Capsaicin: a novel radio-sensitizing agent for prostate cancer.

INTRODUCTION: Radio-sensitizing agents sensitize tumor cells to the lethal effects of radiotherapy (RT) allowing for use of lower doses of radiation to achieve equivalent cancer control, while minimizing adverse effects to normal tissues. Given their limited toxicity and ability to easily integrate into the diet, compounds occurring naturally in the diet make ideal potential radio-sensitizing agents. In this study, we have examined whether capsaicin, the active compound in chilli peppers, can modulate the response to RT in preclinical models of prostate cancer (PCa). METHODS: The effects of RT (1-8 Gy) and/or capsaicin (1-10 µM) on colony formation rates in human PCa cells were assessed using clonogenic assays. Mechanistic studies were performed by Western Blot, immunocytochemistry, and flow cytometry. Athymic mice (n = 40) were inoculated with human LNCaP cells. Once tumors reached 100 mm(3) , animals were randomized into four groups: control, capsaicin alone (5 mg/kg/d), RT alone (6 Gy), and capsaicin and RT. RESULTS: Capsaicin reduced colony formation rates and radio-sensitized human PCa cells (Sensitizer enhancement ratio = 1.3) which corresponded to the suppression of NFκB, independent of TRP-V1 receptor. Cell cycle modulation occurred following RT and capsaicin treatment independently. In vivo, oral administration of capsaicin with RT resulted in a 'greater than additive' growth delay and reduction in the tumor growth rate greater than capsaicin (P < 0.001) or RT (P < 0.03) alone. Immunohistochemical analysis revealed a reduction in proliferation and NFκB expression, and increase in DNA damage. DISCUSSION: Our findings suggest that capsaicin acts as a radio-sensitzing agent for PCa through the inhibition of NFκB signalling.

Upper limit of cancer extent on biopsy defining very low-risk prostate cancer.

OBJECTIVE: To investigate how much Gleason pattern 3 cancer prostate biopsy specimens may contain without an increased risk of undetected more aggressive cancer, compared with the risk for cancers fulfilling the National Comprehensive Cancer Network (NCCN) criteria for very low-risk prostate cancer. PATIENTS AND METHODS: We identified 1286 men aged <70 years in the National Prostate Cancer Register of Sweden who underwent primary radical prostatectomy (RP) for stage T1c or T2 prostate cancer with Gleason pattern ≤3 only, prostate-specific antigen (PSA) level of <10 ng/mL and a PSA density of <0.15 ng/mL/mL. The association between the extent of cancer in the biopsies (the number and proportion of positive cores and the total cancer length in the cores in millimetres) and the likelihood of Gleason pattern 4-5 in the RP specimen was analysed with logistic regression. RESULTS: In all, 438 (34%) of the 1286 men had Gleason pattern 4-5 in the RP specimen. Increasing number and proportion of positive biopsy cores, as well as increasing biopsy cancer length were both significantly associated with increased risk of upgrading at RP in univariable analysis, but in multivariable analysis only biopsy cancer length remained significant. The 684 men with stage T1c and <8 mm cancer had similar risk of upgrading regardless of whether the number of positive biopsy cores was 1-2 or 3-4 (28% vs 27% risk); upgrading was more common among the remaining men (40%, P < 0.01). CONCLUSIONS: Men aged <70 years with stage T1c prostate cancer and 3-4 biopsy cores with Gleason pattern 3 are not more likely to have undetected Gleason pattern 4-5 cancer than men with 1-2 cores with cancer, provided that the total biopsy cancer length is <8 mm. We propose that the definition of very low-risk prostate cancer is widened accordingly.

Vitamin E and the risk of prostate cancer: the Selenium and Vitamin E Cancer Prevention Trial (SELECT).

CONTEXT: The initial report of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) found no reduction in risk of prostate cancer with either selenium or vitamin E supplements but a statistically nonsignificant increase in prostate cancer risk with vitamin E. Longer follow-up and more prostate cancer events provide further insight into the relationship of vitamin E and prostate cancer. OBJECTIVE: To determine the long-term effect of vitamin E and selenium on risk of prostate cancer in relatively healthy men. DESIGN, SETTING, AND PARTICIPANTS: A total of 35,533 men from 427 study sites in the United States, Canada, and Puerto Rico were randomized between August 22, 2001, and June 24, 2004. Eligibility criteria included a prostate-specific antigen (PSA) of 4.0 ng/mL or less, a digital rectal examination not suspicious for prostate cancer, and age 50 years or older for black men and 55 years or older for all others. The primary analysis included 34,887 men who were randomly assigned to 1 of 4 treatment groups: 8752 to receive selenium; 8737, vitamin E; 8702, both agents, and 8696, placebo. Analysis reflect the final data collected by the study sites on their participants through July 5, 2011. INTERVENTIONS: Oral selenium (200 µg/d from L-selenomethionine) with matched vitamin E placebo, vitamin E (400 IU/d of all rac-α-tocopheryl acetate) with matched selenium placebo, both agents, or both matched placebos for a planned follow-up of a minimum of 7 and maximum of 12 years. MAIN OUTCOME MEASURES: Prostate cancer incidence. RESULTS: This report includes 54,464 additional person-years of follow-up and 521 additional cases of prostate cancer since the primary report. Compared with the placebo (referent group) in which 529 men developed prostate cancer, 620 men in the vitamin E group developed prostate cancer (hazard ratio [HR], 1.17; 99% CI, 1.004-1.36, P = .008); as did 575 in the selenium group (HR, 1.09; 99% CI, 0.93-1.27; P = .18), and 555 in the selenium plus vitamin E group (HR, 1.05; 99% CI, 0.89-1.22, P = .46). Compared with placebo, the absolute increase in risk of prostate cancer per 1000 person-years was 1.6 for vitamin E, 0.8 for selenium, and 0.4 for the combination. CONCLUSION: Dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT00006392.

Statin Clinical Trial (REALITY) for prostate cancer: an over 15-year wait is finally over thanks to a dietary supplement.

Support for a prescription statin clinical trial for the prevention or treatment of prostate cancer has been lacking, although recent data have provoked interest in such a study. The authors have initiated a pilot trial of red yeast rice (RYR) extract and prostate cancer. RYR significantly reduces low-density lipoprotein and is an option for statin-intolerant patients. RYR appears to be an adequate proxy for some statins as long as quality control is monitored. The REALITY (REduction in Active surveillance Lipid Indices Through Yeast of red rice) trial will be conducted in Toronto, Canada.

MRI-guided transurethral ultrasound therapy of the prostate gland using real-time thermal mapping: initial studies.

OBJECTIVE: To confirm the correlation between planning and thermal injury of the prostate as determined by magnetic resonance imaging (MRI) and histology in canine and humans treated with transurethral ultrasound. MATERIAL AND METHODS: Canine studies: 2 sets of in vivo studies were performed under general anesthesia in 1.5 T clinical MRI. Nine dogs were treated using single transducer; 8 dogs were treated using urethral applicator with multiple transducers. Rectal cooling was maintained. After initial imaging, a target boundary was selected and high-intensity ultrasound energy delivered. The spatial temperature distribution was measured continuously every 5 seconds with MR thermometry using the proton-resonant frequency shift method. The goal was to achieve 55 °C at the target boundary. After treatment, the prostate was harvested and fixed with adjoining tissue, including rectum. Temperature maps, anatomical images, and histologic sections were registered to each other and compared. Human studies: To date, 5 patients with localized prostate cancer have been treated immediately before radical prostatectomy. Approximately 30% of the gland volume was targeted. RESULTS: A continuous pattern of thermal coagulation was successfully achieved within the target region, with an average spatial precision of 1-2 mm. Radical prostatectomy was routine, with an uncomplicated postoperative course in all patients. The correlation between anatomical, thermal, and histologic images was ≤3 mm. Treatment time was <30 minutes. No thermal damage to rectal tissue was observed. CONCLUSIONS: Thermal ablation within the prescribed target of the prostate has been successfully demonstrated in canine studies. The treatment is also feasible in humans.

Micronutrients attenuate progression of prostate cancer by elevating the endogenous inhibitor of angiogenesis, platelet factor-4.

BACKGROUND: Longstanding evidence implicates an inadequate diet as a key factor in the onset and progression of prostate cancer. The purpose herein was to discover, validate and characterize functional biomarkers of dietary supplementation capable of suppressing the course of prostate cancer in vivo. METHODS: The Lady transgenic mouse model that spontaneously develops prostate cancer received a diet supplemented with a micronutrient cocktail of vitamin E, selenium and lycopene ad libitum. A proteomic analysis was conducted to screen for serum biomarkers of this dietary supplementation. Candidate peptides were validated and identified by sequencing and analyzed for their presence within the prostates of all mice by immunohistochemistry. RESULTS: Dietary supplementation with the combined micronutrients significantly induced the expression of the megakaryocyte-specific inhibitor of angiogenesis, platelet factor-4 (P = 0.0025). This observation was made predominantly in mice lacking tumors and any manifestations associated with progressive disease beyond 37 weeks of life, at which time no survivors remained in the control group (P < 0.0001). While prostates of mice receiving standard chow were enlarged and burdened with poorly differentiated carcinoma, those of mice on the supplemented diet appeared normal. Immunohistochemical analysis revealed marked amplifications of both platelet binding and platelet factor-4 within the blood vessels of prostates from mice receiving micronutrients only. CONCLUSION: We present unprecedented data whereby these combined micronutrients effectively promotes tumor dormancy in early prostate cancer, following initiation mutations that may drive the angiogenesis-dependent response of the tumor, by inducing platelet factor-4 expression and concentrating it at the tumor endothelium through enhanced platelet binding.

A combination of micronutrients is beneficial in reducing the incidence of prostate cancer and increasing survival in the Lady transgenic model.

We have previously shown that administration of a combination of micronutrients (selenium, vitamin E, and lycopene) inhibits prostate cancer (PCa) development in the Lady transgenic model. In the present study, we examine timing of initiation of micronutrients, and the effect of micronutrient combinations, on PCa development in Lady transgenic model. Transgenic males were randomized to either a control diet; control diet supplemented with human equivalent doses of vitamin E, selenium, and lycopene (E+S+L); or control diet supplemented with vitamin E and selenium (E+S). In separate experiments, the combination of E+S+L was initiated at varying time points (4, 8, 20, and 36 weeks of age). A combination of E+S+L resulted in a significant reduction in PCa and liver metastasis when intervention was commenced within 8 weeks of age (P < 0.0001). Immunohistochemical analysis revealed a strong correlation between disease-free state with up-regulation of the prognostic marker p27(Kip1) (P < 0.0001) and decreased expression of proliferating cell nuclear antigen and significantly increased apoptotic index (P < 0.0001). On the contrary, a combination of E+S was not effectual in preventing PCa, with a high proportion (84.6%) of animals developing PCa and a small proportion (11.5%) developing high-grade PIN. Early commencement of micronutrients (E+S+L) is beneficial in reducing PCa. Lycopene is an essential component of the combination and effective (when used with E+S) for PCa prevention. These observations provide support for their chemopreventive effect and some clues about their mechanism of action. These key findings will be complementary to the outcome from the Selenium and Vitamin E Chemoprevention Trial.

The impact of diet and micronutrient supplements on the expression of neuroendocrine markers in murine Lady transgenic prostate.

BACKGROUND: Neuroendocrine (NE) differentiation (NED) in prostate cancer (PCa) is associated with morbidity and death; however, the underlying cause(s) promoting NED in PCa have yet to be determined. In this study, we examined the effect of both diet and micronutrient supplementation on the expression of NE markers using the Lady (12T-10) transgenic model of PCa. Lady (12T-10) transgenic animals develop advanced adenocarcinoma with NE characteristics that exhibits metastases in approximately 80% of cases. In this model a high fat diet has been shown to increase the severity of disease, while the use of micronutrients can inhibit this progression. METHODS: In this study we used immunohistochemical analysis to determine expression of the NE markers: chromogranin A (CgA), neuron-specific enolase (NSE), bombesin, parathyroid hormone-related peptide (PTHrP), neurotensin and serotonin in prostates of PCa-bearing Lady (12T-10) mice. RESULTS: High fat diet was correlated with significantly elevated expression of CgA and serotonin in prostate tissue of Lady (12T-10) mice. Addition of micronutrients to the control and high fat diet reproducibly elevated PTHrP and bombesin expression and suppressed NSE expression, while prostate tissue from the control diet supplemented with micronutrients exhibited significantly lower numbers of calcitonin- and neurotensin-positive cells. CONCLUSIONS: These results highlight the importance of dietary control in management of disease and identify differential changes in NE marker expression, which may be diagnostically viable in monitoring the impact of therapies on disease status.

Antioxidants block prostate cancer in lady transgenic mice.

The development of chemopreventive agents against prostate cancer would benefit from conclusive evidence of their efficacy in animal models that emulate human disease. To date there has been little in vivo evidence supporting their preventive capabilities. The 12T-10 Lady transgenic model spontaneously develops localized prostatic adenocarcinoma and neuroendocrine cancer followed by metastases, recapitulating the natural history of human prostate cancer in many respects. Using male Lady version of the transgenic adenocarcinoma of the mouse prostate mice, we show that administration of antioxidants (vitamin E, selenium, and lycopene) in the diet dramatically inhibits prostate cancer development and increases the disease free survival. Treatment of animals with the antioxidants resulted in a 4-fold reduction in the incidence of prostate cancer compared with the untreated animals. Prostate cancer developed in 73.68% (14 of 19) and 100% (19 of 19) of the animals from the standard and high fat diet, respectively. In contrast, only 10.53% (2 of 19) and 15.79% (3 of 19; P < 0.0001) of the animals in the standard and high fat diets supplemented with antioxidants developed tumors. The micronutrients were well tolerated with no evidence of antioxidant-related toxicity. Histopathological analysis confirmed absence of cancer in the additive treated groups. Immunohistochemistry demonstrated a strong correlation between disease-free state and increased levels of the prognostic marker p27(Kip1) and a marked decrease in proliferating cell nuclear antigen expression. These observations provide support for the chemopreventive effect of these micronutrients and some clues as to their mechanism of action.

Soy consumption and phytoestrogens: effect on serum prostate specific antigen when blood lipids and oxidized low-density lipoprotein are reduced in hyperlipidemic men.

PURPOSE: Herbal remedies high in phytoestrogens have been shown to reduce serum prostate specific antigen (PSA) and have been proposed as a treatment for prostate cancer. Soy proteins used to lower serum cholesterol are rich sources of phytoestrogens. Therefore, we assessed the effect of soy consumption on serum PSA in men who had participated in cholesterol lowering studies. MATERIALS AND METHODS: For 3 to 4 weeks 46 healthy middle-aged men with a range of starting PSA values took soy (mean 44 gm. soy protein daily, 116 mg. isoflavones daily) or control foods, and a subgroup of men took a lower level of soy supplements for 3 months. PSA was measured at the start and end of each treatment. RESULTS: Soy had no significant effect on serum total or free PSA, independent of PSA starting value or isoflavone intake. The lack of effect on PSA was seen, although soy intake was sufficient to reduce low-density lipoprotein cholesterol (5.8 +/- 2.2%, p = 0.012), the estimated coronary heart disease risk (6.1 +/- 2.8% for 10 years, p = 0.032) and the serum concentration of oxidized low-density lipoprotein measured as conjugated dienes (9.5 +/- 3.4%, p = 0.008) in the 3 to 4-week study. In addition, the lack of effect of soy on PSA persisted for the 3 months of the extended study. CONCLUSIONS: At levels of soy intake which reduce low-density lipoprotein cholesterol any potential benefits of soy consumption on prostate cancer are likely to occur for reasons other than alterations in hormone activity.

Analytical accuracy and reliability of commonly used nutritional supplements in prostate disease.

PURPOSE: We determine the analytical accuracy and reliability of commonly used nutritional supplements for prostate disease by comparing the amounts of active ingredients of several brands of vitamin E, vitamin D, selenium, lycopene and saw palmetto. We also compared the amounts of active compound in different lots of the same brand to determine the consistency of the manufacturing process. MATERIALS AND METHODS: Samples purchased at pharmacies and specialty stores were sent for independent chemical analysis. The measured dose was compared to the stated dose on the product label. Analysis of variance was performed to test for significance in interlot reliability. RESULTS: Vitamin E (7 samples) and selenium (5) were within a range of -41% to +57% and -19% to +23% of the stated dosage, respectively. All vitamin D brands (4 samples) were within 15% of the stated dose. Saw palmetto (6 samples) were within a range -97% to +140% of the stated dosages with 3 containing less than 20% of the stated dosages. Lycopene brands were between -38% and +143% of stated dosages. Among the reliability assays 1 of 3 brands of vitamin E, 1 of 2 brands of selenium and 1 of 2 brands of saw palmetto demonstrated statistical differences in interlot dosage (p <0.0055, approximate 20% to 25% differences in dose). The 1 assayed form of vitamin D was reliable between lots. CONCLUSIONS: Commonly used nutritional supplements for prostate disease vary widely in measured dose. Saw palmetto demonstrated tremendous variability with some samples containing virtually no active ingredients. In contrast, the more regulated substances we measured, such as vitamins and minerals, demonstrated less variation.

Selenium modulation of cell proliferation and cell cycle biomarkers in human prostate carcinoma cell lines.

Prostate cancer (PCA) is the most common histological malignancy and the second leading cause of cancer deaths among North American men. There has been considerable interest in the chemopreventative properties of selenium. In this study, we assessed whether selenium inhibits cell growth and associated cell cycle regulatory proteins. Human PCA cells (LNCaP, PC3, PC3-AR2, and PC3-M) were incubated with and without selenium (Seleno-DL-methionine, 150 microM) for 24, 48, and 72 h. Cells were fixed and stained with propidium iodide for flow cytometry analysis. In parallel experiments, total protein was extracted, immunoprecipitated with cyclin E antibody, and analyzed by Western blot for the expression of cell cycle markers. Treatment with selenium caused G1 arrest and an 80% reduction in the S phase of LNCaP with no effect on PC3. However, PC3 cells transfected with the androgen receptor (PC3-AR2) exhibited a G2/M arrest and a marked reduction (57%) in the S phase during cell cycle progression. In the analysis of cell cycle regulatory molecules, selenium-treated cells demonstrated a significant induction of cyclin-dependent kinase inhibitors Cip1/p21 and Kip1/p27. These data suggest that selenium possesses strong antiproliferative properties in regard to human PCA. This effect appears to be dependent on the presence of a functioning androgen receptor. This provides a theoretical basis for Phase III studies of selenium in PCA prevention.