| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Epidemiology and Prevention |
1 Department of Medicina Sperimentale, University of Parma, Parma; 2 Urology, S. Agostino Hospital; and 3 Department of Scienze Biomediche, University of Modena and Reggio Emilia, Modena, Italy
Requests for reprints: Saverio Bettuzzi, Dipartimento di Medicina Sperimentale, Sezione di Biochimica, Università di Parma, Via Volturno 39, 43100 Parma, Italy. Phone: 39-0521-903803; Fax: 39-0521-903802; E-mail: saverio.bettuzzi{at}unipr.it.
| Abstract |
|---|
|
|
|---|
3%), whereas nine cancers were found among the 30 placebo-treated men (incidence, 30%). Total prostate-specific antigen did not change significantly between the two arms, but GTCs-treated men showed values constantly lower with respect to placebo-treated ones. International Prostate Symptom Score and quality of life scores of GTCs-treated men with coexistent benign prostate hyperplasia improved, reaching statistical significance in the case of International Prostate Symptom Scores. No significant side effects or adverse effects were documented. To our knowledge, this is the first study showing that GTCs are safe and very effective for treating premalignant lesions before CaP develops. As a secondary observation, administration of GTCs also reduced lower urinary tract symptoms, suggesting that these compounds might also be of help for treating the symptoms of benign prostate hyperplasia. (Cancer Res 2006; 66(2): 1234-40) | Introduction |
|---|
|
|
|---|
Lifestyle-related factors, particularly the diet, are considered to be the major contributors to CaP promotion. Although clinical evidences are still rather sparse and not definitive, several epidemiologic studies have focused on the lower incidence of CaP in Asian countries where green tea is consumed regularly (1), as compared with western populations. Moreover, the risk for CaP returns in Asian immigrants to the U.S. if original dietary habits are abandoned (1). Recently, a case-control study conducted in China showed that green tea consumption is etiologically associated with CaP, suggesting the protective effect of green tea against this disease (2). This body of evidence has suggested that administration of biologically active compounds from green tea might be effective in lowering the incidence of CaP.
It is well known that the active compounds released and found in highest amounts in the dry matter of green tea infusion are catechins, the most common of which are ()-epigallocatechin-3-gallate (EGCG), ()-epigallocathechin (EGC), ()-epicatechin-3-gallate (ECG), and ()-epicatechin (EC). Green tea catechins (GTCs), and especially EGCG, have been shown to be potent chemopreventive agents in vitro and in many in vivo animal models of induced carcinogenesis (3, 4). The systematic study of the biological and biochemical properties of GTCs only started quite recently, searching for possible molecular explanations for their effect on cancer cells. Endocrine changes occurring upon GTCs or EGCG administration (5), and/or inhibition of 5-
-reductase (the prostatic enzyme transforming testosterone into the more active androgen, 5-
-dihydrotestosterone) have been often suggested as key events capable of inhibiting CaP burden (6, 7). We previously showed that apoptotic cell death was specifically induced by EGCG in both SV40-immortalized (PNT1A) and tumorigenic (PC-3) human prostate cells by the activation of caspase-cascade without any significant effect on benign controls (normal human prostate epithelial cells in primary culture from cystectomy; ref. 8).
The transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse model is a well known in vivo animal model for CaP displaying in situ and invasive carcinoma of the prostate that mimics the whole spectrum of human CaP progression from prostate intraepithelial neoplasia (PIN) to androgen-independent disease (9, 10). Recent studies have shown that GTCs administration can actually prevent CaP development in this model (11). We confirmed this finding, showing that p.o. administration of GTCs to TRAMP mice reduced CaP incidence at 24 weeks from 100% to 20% without any side effects (8), and suggested that GTC's action might be mediated by the induction of the expression of Clusterin (CLU). The CLU gene is potently up-regulated during prostate gland involution (12), but is down-regulated in human CaP specimens (13, 14) and, as previously reported by us, in PNT1a and PC-3 cells, it exerts antiproliferative (15) and proapoptotic activities (1619). In the prostate glands of TRAMP mice responding to GTCs treatment, CLU expression was maintained at high levels, and, shortly before the induction of casp-9 expression/activation, and concomitantly to decreased expression of histone H3 mRNA (a specific marker of cell proliferation; ref. 8), localized to the nuclei, in which it is known to exert a proapoptotic role (1719). These data, altogether, confirmed that GTCs exert potent and selective in vitro and in vivo proapoptotic activity on prostate cancer cells.
Nevertheless, no definitive clinical data demonstrating the efficacy of GTCs as chemopreventive agents in humans have thus far been produced. Thus, clinical studies for the evaluation of safety and effectiveness of these agents in cancer chemoprevention, both individually and in combination, are needed (20). Our preclinical results prompted us to do a proof-of-principle clinical trial to assess the possible efficacy of GTCs for the chemoprevention of CaP.
In order to obtain this information as quickly as possible, the study was done in a selected population of 60 human volunteers with high-grade PIN (HG-PIN), the main premalignant lesion of CaP (21), known to result in a substantial number of cancers in a 1-year period (22, 23). Because, at present, no treatment is given to these patients until CaP is diagnosed, our study can be envisaged as an attempt to fill this therapeutic void. The primary end point of this study was to determine a possible difference in the prevalence of CaP in the GTCs-treated arm in comparison to placebo. Possible changes in total serum prostate-specific antigen (PSA) values, as well as possible variations in lower urinary tract symptoms (LUTS), as assessed by International Prostate Symptom Score (IPSS; ref. 24) and quality of life score (QoL; ref. 25) in men with coexistent benign prostate hyperplasia (BPH) were also pursued as secondary observations.
| Materials and Methods |
|---|
|
|
|---|
To investigate whether the administration of GTCs could prevent malignancy in men at high-risk, 60 volunteers (Caucasian men) bearing HG-PIN lesions, to whom no therapy is commonly given, were enrolled in this double-blind, placebo-controlled study. Because pure HG-PIN is a rather rare finding, recruitment time extended up to 18 months to reach the appropriate number of subjects for each arm. Volunteers were randomly assessed to a placebo- or GTCs-arm by simple randomization. More precisely, subjects were called for an informative interview within 2 weeks from the time of diagnosis and asked to join the study by signing the informed consent. That same day, they were alternatively assigned to the placebo- or GTCs-arm and given the appropriate treatment. To all subjects, capsules were given by the urologist according to the double blind method. Compliance with study medication was assessed by pill count/returned blister packs. Due to the enthusiastic adherence to the study by highly motivated subjects at high risk for CaP, all volunteers took the complete medication assigned in all cases, thus the compliance was very good in both arms and did not differ between the two groups. The GTCs-arm volunteers received three capsules per day containing 200 mg each of GTCs, for a total of 600 mg of GTCs per day. GTCs were given as a high-quality preparation whose content was determined by high-performance liquid chromatography as previously published (8). Content was as follows: EGC, 5.5%; EC, 12.24%; EGCG, 51.8%; ECG, 6.12%; total GTCs, 75.7%; virtually caffeine-free (caffeine <1%). In the second arm, men received placebo (three identical capsules per day). The primary end point was the prevalence of CaP during the 1-year study in the two arms. Although the study was specifically designed for assessing the possible chemopreventive action of GTCs, we also recorded possible changes in total serum PSA values during the whole study, and possible variations in LUTS, as assessed by IPSS and QoL scores before GTCs administration, and after 3 months of treatment in a subset of men with coexistent BPH, not receiving any other therapy. In case of cancer diagnosis, subjects were excluded from the chemoprevention trial (failure of chemoprevention) and recommended to clinical management.
Eligibility criteria. Men ages 45 to 75 years old with HG-PIN found after the collection of 8 to 18 needle biopsies according to prostate volume. All subjects were volunteers, who were made aware of the study details, and agreed to sign an informed consent form.
Exclusion criteria. Men aged >75 years, consuming green tea or derived products, vegetarians, taking antioxidants, and following antiandrogenic therapy. Patients diagnosed with cancer were excluded from the chemoprevention trial (failure of chemoprevention) and recommended to clinical management.
Clinical trial results and follow-up studies. Medical history, physical examination, and evaluation of total PSA were carried out every 3 months following the recruitment date. Six and 12 months after the beginning of the study, each subject had prostate mapping by 8 to 14 core needle biopsy examination, the number chosen according to prostate volume. Subjects exhibiting a sudden increase of total PSA levels, alterations of other clinical variables or symptoms of prostate disease (referred during physical examination) underwent needle biopsy earlier, at the physician's discretion. During the whole study, the urologists were continuously in contact with volunteers to detect any possible adverse or side effects.
Total serum PSA determination. All total serum PSA determinations were carried out in the same central laboratory of the hospital by using a two-site immunoluminometric in vitro commercially available assay kit for quantitative determination of human prostatespecific antigen in human serum and plasma.
Statistical analysis. For PSA, data are expressed as mean values ± SD. For IPSS and QoL, data are expressed as mean values. Statistical significance was calculated by the Student's t test and P values are indicated with 95% confidence. Multivariate analyses of variables in Table 1 were done with the one-way MANOVA test.
|
| Results |
|---|
|
|
|---|
|
|
|
| Discussion |
|---|
|
|
|---|
It is worth noticing that, as a secondary observation, we found a small but statistically significant improvement in LUTS in 65% of GTCs-treated volunteers with coexistent BPH as assessed by IPSS. Improvements were also found with regard to QoL score in the same men. This suggests that GTCs administration might also be of help to relieve the symptoms of BPH, although the possible mechanisms of action of GTCs on benign prostate diseases is still unknown. Nevertheless, because this result was not accompanied by a significant reduction of prostate volume (Table 1C), it seems unlikely to be related to a possible antiandrogenic action. Unfortunately, due to the fact that our study was not specifically designed to investigate the possible effects of GTCs on BPH, no further data are available on this cohort of men. Thus, the positive effect on LUTS recorded here should just be considered a rather promising observation for future research suggesting that other potential benefits may accompany GTCs administration.
It seems rather obvious that the chemopreventive effect exerted by GTCs on CaP development must be quickly confirmed by a larger study. Considering that all volunteers enrolled in this study were Caucasians, it would be particularly important to check whether GTCs treatment is also effective in high-risk men with different genetic backgrounds. Although follow-ups will continue for up to 5 years in the cohort of subjects studied here, a larger confirmatory study extending GTCs administration for up to 5 years would allow us to understand whether CaP onset could be definitively prevented or simply delayed by the treatment, and to exclude possible negative effects caused by long-term GTCs treatment. In addition, comparison of the histologic features of the tumors diagnosed in the two arms will also permit us to verify the possible effects of GTCs on cell differentiation, clinical stage and aggressiveness of CaPs, goals that could not be achieved in the present contribution. The importance of this issue is supported by a recent report showing that Finasteride was effective in reducing the prevalence of CaP by 28.8% over a 7-year period, but apparently, cancers with Gleason grade from 7 to 10 were more common in the Finasteride arm than in the placebo arm (30). The number of cancers found at the end of the trial were too small to evaluate the effect of GTCs on cancer grade. We still believe that knowing whether or not long-term GTCs administration affects the grading and staging of CaPs is crucial information that is needed and could possibly be obtained with a second confirmatory study employing a much larger number of volunteers.
| Acknowledgments |
|---|
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
We are indebted to the 60 volunteers who participated in this study. We thank Dr. Daniel Remondini, Dipartimento di Morfofisiologia Veterinaria e Produzioni Animali, Università di Bologna, Italy, for statistical and multivariate analysis.
| Footnotes |
|---|
Received 4/ 5/05. Revised 9/20/05. Accepted 11/ 4/05.
| References |
|---|
|
|
|---|
-reductase isozymes by tea epicatechin-3-gallate and epigallocatechin-3-gallate. Biochem Biophys Res Commun 1995;214:8338.[CrossRef][Medline]
-reductases by polyphenols. Biochem Pharmacol 2002;63:116576.[CrossRef][Medline]This article has been cited by other articles:
![]() |
R. Vene, P. Larghero, G. Arena, M. B. Sporn, A. Albini, and F. Tosetti Glycogen Synthase Kinase 3{beta} Regulates Cell Death Induced by Synthetic Triterpenoids Cancer Res., September 1, 2008; 68(17): 6987 - 6996. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Auger, W. Mullen, Y. Hara, and A. Crozier Bioavailability of Polyphenon E Flavan-3-ols in Humans with an Ileostomy J. Nutr., August 1, 2008; 138(8): 1535S - 1542S. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Umeda, S. Yano, K. Yamada, and H. Tachibana Green Tea Polyphenol Epigallocatechin-3-gallate Signaling Pathway through 67-kDa Laminin Receptor J. Biol. Chem., February 8, 2008; 283(6): 3050 - 3058. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. H. Ravindranath, V. Ramasamy, S. Moon, C. Ruiz, and S. Muthugounder Differential Growth Suppression of Human Melanoma Cells by Tea (Camellia sinensis) Epicatechins (ECG, EGC and EGCG) Evid. Based Complement. Altern. Med., January 3, 2008; (2008) nem140v2. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. N. Syed, N. Khan, F. Afaq, and H. Mukhtar Chemoprevention of Prostate Cancer through Dietary Agents: Progress and Promise Cancer Epidemiol. Biomarkers Prev., November 1, 2007; 16(11): 2193 - 2203. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Wolfram Effects of Green Tea and EGCG on Cardiovascular and Metabolic Health J. Am. Coll. Nutr., August 1, 2007; 26(4): 373S - 388S. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Albini, D. M. Noonan, and N. Ferrari Molecular Pathways for Cancer Angioprevention Clin. Cancer Res., August 1, 2007; 13(15): 4320 - 4325. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Kopelovich, J. R. Fay, C. C. Sigman, and J. A. Crowell The Mammalian Target of Rapamycin Pathway as a Potential Target for Cancer Chemoprevention Cancer Epidemiol. Biomarkers Prev., July 1, 2007; 16(7): 1330 - 1340. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. P. Kumar, S. Bhaskaran, M. Ganapathy, K. Crosby, M. D. Davis, P. Kochunov, J. Schoolfield, I-T. Yeh, D. A. Troyer, and R. Ghosh Akt/cAMP-Responsive Element Binding Protein/Cyclin D1 Network: A Novel Target for Prostate Cancer Inhibition in Transgenic Adenocarcinoma of Mouse Prostate Model Mediated by Nexrutine, a Phellodendron Amurense Bark Extract Clin. Cancer Res., May 1, 2007; 13(9): 2784 - 2794. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. M. Adhami, A. Malik, N. Zaman, S. Sarfaraz, I. A. Siddiqui, D. N. Syed, F. Afaq, F. S. Pasha, M. Saleem, and H. Mukhtar Combined Inhibitory Effects of Green Tea Polyphenols and Selective Cyclooxygenase-2 Inhibitors on the Growth of Human Prostate Cancer Cells Both In vitro and In vivo Clin. Cancer Res., March 1, 2007; 13(5): 1611 - 1619. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. H. Kang, J. H. Lee, C. K. Song, H. D. Han, B. C. Shin, S. I. Pai, C.-F. Hung, C. Trimble, J.-S. Lim, T. W. Kim, et al. Epigallocatechin-3-Gallate Enhances CD8+ T Cell-Mediated Antitumor Immunity Induced by DNA Vaccination Cancer Res., January 15, 2007; 67(2): 802 - 811. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. P Singh and R. Agarwal Mechanisms of action of novel agents for prostate cancer chemoprevention. Endocr. Relat. Cancer, September 1, 2006; 13(3): 751 - 778. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. J. Kelloff, S. M. Lippman, A. J. Dannenberg, C. C. Sigman, H. L. Pearce, B. J. Reid, E. Szabo, V. C. Jordan, M. R. Spitz, G. B. Mills, et al. Progress in Chemoprevention Drug Development: The Promise of Molecular Biomarkers for Prevention of Intraepithelial Neoplasia and Cancer--A Plan to Move Forward Clin. Cancer Res., June 15, 2006; 12(12): 3661 - 3697. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Meeting Abstracts Online |