obtained from GIBCO (Gaithersburg, MD). Other chemicals were from Sigma (St. Louis, MO). [α-³²P]dCTP (>3000 Ci/mmol) was purchased from ICN Chemical, Radioisotope Division (Irvine, CA).

Tissue culture

WI38 cells (AG06814, passage number 12) and the SV40 virally transformed WI38VA cells (AG07217) were obtained from the National Institute on Aging Repository, Coriell Institute for Medical Research (Camden, NJ). Colon cancer cells, Caco-2 (ATCC #

Differential effect of EGCG on the growth of WI38 and WI38VA cells

WI38 cells are normal human diploid lung fibroblasts with a finite life-span [14]and the immortalized WI38VA cell line is derived from WI38 cells by SV40 virus transformation [15]. The pair has been used as an in vitro transformed and non-transformed cell model [15]. Fig. 1A shows that the transformed WI38VA cells were more sensitive to the inhibition of growth than the normal WI38 cells. Thus, EGCG at 40 μM completely inhibited the growth of WI38VA cells, but had little effect on the growth of

Discussion

Polyphenols from green tea, particularly EGCG, have been demonstrated to possess anticarcinogenic and chemopreventive effects both in vitro and in vivo 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Since comparative studies of the effects of EGCG on normal and transformed cells have not been done previously, it is not clear whether these pharmacological effects of EGCG are specific for cancer cells. Our studies showed for the first time that EGCG at an appropriate dosage inhibited the growth of transformed

Acknowledgements

We are grateful to Dr Robert Rosen for providing us with EGCG and other nutraceuticals and to Dr E. White for the Bax probe. We thank Dr Geetha Ghai for many useful discussions. This study was supported by the Commission on Science and Technology, State of New Jersey as a component of the Program in Pioneering Nutraceutical Research.

References (19)

H. Fujiki et al.
Anticarcinogenic effects of (−)-epigallocatechin gallate
Prev. Med.
(1992)
M. Hirose et al.
Effects of green tea catechins on the progression or late promotion stage of mammary gland carcinogenesis in female Sprague–Dawley rats pretreated with 7,12 dimethylbenz(a)anthracene
Cancer Lett.
(1997)
S. Liao et al.
Growth inhibition and regression of human prostate and breast tumors in athymic mice by tea epigallocatechin gallate
Cancer Lett.
(1995)
M.A. Lea et al.
Inhibitory effects of tea extracts and (−)-epigallocatechin gallate on DNA synthesis and proliferation of hepatoma and erythroleukemia cells
Cancer Lett.
(1993)
Z.P. Chen et al.
Mechanism of regulation of ornithine decarboxylase gene expression by asparagine in variant mouse neuroblastoma cell line
J. Biol. Chem.
(1992)
L. Hayflick
The limited in vitro lifetime of human diploid cell strains
Exp. Cell Res.
(1965)
J. Pang et al.
The age-dependent binding of CBP/tk, a CCAAT binding protein, is deregulated in transformed and immortalized mammalian cells but absent in premature aging cells
Exp. Gerontol.
(1996)
G.D. Stoner et al.
Polyphenols as cancer chemopreventive agents
J. Cell. Biochem.
(1995)
H. Fujiki et al.
Japanese green tea as a cancer preventive agent in humans
Nutr. Rev.
(1996)

There are more references available in the full text version of this article.

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Green tea epigallocatechin gallate shows a pronounced growth inhibitory effect on cancerous cells but not on their normal counterparts

Abstract

Introduction

Section snippets

Materials

Tissue culture

Differential effect of EGCG on the growth of WI38 and WI38VA cells

Discussion

Acknowledgements

Prev. Med.

Cancer Lett.

Cancer Lett.

Cancer Lett.

J. Biol. Chem.

Exp. Cell Res.

Exp. Gerontol.

Polyphenols as cancer chemopreventive agents

J. Cell. Biochem.

Japanese green tea as a cancer preventive agent in humans

Nutr. Rev.