The treatment of prostate cancer: an overview of current options

Chemotherapeutics activities of dietary phytoestrogens against prostate cancer: From observational to clinical studies

Prostate cancer remains one of the most frequent and deadliest malignancies in males, where the rate of disease progression is closely associated with the type of dietary intake, specifically Western-style diet. Indeed intake of the Asian diet, which contains abundant phytoestrogens, is inversely correlated with a higher risk of prostate cancer, suggesting a chemoprotective effect of phytoestrogen against cancer progression. Although the role of phytoestrogens in cancer treatment was well documented, their impact on prostate cancer is not well understood. Therefore, the present review discusses the possible chemopreventive effect of phytoestrogens, emphasizing their efficacy at the different stages of carcinogenesis. Furthermore, phytoestrogens provide a cytoprotective effect in conventional chemotherapy and enhance chemosensitivity to tumor cells, which have also been discussed. This compilation provides a solid basis for future research on phytoestrogens as a promising avenue for anticancer drug development and also recommends these beneficiary compounds in the daily diet to manage and prevent prostate cancer.

Glycyrrhiza glabra (Licorice): A Comprehensive Review on Its Phytochemistry, Biological Activities, Clinical Evidence and Toxicology

There are more than 30 species of Glycyrrhiza genus extensively spread worldwide. It was the most prescribed herb in Ancient Egyptian, Roman, Greek, East China, and the West from the Former Han era. There are various beneficial effects of licorice root extracts, such as treating throat infections, tuberculosis, respiratory, liver diseases, antibacterial, anti-inflammatory, and immunodeficiency. On the other hand, traditional medicines are getting the attraction to treat many diseases. Therefore, it is vital to screen the medicinal plants to find the potential of new compounds to treat chronic diseases such as respiratory, cardiovascular, anticancer, hepatoprotective, etc. This work comprehensively reviews ethnopharmacological uses, phytochemistry, biological activities, clinical evidence, and the toxicology of licorice, which will serve as a resource for future clinical and fundamental studies. An attempt has been made to establish the pharmacological effect of licorice in different diseases. In addition, the focus of this review article is on the molecular mechanism of licorice extracts and their four flavonoids (isoliquiritigenin, liquiritigenin, lichalocone, and glabridin) pharmacologic activities. Licorice could be a natural alternative for current therapy to exterminate new emerging disorders with mild side effects. This review will provide systematic insights into this ancient drug for further development and clinical use.

Comparative Effectiveness of Conservative Management Compared to Cryotherapy in Localized Prostate Cancer Patients

The high frequency of treatment-related side effects for men with localized prostate cancer creates uncertainty for treatment outcomes. This study assessed the comparative effectiveness of treatment-related side effects associated with conservative management and cryotherapy in patients with localized prostate cancer. A retrospective longitudinal cohort study was conducted, using the linked data of the Surveillance, Epidemiology, and End Results and Medicare, which included patients diagnosed from 2000 through year 2013, and their Medicare claims information from 2000 through 2014. To compare the differences in baseline characteristics and treatment-related side effects between the study cohorts, χ² tests were conducted. Multivariate logistic regression was used to assess the association between treatment selection and side effects. There were 7,998 and 3,051 patients in the conservative management and cryotherapy cohort, respectively. The likelihood of erectile dysfunction, lower urinary tract obstruction, urinary fistula, urinary incontinence, and hydronephrosis was reported to be significantly lower (53%, 35%, 69%, 65%, and 36%, respectively) in the conservative management cohort. Conservative management had a lower likelihood of treatment-related side effects compared to cryotherapy. However, further research is needed to compare other significant long-term outcomes such as costs associated with these treatment choices and quality of life.

Targeting protein geranylgeranylation slows tumor development in a murine model of prostate cancer metastasis

The isoprenoid biosynthetic pathway (IBP) plays a critical role in providing substrates and enzymes necessary for the post-translational modification and thus activation of a number of proteins involved in prostate cancer metastasis. Previous work by our lab found novel compound disodium [(6Z,11E,15E)-9-[bis(sodiooxy)phosphoryl]-17-hydroxy-2,6,12,16-tetramethyheptadeca-2,6,11,15-tetraen-9-yl]phosphonate (GGOHBP), which inhibits the IBP enzyme geranylgeranyl diphosphate synthase (GGDPS), reduced protein geranylgeranylation without altering protein farnesylation. This activity significantly reduced adrenal gland tumor burden in a murine model of human prostate cancer metastasis which relied on treatment of established disease. The present study determined the ability of GGDPS inhibition to slow the development of prostate cancer metastasis in a preventative murine model. Using tail vein injection of human derived PC-3 prostate cancer cells 4 d after initiating daily GGOHBP or vehicle treatments, we found GGOHBP significantly reduced whole body tumor burden, significantly slowed the development of tumors, and prolonged overall survival as compared to vehicle treated animals. The observed reduction in soft tissue tumor burden corresponded to a biochemical reduction in Rap1A geranylgeranylation, which for prostate cancer is important in its own merit and which serves as a surrogate marker for Rho family, i.e. Rac, protein modification. This effect was present in all treated mice pointing to strong target engagement, which was not observed in non-tumor burdened tissues or control mice. Our findings reiterate a role for protein geranylgeranylation in the development of prostate cancer metastasis in vivo.

Retrospective Review of Percutaneous Image-Guided Ablation of Oligometastatic Prostate Cancer: A Single-Institution Experience

PURPOSE

To retrospectively review and report the efficacy and safety of percutaneous image-guided ablation (cryoablation or radiofrequency ablation) in the treatment of oligometastatic prostate cancer.

MATERIALS AND METHODS

An institutional registry was retrospectively reviewed and revealed 16 patients with oligometastatic prostate cancer (median age, 67 y; range, 50-86 y) who underwent percutaneous image-guided ablation to treat 18 metastatic sites. A subgroup of 7 patients with 8 metastases were androgen-deprivation therapy (ADT)-naïve and underwent ablation to delay initiation of ADT. Local tumor control, progression-free survival (PFS), ADT-free survival, and procedural complications were analyzed.

RESULTS

Local tumor control was achieved in 15 of 18 metastases (83%) at a median follow-up of 27 months (range, 5-56 mo). Local tumor recurrence was found in 3 of 18 metastases (17%), with a median time to local recurrence of 3.5 months (range, 3-38 mo). Estimated PFS rates at 12 and 24 months were 56% (95% confidence interval [CI], 30%-76%) and 43% (95% CI, 19%-65%), respectively. In the 7 ADT-naïve patients, local tumor control was achieved in all metastases, and the median ADT-free survival period was 29 months. There were no major procedural complications.

CONCLUSIONS

In this cohort of patients with oligometastatic prostate cancer, percutaneous image-guided ablation was feasible and well tolerated and achieved acceptable local tumor control rates. Percutaneous ablation may be of particular utility in patients who wish to delay initiation of ADT.

Local Administration of Tranexamic Acid During Prostatectomy Surgery: Effects on Reducing the Amount of Bleeding

BACKGROUND

One of the issues in prostatectomy surgery is bleeding. Although tranexamic acid (TRA) is an antifibrinolytic agent for reducing bleeding, controversies surround its use.

OBJECTIVES

In this study, the effect of local administration of TRA on reducing bleeding during prostatectomy surgery was evaluated.

METHODS

A total of 186 patients who underwent prostatectomy surgery were assessed in this clinical trial study. Patients were divided randomly into two groups. After prostate removal, TRA (500 mg TRA with 5 mL total volume) to the intervention group and normal saline to the control group were sprayed with the same volume. At the end of surgery, the prescribed blood bags were measured and recorded. Hemoglobin and platelet levels were recorded 6 hours after the test. Moreover, the amounts of blood inside the blood bags in the first 24 hours, the second 24 hours, and the total length of hospital stay were recorded and compared in each group.

RESULTS

By comparing the measured values before and after surgery, we found that the amounts of hemoglobin, hematocrit, and platelet decreased. The mean blood loss in the intervention group was recorded at 340 mL and that in the control group was 515 mL. The maximum bleeding in the control group was almost twice as much as that in the intervention group. Blood loss in the intervention group with the administration of TRA was significantly lesser than that in the control group (P = 0.01). The decrease in platelet level in the intervention group was significantly lower than that in the control group (P = 0.03).

CONCLUSIONS

The present study showed that local administration of TRA significantly reduces bleeding after prostatectomy surgery and is effective in preventing postoperative hemoglobin decrease.

Androgen deprivation therapy in prostate cancer: anticipated side-effects and their management

PURPOSE OF REVIEW

In men with metastatic or recurrent prostate cancer, androgen deprivation therapy (ADT) is the standard of care. Although effective in cancer control, ADT is associated with multiple adverse effects of which physicians and patients should be aware herein we review these side-effects and their potential management.

RECENT FINDINGS

ADT reduces serum levels of testosterone and estrogen, resulting in changes in body composition, increased fracture risk, development of insulin resistance, and an unfavorable lipid profile. A number of studies have investigated the association of ADT with cardiovascular mortality; however, it is unclear whether such an association exists. Recently, two separate clinical trials have found that denosumab, a monoclonal antibody, and toremifene citrate, a selective estrogen receptor modulator, could be used to reduce the incidence of fracture in men on ADT.

SUMMARY

By providing clinicians with a greater awareness of the literature on ADT, we may minimize the physical and psychological impact of its side-effects. Physicians should be aware of a recent statement by a multilateral advisory panel, stating that there is no indication for a cardiovascular evaluation before starting ADT. Finally, physicians should be informed of recent developments in the prevention of vertebral fractures in men on ADT.

Radical retropubic prostatectomy: a review of outcomes and side-effects

BACKGROUND

Radical prostatectomy (RP) is worldwide probably the most common procedure to treat localized prostate cancer (PC). Due to a more widespread use of Prostate-Specific Antigen (PSA) testing, patients operated today are often younger and have organ confined disease justifying a more preservative surgery. At the same time, surgical technique has improved resulting in lower risk of permanent side-effects. This paper aims to give an overview of results from modern surgery regarding cancer control and side-effects. A brief overview of the history is given.

MATERIAL AND METHODS

A literature research identified recently published papers focusing on outcome and side-effects after RP.

RESULTS

One large randomized study (SPCG-4) compared RP and watchful waiting (WW). The study showed that RP was superior to WW in preventing local progression (RR = 0.36), distant metastasis (RR = 0.65) and death from PC (RR = 0.65). Observational studies also show a better outcome for men treated with RP compared to WW. Peri-operative mortality after RP is low in most material around 0.1%. The risk of stricture of the vesico-urethral anastomosis has decreased with improved technique from historically 10-20% to a low incidence of around 2-9% today. Also the risk of incontinence has declined with improved technique. However, while the rates of severe incontinence is usually very low, as many as 30% still report light incontinence after long-term follow-up. Erectile dysfunction (ED) is still a frequent side-effect after RP. This risk is dependent on age, pre-operative sexual function, surgical technique and other risk factors for ED such as smoking, diabetes, etc. In selected subgroups the risk of ED is low. Inguinal hernia is a more recently described complication after open retropubic RP with a postoperative incidence of 15-20% within three years of surgery.

CONCLUSION

RP is an effective method to achieve cancer control in selected patients. With modern technique it is a safe procedure with a low risk of permanent side-effects except for ED.

Arachidonate 12-lipoxygenase may serve as a potential marker and therapeutic target for prostate cancer stem cells

The presence of arachidonate 12-lipoxygenase (12-LOX) potentiates prostate cancer (PCa) progression and therefore may be a good therapeutic target and/or a potential diagnostic predictor for PCa. In this study, we examined the expression of 12-LOX in PCa stem cells (PCa SCs) to test if it can serve as a unique marker and therapeutic target for PCa SCs. To this end, we isolated the cancer stem cell-like side population (SP) cells from the human PCa cell line DU-145 by a flow cytometry-based SP technique. The isolated DU-145 SP cells comprised a small population of the DU-145 cells. The SP cells had an up-regulation of ATP-binding cassette sub-family G member 2 (ABCG2) which enables these cells to efflux vital dyes and chemotherapeutic drugs. Furthermore, we detected a strong up-regulation of 12-LOX in these DU-145 SP cells compared to the parental DU-145 cells by RT-PCR and Western blot approaches. We also detected 12-LOX overexpression in PCa SCs in human PCa tissue samples by paraffin-section based immunofluorescent 4-channel confocal microscopy. However, no 12-LOX was detected in normal prostate epithelial SCs in normal prostate tissue samples. These multiple lines of evidence support the possibility that 12-LOX may serve as a unique marker and therapeutic target for PCa SCs.

Radical prostatectomy versus watchful waiting for prostate cancer

BACKGROUND

The lack of evidence regarding the effectiveness of treatment options for clinically localised prostate cancer continues to impact on clinical decision-making. Two such options are radical prostatectomy (RP) and watchful waiting (WW). WW involves providing no initial treatment and monitoring the patient with the intention of providing palliative treatment if there is evidence of disease progression.

OBJECTIVES

To compare the beneficial and harmful effects of RP versus WW for the treatment of localised prostate cancer.

SEARCH STRATEGY

MEDLINE, EMBASE, The Cochrane Library, ISI Science Citation Index, DARE and LILACS were searched through 30 July 2010.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing the effects of RP versus WW for clinically localised prostate cancer.

DATA COLLECTION AND ANALYSIS

Data extraction and quality assessment were carried out independently by two authors.

MAIN RESULTS

Two trials met the inclusion criteria. Both trials commenced prior to the widespread availability of prostate-specific antigen (PSA) screening; hence the results may not be applicable to men with PSA-detected disease.One trial (N = 142), conducted in the US, was judged to be of poor quality. All cause (overall) mortality was not significantly different between RP and WW groups after fifteen years of follow up (Hazard Ratio (HR) 0.9 (95% Confidence Interval (CI) 0.56 to 1.43).The second trial (N = 695), conducted in Scandinavia, was judged to be of good quality. After 12 years of follow up, the trial results were compatible with a beneficial effect of RP on the risks of overall mortality, prostate cancer mortality and distant metastases compared with WW but the precise magnitude of the effect is uncertain as indicated by the width of the confidence intervals for all estimates (risk difference (RD) -7.1% (95% CI -14.7 to 0.5); RD -5.4% (95% CI -11.1 to 0.2); RD -6.7% (95% CI -13.2 to -0.2), respectively).        Compared to WW, RP increased the absolute risks of erectile dysfunction (RD 35% (95% CI 25 to 45)) and urinary leakage (RD 27% (95% CI 17 to 37)). These estimates must be interpreted cautiously as they are derived from data obtained from a self-administered questionnaire survey of a sample of the trial participants (N = 326), no baseline quality of life data were obtained and nerve-sparing surgery was not routinely performed on trial participants undergoing RP.

AUTHORS' CONCLUSIONS

The existing trials provide insufficient evidence to allow confident statements to be made about the relative beneficial and harmful effects of RP and WW for patients with localised prostate cancer. The results of ongoing trials should help to inform treatment decisions for men with screen-detected localised prostate cancer.

Androgen deprivation therapy and estrogen deficiency induced adverse effects in the treatment of prostate cancer

Androgen deprivation therapy (ADT) is the standard of care for metastatic prostate cancer and is increasingly used to treat asymptomatic patients with prostate-specific antigen recurrence after failed primary therapy. Although effective, ADT is associated with multiple adverse effects, many of which are related to the estrogen deficiency that occurs as a result of treatment. These include increased fracture risk, hot flashes, gynecomastia, serum lipid changes and memory loss. By providing clinicians with a greater awareness of the estrogen deficiency induced adverse effects from ADT, they can proactively intervene on the physical and psychological impact these effects have on patients.

Androgens transduce the G alphas-mediated activation of protein kinase A in prostate cells

Androgens regulate the development and function of male reproductive organs and play a crucial role in the onset and progression of prostate cancer. Androgen action is primarily mediated through the nuclear androgen receptor (AR) which acts as a ligand-dependent transcription factor. This mode of androgen action takes hours to manifest and is called the genomic pathway. The androgen-mediated genomic responses require activity of cyclic AMP (cAMP)-dependent protein kinase (PKA). Androgens also act through nongenomic pathways in certain cell types to evoke rapid responses (manifested in minutes) that are mediated through changes in ion currents and second messengers. Here, we show that androgen causes the rapid and cAMP-dependent activation of PKA in prostate cells. The androgen-induced PKA activation is not inhibited by nuclear AR antagonist bicalutamide and can be observed in cells that do not express nuclear AR gene. Reduction of G alphas expression with siRNA attenuates the androgen-mediated activation of PKA, which is required for the androgen-induced prostate cell proliferation. We conclude that androgen actively evokes a nongenomic signaling pathway to activate PKA that is needed for the genomic functioning of nuclear AR. The inhibition of PKA activation, together with standard AR-targeted therapies, may be more efficacious for treatment of patients with prostate cancer.

Symptoms and symptom distress in localized prostate cancer

For over a decade, symptom distress has been a key concept in several studies of cancer. However, the definition of symptom distress is still unclear, and there are few measures targeting symptom distress, in general, and specific cancers, in particular. Prostate cancer is the sixth most common cancer worldwide and the second leading cause of death in American men. Many men with clinically localized prostate cancer may experience unique and multidimensional symptoms that occur from diagnosis through treatment, and thereafter. These symptoms associated with the disease and its treatments are in the form of physical and psychological sequelae such as urinary and bowel problems and sexual dysfunction. The purposes of this article are to (1) systematically review literature on symptoms and symptom distress in localized prostate cancer and (2) synthesize evidence of symptom distress applications and measurement in this group. A comprehensive, systematic review was conducted to identify original, data-based studies of symptoms and symptom distress in localized prostate cancer. Clarification of symptom distress and more comprehensive information about symptoms and symptom distress will provide nurses with a better foundation for developing self-management interventions aimed at ameliorating symptom distress and, ultimately, enhancing the quality of life of patients with localized prostate cancer.

The radiosensitization effect of parthenolide in prostate cancer cells is mediated by nuclear factor-kappaB inhibition and enhanced by the presence of PTEN

Parthenolide has been shown to have anti-inflammatory and antitumor properties. However, whether and how parthenolide enhances tumor sensitivity to radiation therapy are unknown. In this study, we show that inhibition of the nuclear factor-kappaB (NF-kappaB) pathway is a common mechanism for the radiosensitization effect of parthenolide in prostate cancer cells LNCaP, DU 145, and PC3. Parthenolide inhibits radiation-induced NF-kappaB DNA-binding activity and the expression of its downstream target sod2, the gene coding for an important antiapoptotic and antioxidant enzyme (manganese superoxide dismutase) in the three prostate cancer cells. Different susceptibilities to parthenolide's effect are observed in two radioresistant cancer cells, DU 145 and PC3, with DU 145 cells showing higher sensitivity. This differential susceptibility to parthenolide is due, in part, to the fact that in addition to NF-kappaB inhibition, parthenolide activates the phosphatidylinositol-3-kinase/Akt prosurvival pathway in both cell lines. However, the activated Akt in DU 145 cells is kept at a relatively low level compared with that in PC3 cells due to the presence of functional PTEN. Transfection of wild-type PTEN into PTEN-null cells, PC3, confers the enhanced radiosensitization effect of parthenolide in PTEN-expressing cells. When PTEN expression is knocked down in DU 145 cells, the cells become more resistant to parthenolide's effect. Taken together, these results suggest that parthenolide inhibits the NF-kappaB pathway and activates the phosphatidylinositol-3-kinase/Akt pathway in prostate cancer cells. The radiosensitization effect of parthenolide is due, in part, to the inhibition of the NF-kappaB pathway. The presence of PTEN enhances the radiosensitization effect of parthenolide, in part, by suppressing the absolute amount of activated p-Akt.

Ligand-specific dynamics of the androgen receptor at its response element in living cells

Androgens have key roles in normal physiology and in male sexual differentiation as well as in pathological conditions such as prostate cancer. Androgens act through the androgen receptor (AR), which is a ligand-modulated transcription factor. Antiandrogens block AR function and are widely used in disease states, but little is known about their mechanism of action in vivo. Here, we describe a rapid differential interaction of AR with target genomic sites in living cells in the presence of agonists which coincides with the recruitment of BRM ATPase complex and chromatin remodeling, resulting in transcriptional activation. In contrast, the interaction of antagonist-bound or mutant AR with its target was found to be kinetically different: it was dramatically faster, occurred without chromatin remodeling, and resulted in the lack of transcriptional inhibition. Fluorescent resonance energy transfer analysis of wild-type AR and a transcriptionally compromised mutant at the hormone response element showed that intramolecular interactions between the N and C termini of AR play a key functional role in vivo compared to intermolecular interactions between two neighboring ARs. These data provide a kinetic and mechanistic basis for regulation of gene expression by androgens and antiandrogens in living cells.

Novel expressed sequences identified in a model of androgen independent prostate cancer

Background

Prostate cancer is the most frequently diagnosed cancer in American men, and few effective treatment options are available to patients who develop hormone-refractory prostate cancer. The molecular changes that occur to allow prostate cells to proliferate in the absence of androgens are not fully understood.

Results

Subtractive hybridization experiments performed with samples from an in vivo model of hormonal progression identified 25 expressed sequences representing novel human transcripts. Intriguingly, these 25 sequences have small open-reading frames and are not highly conserved through evolution, suggesting many of these novel expressed sequences may be derived from untranslated regions of novel transcripts or from non-coding transcripts. Examination of a large metalibrary of human Serial Analysis of Gene Expression (SAGE) tags demonstrated that only three of these novel sequences had been previously detected. RT-PCR experiments confirmed that the 6 sequences tested were expressed in specific human tissues, as well as in clinical samples of prostate cancer. Further RT-PCR experiments for five of these fragments indicated they originated from large untranslated regions of unannotated transcripts.

Conclusion

This study underlines the value of using complementary techniques in the annotation of the human genome. The tissue-specific expression of 4 of the 6 clones tested indicates the expression of these novel transcripts is tightly regulated, and future work will determine the possible role(s) these novel transcripts may play in the progression of prostate cancer.

A novel computer based expert decision making model for prostate cancer disease management

PURPOSE

We propose a strategic, computer based, prostate cancer decision making model based on the analytic hierarchy process. We developed a model that improves physician-patient joint decision making and enhances the treatment selection process by making this critical decision rational and evidence based.

MATERIALS AND METHODS

Two groups (patient and physician-expert) completed a clinical study comparing an initial disease management choice with the highest ranked option generated by the computer model. Participants made pairwise comparisons to derive priorities for the objectives and subobjectives related to the disease management decision. The weighted comparisons were then applied to treatment options to yield prioritized rank lists that reflect the likelihood that a given alternative will achieve the participant treatment goal. Aggregate data were evaluated by inconsistency ratio analysis and sensitivity analysis, which assessed the influence of individual objectives and subobjectives on the final rank list of treatment options.

RESULTS

Inconsistency ratios less than 0.05 were reliably generated, indicating that judgments made within the model were mathematically rational. The aggregate prioritized list of treatment options was tabulated for the patient and physician groups with similar outcomes for the 2 groups. Analysis of the major defining objectives in the treatment selection decision demonstrated the same rank order for the patient and physician groups with cure, survival and quality of life being more important than controlling cancer, preventing major complications of treatment, preventing blood transfusion complications and limiting treatment cost. Analysis of subobjectives, including quality of life and sexual dysfunction, produced similar priority rankings for the patient and physician groups. Concordance between initial treatment choice and the highest weighted model option differed between the groups with the patient group having 59% concordance and the physician group having only 42% concordance.

CONCLUSIONS

This study successfully validated the usefulness of a computer based prostate cancer management decision making model to produce individualized, rational, clinically appropriate disease management decisions without physician bias.

A study on staging bone scans in newly diagnosed prostate cancer

OBJECTIVE

This study aimed to evaluate the role of bone scan as a staging investigation in newly diagnosed untreated prostate cancers.

MATERIALS AND METHODS

Bone scan results in patients with newly diagnosed prostate cancer were reviewed and correlated with clinical stage, prostate-specific antigen (PSA) and Gleason scores from the biopsy specimen.

RESULTS

In all, 124 patients fulfilled inclusion criteria with an age range of 51-94 (mean 72.3) years. Pre-biopsy PSA ranged from 2.2 to 5,864 with a median of 21.1 ng/ml. Clinical stage was T0-T1c 14.5%, T2a 41.9%, T2b 17.7%, T3 16.9%, and T4 9%. A Gleason score of 7 was found in 31%. Four patients' samples were not suitable for Gleason scoring. Twenty patients (16.1%) had a positive bone scan with a mean age of 79.4 years (median 83). Two patients with PSA<20 ng/ml were positive. Of the 44 scans performed in the patients with PSA<or=20 ng/ml, clinical stage<T4 and Gleason sum<or=7 (with the major Gleason<4), none was positive. The above criteria give a 100% negative predictive value for avoiding bone scans as a staging investigation.

CONCLUSIONS

Staging bone scan can be safely omitted in patients with a clinical stage of <T4, PSA level of <or=20 ng/ml and a Gleason score of <or=7 (with major Gleason pattern<4) unless the symptoms are suggestive of metastasis.

Matrix metalloproteinase inhibitor Ro 28-2653 in combination with estramustine: tumor-reducing effects on hormone-sensitive prostate cancer in rats

Therapeutic efficacy of the novel matrix metalloproteinase (MMP) inhibitor, Ro 28-2653 (5-biphenyl-4-yl-5-[4-(-nitro-phenyl)-piperazin-1-yl]-pyrimidine-2,4,6-trione), has been shown in various models of different tumor entities. The tumor growth-reducing effect has been demonstrated in the orthotopic rat prostate Dunning model (subline MatLyLu). Based on these results we investigated Ro 28-2653 in combination with estramustine on the G subline of the Dunning tumor. This subline is characterized by a low metastatic ability and androgen sensitivity. Efficacy was determined by recording tumor growth in vivo by magnetic resonance imaging (MRI). Tumor cells were injected into the prostates of 81 Copenhagen rats. MRI was performed at day 100 and at day 126 after tumor cell injection. The duration of therapy was 17 days with daily oral application of Ro 28-2653 (100 mg/kg) and four i.p. injections of estramustine (7.5 mg/kg). Histological evaluations were conducted to provide further information about the effects on tumor morphology. Orthotopic tumor induction was successful in 100% of the animals. Tumor volume calculations with MRI showed a significant difference between the control groups, the animals treated with Ro 28-2653, and the animals treated with the combination of Ro 28-2653 and estramustine. The new MMP inhibitor Ro 28-2653 reduces tumor growth and provides a compatible therapeutic alternative for patients with prostate cancer.

Prostate secretory protein of 94 amino acids (PSP-94) and its peptide (PCK3145) as potential therapeutic modalities for prostate cancer

This review focuses on the promising roles of prostate secretory protein of 94 amino acids (PSP-94) and one of its derived peptides (PCK3145) as potential therapeutic modalities for prostate cancer and its associated complications. Evaluation of these compounds was carried out in vitro and in vivo using syngeneic models of rat prostate cancer. Overproduction of parathyroid hormone-related protein (PTHrP) results in the development of hypercalcemia of malignancy in several malignancies including prostate cancer. In order to evaluate the effect of PSP-94 and PCK3145 on prostate cancer progression, the rat Dunning R3227 MatLyLu cell line transfected with full-length cDNA encoding PTHrP (MatLyLu-PTHrP) was used. As the main pathogenetic factor of hypercalcemia of malignancy, overexpression of PTHrP was aimed at mimicking the hypercalcemic nature seen in patients suffering from late-stage cancer. In vitro studies showed that PSP-94 and PCK3145 can cause a dose-dependent inhibition in the growth of MatLyLu-PTHrP cells. For in vivo studies, male Copenhagen rats were inoculated either s.c. into the right flank or directly into the left ventricle via intracardiac (i.c.) inoculation with MatLyLu-PTHrP cells. In these models, s.c. injection of MatLyLu cells results in the development of primary tumor growth, whereas i.c. inoculation routinely results in the development of experimental skeletal metastases in the lumbar vertebrae causing hind-limb paralysis. Administration of PSP-94 and PCK3145 into tumor-bearing animals resulted in a dose-dependent inhibition of primary tumor growth, and tumoral and plasma PTHrP levels, and in the reduction of plasma calcium levels. Additionally, treatment with PSP-94 or PCK3145 caused an inhibition of skeletal metastases resulting in a significant delay in the development of hind-limb paralysis. Interestingly, equimolar concentrations of PCK3145 were shown to be more effective in delaying the development of experimental skeletal metastases as compared to PSP-94. One of the possible mechanisms of action of these modalities is through the induction of apoptosis which was observed by both in-vitro and in-vivo analyses of MatLyLu-PTHrP cells and tumors. Several intracellular mechanisms can also be involved in inhibiting PTHrP production and anti-tumor effects of PSP-94 and PCK3145. Collectively, these studies warrant the continued clinical development of these agents as therapeutic agents for patients with hormone-refractory prostate cancer.

Combined radical prostatectomy and bladder augmentation for concomitant prostate cancer and detrusor instability

OBJECTIVES

To determine the outcomes of a select cohort of patients with severe voiding dysfunction, refractory to medical management, and a concomitant diagnosis of prostate cancer, who were treated with radical prostatectomy and augmentation enterocystoplasty.

METHODS

Four men with biopsy-proven prostatic adenocarcinoma, as well as a diagnosis of severe overactive bladder, underwent combined radical retropubic prostatectomy and augmentation enterocystoplasty. All patients underwent fluorourodynamic testing confirming nonobstructive detrusor instability or hyperreflexia. Three patients underwent nerve-sparing radical retropubic prostatectomy with a clamshell ileocystoplasty, and one with neurogenic hyperreflexia underwent sigmoid cystoplasty with a continent catheterizable stoma at radical retropubic prostatectomy.

RESULTS

The mean follow-up was 21.5 months (range 8 to 48). All patients had an undetectable prostate-specific antigen level postoperatively. The average hospitalization was 8 days. Perioperative complications occurred in 2 patients, including a prolonged urine leak managed with catheter drainage and postoperative hematuria requiring cystoscopic clot evacuation. Erectile function was preserved in 2 patients with good preoperative erections. At last follow-up, the 3 patients who voided per urethra had minimal postvoid residual urine volumes and maintained good continence, with only 1 patient describing occasional mild stress incontinence. At last follow-up, the patient with the sigmoid cystoplasty catheterized every 4 hours with volumes of about 300 mL and complete stomal continence. No patient required anticholinergic medications postoperatively.

CONCLUSIONS

The concomitant diagnosis of prostate cancer and severe detrusor instability may be difficult to treat. The results of our study have shown that for those desiring surgical management for their prostate cancer, a combined bladder augmentation and radical prostatectomy may be performed with minimal added morbidity and significantly improved voiding function in the properly selected individual.

3D proton MR spectroscopic imaging of prostate cancer using a standard spine coil at 1.5�T in clinical routine: a feasibility study

The objective of this study was to demonstrate the feasibility of 3D proton MR spectroscopic imaging (MRSI) of the prostate using a standard spine instead of a dedicated endorectal coil at 1.5 T. Twenty-eight patients (25 with biopsy proven prostate cancers and three patients with a benign prostate hyperplasia) were examined. MRI and MRSI were conducted with commercial array surface coils at 1.5 T. Ratios of choline (Cho), creatine (Cr) and citrate (Ci) were calculated for tumour, central and peripheral zone retrospectively, based on axial T2 weighed MR images and histology reports. Prostate cancer was characterized by significantly elevated (Cho+Cr)/Ci ratio compared with non-tumourous prostate tissue. The quality of all proton MR spectra was considered to be good or acceptable in 17/28 patients (61%) and poor in 11/28 (39%) examinations. In 20/25 patients with proven malignancy (80%), MRSI was considered to be helpful for the detection of prostate cancer. In 4/25 patients with proven malignancy (16%) who underwent seed implantation, radiotherapy or hormone deprivation before MR examination spectroscopy was of poor and non-diagnostic quality. MRSI of the prostate is feasible within clinical routine using the spine array surface coil at 1.5 T. It can consequently be applied to patients even with contraindications for endorectal coils. However, spectral quality and signal-to-noise ratio is clearly inferior to 3D MRSI examinations with endorectal coils.

Diagnosis and treatment of prostate cancer

Many controversies surround the management of prostate cancer to include screening practices, diagnosis, and treatment options. The lack of randomized prospective studies comparing the various definitive treatment modalities currently available occasionally can make the decision process challenging for patients and their providers. In this setting of controversy, the cost of treating clinically localized prostate cancer is significant. In the face of these unanswered questions, this article summarizes some important principles regarding the diagnosis and treatment of prostate cancer. This review is limited to the diagnosis and management of clinically localized disease.

The androgen receptor: a potential target for therapy of prostate cancer

The androgen receptor plays a pivotal role in the prostate. Its primary function is to provide responsive gene products for differentiation and growth, but under abnormal conditions it contributes to the development of prostate cancer. The goal of this review is to elucidate the molecular functions of the androgen receptor and its role in prostate cancer. Initially the function of the androgen receptor will be described. Next, the clinical diagnosis, epidemiological impact, and treatments of androgen-dependent and -independent prostate cancer will be discussed. Finally we will examine how the mechanism of androgen action has played a role in the translation of new therapies and how this may influence future treatment modalities of prostate cancer.

Dynamic Magnetic Resonance Tomography and Proton Magnetic Resonance Spectroscopy of Prostate Cancers in Rats Treated by Radiotherapy

RATIONALE AND OBJECTIVES

To establish an experimental setting for monitoring perfusion and metabolism in orthotopic prostate cancer at 1.5 T using dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and 1H-MR spectroscopy (MRS).

METHODS

Dunning rat prostate cancer cells were injected into the prostate by open surgery. Twelve tumor-bearing rats (5 of these irradiated) and 6 healthy controls were followed up using gadolinium-diethylenetriaminepentaacetic acid -enhanced dynamic MRI and 1H-MRS. Amplitude and the exchange rate constant kep were calculated (2-compartment model). From 1H-MR spectra, ratios of choline (Cho) and creatine (tCr) were calculated. All tumors were examined histologically.

RESULTS

On DCE MRI parameter maps, tumors showed increased vascularization. kep and microvessel density were correlated (r = 0.97). Tumors showed elevated Cho/tCr and an unexpected lipid fraction (2.0-2.2 parts per million). Irradiation slowed tumor growth significantly. Changes of perfusion and metabolism could be detected in all tumors during follow up.

CONCLUSION

DCE MRI and 1H-MRS has potential to characterize orthotopic Dunning prostate cancer in rats, which is a promising model similar to human prostate carcinomas.

System for MR image-guided prostate interventions: canine study

The purpose of this study was to demonstrate the use of a transrectal system that enables precise magnetic resonance (MR) image guidance and monitoring of prostate interventions. The system used a closed-bore 1.5-T MR imaging unit and enables one to take advantage of the higher signal-to-noise ratio achieved with traditional magnet designs, which is crucial for accurate targeting and monitoring of prostate interventions. In the first of the four canine studies, reliable needle placement, with all needles placed within 2 mm of the desired target site, was achieved. In two other studies, MR imaging was used to monitor distribution of injected contrast agent solution (gadopentetate dimeglumine mixed with trypan blue dye) in and around the prostate, thereby confirming that solution had been delivered to the desired tissue and also detecting faulty injections. In the final study, accurate placement and MR imaging of brachytherapy seeds in the prostate were demonstrated. The described system provides a flexible platform for a variety of minimally invasive MR image-guided therapeutic and diagnostic prostate interventions.

Differential requirement of SWI/SNF for androgen receptor activity

The androgen receptor (AR) is a ligand-dependent transcription factor whose activity is required for prostate cancer proliferation. Because ablation of AR activity is a critical goal of prostate cancer therapy, much emphasis has been placed on understanding the accessory proteins that regulate AR function in the prostate. Several co-activators have been shown to be required for full AR activity, including histone acetyl-transferases and TRAP/mediator complexes. SWI/SNF comprises a family of large, multisubunit complexes present in the cell, which contain one of two core ATPases required for nucleosome re-positioning, BRG1 or hBRM. We investigated the specific requirement of the SWI/SNF core ATPases for AR function. Using cells deficient in both BRG1 and hBRM, we show that activation of one AR target promoter, prostate-specific antigen (PSA), requires SWI/SNF chromatin remodeling for activity. A second AR target promoter, probasin, maintained a low level of activation in the absence of SWI/SNF. AR stimulation on the probasin core promoter could be partially induced with BRG1, but hBRM strongly stimulated AR activity. The PSA promoter was only induced by the restoration of hBRM. In contrast, ligand-dependent activation of the estrogen receptor was equally stimulated by BRG1 or hBRM. We demonstrate that the addition of a known enhancer region to the core PSA promoter bypasses the requirement for SWI/SNF on the PSA promoter, indicating that elements upstream of specific proximal promoters can impact the influence of the SWI/SNF complex on target gene activation. Addition of the enhancer to the probasin core promoter failed to impact the SWI/SNF requirement. In summary, SWI/SNF function potently regulates core AR target gene promoter activation, with a preference for hBRM-containing complexes. These studies highlight a role for the enhancer in altering the impact of SWI/SNF action and suggest a disparity in AR target genes for SWI/SNF requirement.

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.

Synthesis and application of functional peptides as cell nucleus-directed molecules in the treatment of malignant diseases

The unique functions of biomolecules, including transport across biological membranes (e.g. the cell membrane, the nuclear envelope), modulation of protein function, gene transcription, reconstitution of the malignant transformation, and viral, bacterial and fungal activities underlie a high pharmaceutical potential. The development of combinatorial functional peptide modules in this important area has been slow, in contrast to the rapid development in the synthesis of small biopolymers. The conjugation of a short transmembrane transport peptide module with a cell nucleus address peptide module and with any substance is attractive for preparation of BioShuttle-based peptides because of the well-established automated synthesis of peptides. Variation of the different functional modules for drug targeting and the choice of substances can be combined to create novel bioconjugates with unique properties. This article provides an overview of previous work on the BioShuttle technology and outlines the promising use of this approach in combinatorial peptide synthesis and drug discovery.

Baculoviruses as Vectors for Gene Therapy against Human Prostate Cancer

Current curative strategies for prostate cancer are restricted to the primary tumour, and the effect of treatments to control metastatic disease is not sustained. Therefore, the application of gene therapy to prostate cancer is an attractive alternative. Baculoviruses are highly restricted insect viruses, which can enter, but not replicate in mammalian cells. Baculoviruses can incorporate large amounts of extra genetic material, and will express transgenes in mammalian cells when under the control of a mammalian or strong viral promoter. Successful gene delivery has been achieved both in vitro and in vivo and into both dividing and nondividing cells, which is important since prostate cancers divide relatively slowly. In addition, the envelope protein gp64 is sufficiently mutable to allow targeted transduction of particular cell types. In this review, the advantages of using baculoviruses for prostate cancer gene therapy are explored, and the mechanisms of viral entry and transgene expression are described.

Normal human salivary gland cells produce carcinoembryonic antigen-related antigen in collagen gels

The Arrhenius and thermal isoeffective dose (TID) models are the two most commonly used models for predicting hyperthermic injury. The TID model is essentially derived from the Arrhenius model, but due to a variety of assumptions and simplifications now leads to different predictions, particularly at temperatures higher than 50°C. In the present study, the two models are compared and their appropriateness tested for predicting hyperthermic injury in both the traditional hyperthermia (usually, 43–50°C) and thermal surgery (or thermal therapy/thermal ablation, usually, >50°C) regime. The kinetic parameters of thermal injury in both models were obtained from the literature (or literature data), tabulated, and analyzed for various prostate and kidney systems. It was found that the kinetic parameters vary widely, and were particularly dependent on the cell or tissue type, injury assay used, and the time when the injury assessment was performed. In order to compare the capability of the two models for thermal injury prediction, thermal thresholds for complete killing (i.e., 99% cell or tissue injury) were predicted using the models in two important urologic systems, viz., the benign prostatic hyperplasia tissue and the normal porcine kidney tissue. The predictions of the two models matched well at temperatures below 50°C. At higher temperatures, however, the thermal thresholds predicted using the TID model with a constant R value of 0.5, the value commonly used in the traditional hyperthermia literature, are much lower than those predicted using the Arrhenius model. This suggests that traditional use of the TID model (i.e., R=0.5) is inappropriate for predicting hyperthermic injury in the thermal surgery regime (>50°C). Finally, the time-temperature relationships for complete killing (i.e., 99% injury) were calculated and analyzed using the Arrhenius model for the various prostate and kidney systems.