Prospective trial of the herbal supplement PC-SPES in patients with progressive prostate cancer

A hidden cause of hypokalemic paralysis in a patient with prostate cancer

Hypokalemic paralysis is a medical emergency due to the risks of cardiac arrhythmia, respiratory failure, and rhabdomyolysis. Besides supplementing patients with KCl to hasten recovery, the astute physician must search for the underlying cause to avoid missing a treatable and curable disorder. We report on an elderly Korean man who presented with marked limb paralysis, myalgias, and mild hypertension. He had prostate cancer treated with orchiectomy and hormone therapy 2 years previously. The major biochemical abnormalities were hypokalemia (K+: 1.7 mmol/l) associated with high renal K+ wasting and metabolic alkalosis (HCO3-: 42.6 mmol/l). Low plasma renin activity, low aldosterone concentration, and normal cortisol concentration pointed to a state of pseudohyperaldosteronism. While reviewing his drug history, the patient revealed he had been consuming eight packs (100 ml/pack) of a Korean herbal tonic daily to treat his prostate cancer for the past 2 months. A significant amount of glycyrrhizic acid (0.23 mg/ml), an active ingredient of licorice, was detected in the tonic. Discontinuation of the herbal tonic along with KCl supplementation achieved recovery in 2 weeks. As many complementary/alternative medicines for cancer contain licorice, this must be kept in mind as a cause of hypokalemia in cancer patients.

Licochalcone-A, a novel flavonoid isolated from licorice root (Glycyrrhiza glabra), causes G2 and late-G1 arrests in androgen-independent PC-3 prostate cancer cells

Licochalcone (LA) is a novel estrogenic flavonoid isolated from PC-SPES composition herb licorice root that was reported to show significant antitumor activity in various malignant human cell lines. To better understand its anti-CaP activities, we have investigated LA-elicited growth control and induction of apoptosis using androgen-independent p53-null PC-3 prostate cancer cells. LA induced modest level of apoptosis but had more pronounced effect on cell cycle progression arresting cells in G2/M, accompanied by suppression of cyclin B1 and cdc2. It also inhibited phosphorylation of Rb, specifically phosphorylation of S780 with no change of phosphorylation status of T821, decreased expression of transcription factor E2F concurrent with reduction of cyclin D1, down-regulation of CDKs 4 and 6, but increased cyclin E expression. These findings provide mechanistic explanation for LA activity and suggest that it may be considered as a chemopreventive agent and its anticancer properties should be further explored.

Is there a role for chemotherapy in prostate cancer?

There is evidence from randomised-controlled trials that patients with symptomatic hormone-refractory prostate cancer may experience palliative benefit from chemotherapy with mitoxantrone and prednisone. This treatment is well tolerated, even by elderly patients, although the cumulative dose of mitoxantrone is limited by cardiotoxicity. Treatment with docetaxel or paclitaxel, with or without estramustine, appears to convey higher rates of prostate-specific antigen response in phase II trials, but is more toxic. Large phase III trials comparing docetaxel with mitoxantrone have completed accrual. There is no role for chemotherapy in earlier stages of disease except in the context of a well-designed clinical trial.

PC-SPES: a herbal therapy for the treatment of hormone refractory prostate cancer

In this review the authors consider the commercially available herbal product PC-SPES. This is a combination of eight different herbs marketed for its effects of reducing prostate specific antigen (PSA) levels, improving pain, and enhancing the quality of life of those with hormone refractory prostate cancer. The evidence for these claims does not appear to be as conclusive as reported by the manufactures of this product. There also appears to be a significant risk of deep vein thrombosis (DVT) in those treated with PC-SPES. There have been 116 clinical and laboratory based studies of PC-SPES published to date, but there have been no randomised controlled trials conducted. Many of these studies contain very few patients, thus making the drawing of conclusions difficult. Despite this lack of information, there still remains a large patient group taking this supplement, therefore caution should be advised in the usage of PC-SPES in the treatment of hormone refractory prostate cancer.

Prospective, multicenter, randomized phase II trial of the herbal supplement, PC-SPES, and diethylstilbestrol in patients with androgen-independent prostate cancer

PURPOSE

To evaluate the herbal combination, PC-SPES, and diethylstilbestrol (DES) in patients with androgen independent prostate cancer (AIPC).

PATIENTS AND METHODS

A randomized phase II study was conducted with cross-over design. Patients were randomly assigned to receive either three PC-SPES capsules orally three times a day or DES 3 mg orally once a day. Prophylactic warfarin was administered. At clinical or prostate-specific antigen progression, patients received the other therapy. The study closed prematurely after PC-SPES was withdrawn from the market. Chemical analyses were performed on multiple lots of PC-SPES.

RESULTS

Ninety patients were enrolled, of whom 85 were assessable for response. Prostate-specific antigen declines > or = 50% were noted in 40% (95% CI, 25% to 56%) with PC-SPES, and 24% (95% CI, 12% to 39%) with DES. Median response duration was not reached with PC-SPES, and was 3.8 months with DES. Median time to progression for randomly assigned patients was 5.5 months for PC-SPES and 2.9 months for DES. Common toxicities included mild fatigue, gynecomastia, and mastodynia. Five thromboembolic events occurred (one PC-SPES, four DES). Responses in the cross-over phase were inconclusive. Four lots of PC-SPES had measurable quantities of DES, ranging from 0.01% to 3.1% of the dose used in the DES arm. Ethinyl estradiol was also detected in PC-SPES lots.

CONCLUSION

PC-SPES and DES demonstrate activity in AIPC and are well tolerated. However, the synthetic estrogens, DES and ethinyl estradiol, were detected in various lots of PC-SPES, including those used in this trial. Clinical trials that utilize herbal therapies must account for issues of purity and consistency.

Complementary and alternative therapies for cancer

Many cancer patients use therapies promoted as literal alternatives to conventional medical care. Such "alternative" modalities are unproven or were studied and found worthless. These can be harmful. An even greater proportion of cancer patients uses "complementary" therapies along with mainstream cancer treatment. Most are helpful adjunctive approaches that control symptoms and enhance quality of life. This review describes alternative as well as complementary therapies commonly used today by cancer patients. Herbal remedies also are discussed. Evidence regarding the efficacy and safety of complementary/alternative medicine (CAM) is reviewed, and implications for oncologists are discussed. To encourage open communication of CAM use by patients, oncologists should be knowledgeable about the most popular remedies and know where to find reliable information for themselves and for their patients.

Phase I and clinical pharmacology of a type I and II, 5-alpha-reductase inhibitor (LY320236) in prostate cancer: elevation of estradiol as possible mechanism of action

OBJECTIVES

To study the safety, pharmacokinetics, biologic activity, and preliminary efficacy of the bispecific 5-alpha-reductase inhibitor (LY320236) in prostate cancer.

METHODS

Fifty-one patients with recurrent or metastatic prostate cancer were sequentially (nonrandomly) assigned in cohorts to receive one of five single daily oral doses of LY320236 (10, 50, 150, 250, and 500 mg). Serial evaluations included serum testosterone, dihydrotestosterone, androstenediol glucuronide, estradiol, and pharmacokinetics on days 1, 29, and 57. Toxicity assessments, x-rays/scans, and blood tests, including serum prostate-specific antigen (PSA) determination, were done at regular intervals.

RESULTS

Overall, treatment was well tolerated, with 3 of 51 patients developing reversible grade 3-4 toxicity (one diarrhea, two elevated liver enzymes). Peak blood levels (2 to 3 hours after drug administration) were greater for doses of 150 mg or greater compared with less than 150-mg doses with slow accumulation. Serum levels of testosterone, dihydrotestosterone, and androstenediol glucuronide did not change significantly during treatment; however, a statistically significant increase occurred in serum estradiol levels in both the castration and noncastration groups. One of 26 in the noncastration group and 4 (27%) of 15 in the castration group with baseline PSA levels of 5 ng/mL or greater had a 50% or greater PSA decline for 4 weeks or longer.

CONCLUSIONS

LY320236 treatment is associated with modest reversible toxicity. An elevation of estradiol levels was seen in both castration and noncastration groups, although PSA declines were primarily seen in the castration group. The absence of cardiovascular toxicity suggests that this agent may be a promising alternative to exogenous estrogens in patients with prostate cancer who demonstrate evidence of disease progression after initial androgen deprivation treatment.

The evolving role of estrogen therapy in prostate cancer

Estrogens, including diethylstilbestrol (DES), were used as the primary medical treatment for metastatic prostate cancer for many years but have been superceded in the past two decades by luteinizing hormone-releasing hormone (LHRH) agonists, primarily because of the cardiovascular toxicity associated with oral estrogen therapy. Recently, a renewed interest in estrogen therapy for prostate cancer in the United States has developed as a result of 3 major issues. First, when measured by declines in prostate-specific antigen of > or = 50%, clinical trials have demonstrated activity of DES, DES-diphosphate, and the estrogenic herbal therapy PC-SPES in 21%-86% of patients treated in phase II trials of androgen-independent prostate cancer patients. Second, the recent description of estrogen receptor (ER)-b has led to a reevaluation of the role of estrogens in normal prostate development and cancer pathogenesis. In contrast to ER-a, ER-b is strongly expressed in normal prostate epithelium. Furthermore, loss of ER-b expression has been demonstrated in prostate cancers, suggesting a possible role for this pathway in the development of cancer. Finally, the issues of cost and safety of estrogens are being reassessed in the current environment of rising health care costs and improved cardiovascular care. In Europe, estrogen therapy is more accepted as a low-cost and effective alternative to LHRH agonists and antiandrogens. Toxicity of DES and other estrogens has also been attenuated by strategies that use lower doses and parenteral routes of administration, thereby avoiding hepatic first-pass metabolism and decreasing the risk of thromboembolism. Nonetheless, there remain many unanswered questions about the role of estrogen therapy in prostate cancer, including differences between specific drugs, optimal dose, timing, and patient selection. Further research is needed.

Rasagenthi lehyam (RL) a novel complementary and alternative medicine for prostate cancer

PURPOSE

The use of complementary and alternative medicine (CAM) in cancer has been increasing. The therapeutic modalities which originated from India, viz., Ayurveda and Siddha, have phytotherapy as their fundamental basis and, therefore, produce few side effects. They are among the most ancient medicinal systems and are still being practiced in India and elsewhere, to cure cancer and other diseases. Many Siddha practitioners in the southern parts of India prescribe rasagenthi lehyam (RL) as a drug for cancer. RL contains 38 different botanicals, many of which have been shown to possess therapeutic efficacy, and 8 inorganic compounds, all prepared into a paste in a palm sugar and hen's egg base. The efficacy of RL in killing prostate cancer cells in vitro was investigated in this study to determine whether RL could be recommended as a CAM for prostate cancer.

METHODS

In order to scientifically validate the anticancer activity of RL on prostate cancer, a methanolic extract of RL was serially extracted with four organic solvents, and the extracts were tested for clonogenic inhibition and induction of apoptosis in PC-3 prostate cancer cells, with and without irradiation. n-Hexane, ethyl acetate and chloroform extracts of RL effectively killed PC-3 cells.

RESULTS

The IC(50) values of n-hexane, ethyl acetate and chloroform extracts of RL were 3.84 microg/ml, 3.68 microg/ml and 75 ng/ml, respectively. All three extracts induced apoptosis in PC-3 cells. Further, all the three extracts when combined with radiation, caused enhanced effect on killing of PC-3 cells. Among the three extracts, the chloroform extract showed the most significant radiation-sensitizing effect.

CONCLUSION

RL, either in its original formulation prepared under strict quality control or its chloroform extract, could potentially be an alternative medicine for prostate cancer, and also a sensitizing agent in the context of radiation therapy for prostate cancer, as a complementary medicine. A more directed study could lead to the identification of the active principle(s) in the chloroform extract of RL for use in prostate cancer therapy.

Estrogens and anti-estrogens: Key mediators of prostate carcinogenesis and new therapeutic candidates

Despite the historical use of estrogens in the treatment of prostate cancer (PCa) little is known about their direct biological effects on the prostate, their role in carcinogenesis, and what mechanisms mediate their therapeutic effects on PCa. It is now known that estrogens alone, or in synergism with an androgen, are potent inducers of aberrant growth and neoplastic transformation in the prostate. The mechanisms of estrogen carcinogenicity could be mediated via induction of unscheduled cell proliferation or through metabolic activation of estrogens to genotoxic metabolites. Age-related changes and race-/ethnic-based differences in circulating or locally formed estrogens may explain differential PCa risk among different populations. Loss of expression of estrogen receptor (ER)-beta expression during prostate carcinogenesis and prevention of estrogen-mediated oxidative damage could be exploited in future PCa prevention strategies. Re-expression of ER-beta in metastatic PCa cells raises the possibility of using ER-beta-specific ligands in triggering cell death in these malignant cells. A variety of new estrogenic/anti-estrogenic/selective estrogen receptor modulator (SERM)-like compounds, including 2-methoxyestradiol, genistein, resveratrol, licochalcone, Raloxifene, ICI 182,780, and estramustine are being evaluated for their potential in the next generation of PCa therapies. Increasing numbers of patients self-medicate with herbal formulations such as PC-SPES. Some of these compounds are selective ER-beta ligands, while most of them have minimal interaction with ER-alpha. Although many may inhibit testosterone production by blockade of the hypothalamal-pituitary-testis axis, the most effective agents also exhibit direct cytostatic, cytotoxic, or apoptotic action on PCa cells. Some of them are potent in interfering with tubulin polymerization, blocking angiogenesis and cell motility, suppressing DNA synthesis, and inhibiting specific kinase activities. Further discovery of other compounds with potent apoptotic activities but minimal estrogen action should promote development of a new generation of effective PCa preventive or treatment regimens with few or no side-effects due to estrogenicity. Further advancement of our knowledge of the role of estrogens in prostate carcinogenesis through metabolic activation of estrogens and/or ER-mediated pathways will certainly result in better preventive or therapeutic modalities for PCa.

Approaching Complementary and Alternative Medicine Use in Patients With Cancer

Complementary and alternative medicine (CAM) is becoming a significant factor in the arena of cancer care. There is an increasing body of research along with widespread popularity and use by patients with cancer. This article reviews current knowledge about the worldwide use of CAM in the treatment of cancer and patients' motives and reasoning for this use. Clinical research in CAM cancer treatments and physicians' attitudes toward this popular trend among patients with cancer are discussed as well. The physician-patient communication and its relevance to CAM use is emphasized. A step approach is suggested for primary care physicians including the discussion of CAM in the management of cancer in order to enrich the physician-patient dialogue and improve the quality of the clinical encounter.

PC-SPES: A Potent Inhibitor of Nuclear Factor-κB Rescues Mice from Lipopolysaccharide-Induced Septic Shock

Septic shock is the most common cause of death in intensive care units, and no effective treatment is available at present. Lipopolysaccharide (LPS) is the primary mediator of Gram-negative sepsis by inducing the production of macrophage-derived proinflammatory cytokines, in which activation of nuclear factor-kappaB (NF-kappaB) plays an important role. PC-SPES is an eight-herb mixture active against a variety of malignancies, including prostate cancer and leukemia. In this study, we demonstrated that PC-SPES inhibited the LPS-induced NF-kappaB reporter activity in RAW264.7 macrophages. Electrophoretic mobility shift assay showed that PC-SPES inhibited the binding of NF-kappaB to specific DNA sequences; however, it did not affect either degradation of inhibitory kappaBalpha or nuclear translocation of NF-kappaB. Also, we explored the effect of PCSPES on LPS-induced mitogen-activated protein (MAP) kinase signaling; PC-SPES did not affect LPS-induced phosphorylation of MAP kinases, including c-Jun NH2-terminal kinase, p38, and extracellular signal-regulated kinase 1/2. Moreover, PC-SPES decreased the production of proinflammatory cytokines and inducible enzymes, such as tumor necrosis factor (TNF) alpha, interleukin (IL)-1beta, IL-6, cyclooxygenase-2, as well as inducible nitric-oxide synthase in RAW264.7 macrophages and peritoneal macrophages from C57BL/6 mice after the cells were stimulated by either LPS or LPS and interferon-gamma. Furthermore, PC-SPES rescued C57BL/6 mice from death caused by LPS-induced septic shock in conjunction with decreased serum levels of TNFalpha and IL-1beta. Together, PC-SPES is a potent inhibitor of NF-kappaB and might be useful for the treatment of sepsis and inflammatory diseases.

Phytomedicines for the prostate

Phytomedicines are becoming more popular all over the world. Prostate cancer patients and those with benign prostatic hyperplasia are increasingly exploring the use of complementary alternative medicine especially due to the risk of mortality and long-term morbidity associated with surgical procedures. The incidences of prostate diseases are continually rising and the effect of phytomedicines already tested do provide relief, are well comparable with that of traditional forms of treatment. This paper reviews the phytomedicines used in Africa, Western countries and China as a treatment of benign prostatic hyperplasia, prostatitis and prostate cancer. Herbals which hold potential promise are mentioned, although much research is still required.

Induction of apoptosis by takrisodokyeum through generation of hydrogen peroxide and activation of caspase-3 in HL-60 cells

Takrisodokyeum (TRSDY), a Chinese herbal medicine, has been known to exert anti-tumoral activity in Korea. However, its molecular mechanism of action is not understood. In this study, we found that TRSDY induced apoptosis in HL-60 cells as evidenced by both a characteristic ladder pattern of discontinuous DNA fragments and an increase of annexin V+/PI- stained cell population. Our data demonstrated that TRSDY-induced apoptotic cell death was accompanied by activation of caspase-3 and cleavages of its substrates, poly(ADP-ribose) polymerase (PARP) and RhoGDP dissociation inhibitor (RhoGDI-2; also called D4-GDI) in a time- and concentration-dependent manner. Caspase-3 inhibitor, but not caspase-1 inhibitor, prevented TRSDY-induced apoptosis. Furthermore, treatment with TRSDY increased the production of intracellular hydrogen peroxide and pretreatment of cells with anti-oxidants conferred complete protection against hydrogen peroxide generation and subsequent caspase-3 activation. Taken together, these results suggest that TRSDY induces hydrogen peroxide generation, which, in turn, causes activation of caspase-3, degradation of PARP and D4-GDI, and eventually leads to apoptotic cell death.

Metastatic prostate cancer: complications and treatment

Despite highly successful treatments for localized prostate cancer, approximately 35% to 40% of men will eventually experience a detectable rise in serum prostate specific antigen. A portion of these men will go on to experience clinically expressed extracapsular disease, with as many as two-thirds having evidence of bone involvement. Diagnosis of skeletal involvement involves serum markers of disease progression and radiological evaluation. Skeletal-related events are numerous and include bone pain, spinal cord compression, vertebral collapse, and pathological fractures. Current treatments for advanced prostate cancer include individual or combined hormonal therapies, chemotherapy, radiotherapy, surgical treatments, and most recently, antiresorptive medications.

Effects of ganopoly (a Ganoderma lucidum polysaccharide extract) on the immune functions in advanced-stage cancer patients

Preclinical studies have established that the Ganoderma lucidum polysaccharide (GLPS) fractions have potent anti-tumor activity, which has been associated with the immuno-stimulating effects of GLPS. However, it is unclear whether GLPS has immuno-modulating effects in humans in vivo. This study aimed to investigate the effects of Ganopoly, the polysaccharides fractions extracted from G. lucidum, on the immune function of advanced-stage cancer patients. Thirty-four advance-stage cancer patients were entered onto this study, and treated with 1800 mg Ganopoly, three times daily orally before meals for 12 weeks. Immune parameters (cytokines, T cell subsets, mitotic response to phytohemagglutinin (PHA) and natural killer activity) were compared between baseline and after 12-week treatment. Thirty patients are assessable for their immune functions. Treatment of Ganopoly for 12 weeks resulted in a significant (P < 0.05) increase in the mean plasma concentrations of interleukin (IL-2), IL-6, and interferon (IFN)-gamma, whereas the levels of IL-1 and tumor necrosis factor (TNF-alpha) were significantly (P < 0.05) decreased. A marked variability among patients with advanced-stage cancer was observed in the numbers of each lymphocyte subset at baseline. The mean absolute number of CD56+ cells was significantly (P < 0.05) increased after 12-week treatment of Ganopoly, whereas the numbers of CD3+, CD4+, and CD8+ were just marginally increased compared to baseline levels, with the CD4:CD8 T cell ratios unchanged. PHA responses after 12-week treatment with Ganopoly were enhanced in most patients, when compared to pretreatment baselines (P < 0.05). In addition, Ganopoly treatment resulted in a significant increase (P < 0.05) in the mean NK activity compared to baselines (34.5 +/- 11.8% vs 26.6 +/- 8.3%). The present study indicates that Ganopoly enhanced the immune responses in patients with advanced-stage cancer. Clinical evaluations of response and toxicity are ongoing.

Biologic Activity of Spores and Dried Powder from Ganoderma lucidum for the Inhibition of Highly Invasive Human Breast and Prostate Cancer Cells

OBJECTIVE

Ganoderma lucidum has been used in East Asia as a home remedy to prevent or cure cancer. Furthermore, Ganoderma lucidum is one of the herbs in the herbal mixture PC-SPES that has become an alternative herbal therapy for prostate cancer. Because the dried powder of ganoderma is commercially available as a dietary supplement itself, the purpose of this study was to evaluate the biologic activity of samples of Ganoderma lucidum from different sources.

METHODS

Samples of Ganoderma lucidum were characterized morphologically and evaluated for their ability to inhibit cell migration of highly invasive breast cancer MDA-MB-231 cells and prostate cancer PC-3 cells. Because the inhibition of cell motility is directly linked to the inhibition of the signaling pathway for constitutively active NF-kappaB in breast and prostate cancer cells, we determined how different samples of Ganoderma lucidum inhibit constitutively active NF-kappaB in a reporter gene assay.

RESULTS

Some of the samples of Ganoderma lucidum demonstrated strong inhibition of cancer cell migration comparable to the inhibition of constitutively active NF-kappaB, whereas other samples showed less or no activity in highly invasive estrogen receptor-negative breast cancer cells or androgen receptor-negative prostate cancer cells, respectively. Interestingly, we did not find any correlation between the purity and composition (spores versus powder) of Ganoderma lucidum and biologic activity.

CONCLUSIONS

Ganoderma lucidum has demonstrated strong activity against breast and prostate cancer cells. Nevertheless, the composition of samples did not correlate with their ability to inhibit cell migration and activation of NF-kappaB in vitro.

In vivo effect of PC-SPES on prostate growth and hepatic CYP3A expression in rats

PC-SPES, a proprietary mixture composed of eight different herbs, is used worldwide as an alternative treatment by prostate cancer patients. It has been suggested that the clinical and in vitro antitumor activity exhibited by PC-SPES may be due to estrogenic activity, which in turn may be mediated by the presence of undeclared prescription drug contaminants. Here, we evaluated the in vivo effects of two different commercial lots of PC-SPES in male and female rats. Our high-pressure liquid chromatography analysis coupled with gas chromatography/mass spectrometry analysis by an independent laboratory suggested that PC-SPES lot 5430125 was contaminated with diethylstilbestrol (DES), whereas lot 5431249 was not. Treatment of male rats with PC-SPES lot 5430125 or DES alone reduced the weight of androgen target organs and decreased circulating levels of sex steroids and luteinizing hormone, whereas lot 5431249 was without effect. In addition, lot 5430125 and DES, but not lot 5431249 increased uterine weight in female rats. These results suggest that the inhibitory effects on androgen targets are mediated through suppression of the hypothalamic-pituitary axis and this suppression is probably due to DES contamination. We assessed the effects of both lots of PC-SPES and DES on hepatic cytochrome P450 expression and activity. Both lots of PC-SPES and DES reduced CYP3A activity and protein levels. Because the response of CYP3A to PC-SPES was not dependent on whether it contained DES, a phytochemical component of PC-SPES is most likely responsible for this effect. Inhibition of CYP3A has important implications for potential herbal-drug interactions.

PC-SPES for treatment of prostate cancer: herbal medicine

The number of patients who seek treatment with complementary and alternative medicine has increased during the past decade. The trend is primarily driven by consumers who start to change their views toward conventional pharmaceutical approaches that are offered to them. Among all complementary and alternative therapies used in the management of prostate cancer, Prostate Cancer-SPES (PC-SPES) has attracted much national attention because of its potency, controversy, and recall by the US Food and Drug Administration. PC-SPES contains extracts from a mixture of eight common herbs that have been used for thousands of years. This article is devoted to reviewing the basic and clinical data of using PC-SPES in prostate cancer therapy. It also explores the difference in philosophies between Western medicine and herbal medicine and explains the inherent difficulties in evaluating herbal medicine. The article concludes that PC-SPES cannot be evaluated by the same standards established to test synthetic pharmaceutical compounds. Thus, new standards need to be developed for the evaluation of herbal medicine.

Critical review of complementary therapies for prostate cancer

Despite its prominence as the most frequently diagnosed solid tumor among men in the United States, relatively little is known about the etiology of prostate cancer. Furthermore, research into treatment strategies for prostate cancer continues to lag behind research for the other most common cancers. At the same time, however, the popularity of complementary therapies among prostate cancer patients continues to grow. In this article, we provide a critical review of the most recent evidence for dietary modifications, food supplements, and herbs in prostate cancer prevention and treatment. Despite encouraging data for some of these interventions, even the strongest proponents of complementary therapy agree that only randomized controlled trials can provide sufficient evidence on which to create universal guidelines. However, such trials are highly complex and expensive, and they require lengthy follow-up. Until such trials are completed, an opportunity exists for health care professionals to improve their knowledge and understanding of the current evidence for or against complementary therapy in prostate cancer.

Current strategies in the management of hormone refractory prostate cancer

Prostate cancer is the most common cancer diagnosed in American males, and is the second leading cause of cancer-related deaths. Most patients who develop metastatic disease will initially respond to androgen deprivation, but response is invariably temporary. Most patients will develop androgen-independent ("hormone-refractory") disease that results in progressive clinical deterioration and ultimately death. This progression to androgen independence is accompanied by increasingly evident DNA instability and alterations in genes and gene expression, including mutations in p53, over-expression of Bcl2, and mutations in the androgen receptor gene, among others. Treatment options for hormone refractory disease include intensive supportive care, radiotherapy, bisphosphonates, second-line hormonal manipulations, cytotoxic chemotherapy and investigational agents. A post-treatment reduction in the level of prostate specific antigen (PSA) by 50% has been shown to correlate with survival and has been accepted by consensus as a valid endpoint in clinical trials. Chemotherapeutic agents such as mitoxantrone, estramustine, and the taxanes have yielded improved response rates and palliative benefit, but not improved survival. Therefore, current efforts must be focused on enrolling patients onto clinical trials of investigational agents with novel mechanisms of action, and on using survival, time to progression, and quality of life as end points in routine clinical practice.

Isoliquiritigenin inhibits the growth of prostate cancer

OBJECTIVE

Isoliquiritigenin, one of the components in the root of Glycyrrhiza glabra L., is a member of the flavonoids, which are known to have an anti-tumor activity in vitro and in vivo. In this study, we investigated the anti-tumor effect of isoliquiritigenin on prostate cancer in vitro.

METHODS

DU145 and LNCaP prostate cancer cell lines were used as targets. We examined the effects of isoliquiritigenin on cell proliferation, cell cycle regulation and cell cycle-regulating gene expression. Further, we investigated the effects of isoliquiritigenin on the GADD153 mRNA and protein expression, and promoter activity.

RESULTS

Isoliquiritigenin significantly inhibited the proliferation of prostate cancer cell lines in a dose-dependent and time-dependent manner. Fluorescence-activated cell sorting (FACS) analysis indicated that isoliquiritigenin induced S and G2/M phase arrest. Isoliquiritigenin enhanced the expression of GADD153 mRNA and protein associated with cell cycle arrest. Further, isoliquiritigenin stimulated transcriptional activity of GADD153 promoter dose-dependently.

CONCLUSION

These findings suggest that isoliquiritigenin is a candidate agent for the treatment of prostate cancer and GADD153 may play an important role in isoliquiritigenin-induced cell cycle arrest and cell growth inhibition.

Complementary and alternative therapies

Patients with prostate cancer increasingly use complementary and alternative therapies. A well-informed oncologist can guide patients to use such treatments to maximize their benefits and reduce the risk of harm. Patients should be dissuaded from using alternative therapies instead of mainstream care to treat cancer. Preliminary evidence suggests that botanical medicines such as PC-SPES may be of benefit, but comparative human trials are yet to be conducted and problems of contamination resolved. Some complementary therapies help reduce symptoms in early-stage prostate cancer, but botanical remedies must be treated with caution because of the possibility of adverse effects and interactions with conventional medicine.

Chemoprevention of prostate cancer

Dietary factors and other naturally occurring substances may emerge as potent therapeutic or preventative agents in the battle against prostate cancer. Much of the current support for these agents is epidemiologically based, but new prospective studies are now underway which may support their use in conventional medical practice.

Gene profiling and promoter reporter assays: novel tools for comparing the biological effects of botanical extracts on human prostate cancer cells and understanding their mechanisms of action

The use of botanical mixtures is commonplace in patients with prostate cancer, yet the majority of these products have not been rigorously tested in clinical trials. Here we use PC-SPES, a combination of eight herbs that has been shown to be effective in clinical trials in patients with prostate cancer, as a model system to demonstrate 'proof of principle' as to how gene expression profiling coupled with promoter assays can evaluate the effect of herbal cocktails on human prostate cancer. In addition, we demonstrate how such approaches may be used for standardization of herbal extract activity by comparing the gene profile of PC-SPES with that of PC-CARE, a product with a similar herbal composition. Since prior studies have shown that PC-SPES contains estrogenic organic compounds, and such compounds are known to affect prostate cancer, an important issue is whether these are the primary drivers of the gene profile. Our data suggest that gene expression profiles of LNCaP human prostate cancer cells in response to PC-SPES are different from those found when diethylstilbestrol (DES), a synthetic estrogen, is used, suggesting that the estrogenic moieties within PC-SPES do not drive this expression signature. In contrast, the expression profile of PC-CARE was almost identical to that of DES, highlighting that mixtures containing similar herbal compositions do not necessarily result in similar biological activities. Interestingly, these three agents cause similar in vitro morphological changes and growth effects on LNCaP. To validate the expression profiling data, we evaluated the protein expression and promoter activity of prostate-specific antigen (PSA), a gene induced by PC-SPES but repressed by DES. In order to gain a mechanistic understanding of how PC-SPES and DES affect PSA expression differently, LNCaP cells were transiently transfected with wild-type and mutagenized PSA promoter, ARE concatemers and appropriate controls. We provide evidence that androgen response elements (ARE) II and III within the promoter region are responsible for the suppressive effects of DES and stimulatory effects of PC-SPES. In addition, we show that the effects on PSA transcription are ARE specific in the case of DES while PC-SPES affects this promoter nonspecifically. In conclusion, expression profiling coupled with mechanistic target validation yield valuable clues as to the mode of action of complex botanical mixtures and provides a new way to compare objectively mixtures with similar components either for effect or quality assurance prior to their use in clinical trials.

Pancreatic cancer in vitro toxicity mediated by Chinese herbs SPES and PC-SPES: implications for monotherapy and combination treatment

One of the greatest challenges in the treatment of pancreatic cancer remains its inherent lack of beneficial response to cytotoxic chemotherapy. Chinese herbal extracts have been widely used for the treatment of various cancers, but objective information on their efficacy in pancreatic cancer is lacking. Eight human pancreatic cancer cell lines (MIA, Panc-1, BxPC, ASPC, HS-766T, CaPan-2, CFPAC, and HTB-147) were studied for in vitro susceptibility to ethanol extracts of SPES and PC-SPES, two quality-controlled, dried, encapsulated supplements of 15 and eight Chinese herbs, respectively. Resulting toxicities, alone and in combination with doxorubicin or gemcitabine, were analyzed by [(3)H]thymidine incorporation or sulforhodamine B staining, colony formation, and TUNEL flow cytometry assays. Combination toxicity mechanisms were calculated by the combination index method of Chou and Talalay. In all cell lines, there was dose-dependent inhibition of proliferation. By [(3)H]thymidine incorporation assay, 50% growth inhibition after 48 h continuous exposure (IC(50)) occurred at concentrations of 0.2-0.8 microl/ml SPES and 0.4-1.3 microl/ml PC-SPES. Growth inhibition was accompanied by a significant enhancement of the TUNEL-positive apoptotic fraction of all cell lines after treatment with either extract. After treatment with PC-SPES, the cell lines consistently displayed a G2 cell cycle block; SPES induced an increase in S phase, with a smaller impact on G2. When added at a concentration of 0.2 microl/ml (approximately IC(20)), both extracts enhanced Panc-1 cell killing mediated by doxorubicin, with an average decrease in the corresponding IC(50) of 33% (range 11-62%). Combination effects with either extract appeared to be antagonistic in the case of gemcitabine and additive to mildly synergistic in the case of doxorubicin. Both SPES and PC-SPES exhibited significant toxicity in pancreatic cancer cells, mediated via induction of apoptosis. Both mixtures should be evaluated for their in vivo and clinical therapeutic utility as monotherapy agents against pancreatic cancer. SPES could possibly be combined with cell cycle-independent cytotoxic drugs. Due to a consistent G2 blocking pattern, PC-SPES may prove useful as a radiation sensitizer.

Attitudes and use of alternative therapies in UK prostate cancer patients-isn't it time we were in the know?

With increasing media interest in prostate cancer and the availability of data to patients from support groups and the Internet, the knowledge and use of alternative therapies by patients is becoming more common. The purpose of our study was to quantify patient awareness and use of alternative therapies for the prevention and treatment of prostate cancer in the UK. In May 2000, we performed a survey of men attending our urology outpatient clinic for prostate cancer evaluation or follow-up. All men diagnosed with and those at high risk (abnormal prostate specific antigen) for prostate cancer were eligible for the study. Each eligible patient was then sent an anonymous 25-item questionnaire to explore their knowledge and use of various alternative therapies for prostate cancer. Out of 195 patients who were sent the questionnaire, 168 responded, for a response rate of 86%. One hundred and sixty-four were analysed. Eight-two out of 164 (50%) were aware of alternative therapies for prevention/treatment of prostate cancer, the most common were tomatoes/tomato-based products and low-fat diet. There were 27 (16.5%) respondents taking alternative therapies for their prostate. Private patients were more aware (60.4% private vs 46.2% NHS) of complimentary therapies and were more likely to take them (27.9% private vs 12.4% NHS) than National Health Service patients. The majority of patients (60%) had not informed their GP or urologist. Fifteen therapies and 12 medication sources were recorded. Asked if doctors should discuss non-prescribed therapies, even if there is no proven benefit, 62% said 'yes' while 29% said 'no'. Alternative therapy use for prostate cancer is likely to increase. If we don't ask patients specifically whether they are taking them, patients are unlikely to tell us. Urologists and clinical oncologists treating men with prostate cancer need to be aware of alternative therapies and have some understanding of any benefit or harm, not only to be able to answer patient's questions and offer advice, but also to consider interactions with other treatments.Prostate Cancer and Prostatic Diseases (2001) 4, 235-241.

Botanical medicines for the treatment of cancer: rationale, overview of current data, and methodological considerations for phase I and II trials

There appears to be exceptional and growing public enthusiasm for botanical, or "herbal", medicines, especially amongst cancer patients. This has recently begun to be matched by increasing scientific attention. Whilst it is known that plant extracts are active against cancer, the standard approach has been to isolate, synthesize and administer the single chemical compound thought responsible for this effect. However, different components in a botanical may have synergistic activities. There is also some evidence that the presence of multiple compounds in a botanical extract can buffer the toxic effects of a single constituent. Though many of the botanicals popular among patients are probably not of benefit (e.g. Mistletoe, Pau D'arco), several botanicals have shown promise in Phase III (Sho-saiko-to, PSK) or Phase II (PC-SPES) trial. Quality control of botanicals poses significant challenges: small differences in genetics, soil, temperature, moisture and time of harvesting can lead to significant differences in the concentration of important constituents. Phase I and II methodology is also problematic: botanicals have low toxicity and are unlikely to cause rapid tumor regression. There is currently minimal regulation of botanical medicines.

Attitudes and use of complementary medicine in men with prostate cancer

PURPOSE

Patients with cancer are increasingly incorporating complementary therapies into the overall treatment. We determine the prevalence and patterns of use of complementary therapies among patients with prostate cancer.

MATERIALS AND METHODS

Patients attending 6 urology institutions for prostate cancer management completed a self-administered questionnaire on complementary therapy. All men diagnosed with prostate cancer were eligible, regardless of age, stage of disease or treatment.

RESULTS

A total of 1,099 patients returned the questionnaire. The overall response rate was 78.5%. Complementary therapies had previously been or were currently being used by 23.5% (258) and 18.2% (200) of patients, respectively. Higher levels of education and income were associated with greater use of complementary therapy (p <0.002 by logistic regression). Patients with progressive disease or those primarily treated with hormones were most likely to use complementary therapy. Among the patients using complementary therapy 90% believed that it would help them live longer and improve quality of life, 60% believed it would relieve symptoms and 47% expected it to cure disease.

CONCLUSIONS

Complementary therapies are used by a large number of patients with prostate cancer, particularly those with progressive disease or who have undergone multiple treatments. Health care providers need to recognize this growing pattern of use of complementary therapy. Among patients who use complementary therapy the perception of benefit is much greater than that supported by scientific data. Future research should aim to unravel the complex psychosocial dynamics that influence the decision to use complementary therapy by men with prostate cancer and to educate patients about the efficacy of such therapies.

Complementary and alternative medicine: opportunities and challenges for cancer management and research

Given the widespread use of diverse complementary and alternative medicine (CAM) approaches by cancer patients, research to establish their safety and efficacy is critical as is improved patient-physician communication about their possible risks and benefits. The mission of the National Center for Complementary and Alternative Medicine (NCCAM) is to support exacting research and disseminate clear and compelling information on CAM. Although many of the challenges facing such research are not unique to CAM, these approaches do present unique challenges, but the opportunities are many for prevention, palliation, and even treatment. Using the current research portfolio of NCCAM to illustrate how the field may mature, this report summarizes the challenges facing CAM investigators, the most fruitful areas for exploration, and existing information resources.

Complementary and alternative therapies in prostate cancer

Complementary and alternative therapies are used with increasing frequency in men with prostate cancer. However, little is known about the efficacy of such therapies for this cancer. While epidemiological data support the association between intake of certain micronutrients with development of prostate cancer, there exist limited prospective data that support the chemopreventative or therapeutic value of such nutritional agents in prostate cancer. To date, one of the most studied treatments has been PC-SPES, a combination of eight herbal therapies with activity against prostate cancer. Studies in cell lines of human prostate cancer demonstrate significant dose-dependent decreases in cellular viability after exposure to extracts of this agent. Clinical studies suggested that PC-SPES could reduce prostate specific antigen levels in patients with either androgen-dependent or androgen-independent prostate cancer. Toxicity was mild, although there was a low risk of thromboembolic events with such treatment. Manufacture of PC-SPES was recently halted, after revelations that the herbal combination was contaminated with warfarin, which led to a recall by the manufacturer. Subsequent analyses also revealed the presence of diethylstilbestrol (DES) and indomethacin in some lots of PC-SPES. Available data regarding other alternative therapies are reviewed as well.

Selective aromatase inhibition for patients with androgen-independent prostate carcinoma

BACKGROUND

First and second-generation aromatase inhibitors have shown activity in patients with androgen-independent prostate carcinoma. These early-generation aromatase inhibitors are nonselective, however, and inhibition of other steroidogenic enzymes may contribute to their reported clinical activity. The authors conducted a Phase II clinical study of letrozole to determine the safety and efficacy of a potent and selective third-generation aromatase inhibitor in men with androgen-independent prostate carcinoma.

METHODS

Forty-three men with androgen-independent prostate carcinoma were treated with oral letrozole (2.5 mg daily). Treatment was continued until progressive disease or Grade 3 toxicity developed. Response and progressive disease were defined according to recommendations of the Prostate Specific Antigen Working Group.

RESULTS

In total, 380 weeks of treatment were administered to the 43 study patients. The median duration of treatment was 8 weeks. Forty men discontinued treatment due to progressive disease. Only one patient responded to treatment with a sustained decrease > 50% in serum prostate specific antigen (PSA) levels. Three other patients experienced transient minor decreases (< 50%) in serum PSA levels. There were no serious treatment-related adverse events.

CONCLUSIONS

Selective aromatase inhibition with letrozole is not active in men with androgen-independent prostate carcinoma.

Prevention and management of prostate cancer using PC-SPES: a scientific perspective

Complementary and alternative therapies are increasingly used in the United States by individuals diagnosed with cancer. PC-SPES is a multiherb dietary supplement used by many patients with prostate cancer (CaP). The wide acceptance of PC-SPES for hormone-naive and end-stage CaP relates to clinical trials demonstrating significant efficacy and low toxicity. Although the clinical efficacy of PC-SPES is highly encouraging, its scientific basis has progressed more slowly. This article describes our understanding of the in vitro mechanisms of action of PC-SPES in androgen-dependent LNCaP cells. We first demonstrated significant suppression of cancer cell growth by restriction of cell cycle progression at G(1)/S and drastic reductions in the expression of androgen receptor and prostate-specific antigen (PSA) by PC-SPES, providing a mechanistic rationale for its observed clinical effects. Further investigation of the anti-CaP properties of PC-SPES revealed that two of its multicomponent herbs, Glycyrrhiza uralensis and Scutellaria baicalensis, inhibited cell growth and down-regulated PSA in a manner comparable with PC-SPES. Exhaustive characterization of S. baicalensis resulted in the isolation of baicalein. Here we report that baicalein effectively suppressed growth and PSA expression and induced G(1)/S arrest in LNCaP cells. Although baicalein cannot account for the entire activity of PC-SPES, it does display similar anti-CaP activities. These data suggest that a single herb or bioactive compound could suffice for CaP chemoprevention by effecting multiple changes in target cells to intervene in CaP progression. These studies provide the impetus for further evaluation of the composition herbs within PC-SPES and the precise characterization of their bioactive ingredients.

PC-SPES: herbal formulation for prostate cancer

PC-SPES is a potent eight-herb formulation sold directly to consumers; it has promising efficacy in the treatment of prostate cancer (CaP). The product induces a castrate status in most, if not all, men, resulting in a 50% or greater prostate-specific antigen reduction in the great majority of men with androgen-dependent CaP and in more than one half of the men with androgen-independent CaP. The duration of response is not yet clear. The efficacy of PC-SPES appears to exceed that of androgen ablation alone, but is not necessarily separate from an estrogenic effect. Common side effects include gynecomastia, nipple tenderness, loss of libido, and impotency; uncommon side effects include a 4% incidence of thromboembolic phenomena, but also two reports of bleeding diatheses. The mechanisms of action may involve downregulation of the androgen receptor, induction of apoptosis by way of inhibition of the bcl-2 gene, and increased expression of p53. Two marker compounds in PC-SPES are baicalin and oridonin, both of which exhibit antiproliferative effects in CaP cell lines. Thousands of men are currently obtaining this nonprescription medicine, and physicians should ask patients specifically about its use. PC-SPES is of great interest in men with androgen-independent CaP, an area in which future research should be primarily directed.

Secondary hormonal therapies in the treatment of prostate cancer

Patients with androgen-independent prostate cancer demonstrate progression of disease, despite chemical or surgical castration, and have a poor prognosis. Cancer progression may be manifest as an asymptomatic increase in serum prostate-specific antigen (PSA) or may be accompanied by symptomatic and/or radiographic evidence of tumor growth. Observation remains a reasonable choice for asymptomatic patients. However, many patients remain anxious about withholding further treatment and, although studies have not demonstrated a survival benefit with second-line hormonal therapy, it may be appropriate to consider these therapies. In patients who have radiographic and/or symptomatic progression, the use of second-line hormonal therapy is more easily justified. Treatment options include: (1) secondary use of antiandrogens (eg, high-dose bicalutamide), (2) therapies targeted against adrenal steroid synthesis (eg, ketoconazole, aminoglutethimide, and corticosteroids), and (3) estrogenic therapies (eg, diethylstilbestrol). Symptomatic improvement and PSA-level decreases of > or =50% have been reported in approximately 20% to 80% of patients with androgen-independent prostate cancer who receive such second-line hormone therapies, with a typical response duration of 2 to 6 months. Toxicity is generally mild for these oral therapies, although serious side effects, including adrenal insufficiency, liver toxicity, and thrombosis, may occur. In conclusion, secondary hormonal therapies have a significant role in the treatment of patients with androgen-independent prostate cancer. Further research is needed to understand their optimal use.

Highlights of contemporary issues in the medical management of prostate cancer

This paper highlights contemporary issues in the medical management of prostate cancer. Controversies surrounding adjuvant and neo-adjuvant hormonal therapy in localized prostate cancer are reviewed, as well as the use of chemohormonal therapy in high risk localized disease. The latent period of asymptomatic biochemical progression prior to clinical progression is an opportunity to evaluate new non-toxic therapies. In patients with advanced metastatic disease hormonal therapy and new alternatives are discussed. Chemotherapy in hormone refractory prostate cancer (HRPC) is extensively covered as well as the emerging role of molecular-targeted therapies.

Cancer: current research in alternative therapies

Apparent increases in the use of alternative medical interventions by patients with cancer represent a challenge and an opportunity for the conventional medical research establishment and medical practice communities. Conventional cancer researchers are beginning to investigate alternative medical interventions that are used by patients with cancer, and eventually this exploration will generate sufficient data to permit evidence-based recommendations about these modalities.

Herbal supplement PC-Spes for prostate cancer

OBJECTIVE

To determine the efficacy and toxicity of the herbal supplement PC-Spes in prostate cancer patients.

METHODS

Literature search through MEDLINE (1966-October 2001), PubMed, and abstracts from the Annual Meeting of the American Society of Clinical Oncology (1995-2001).

RESULTS

PC-Spes was associated with biochemical and clinical response in some prostate cancer patients. The mechanisms of action of PC-Spes appeared to be related to its estrogenic activity.

CONCLUSIONS

PC-Spes is associated with some efficacy in prostate cancer patients. Due to the limited data available, it should not be used to replace standard androgen suppression therapy in androgen-dependent patients. PC-Spes may have a role for patients who have failed standard treatments for androgen-independent disease and have no history of thromboembolism or abnormal bleeding. PC-Spes has a toxicity profile similar to those of androgen suppression and estrogen therapy.