Green tea polyphenols and its constituent epigallocatechin gallate inhibits proliferation of human breast cancer cells in vitro and in vivo

Cancer Lett. 2007 Jan 8;245(1-2):232-41. doi: 10.1016/j.canlet.2006.01.027. Epub 2006 Mar 6.

Abstract

Tea [Camellia sinensis (Theaceae)] intake is second only to water in terms of worldwide popularity as a beverage. The Green tea polyphenols have been shown to have a protective effect in prostate cancer in various pre-clinical animal models and has been reported to be effective in several other cancer types as well. An inverse association between the risk of breast cancer and the intake of green tea has also been reported in Asian Americans. Several epidemiological studies have shown that breast cancer progression is delayed in the Asian population that consumes green tea on regular basis. In this study, we report the effectiveness of green tea polyphenols (GTP) and its constituent Epigallocatechin Gallate (EGCG) in tumor regression using both in-vitro cell culture models and in vivo athymic nude mice models of breast cancer. The anti-proliferative effect of GTP and EGCG on the growth of human breast cancer MDA-MB-231 cell was studied using a tetrazolium dye-based (MTT) assay. Both GTP and EGCG treatment had the ability to arrest the cell cycle at G1 phase as assessed by flow cytometry. The expression of Cyclin D, Cyclin E, CDK 4, CDK 1 and PCNA were down regulated over the time in GTP and EGCG treated experimental group, compared to the untreated control group as evaluated by western blot analysis for cell cycle proteins, which corroborated the G1 block. Nude mice inoculated with human breast cancer MDA-MB-231 cells and treated with GTP and EGCG were effective in delaying the tumor incidence as well as reducing the tumor burden when compared to the water fed and similarly handled control. GTP and EGCG treatment were also found to induce apoptosis and inhibit the proliferation when the tumor tissue sections were examined by immunohistochemistry. Our results suggest that GTP and EGCG treatment inhibits proliferation and induce apoptosis of MDA-MB-231 cells in-vitro and in-vivo. All together, these data sustain our contention that GTP and EGCG have anti-tumor properties.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Administration, Oral
  • Animals
  • Anticarcinogenic Agents / administration & dosage
  • Anticarcinogenic Agents / pharmacology
  • Apoptosis / drug effects
  • Blotting, Western
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Breast Neoplasms / prevention & control
  • Catechin / administration & dosage
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology
  • Cell Cycle / drug effects
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / drug effects*
  • Dose-Response Relationship, Drug
  • Female
  • Flavonoids / administration & dosage
  • Flavonoids / pharmacology*
  • G1 Phase / drug effects
  • Guanosine Triphosphate / pharmacology
  • Humans
  • Immunohistochemistry
  • Mammary Neoplasms, Experimental / metabolism
  • Mammary Neoplasms, Experimental / pathology
  • Mammary Neoplasms, Experimental / prevention & control*
  • Mice
  • Mice, Nude
  • Phenols / administration & dosage
  • Phenols / pharmacology*
  • Polyphenols
  • Proliferating Cell Nuclear Antigen / analysis
  • Tea / chemistry*
  • Xenograft Model Antitumor Assays

Substances

  • Anticarcinogenic Agents
  • Cell Cycle Proteins
  • Flavonoids
  • Phenols
  • Polyphenols
  • Proliferating Cell Nuclear Antigen
  • Tea
  • Guanosine Triphosphate
  • Catechin
  • epigallocatechin gallate