Jankun, Jerzy; Selman, Steven H.; Swiercz, Rafal; Skrzypczak-Jankun, Ewa

Nature, Volume 387, Issue 6633, pp. 561 (1997).

Epidemiological studies suggest that the consumption of green tea may help prevent cancers in humans; also, breast and prostate cancers in animal models are reduced by green, but not black, tea. Here we offer a possible explanation. We have inferred (using molecular modelling) and subsequently demonstrated that one of the major ingredients of green tea inhibits urokinase, an enzyme crucial for cancer growth.

“The preliminary research on cancer prevention in human populations indicates that a certain enzyme that’s needed for cancer growth (urokinase, uPA) can be inhibited by daily consumption of green tea.  This article indicates that green tea can be consumed in high quantities on a daily basis to improve risk factors of cancer.  This article also compared daily consumption of green tea to small doses of medication and the advantage of being able to consume green tea daily!  Another great addition to the body of knowledge on green tea and cancer.”  – Josh Smith

EGCG inhibits growth, invasion, angiogenesis and metastasis of pancreatic cancer.Shankar S, Ganapathy S, Hingorani SR, Srivastava RK.Department of Biochemistry, University of Texas Health Science Center at Tyler, Tyler, Texas 75703, USA.

We have shown that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, inhibits growth and induces apoptosis in human pancreatic cancer cells. However, the preclinical potential of EGCG in a suitable mouse model has not been examined. In this study, we examined the molecular mechanisms by which EGCG inhibited growth, invasion, metastasis and angiogenesis of human pancreatic cancer cells in a xenograft model system. EGCG inhibited viability, capillary tube formation and migration of HUVEC, and these effects were further enhanced in the presence of an ERK inhibitor. In vivo, AsPC-1 xenografted tumors treated with EGCG showed significant reduction in volume, proliferation (Ki-67 and PCNA staining), angiogenesis (vWF, VEGF and CD31) and metastasis (MMP-2, MMP-7, MMP-9 and MMP-12) and induction in apoptosis (TUNEL), caspase-3 activity and growth arrest (p21/WAF1). EGCG also inhibited circulating endothelial growth factor receptor 2 (VEGF-R2) positive endothelial cells derived from xenografted mice. Tumor samples from EGCG treated mice showed significantly reduced ERK activity, and enhanced p38 and JNK activities. Overall, our data suggest that EGCG inhibits pancreatic cancer growth, invasion, metastasis and angiogenesis, and thus could be used for the management of pancreatic cancer prevention and treatment.

“The findings of this study are a huge step in the direction of a lifestyle interventions that can be used on an individual basis for specific chronic diseases.  After reading this the evidence continues to compile for consuming wholesome EGCG’s on a daily basis.  I get mine from GreenTeaHP! ” – Josh Smith

These results bring us one step closer to better understanding the disease and potentially new and naturally occurring therapies.

The Study

Epidemiological studies suggest that green tea and its major constituent, EGCG, can provide some protection against cancer. Because these studies were very limited, the anti-cancer mechanism of green tea and EGCG was not clear. As a result, the researchers examined whether drinking EGCG (just the antioxidant infused in water) inhibited the following: expression of VEGF (vascular endothelial growth factor, which is found in a variety of breast cancer types); tumor angiogenesis (thought to help tumors expand by supplying them with nutrients); and the growth of breast cancer in female mice.

Seven week old female mice were given EGCG (25 mg/50 ml) in drinking water for five weeks (approximately 50-100 mg/kg/day.) The control mice received regular drinking water. In the second week of the study mouse breast cancer cells were injected in the left fourth mammary glands of the mice. Tumor size was monitored by measuring the tumor cross section area (TCSA). Tumors were eventually isolated and measured for tumor weight, intratumoral microvessel (IM) density (using staining), and VEGF protein levels (using ELISA).

At the end of the five week period the researchers found that oral consumption of EGCG caused significant decreases in TCSA (66%), tumor weight (68%), IM density 155±6 vs.111±20 IM#mm^2) and VEGF protein levels (59.0±3.7 vs. 45.7±1.4 pg/mg) in the breast tumors vs. the control mice, respectively (N=8; P<0.01).  Further, VEGF plasma levels were lower in EGCG mice than in control mice (40.8±3.5 vs. 26.5±3.8 pg/ml P< 0.01).

The study was conducted by Jian-Wei Gu, Emily Young, Jordan Covington, James Wes Johnson, and Wei Tan, all of the Department of Physiology & Biophysics, University of Mississippi Medical Center, Jackson, MS. Dr. Gu will present his team’s findings, entitled, Oral Administration of EGCG, an Antioxidant Found in Green Tea, Inhibits Tumor Angiogenesis and Growth of Breast Cancer in Female Mice, at the  121st Annual Meeting of the American Physiological Society, part of the Experimental Biology 2008 scientific conference.

Dr. Gu, the senior researcher for the study, hypothesized that the reason for the link between EGCG and the reductions in the cancer data was because EGCG directly targets both tumor blood vessels and tumor cells of breast cancer for suppressing the new blood vessels formation in breast tumor, the proliferation and migration of breast cancer cells.

Gu concluded by saying, “In this study we have demonstrated that the frequent ingestion of EGCG significantly inhibits breast tumor growth, VEGF expression and tumor angiogenesis in mice. We believe our findings will help lead to new therapies for the prevention and treatment of breast cancer in women.”