Prostate cancer prevention: past, present, and future

Clinical Management of Prostate Cancer in High-Risk Genetic Mutation Carriers

Simple Summary

Men with certain genetic differences are at much higher risks of developing metastatic and lethal prostate cancer. With the recent introduction of a new class of medications specifically targeted to these gene repair pathways (PARP inhibitors), it is critical to review the state of the literature surrounding the management of men with prostate cancer who have these genetic differences. We review the existing literature to address common clinical questions pertaining to this population. There is an urgent need for further research regarding clinical management in these scenarios as patients are increasingly seeking out genetic testing and consulting healthcare professionals for guidance.

Abstract

Background: Prostate cancer is a leading cause of death. Approximately one in eight men who are diagnosed with prostate cancer will die of it. Since there is a large difference in mortality between low- and high-risk prostate cancers, it is critical to identify individuals who are at high-risk for disease progression and death. Germline genetic differences are increasingly recognized as contributing to risk of lethal prostate cancer. The objective of this paper is to review prostate cancer management options for men with high-risk germline mutations. Methods: We performed a review of the literature to identify articles regarding management of prostate cancer in individuals with high-risk germline genetic mutations. Results: We identified numerous publications regarding the management of prostate cancer among high-risk germline carriers, but the overall quality of the evidence is low. Conclusions: We performed a review of the literature and compiled clinical considerations for the management of individuals with high-risk germline mutations when they develop prostate cancer. The quality of the evidence is low, and there is an immediate need for further research and the development of consensus guidelines to guide clinical practice for these individuals.

The effect of heated lidocaine gel on pain reduction during transrectal ultrasound-guided prostate biopsy: a randomized-controlled study

PURPOSE

To determine whether intrarectal local anesthesia (IRLA) with heated lidocaine gel provides pain reduction during transrectal ultrasound (TRUS)-guided prostate biopsy.

METHODS

We conducted a randomized-controlled study with 153 participants who underwent TRUS-guided, systematic 12-core prostate biopsy from May 2018 to June 2019. These participants were divided into three test groups. Before prostate biopsy, group A (51 patients) received no local anesthesia, group B (51 patients) received IRLA with 20 mL 2% lidocaine gel stored at room temperature, and group C (51 patients) received IRLA with heated (40 ℃) 20 mL 2% lidocaine gel. Pain was assessed using the 0-10 visual analogue scale (VAS) at three time points: VAS-1: during probe insertion, VAS-2: during biopsy, VAS-3: 30 min after the procedure. Complications during and after the procedure were evaluated.

RESULTS

The mean VAS-2 score was significantly lower in group C compared to groups A and B (A, 4.6; B, 4.2; and C, 3.2; p < 0.05). There was no significant difference among the three groups in mean VAS-1 and VAS-3 scores. No significant difference was detected in incidence of complications between the three groups. No allergic reactions to lidocaine gel were observed.

CONCLUSION

IRLA with heated lidocaine gel provides more effective pain control during TRUS-guided prostate biopsy than does conventional IRLA and no local anesthesia, without an increase of complications.

Evaluation of the Effects of Nobiletin on Toll-Like Receptor 3 Signaling Pathways in Prostate Cancer In Vitro

Nobiletin as a nontoxic dietary citrus flavonoid has anticancer effects in cancer. Toll-like receptor three has a role in prostate cancer progression. However the relationship among NOB and TLR3 signaling in PCa has not been elucidated, yet. Therefore, we aimed to evaluate the effects of NOB on the activation of TLR3 signaling pathways in PCa In Vitro. PC-3, LNCaP and HUVEC cells were used for comparison of NOB-mediated TLR3 signaling pathways. After treatment with NOB and Poly I:C alone and NOB + Poly I:C, RT-PCR, western blotting and ELISA assay were performed to evaluate changes in gene and protein expression level, as well as CASP8. NOB potentially induced TLR3/IRF3 signaling pathway and the activation of TLR3/IRF3 signaling pathway by both NOB and Poly I:C was more profound in LNCaP than PC-3 cells. However, the level of TRIF protein and CASP8 decreased after both NOB and Poly I:C incubation. NOB could mediate TLR3 signaling pathways. NOB + Poly I:C could improve the activation of TLR3/IRF3 signaling pathway. However, the activation of TRIF/RIPK1/FADD signaling pathway reduced. Therefore, the elucidation of molecular mechanisms of TLR3 signaling pathways and the combination effects of NOB + Poly I:C on apoptotic cell death are further studied.

Epidemiology of Prostate Cancer

Prostate cancer is the second most frequent cancer diagnosis made in men and the fifth leading cause of death worldwide. Prostate cancer may be asymptomatic at the early stage and often has an indolent course that may require only active surveillance. Based on GLOBOCAN 2018 estimates, 1,276,106 new cases of prostate cancer were reported worldwide in 2018, with higher prevalence in the developed countries. Differences in the incidence rates worldwide reflect differences in the use of diagnostic testing. Prostate cancer incidence and mortality rates are strongly related to the age with the highest incidence being seen in elderly men (> 65 years of age). African-American men have the highest incidence rates and more aggressive type of prostate cancer compared to White men. There is no evidence yet on how to prevent prostate cancer; however, it is possible to lower the risk by limiting high-fat foods, increasing the intake of vegetables and fruits and performing more exercise. Screening is highly recommended at age 45 for men with familial history and African-American men. Up-to-date statistics on prostate cancer occurrence and outcomes along with a better understanding of the etiology and causative risk factors are essential for the primary prevention of this disease.

Comparison of the Effect of Intra-Rectal Administration of Lidocaine Gel and Lidocaine Plus Fentanyl on Pain Reduction in Prostate Biopsy: A Randomized Clinical Trial

Objectives

The aim of this study was to compare the effect of intra-rectal administration of lidocaine gel alone versus lidocaine gel plus topical fentanyl on pain reduction in prostate biopsy.

Methods

In a double-blind randomized clinical trial, 96 patients who met the inclusion criteria were randomly assigned into two groups. 1) The treatment group: Lidocaine gel (2%) 50 g and 2) the intervention group: Lidocaine gel (2%) 50 g and fentanyl gel 50 µg. During the prostate biopsy, the VAS score was recorded. Blood pressure, heart rate, and patient level of consciousness were also analyzed.

Results

The mean VAS score was 5.1 ± 2 and 3.0 ± 2, which was lower in the intervention group (P value < 0.001). In terms of consciousness after biopsy, there was no difference between the two groups (P value = 0.358). There was no difference between the groups in terms of mean blood pressure and heart rate before and during the prostate biopsy. Finally, in terms of consciousness after the prostate biopsy, there was no difference between the current treatment and intervention groups.

Conclusions

The combination of lidocaine gel and fentanyl with a dose of 50 µg has a significant effect on reducing the pain associated with prostate biopsy in comparison with lidocaine gel alone. The antinociceptive effect of the above regimens is not associated with hemodynamic changes and changes in patients' consciousness.

Childhood diet and growth in boys in relation to timing of puberty and adult height: the Longitudinal Studies of Child Health and Development

PURPOSE

To begin to explore the possible roles of childhood diet and growth in prostate cancer (PCa) development, we investigated these exposures in relation to two known/suspected PCa risk factors, earlier pubertal timing and greater attained height, in the Longitudinal Studies of Child Health and Development.

METHODS

We used biannual/annual height, weight, and dietary history data to investigate childhood diet, body mass index (BMI), birth length, and childhood height in relation to PCa risk factors (age at peak height velocity (APHV), height at age 13, and adult height) for 64 Caucasian American boys.

RESULTS

In adjusted models, childhood fat and animal protein intake was positively associated with height at age 13 and adult height (P < 0.05). A childhood diet high in fat and animal protein and low in vegetable protein was also associated with earlier APHV (P < 0.05), whereas no associations were observed for childhood energy intake or BMI. Birth length and childhood height were positively associated with height at age 13 and adult height, and childhood height was inversely associated with APHV (P < 0.05).

CONCLUSION

Our findings suggest that both childhood diet and growth potential/growth contribute to earlier pubertal timing and taller attained height in males, supporting roles of these factors in PCa development.

The role of dietary fat throughout the prostate cancer trajectory

Prostate cancer is the second most common cancer diagnosed world-wide; however, patients demonstrate exceptionally high survival rates. Many lifestyle factors, including obesity and diet, are considered risk factors for advanced prostate cancer. Dietary fat is a fundamental contributor to obesity and may be specifically important for prostate cancer patients. Prostate cancer treatment can result in changes in body composition, affecting quality of life for survivors by increasing the risk of co-morbidities, like cardiovascular disease and diabetes. We aim to examine dietary fat throughout the prostate cancer treatment trajectory, including risk, cancer development and survivorship. Focusing on one specific nutrient throughout the prostate cancer trajectory provides a unique perspective of dietary fat in prostate cancer and the mechanisms that may exacerbate prostate cancer risk, progression and recurrence. Through this approach, we noted that high intake of dietary fat, especially, high intake of animal and saturated fats, may be associated with increased prostate cancer risk. In contrast, a low-fat diet, specifically low in saturated fat, may be beneficial for prostate cancer survivors by reducing tumor angiogenesis and cancer recurrence. The insulin-like growth factor (IGF)/Akt signaling pathway appears to be the key pathway moderating dietary fat intake and prostate cancer development and progression.

Analysis of the anticancer activity of curcuminoids, thiotryptophan and 4-phenoxyphenol derivatives

Curcumin, a non-nutritive yellow pigment derived from the rhizome of Curcuma longa (turmeric), is considered to be an established nutraceutical with anticancer activity. Turmeric contains three principal components, curcumin, demethoxycurcumin and bisdemethoxycurcumin, of which curcumin is most abundant and potent. The concurrence of a high consumption of turmeric and a low incidence of prostate cancer in Asian countries may suggest a role for curcumin in chemoprevention. Curcumin has been identified to exhibit anti-inflammatory, anti-oxidative and anticarcinogenic properties. Since the compound does not exhibit side effects, curcumin has been designated for several clinical trials as a treatment for human cancers. The pro-apototic, antioxidant and anti-inflammatory characteristics of curcumin are implicated in its anticancer activity, yet the mechanism of action of curcumin remains unknown. To achieve an effective pharmacological outcome, curcumin must reach and sustain appropriate levels at the site of action. However, the main disadvantage of curcumin is its high metabolic instability and poor aqueous solubility that limits its systemic bioavailability. To overcome this difficulty, the present study tested the anticancer activity of new curcumin-like compounds (E21cH and Q012095H). Also, the use of new medicaments requires an understanding of their pharmacokinetic profiles and targets. Thus, molecular modeling methods were used to identify the targets of curcumin and curcumin-like compounds compared with other anticancer drugs (Q012138 and Q012169AT), which were used as the controls. The present study identified several enzymes that are targeted by curcumin, aldo-keto reductase family 1 member B10 (AKR1B10), serine/threonine-protein kinase, protein kinase C, matrix metalloproteinase (MMP), cyclooxygenase and epidermal growth factor receptor, which were tested as targets for these anticancer chemicals. All the examined small compounds demonstrated anticancer activity in the in vitro experiments and may impact cancer cells by acting on AKR1B10, MMP-9 and their targets.

Genetic polymorphisms of GSTM1, GSTT1, and GSTP1 with prostate cancer risk: a meta-analysis of 57 studies

Background and Objectives

The GSTM1, GSTT1 and GSTP1 polymorphisms might be involved in inactivation of procarcinogens that contribute to the genesis and progression of cancers. However, studies investigating the association between GSTM1, GSTT1 or GSTP1 polymorphisms and prostate cancer (PCa) risk report conflicting results, therefore, we conducted a meta-analysis to re-examine the controversy.

Methods

Published literature from PubMed, Embase, Google Scholar and China National Knowledge Infrastructure (CNKI) were searched (updated to June 2, 2012). According to our inclusion criteria, studies that observed the association between GSTM1, GSTT1 or GSTP1 polymorphisms and PCa risk were included. The principal outcome measure was the odds ratio (OR) with 95% confidence interval (CI) for the risk of PCa associated with GSTM1, GSTT1 and GSTP1 polymorphisms.

Results

Fifty-seven studies involving 11313 cases and 12934 controls were recruited. The overall OR, which was 1.2854 (95% CI = 1.1405–1.4487), revealed a significant risk of PCa and GSTM1 null genotype, and the similar results were observed when stratified by ethnicity and control source. Further, the more important is that the present study first reported the high risks of PCa for people who with dual null genotype of GSTM1 and GSTT1 (OR = 1.4353, 95% CI = 1.0345–1.9913), or who with GSTT1 null genotype and GSTP1 A131G polymorphism (OR = 1.7335, 95% CI = 1.1067–2.7152). But no association was determined between GSTT1 null genotype (OR = 1.102, 95% CI = 0.9596–1.2655) or GSTP1 A131G polymorphism (OR = 1.0845, 95% CI = 0.96–1.2251) and the PCa risk.

Conclusions

Our meta-analysis suggested that the people with GSTM1 null genotype, with dual null genotype of GSTM1 and GSTT1, or with GSTT1 null genotype and GSTP1 A131G polymorphism are associated with high risks of PCa, but no association was found between GSTT1 null genotype or GSTP1 A131G polymorphism and the risk of PCa. Further rigorous analytical studies are highly expected to confirm our conclusions and assess gene-environment interactions with PCa risk.

Epidemiology of prostate cancer and treatment remarks

Prostate cancer is one of the most common types of cancer and one of the leading causes of cancer death among men in the Western countries. The aim of the present analysis is to assess the cancer burden in order to ensure accurate strategies for chemoprevention and treatment, including the major therapeutic approaches for localized high-risk disease - surgery and radiation therapy - and quality of life issues related to each option.

Dutasteride in localised prostate cancer management: the REDEEM randomised, double-blind, placebo-controlled trial

BACKGROUND

We aimed to investigate the safety and efficacy of dutasteride, a 5α-reductase inhibitor, on prostate cancer progression in men with low-risk disease who chose to be followed up with active surveillance.

METHODS

In our 3 year, randomised, double-blind, placebo-controlled study, undertaken at 65 academic medical centres or outpatient clinics in North America, we enrolled men aged 48-82 years who had low-volume, Gleason score 5-6 prostate cancer and had chosen to be followed up with active surveillance. We randomly allocated participants in a one-to-one ratio, stratified by site and in block sizes of four, to receive once-daily dutasteride 0·5 mg or matching placebo. Participants were followed up for 3 years, with 12-core prostate biopsy samples obtained after 18 months and 3 years. The primary endpoint was time to prostate cancer progression, defined as the number of days between the start of study treatment and the earlier of either pathological progression (in patients with ≥1 biopsy assessment after baseline) or therapeutic progression (start of medical therapy). This trial is registered with ClinicalTrials.gov, number NCT00363311.

FINDINGS

Between Aug 10, 2006, and March 26, 2007, we randomly allocated 302 participants, of whom 289 (96%) had at least one biopsy procedure after baseline and were included in the primary analysis. By 3 years, 54 (38%) of 144 men in the dutasteride group and 70 (48%) of 145 controls had prostate cancer progression (pathological or therapeutic; hazard ratio 0·62, 95% CI 0·43-0·89; p=0·009). Incidence of adverse events was much the same between treatment groups. 35 (24%) men in the dutasteride group and 23 (15%) controls had sexual adverse events or breast enlargement or tenderness. Eight (5%) men in the dutasteride group and seven (5%) controls had cardiovascular adverse events, but there were no prostate cancer-related deaths or instances of metastatic disease.

INTERPRETATION

Dutasteride could provide a beneficial adjunct to active surveillance for men with low-risk prostate cancer.

FUNDING

GlaxoSmithKline.

Bioavailability of phytochemical constituents from a novel soy fortified lycopene rich tomato juice developed for targeted cancer prevention trials

Studies suggest that tomato and soy foods may contribute to a lower risk of certain cancers. We developed a novel soy germ tomato juice to be used in controlled cancer prevention trials. This study describes an initial test of compliance, phytochemical bioavailability, and effects on biomarkers of blood lipids. Healthy men and women (n = 18) consumed a soy germ-fortified juice daily (300 mL supplying 66 mg isoflavones and 22 mg lycopene) for 8 wk. A single-dose bioavailability study was completed on day 1 and isoflavones in plasma and urine, and lycopene in the plasma, were measured. All subjects completed the trial, with 97.7% ± 3.5% (mean ± SD) of the scheduled juice consumed. No adverse effects were documented. The postprandial study indicated that 3.1% ± 2.3% of lycopene was absorbed and that 49.3% ± 12.1% isoflavones ingested were recovered in 24-h urines. Lycopene plasma concentration changed from 0.60 ± 0.22 to 1.24 ± 0.30 μmol/L during 8 wk of consumption. Juice consumption significantly improved resistance of LDL+VLDL-C to Cu(2+)-mediated oxidation (P = 0.039), HDL-C (47.3 ± 15.8 to 51.7 ± 14.8 mg/dL, P < 0.001), and the ratio of total-C/HDL-C (4.25 ± 1.59 to 3.63 ± 1.16, P < 0.001) at 8 wk. A well-characterized soy-fortified tomato juice can be produced in large scale for multiinstitutional long-term cancer prevention trials and showed excellent compliance with no toxicity, while demonstrating absorption of biologically active phytochemicals.

Differential expression of thrombospondin (THBS1) in tumorigenic and nontumorigenic prostate epithelial cells in response to a chromatin-binding soy peptide

The chemopreventive properties of the chromatin-binding soy peptide, lunasin, are well documented, but its mechanism of action is unclear. To elucidate the mechanism by which lunasin reduces tumor foci formation in cultured mammalian cells, nontumorigenic (RWPE-1) and tumorigenic (RWPE-2) human prostate epithelial cells were treated with lunasin followed by gene expression profiling and characterization of the chromatin acetylation status for certain chemopreventive genes. The genes HIF1A, PRKAR1A, TOB1, and THBS1 were upregulated by lunasin in RWPE-1 but not in RWPE-2 cells. Using histone acetyltransferase (HAT) assays with acid-extracted histones as templates, we showed that lunasin specifically inhibited H4K8 acetylation while enhanced H4K16 acetylation catalyzed by HAT enzymes p300, PCAF, and HAT1A. These results suggest a novel mechanism for lunasin-dependent upregulation of gene expression. Chromatin immunoprecipitation (ChIP) revealed hypoacetylation of H4K16 in RWPE-2 cells, specifically at the 5' end of THBS1 containing a CpG island. Moreover, bisulfite PCR (BSP) and subsequent DNA sequencing indicated that this CpG island was hypomethylated in RWPE-1 but hypermethylated in RWPE-2 cells. Histone hypoacetylation and DNA hypermethylation in the 5' region of THBS1 may explain the inability of lunasin to upregulate this gene in RWPE-2 cells.

Life events, cortisol and levels of prostate specific antigen: a story of synergism

BACKGROUND

Previous studies have tested the relationship between stressful life events (LE) and cancer onset, but inconsistent results have been found. One possibility is that the LE-cancer relation may depend on other biological factors pertinent to stress and cancer.

METHODS

This study examined the relationship between LE and prostate specific antigen (PSA) levels, a tumor marker, and whether cortisol mediates or moderates a LE-PSA relationship. During a voluntary screening for prostate cancer risk, 139 men (mean age=57.3 years) were assessed with the Holmes and Rahe questionnaire about their LE during the past 1-5 years, and their PSA and serum cortisol levels were measured.

RESULTS

LE and cortisol alone were unrelated to PSA. However, statistically controlling for age, body mass index and the ratio of triglycerides to HDL cholesterol, we found evidence for a synergistic interaction between LE and cortisol. Among men with low cortisol, number of LE were inversely and significantly correlated with PSA (r=-0.265, p<0.05), while in men with high cortisol, number of LE were positively and significantly correlated with PSA (r=0.344, p<0.01). These results more consistently stemmed from the effects of uncontrollable LE. Similar results were found, using a clinically significant PSA cut-off.

CONCLUSIONS

These results suggest considering the joint effects of psychosocial and biological factors in relation to possible cancer risk, where the hypothalamic pituitary adrenal axis may moderate stress-cancer risk associations.

Growth inhibitory, antiandrogenic, and pro-apoptotic effects of punicic acid in LNCaP human prostate cancer cells

Prostate cancer is a commonly diagnosed cancer in men, and dietary chemoprevention by pomegranate (Punica granatum) extracts has shown noticeable benefits. In this study, we investigated the growth inhibitory, antiandrogenic, and pro-apoptotic effects of 13 pure compounds found in the pomegranate in androgen-dependent LNCaP human prostate cancer cells. Cells deprived of steroid hormones were exposed to increasing concentrations (1-100 μM) of pomegranate compounds in the presence of 0.1 nM dihydrotestosterone (DHT), and the inhibition of cell growth was measured by WST-1 colorimetric assay after a 4 day exposure. Four compounds, epigallocatechin gallate (EGCG), delphinidin chloride, kaempferol, and punicic acid, were found to inhibit DHT-stimulated cell growth at concentrations of 10 μM and above. These four pomegranate compounds inhibited DHT-stimulated androgen receptor nuclear accumulation and the expression of the androgen receptor-dependent genes prostate specific antigen and steroid 5α-reductase type 1 at concentrations ≥10 μM. We determined the possible contribution of apoptosis to the observed decrease in cell growth and found that three compounds, EGCG, kaempferol, and, in particular, punicic acid, induced DNA fragmentation after a 24 h treatment, at concentrations in the 10-100 μM range. Punicic acid, an important fatty acid in pomegranate seeds, was further found to induce intrinsic apoptosis via a caspase-dependent pathway. In conclusion, punicic acid, the main constituent of pomegranate seed (70-80%), exhibited potent growth inhibitory activities in androgen-dependent LNCaP cells, which appear to be mediated by both antiandrogenic and pro-apoptotic mechanisms.

Nutrients and risk of prostate cancer

This study assesses the association between intake of protein, fats, cholesterol, and carbohydrates and the risk of prostate cancer (PCa). Between 1994 and 1997, in 8 Canadian provinces, mailed questionnaires were completed by 1,797 incident, histologically confirmed cases of PCa and 2,547 population controls. Information was collected on socioeconomic status, lifestyle habits, and diet. A 69-item food frequency questionnaire provided data on eating habits 2 yr before the study. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using unconditional logistic regression, including terms for sociodemographic factors, body mass index, alcohol, and total energy intake. Intake of trans fat was associated with the risk of PCa; the OR for the highest vs. the lowest quartile was 1.45 (95% CI = 1.16-1.81); the association was apparently stronger in subjects aged less than 65, normal weight men, and ever smokers. An increased risk was also observed with increasing intake of sucrose and disaccharides. In contrast, men in the highest quartile of cholesterol intake were at lower risk of PCa. No association was found with intake of total proteins, total fat, monounsaturated fats, polyunsaturated fats, monosaccharides, and total carbohydrates. The findings provide evidence that a diet low in trans fat could reduce PCa risk.

Diet and prostate cancer: mechanisms of action and implications for chemoprevention

As one of the most prevalent cancers, prostate cancer has enormous public health significance and prevention strategies would attenuate its economic, emotional, physical and social impact. Until recently, however, we have had only modest information about risk factors for this disease, apart from the well-established characteristics of age, family history and place of birth. The large worldwide variation in the incidence of prostate cancer and the increased risk in migrants who move from low-risk to high-risk countries provide strong support for modifiable environmental factors, particularly diet, in its etiology. Thus, dietary agents have gained considerable attention as chemopreventive agents against prostate cancer. Dietary fat, red and processed meat, vitamin E, selenium, tomatoes, cruciforms and green tea have all been linked with the development and aggressiveness of prostate cancer, through a range of molecular mechanisms. The direction of future clinical trials lies in clarifying the effects of these agents and exploring the biological mechanisms responsible for the prevention of prostate cancer. However, owing to the short time period between diagnosis and treatment, conventional dietary intervention techniques are not always realistic. Until large randomized trials confirm the benefit of chemopreventive and dietary modifications, patients can be advised to pursue a diet and lifestyle that enhances overall health.

Lipoproteins, sex hormones and inflammatory markers in association with prostate cancer

OBJECTIVE

To evaluate lipoprotein profile and sex hormones in patients with prostate cancer (PCa) and benign prostatic hyperplasia (BPH) and their possible associations with some inflammatory markers linked to PCa.

METHODS

A total of 150 men (50-65 years), matched by age and body mass index (BMI), included in this study and divided into three groups according to total prostate specific antigen (PSA), digital rectal examination and prostate biopsy: 50 PCa, 50 BPH and 50 controls. Total cholesterol (Chol), HDL-chol, LDL-chol, triglycerides (TG), total testosterone (T), free T (FT), bioavailable T (BioT), estradiol and SHBG were measured. The free androgen index (FAI) and TG/HDL-chol were calculated. In 25 PCa and 25 controls, C-reactive protein (hs-CRP), adiponectin and insulin were determined.

RESULTS

Patients with PCa showed higher TG/HDL-chol and diminished HDL-chol than Controls and BPH. PSA correlated inversely with HDL-chol and directly with TG/HDL-chol. FAI, FT, BioT and estradiol levels were higher, and SHBG and adiponectin were lower in PCa than in Controls. No differences were found in androgens between BPH and PCa.

CONCLUSION

Our most novel findings are that the patients with PCa presented lower total Chol and HDL-chol and higher TG/HDL-chol than BPH and Controls. Patients with PCa showed higher androgens and lower adiponectin than Controls.

Selenium speciation profiles in selenite-enriched soybean (Glycine Max) by HPLC-ICPMS and ESI-ITMS

Soybean (Glycine Max) plants were grown in soil supplemented with sodium selenite. A comprehensive selenium profile, including total selenium concentration, distribution of high molecular weight selenium and characterization of low molecular weight selenium compounds, is reported for each plant compartment: bean, pod, leaf and root of the Se-enriched soybean plants. Two chromatographic techniques, coupled with inductively coupled plasma mass spectrometry (ICPMS) for specific selenium detection, were employed in this work to analyze extract solutions from the plant compartments. Size-exclusion chromatography revealed that the bean compartment, well-known for its strong ability to make proteins, produced high amounts (82% of total Se) of high molecular weight selenospecies, which may offer additional nutritional value and suggest high potential for studying proteins containing selenium in plants. The pod, leaf and root compartments primarily accumulate low molecular weight selenium species. For each compartment, low molecular weight selenium species (lower than 5 kDa) were characterized by ion-pairing reversed phase HPLC-ICPMS and confirmed by electrospray ionization ion trap mass spectrometry (ESI-ITMS). Selenomethionine and selenocystine are the predominant low molecular weight selenium compounds found in the bean, while inorganic selenium was the major species detected in other plant compartments.

Protective actions of sex steroid hormones in Alzheimer's disease

Risk for Alzheimer's disease (AD) is associated with age-related loss of sex steroid hormones in both women and men. In post-menopausal women, the precipitous depletion of estrogens and progestogens is hypothesized to increase susceptibility to AD pathogenesis, a concept largely supported by epidemiological evidence but refuted by some clinical findings. Experimental evidence suggests that estrogens have numerous neuroprotective actions relevant to prevention of AD, in particular promotion of neuron viability and reduction of beta-amyloid accumulation, a critical factor in the initiation and progression of AD. Recent findings suggest neural responsiveness to estrogen can diminish with age, reducing neuroprotective actions of estrogen and, consequently, potentially limiting the utility of hormone therapies in aged women. In addition, estrogen neuroprotective actions are also modulated by progestogens. Specifically, continuous progestogen exposure is associated with inhibition of estrogen actions whereas cyclic delivery of progestogens may enhance neural benefits of estrogen. In recent years, emerging literature has begun to elucidate a parallel relationship of sex steroid hormones and AD risk in men. Normal age-related testosterone loss in men is associated with increased risk to several diseases including AD. Like estrogen, testosterone has been established as an endogenous neuroprotective factor that not only increases neuronal resilience against AD-related insults, but also reduces beta-amyloid accumulation. Androgen neuroprotective effects are mediated both directly by activation of androgen pathways and indirectly by aromatization to estradiol and initiation of protective estrogen signaling mechanisms. The successful use of hormone therapies in aging men and women to delay, prevent, and or treat AD will require additional research to optimize key parameters of hormone therapy and may benefit from the continuing development of selective estrogen and androgen receptor modulators.

Current concepts in diet and prostate cancer

Increasing evidence suggests that diet influences the initiation and progression of prostate cancer. Herein, we review associations of specific foods and nutrients with prostate cancer, summarizing important and clinically relevant emerging data on this complex topic. Foods and nutrients associated with a decreased risk of prostate cancer include lycopene, soy, cruciferous vegetables, vitamin E and selenium. Although prospective clinical trials of dietary supplements and dietary modification to prevent or control prostate cancer are underway, definitive clinical evidence is currently lacking.

Sulforaphane inhibited expression of hypoxia-inducible factor-1alpha in human tongue squamous cancer cells and prostate cancer cells

Previous studies show that a number of natural compounds from our diet have anticancer effects. Sulforaphane is the most characterized isothiocyanates (ITCs), which are identified in cruciferous vegetables. Sulforaphane is viewed as a conceptually promising agent in cancer prevention. Because of its ability to induce cancer cell apoptosis, it inhibits progression of benign tumors to malignant tumors and interrupts metastasis. However, the effect of sulforaphane on tongue cancer cell proliferation has not yet been reported, and the mechanisms that sulforaphane inhibits cancer development are still unclear. Hypoxia-inducible factor 1 (HIF-1) expression is associated with tumorigenesis and angiogenesis. It regulates the expression of many genes including vascular endothelial growth factor (VEGF), inducible nitric oxide synthase, and lactate dehydrogenase A. In our study, we investigated the effects of sulforaphane on expression of hypoxia-inducible factor-1alpha (HIF-1alpha), which was overexpressed in many human malignant tumors, human tongue squamous cell carcinoma and prostate cancer DU145 cells. Sulforaphane inhibited hypoxia induced expression of HIF-1alpha via inhibiting synthesis of HIF-1alpha. Sulforaphane was also found to inhibit hypoxia induced HIF-1alpha expression through activating JNK and ERK signaling pathways, but not AKT pathway. Inhibition of HIF-1alpha by sulforaphane resulted in decreasing expression of VEGF. Taken together, these results suggest that sulforaphane is an effective chemopreventive compound against tongue cancers and prostate cell angiogenesis in vitro, and that the HIF-1alpha target provides a new sight into the mechanisms of sulforaphane's inhibition against tumor cell proliferation.

The REDUCE trial: chemoprevention in prostate cancer using a dual 5alpha-reductase inhibitor, dutasteride

Dutasteride, a dual 5alpha-reductase inhibitor, is used in the treatment of benign prostatic hyperplasia (BPH). It reduces serum prostate-specific antigen levels by approximately 50% at 6 months and total prostate volume by 25% after 2 years. Randomized placebo-controlled trials in BPH patients have shown the efficacy of dutasteride in symptomatic relief, improvements in quality of life and peak urinary flow rate. Side effects occurring with dutasteride are decreased libido, erectile dysfunction, ejaculation disorders and gynecomastia. Preliminary data from placebo-controlled BPH trials have shown a decrease in the detection of prostate cancer in patients treated with dutasteride, although these studies were not designed to look at this issue. Dutasteride differs from finasteride in that it inhibits both isoenzymes of 5alpha-reductase, type I and type II. The landmark Prostate Cancer Prevention Trial at the end of the 7-year study demonstrated a 24.8% reduction in the incidence of prostate cancer in the finasteride group compared with placebo. However, a 25.5% increase in the prevalence of high-grade Gleason tumors has been observed, the clinical significance of which has been debated. Preliminary data suggest a decrease in prostate cancer incidence in dutasteride-treated patients and demonstrate type I alphareductase enzyme expression in prostate cancer. As a result, dutasteride is being investigated for prostate cancer prevention in the ongoing Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial, which is discussed here.

Broccoli consumption interacts with GSTM1 to perturb oncogenic signalling pathways in the prostate

BACKGROUND

Epidemiological studies suggest that people who consume more than one portion of cruciferous vegetables per week are at lower risk of both the incidence of prostate cancer and of developing aggressive prostate cancer but there is little understanding of the underlying mechanisms. In this study, we quantify and interpret changes in global gene expression patterns in the human prostate gland before, during and after a 12 month broccoli-rich diet.

METHODS AND FINDINGS

Volunteers were randomly assigned to either a broccoli-rich or a pea-rich diet. After six months there were no differences in gene expression between glutathione S-transferase mu 1 (GSTM1) positive and null individuals on the pea-rich diet but significant differences between GSTM1 genotypes on the broccoli-rich diet, associated with transforming growth factor beta 1 (TGFbeta1) and epidermal growth factor (EGF) signalling pathways. Comparison of biopsies obtained pre and post intervention revealed more changes in gene expression occurred in individuals on a broccoli-rich diet than in those on a pea-rich diet. While there were changes in androgen signalling, regardless of diet, men on the broccoli diet had additional changes to mRNA processing, and TGFbeta1, EGF and insulin signalling. We also provide evidence that sulforaphane (the isothiocyanate derived from 4-methylsuphinylbutyl glucosinolate that accumulates in broccoli) chemically interacts with TGFbeta1, EGF and insulin peptides to form thioureas, and enhances TGFbeta1/Smad-mediated transcription.

CONCLUSIONS

These findings suggest that consuming broccoli interacts with GSTM1 genotype to result in complex changes to signalling pathways associated with inflammation and carcinogenesis in the prostate. We propose that these changes may be mediated through the chemical interaction of isothiocyanates with signalling peptides in the plasma. This study provides, for the first time, experimental evidence obtained in humans to support observational studies that diets rich in cruciferous vegetables may reduce the risk of prostate cancer and other chronic disease.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00535977.

Toll-like receptor 3 triggers apoptosis of human prostate cancer cells through a PKC-alpha-dependent mechanism

Toll-like receptors (TLRs) are known to play a key role in the innate immune system particularly in inflammatory response against invading pathogens. Recent reports strongly indicate that they play important roles in cancer cells. Prostate cancer represents one of the most common cancer for which no cure is available once metastatic and androgen refractory. Since TLR3 has been recently suggested as a possible therapeutic target in some cancer cell lines, we studied TLR3 expression and functionality in two human prostate cancer cell lines, LNCaP and PC3. We report that both cell lines express TLR3 and that the TLR3 agonist poly (I:C) activates mitogen-activated protein kinases and induces inhibition of proliferation as well as caspase-dependent apoptosis. By using pharmacological and genetic approaches, we demonstrate the involvement of TLR3 in poly (I:C)-induced effects. We also show that a novel interferon-independent pathway involving protein kinase C (PKC)-alpha activation, upstream of p38 and c-jun N-terminal kinase, is responsible for poly (I:C) pro-apoptotic effects on LNCaP cells. To our knowledge, this is the first report describing a role of PKC-alpha in poly (I:C)-mediated apoptosis. The comprehension of the mechanisms underlying TLR3-mediated apoptosis can contribute tools to develop new agonists useful for the treatment of prostate cancer.

Dietary interventions in prostate cancer

Our understanding of the relationship between diet and prostate cancer is still developing. Currently, randomized, controlled trials are under way that will yield evidence on which to base recommendations regarding dietary regimens, functional foods, and supplement use. For now, data mostly derive from epidemiologic investigations with limited ability to demonstrate cause and effect, or from benchtop research that may have limited application to in vivo systems, especially in humans. Insufficient evidence currently exists to support the use of specific dietary supplements or functional food. Clinicians striving for best clinical practice should therefore encourage weight management because data consistently show that overweight and obesity are associated with progressive disease and increased overall mortality from prostate cancer and other diseases, especially cardiovascular disease.

Morphological changes induced by androgen blockade in normal prostate and prostatic carcinoma

Maximal androgen blockade (MAB), combining a luteinizing hormone releasing hormone (LHRH) agonist and a pure or non-steroidal anti-androgen, induces significant morphologic changes in the prostate. The tumor volume, density, capsular penetration, and surgical margin involvement are strongly reduced following such treatment. On histology, normal prostate tissue and tumor undergo marked atrophy and shrinkage. Although residual cancer cells are readily identifiable in most cases, they may often be sparse and easily overlooked. The increased Gleason score apparent after MAB is most likely related to fragmentation of acinar structures, and grading is not recommended following MAB. Residual cancer cells show features of lower activity and increased apoptosis. Such therapy-induced changes may be reversible, although occasional clones of cancer cells are apparently not affected and have probably developed resistance. Finally, MAB leads to marked but reversible morphologic changes and reduction in prevalence and extent of prostatic intra-epithelial neoplasia (PIN). Monotherapy using a variety of agents causes comparable but often less extensive changes.