Chemoprevention using dutasteride: the REDUCE trial

Inhibition of Proliferation of Prostate Cancer Cell Line DU-145 in vitro and in vivo Using Salvia miltiorrhiza Bunge

OBJECTIVE

To investigate the antiproliferative activity of Salvia miltiorrhiza Bunge. (SM) on the castration-resistant prostate cancer (CRPC) cell line DU-145, in vitro and in vivo.

METHODS

Prostate cancer cell line (DU-145) and normal prostate cell line (RWPE-1) were treated with SM at different concentrations (3.125, 12.5, 25 and 50 μg/mL) to investigate the antiproliferative effects. DNA laddering analysis was performed to investigate the apoptosis of DU-145 cells. Molecular mechanism was investigated by Western blot analysis of p53, Bcl-2, prostate specific antigen (PSA), and androgen receptor (AR). Six-week-old male BALB/c nude mice were randomly divided into normal control group (n=101) and treated group (n=101) which administered 500 mg/kg SM for 2 weeks. Tumor volumes were measured.

RESULTS

Treatment with SM resulted in a dose-dependent decrease in cell number of DU-145 cells in comparison with RWPE-1. DNA laddering analysis indicated the apoptosis of DU-145 cells. Treatment with SM increased the expression of p53 and reduced the expression of Bcl-2 proteins. The levels of PSA were considerably reduced in SM-treated group compared to the controls, and a decrease in AR expression was observed when cells were treated with SM in the same pattern as a reduction in PSA. In the tumour xenograft study, SM given once a day for 2 weeks significantly inhibited tumour growth.

CONCLUSION

SM might contribute to the anticancer actions such as induction of apoptosis and inhibition of proliferation of prostate cancer cells.

Strategies for prostate cancer prevention: Review of the literature

The goal of primary chemoprevention is to decrease the incidence of a given cancer, simultaneously reducing treatment-related adverse events, cost of treatment of the disease and mortality. Prostate cancer is an attractive and appropriate target for primary prevention because of its high incidence and prevalence, increased disease-related mortality, long latency and molecular pathogenesis and epidemiological data indicating that modifiable environmental factors may decrease risk. Various agents have been suggested to prevent prostate cancer and many clinical trials are currently on. Ultimately the adoption of a preventive strategy hinges on its potential benefits weighed against the potential risks of the specific agents used. This article is aimed to examine the experimental and epidemiological data spanning a period of 1998 to 2007, demonstrating the chemopreventive activity, safety and toxicity of various nutritional elements and other agents that can help prevent prostate cancer and/or slow disease progression.

Bioactive tanshinones in Salvia miltiorrhiza inhibit the growth of prostate cancer cells in vitro and in mice

Searching for efficacious and safe agents for the chemoprevention and therapy of prostate cancer has become the top priority of research. The objective of this study was to determine the effects of a group of tanshinones from a Chinese herb Salvia Miltiorrhiza, cryptotanshinone (CT), tanshinone IIA (T2A) and tanshinone I (T1) on prostate cancer. The in vitro studies showed that these tanshinones inhibited the growth of human prostate cancer cell lines in a dose-dependent manner via cell cycle arrest and apoptosis induction. Among three compounds, T1 had the most potent activity with IC(50) s around 3-6 μM. On the other hand, tanshinones had much less adverse effects on the growth of normal prostate epithelial cells. The epigenetic pathway focused array assay identified Aurora A kinase as a possible target of tanshinone actions. The expression of Aurora A was overexpressed in prostate cancer cell lines. Moreover, knockdown of Aurora A in prostate cancer cells significantly decreased cell growth. Tanshinones significantly downregulated the Aurora A expression, suggesting Aurora A may be a functional target of tanshinones. Tanshinones, especially T1, also showed potent anti-angiogenesis activity in vitro and in vivo. Furthermore, T1 inhibited the growth of DU145 prostate tumor in mice associated with induction of apoptosis, decrease of proliferation, inhibition of angiogenesis and downregulation of Aurora A, whereas it did not alter food intake or body weight. Our results support that T1 may be an efficacious and safe chemopreventive or therapeutic agent against prostate cancer progression.

Awareness of prostate cancer among patients and the general public: results of an international survey

The objective of this study was to assess the level of awareness of prostate cancer (PCa) among the general public and PCa patients in Europe and North America. A survey was undertaken across four European countries (UK, Germany, Italy and Spain), and across the United States and Canada in late 2007. In total, 1008 men with PCa and their partners (the ‘prostate sample'), and 911 men without PCa and their partners (the ‘well sample') participated in the survey, all aged ⩾50 years. Interviews were conducted through telephone, pen and paper, and online. Many people surveyed (53%) thought that breast cancer is more common than PCa. Moreover, 1 in 10 people from the well sample (10%) thought that PCa affects both men and women. When the prostate sample was asked about their perceived level of risk of PCa before diagnosis, 50% believed that they/their husband or partner were previously at low or very low risk, before they were diagnosed. Awareness of the major risk factors for PCa (age and family history) was generally good, but respondents were less clear about the role of other potential factors, such as smoking and drinking alcohol. This international survey, thought to be largest of its type, shows that although patient and public awareness of PCa is generally satisfactory, there is still a considerable lack of clarity about PCa risk factors, and a danger for people to underestimate their own/their partner's perceived risk for PCa. Programmes to responsibly educate and inform men and their partners about risk factors, prevalence and screening tools for PCa are required.

Combination therapy with dutasteride and tamsulosin for the treatment of symptomatic enlarged prostate

Benign prostatic hyperplasia (BPH) is a frequent cause of lower urinary symptoms, with a prevalence of 50% by the sixth decade of life. Hyperplasia of stromal and epithelial prostatic elements that surround the urethra cause lower urinary tract symptoms (LUTS), urinary tract infection and acute urinary retention. Medical treatments of symptomatic BPH include; 1) the 5α-reductase inhibitors, 2) the α1-adrenergic antagonists, and 3) the combination of a 5α-reductase inhibitor and a α1-adrenergic antagonist. Selective α1-adrenergic antagonists relax the smooth muscle of the prostate and bladder neck without affecting the detrussor muscle of the bladder wall, thus decreasing the resistance to urine flow without compromising bladder contractility. Clinical trials have shown that α1-adrenergic antagonists decrease LUTS and increase urinary flow rates in men with symptomatic BPH, but do not reduce the long-term risk of urinary retention or need for surgical intervention. Inhibitors of 5α-reductase decrease production of dihydrotestosterone within the prostate resulting in decreased prostate volumes, increased peak urinary flow rates, improvement of symptoms, and decreased risk of acute urinary retention and need for surgical intervention. Interim results of the ongoing Combination of Avodart and Tamsulosin (CombAt) study have shown combination therapy with the 5α-reductase inhibitor dutasteride and the α1-adrenergic antagonist tamsulosin offer significant improvements from baseline compared with either drug alone.

Molecular markers in prostate cancer. Part II: potential roles in management

Predicting treatment responses in advanced prostate cancer (PCa) currently centres on prostate-specific antigen (PSA) kinetics and on being able to visualize measurable changes in imaging modalities. New molecular markers have emerged as potential diagnostic and prognostic indicators; these were summarized in Part I of this review in the Asian Journal of Andrology. A number of molecular markers are now being used to enhance PCa imaging and staging. However, management options for advanced and hormone-resistant PCa (HRPC) are limited and additional therapeutic options are needed. Molecular markers have been proposed as potential therapeutic targets using gene therapy and immunomodulation. Additionally, markers identified in early PCa and precursor lesions may offer novel targets for chemoprevention and vaccine development. This review summarizes the current advances regarding the roles of these markers in the management of PCa.

Medical treatments for male and female pattern hair loss

Male and female pattern hair loss affects a large percentage of the population, and patients frequently present for treatment of this to their dermatologist. Here we review the many treatments available for hair loss. We review the evidence for each, and outline the most effective treatment strategies for both men and women.

LEARNING OBJECTIVE

At the conclusion of this article, the reader should be able to describe the most effective treatments for hair loss, understand their mechanism(s) of action, and explain which treatments are the best in different settings.

Update on the use of dutasteride in the management of benign prostatic hypertrophy

Benign prostatic hyperplasia (BPH) is a frequent cause of lower urinary symptoms, with a prevalence of 50% by the sixth decade of life. Hyperplasia of stromal and epithelial prostatic elements that surround the urethra cause lower urinary tract symptoms (LUTS), urinary tract infection, and acute urinary retention. Medical treatments of symptomatic BPH include; 1) the 5alpha-reductase inhibitors, 2) the alpha1-adrenergic antagonists, and 3) the combination of a 5alpha-reductase inhibitor and a alpha1-adrenergic antagonist. Selective alpha1-adrenergic antagonists relax the smooth muscle of the prostate and bladder neck without affecting the detrussor muscle of the bladder wall, thus decreasing the resistance to urine flow without compromising bladder contractility. Clinical trials have shown that alpha1-adrenergic antagonists decrease LUTS and increase urinary flow rates in men with symptomatic BPH, but do not reduce the long-term risk of urinary retention or need for surgical intervention. Inhibitors of 5alpha-reductase decrease production of dihydrotestosterone within the prostate resulting in decreased prostate volumes, increased peak urinary flow rates, improvement of symptoms, and decreased risk of acute urinary retention and need for surgical intervention. The combination of a 5alpha-reductase inhibitor and a alpha1-adrenergic antagonist reduces the clinical progression of BPH over either class of drug alone.

The evolving biology and treatment of prostate cancer

Since the effectiveness of androgen deprivation for treatment of advanced prostate cancer was first demonstrated, prevention strategies and medical therapies for prostate cancer have been based on understanding the biologic underpinnings of the disease. Prostate cancer treatment is one of the best examples of a systematic therapeutic approach to target not only the cancer cells themselves, but the microenvironment in which they are proliferating. As the population ages and prostate cancer prevalence increases, challenges remain in the diagnosis of clinically relevant prostate cancer as well as the management of the metastatic and androgen-independent metastatic disease states.

Looking Back at PCPT: Looking Forward to New Paradigms in Prostate Cancer Screening and Prevention

OBJECTIVES

Provide a critical summary of the latest interpretation of findings from the Prostate Cancer Prevention Trial (PCPT).

METHODS

Findings from PCPT and recently published post-hoc analyses are reviewed.

RESULTS

PCPT demonstrated that finasteride can reduce the prevalence of prostate cancer, permitted the first large-scale assessment of the performance characteristics of prostate-specific antigen for prostate cancer screening, and identified new-onset erectile dysfunction as an early predictor of cardiovascular events.

CONCLUSIONS

PCPT has and will continue to yield valuable information regarding future strategies for prostate cancer prevention and detection, benign prostatic hyperplasia, and other matters of public health importance.

An update on chemoprevention strategies in prostate cancer for 2006

PURPOSE OF REVIEW

An increasing volume of research has been directed at the prevention of prostate cancer. This review proposes to summarize the large trials, novel approaches and molecular mechanisms of effect published in 2004 and 2005.

RECENT FINDINGS

The impact of the Prostate Cancer Prevention Trial continues and subsequent articles have addressed the increase of high-grade prostate cancers detected in the finasteride arm of the trial, as well as the potential costs and benefits of extrapolating the findings to a public health campaign. Studies of risk have been published warning of excessive vitamin E and cyclooxygenase-2 inhibitor use in chemoprevention. Growing evidence supports the concept of chemopreventative agent combinations and further data on the roles of selenium, lycopene, soy, green tea, anti-inflammatories and statins in prostate-cancer prevention are presented.

SUMMARY

Level one evidence exists for the preventative effects of finasteride in prostate cancer. The evidence for other agents is less conclusive but a number of large-scale, appropriately designed trials will hopefully address some of the relevant issues in prostate-cancer prevention over the next decade.

Progress in chemoprevention drug development: the promise of molecular biomarkers for prevention of intraepithelial neoplasia and cancer--a plan to move forward

This article reviews progress in chemopreventive drug development, especially data and concepts that are new since the 2002 AACR report on treatment and prevention of intraepithelial neoplasia. Molecular biomarker expressions involved in mechanisms of carcinogenesis and genetic progression models of intraepithelial neoplasia are discussed and analyzed for how they can inform mechanism-based, molecularly targeted drug development as well as risk stratification, cohort selection, and end-point selection for clinical trials. We outline the concept of augmenting the risk, mechanistic, and disease data from histopathologic intraepithelial neoplasia assessments with molecular biomarker data. Updates of work in 10 clinical target organ sites include new data on molecular progression, significant completed trials, new agents of interest, and promising directions for future clinical studies. This overview concludes with strategies for accelerating chemopreventive drug development, such as integrating the best science into chemopreventive strategies and regulatory policy, providing incentives for industry to accelerate preventive drugs, fostering multisector cooperation in sharing clinical samples and data, and creating public-private partnerships to foster new regulatory policies and public education.

Dutasteride affects progesterone metabolizing enzyme activity/expression in human breast cell lines resulting in suppression of cell proliferation and detachment

Recent evidence indicates that progesterone metabolites play important roles in regulating breast cancer. Previous studies have shown that breast carcinoma and tumorigenic breast cell lines have higher 5alpha-reductase and lower 3alpha-hydroxysteroid oxidoreductase (3alpha-HSO) and 20alpha-HSO activities and mRNA expression levels than normal tissue and non-tumorigenic cell lines. The 5alpha-reduced progesterone metabolites such as 5alpha-dihydroprogesterone (5alphaP) promote both mitogenic and metastatic activity in breast cell lines in culture, whereas the 4-pregnene metabolites, 4-pregnen-3alpha-ol-20-one (3alphaHP) and 4-pregnen-20alpha-ol-3-one (20alphaHP) have the opposite (anti-cancer-like) effects. The 5alpha-reductase inhibitor dutasteride has been shown to inhibit 5alpha-reduction of testosterone to 5alpha-dihydrotestosterone in prostate tissue, resulting in decreased prostate volume. The aim of this study was to determine if dutasteride is an effective inhibitor of progesterone 5alpha-reduction in human breast cell lines and if such inhibition reduces mammary cell proliferation and detachment. The effect of dutasteride on progesterone metabolizing enzyme activities and mRNA expression were examined in tumorigenic MCF-7 and non-tumorigenic MCF-10A human breast cell lines. Dutasteride (10(-6)M) inhibited progesterone conversion to 5alpha-pregnanes by >95% and increased 4-pregnene production. The results indicated that effects of dutasteride on the progesterone metabolizing enzymes are due to direct inhibition of 5alpha-reductase activity and to altered levels of expression of 5alpha-reductase and HSO mRNAs. Treatment of cells with progesterone without medium change for 72 h resulted in significant conversion to 5alpha-pregnanes and increases in cell proliferation and detachment. The increases in proliferation and detachment were blocked by dutasteride and were reinstated by concomitant treatment with 5alphaP, providing proof-of-principle that the effects were due not to progesterone but to the 5alpha-reduced metabolites. This study provides the first evidence that dutasteride is a potent progesterone 5alpha-reductase inhibitor and that such inhibition may be beneficial in breast cancer.

Update on Prostate Cancer Chemoprevention

BACKGROUND

Prostate cancer is the most common type of cancer and the second leading cause of cancer-related deaths in American men. Its high rate of occurrence and long lead time to clinically significant disease make prostate cancer an ideal disease for pharmacologic or nutritional chemoprevention.

METHODS

To identify the various chemoprevention strategies for prostate cancer, a MEDLINE search (from 1967-2005) and bibliographic search of the English-language literature were conducted.

RESULTS

Epidemiologic and retrospective studies have assessed the effect of carotenoids (e.g., lycopene), vitamins, selenium, and nonsteroidal antiinflammatory drugs (NSAIDs) on the rate of occurrence of prostate cancer. The few published prospective trials evaluated prostate cancer as a secondary end point. Lycopene (as beta-carotene) and selenium supplementation have been associated with a reduced risk of prostate cancer in nested case-control studies, but only in subgroups of men with low baseline plasma lycopene (or beta-carotene) and selenium levels respectively. The Prostate Cancer Prevention Trial prospectively evaluated finasteride, a 5-alpha-reductase inhibitor, as chemoprevention. The results showed a 25% relative risk reduction in prostate cancer, albeit at an increased risk of invasive tumors.

CONCLUSION

Data regarding lycopene, vitamin E, and selenium as chemoprevention for prostate cancer appear promising. Prospective trials such as the Selenium and Vitamin E Cancer Prevention Trial (SELECT) will clarify the role of these agents in prostate cancer prevention. The role of NSAIDs is unclear, and the long-term toxicity associated with NSAIDs may limit their usefulness. Although finasteride has decreased overall prostate cancer occurrence, the risk of invasive tumors may outweigh the benefit of this agent. The continuing Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial may help define a role for the 5-alpha-reductase inhibitors in cancer chemoprevention. At this time, nothing has been proven effective as chemoprevention against clinically significant prostate cancer.

Medikamentöse BPS-Therapie

5alpha-Reductase inhibitors and alpha(1)-receptor blockers are established options for symptomatic treatment of benign prostatic hyperplasia (BPH). Achieving maximum efficacy is contingent on correct dosage and requires careful patient selection in view of the substance class employed. All applicable preparations exert only a low-grade effect on prostatic obstruction. This condition should be excluded by appropriate urological examination before treatment is initiated. If the patient's distress is minor, refraining from drug therapy can be considered. Symptomatic patients with small prostate volume are suited for monotherapy with alpha(1)-receptor blockers and symptomatic patients with large prostate volume profit from combination therapy. When 5alpha-reductase inhibitors are used, BPH patients should be made aware of the findings from the Prostate Cancer Prevention Trial.