Histopathological evidence for an association of inflammation with ductal pin-like lesions but not with ductal adenocarcinoma in the prostate of the noble rat

Deregulation of ABCG1 early in life contributes to prostate carcinogenesis in maternally malnourished offspring rats

AIMS

The developmental Origins of Health and Disease (DOHaD) concept has provided the framework to assess how early life experiences can shape health and disease throughout the life course. Using a model of maternal exposure to a low protein diet (LPD; 6% protein) during the gestational and lactational periods, we demonstrated changes in the ventral prostate (VP) transcriptomic landscape in young rats exposed to maternal malnutrition. Male offspring Sprague Dawley rats were submitted to maternal malnutrition during gestation and lactation, and they were weighed, and distance anogenital was measured, followed were euthanized by an overdose of anesthesia at 21 postnatal days. Next, the blood and the ventral prostate (VP) were collected and processed by morphological analysis, biochemical and molecular analyses. RNA-seq analysis identified 411 differentially expressed genes (DEGs) in the VP of maternally malnourished offspring compared to the control group. The molecular pathways enriched by these DEGs are related to cellular development, differentiation, and tissue morphogenesis, all of them involved in both normal prostate development and carcinogenesis. Abcg1 was commonly deregulated in young and old maternally malnourished offspring rats, as well in rodent models of prostate cancer (PCa) and in PCa patients. Our results described ABCG1 as a potential DOHaD gene associated with perturbation of prostate developmental biology with long-lasting effects on carcinogenesis in old offspring rats. A better understanding of these mechanisms may help with the discussion of preventive strategies against early life origins of non-communicable chronic diseases.

Aerobic physical exercise modifies the prostate tumoral environment

Exercise is recognized for its potential role in reducing the risk of certain cancers. However, the molecular mechanisms behind this risk reduction are not fully understood. Here, we hypothesized that aerobic physical exercise induces cancer attenuating effects through the modulation of oxidative stress and inflammation. To test this hypothesis, twenty male Sprague Dawley rats with chemically induced prostate tumors were divided into two groups: Prostate cancer (PC) in the absence and presence of exercise (PC + Ex). Rats in the PC + Ex group performed exercises on a treadmill for 8 weeks, 5 sessions per week, at an intensity of 60 % of maximum capacity. Weight and feed efficiency, Ki-67, apoptosis, prostatic inflammation, and markers of oxidative stress were analyzed. We found that aerobic physical exercise significantly decreased prostate cell proliferation (p < 0.05) across modulation, tumor size, and prostate weight. The PC + Ex group also significantly reduced anti-apoptosis protein expression (p < 0.05) and increased pro-apoptotic protein expression. Furthermore, physical exercise increased enzymatic antioxidant defenses in the prostate, plasma, and whole blood. Moreover, PC + Ex reduced lipid peroxidation and protein carbonyl levels (p < 0.05). In the prostate, there was an increase in anti-inflammatory cytokines (IL-10), and a reduction in pro-inflammatory cytokines (IL-6, TNF-α, and NF-κB) after 8 weeks of physical exercise. In conclusion, we found that aerobic physical exercise is a functional, beneficial, and applicable approach to control PC progression, because it modifies the systemic environment, including the regulation of glucose and circulating lipids. This modification of the cancer cells environment has anti-inflammatory and antioxidant effects that attenuate tumor growth.

Early-life origin of prostate cancer through deregulation of miR-206 networks in maternally malnourished offspring rats

The Developmental Origins of Health and Disease (DOHaD) concept has provided the framework to assess how early life experiences can shape health and disease throughout the life course. While maternal malnutrition has been proposed as a risk factor for the developmental programming of prostate cancer (PCa), the molecular mechanisms remain poorly understood. Using RNA-seq data, we demonstrated deregulation of miR-206-Plasminogen (PLG) network in the ventral prostate (VP) of young maternally malnourished offspring. RT-qPCR confirmed the deregulation of the miR-206-PLG network in the VP of young and old offspring rats. Considering the key role of estrogenic signaling pathways in prostate carcinogenesis, in vitro miRNA mimic studies also revealed a negative correlation between miR-206 and estrogen receptor α (ESR1) expression in PNT2 cells. Together, we demonstrate that early life estrogenization associated with the deregulation of miR-206 networks can contribute to the developmental origins of PCa in maternally malnourished offspring. Understanding the molecular mechanisms by which early life malnutrition affects offspring health can encourage the adoption of a governmental policy for the prevention of non-communicable chronic diseases related to the DOHaD concept.

The Translational Role of Animal Models for Estrogen-Related Functional Bladder Outlet Obstruction and Prostatic Inflammation

The prevalence of LUTS and prostatic diseases increases with age both in humans and companion animals, suggesting that a common underlying cause of these conditions may be age-associated alterations in the balance of sex hormones. The symptoms are present with different and variable micturition dysfunctions and can be assigned to different clinical conditions including bladder outlet obstruction (BOO). LUTS may also be linked to chronic non-bacterial prostatitis/chronic pelvic pain syndrome (CP/CPPS), but the relationship between these conditions is unknown. This review summarizes the preclinical data that supports a role for excessive estrogen action in the development of obstructive voiding and nonbacterial prostatic inflammation. Preclinical studies that are emphasized in this review have unequivocally indicated that estrogens can induce functional and structural changes resembling those seen in human diseases. Recognizing excessive estrogen action as a possible hormonal basis for the effects observed at multiple sites in the LUT may inspire the development of innovative treatment options for human and animal patients with LUTS associated with functional BOO and CP/CPPS.

Why Do Epidemiologic Studies Find an Inverse Association Between Intraprostatic Inflammation and Prostate Cancer: A Possible Role for Colliding Bias?

Inflammation is an emerging risk factor for prostate cancer based largely on evidence from animal models and histopathologic observations. However, findings from patho-epidemiologic studies of intraprostatic inflammation and prostate cancer have been less supportive, with inverse associations observed in many studies of intraprostatic inflammation and prostate cancer diagnosis. Here, we propose collider stratification bias as a potential methodologic explanation for these inverse findings and provide strategies for conducting future etiologic studies of intraprostatic inflammation and prostate cancer.

Characterization a model of prostatic diseases and obstructive voiding induced by sex hormone imbalance in the Wistar and Noble rats

Background

Chronic nonbacterial prostatitis associated with lower urinary tract symptoms (LUTS) is a prevalent condition in men. One potential pathophysiological factor is change in sex hormone, testosterone and estrogen, balance. Inflammation, cancer and obstructive voiding has been induced in the Noble rat strain by altering levels of sex hormones. We evaluated if imbalance of sex hormones could induce comparable diseases also in a less estrogen sensitive Wistar strain rats.

Methods

Subcutaneous testosterone (830 µg/day) and 17β-estradiol (83 µg/day) hormone pellets were used in male Wistar and Noble strain rats to induce prostatic diseases. The rats were followed for 13 and 18 weeks. Urodynamical measurements were performed at the end of the study under anesthesia. Prostates were collected for further histological analysis. A panel of cytokines were measured from collected serum samples.

Results

Noble rats exhibited stromal and glandular inflammation after 13 weeks that progressed into more severe forms after 18 weeks of hormonal treatment. CD68-positive macrophages were observed in the stromal areas and inside the inflamed acini. CD163-positive macrophages were present in the stromal compartment but absent inside inflammatory foci or prostate acini. Thirteen-week hormonal treatment in Noble rats induced obstructive voiding, which progressed to urinary retention after 18-weeks treatment. In the Wistar rats 18-week treatment was comparable to the 13-week-treated Noble rats judged by progression of prostatic inflammation, being also evident for obstructive voiding. Incidence of PIN-like lesions and carcinomas in the periurethal area in Noble rats were high (100%) but lower (57%) and with smaller lesions in Wistar rats. Serum cytokines leptin, CCL5, and VEGF concentrations showed a decrease in the hormone-treated rats compared to placebo-treated rats.

Conclusions

Prostate inflammation and obstructive voiding developed also in the Wistar rats but more slowly than in Noble rats. Male non-castrated Wistar strain rats may thus be suitable to use in studies of pathophysiology and hormone-dependent prostate inflammation and obstructive voiding.

Elevated seminal plasma estradiol and epigenetic inactivation of ESR1 and ESR2 is associated with CP/CPPS

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is associated with urinary tract symptoms and hormonal imbalances amongst others. The heterogeneous clinical presentation, unexplored molecular background and lack of prostate biopsies complicate therapy. Here, using liquid biopsies, we performed a comprehensive translational study on men diagnosed with CP/CPPS type III (n= 50; median age 39.8, range 23-65) and age-matched controls (n= 61; median age 36.8, range 20-69), considering biochemical parameters of blood and ejaculates, and epigenetic regulation of the estrogen receptor genes (ESR1 and ESR2) in leukocytes isolated from blood (systemic regulation) and in somatic cells isolated from ejaculates (local regulation). We found elevated 17β-estradiol (E2) levels in seminal plasma, but not in blood plasma, that was significantly associated with CP/CPPS and impaired urinary tract symptoms. In ejaculated somatic cells of CP/CPPS patients we found that ESR1 and ESR2 were both significantly higher methylated in CpG-promoters and expressionally down-regulated in comparison to controls. Mast cells are reported to contribute to CP/CPPS and are estrogen responsive. Consistent with this, we found that E2 -treatment of human mast cell lines (HMC-1 and LAD2) resulted in altered cytokine and chemokine expression. Interestingly, in HMC-1 cells, possessing epigenetically inactivated ESR1 and ESR2, E2 -treatment led to a reduced transcription of a number of inflammatory genes. Overall, these data suggest that elevated local E2 levels associate with an epigenetic down-regulation of the estrogen receptors and have a prominent role in CP/CPPS. Investigating E2 levels in semen could therefore serve as a promising biomarker to select patients for estrogen targeted therapy.

Long-term oral exposure to safe dose of bisphenol A in association with high-fat diet stimulate the prostatic lesions in a rodent model for prostate cancer

BACKGROUND

Studies have shown that exposure to environmental chemicals known as endocrine disruptors can cause permanent changes in genital organs, such as the prostate. Among these environmental chemicals stands out bisphenol A (BPA). Another factor associated with prostate changes is the consumption of a high-fat diet. Although the relationship between the consumption of a high-fat diet and an increased risk of prostate cancer is well established, the mechanisms that lead to the establishment of this disease are not completely understood, nor the simultaneous action of BPA and high-fat diet.

METHODS

Adult gerbils (100 days old) were divided in four groups (n = 6 per group): Control (C): animals that received a control diet and filtered water; Diet (D): animals that received a high-fat diet and filtered water; BPA: animals that received a control diet and BPA - 50 µg kg^-1 day^-1 in drinking water; BPA + Diet (BPA + D): animals that received a high-fat diet + BPA - 50 µg kg^-1 day^-1 in drinking water. After the experimental period (6 months), the dorsolateral and ventral prostate lobes were removed, and analyzed by several methods.

RESULTS

Histological analysis indicated premalignant and malignant lesions in both prostatic lobes. However, animals of the D, BPA, and BPA + D groups showed a higher incidence and larger number of prostatic lesions; inflammatory foci were also common. Markers to assess prostate lesions, such as increased activation of the DNA repair system (PCNA-positive cells), androgen receptor (AR), and number of basal cells, confirmed the histology. However, serum levels of testosterone did not change under the experimental conditions.

CONCLUSIONS

The results indicated that the methodology used was effective in generating metabolic changes, which directly compromised prostatic homeostasis. Diet and BPA appear to modulate the activation of the AR pathway and thereby optimize tumor establishment in the gerbil prostate.

Combinatorial Effect of Abiraterone Acetate and NVP-BEZ235 on Prostate Tumor Progression in Rats

Use of drug combinations that target different pathways involved in the development and progression of prostate cancer (PCa) has emerged as an alternative to overcome the resistance caused by drug monotherapies. The antiandrogen abiraterone acetate and the PI3K/Akt inhibitor NVP-BEZ235 (BEZ235) may be suitable options for the prevention of drug resistance and the inhibition of PCa progression. The aim of the present study was to evaluate whether abiraterone acetate and BEZ235 achieve superior therapeutic effects to either drug administered as monotherapy, in the early stages of PCa in an androgen-dependent system. Our study showed that each drug might impair tumor growth by reducing proliferation and increasing cell death when administered as monotherapy. However, tumor growth continued to progress with each drug monotherapy and some important side effects were related to BEZ. Conversely, when used in combination, the drugs impaired the inflammatory response, decreased hyperplastic lesions, and blocked tumor progression from premalignant to a malignant stage. Our data showed that the strategy to block the androgenic and PI3K/AKT/mTOR pathway is an effective therapeutic option and should be investigated including distinct PI3K pathway inhibitors.

Stromal Androgen Receptor in Prostate Cancer Development and Progression

Prostate cancer development and progression is the result of complex interactions between epithelia cells and fibroblasts/myofibroblasts, in a series of dynamic process amenable to regulation by hormones. Whilst androgen action through the androgen receptor (AR) is a well-established component of prostate cancer biology, it has been becoming increasingly apparent that changes in AR signalling in the surrounding stroma can dramatically influence tumour cell behavior. This is reflected in the consistent finding of a strong association between stromal AR expression and patient outcomes. In this review, we explore the relationship between AR signalling in fibroblasts/myofibroblasts and prostate cancer cells in the primary site, and detail the known functions, actions, and mechanisms of fibroblast AR signaling. We conclude with an evidence-based summary of how androgen action in stroma dramatically influences disease progression.

Long-term effects of perinatal exposure to low doses of cadmium on the prostate of adult male rats

Developmental toxicity caused by environmental exposure to heavy metals during the perinatal period has raised questions about offspring health. Cadmium (Cd) is an endocrine-disrupting chemical with the potential to interfere with morphogenesis and susceptibility to diseases in reproductive organs. Taking into account that in the rat prostate morphogenesis occurs during the perinatal period, and that pregnant females absorb and retain more dietary Cd than their non-pregnant counterparts, it is important to understand the effects of perinatal Cd exposure on the adult rat prostate. Therefore this study investigated the effects of gestational and lactational Cd exposure on adult offspring rat prostate histopathology. Pregnant rats (n = 20) were divided into two groups: Control (treated with aqueous solution of sodium acetate 10 mg/l) and treated (treated with aqueous solution of cadmium acetate 10 mg/l) administered in the drinking water. After weaning, male offspring from different litters (n = 10) received food and water 'ad libitum'. The animals were euthanized at postnatal day 90 (PND90), the ventral prostates (VPs) were removed, weighed and examined histopathologically. Blood was collected for the measurement of testosterone (T) levels. Immunohistochemistry for androgen receptor (AR) and Ki67, and a TUNEL assay were performed. There were no differences in T levels, cell proliferation and apoptosis indexes, or AR immunostaining between the experimental groups. Stromal inflammatory foci and multifocal inflammation increased significantly in the treated group. These changes were associated with inflammatory reactive epithelial atypia and stromal fibrillar rearrangement. In conclusion, VP was permanently affected by perinatal Cd exposition, with increased incidence of inflammatory disorders with ageing.

Identification of secretaglobin Scgb2a1 as a target for developmental reprogramming by BPA in the rat prostate

Secretoglobins are a superfamily of secreted proteins thought to participate in inflammation, tissue repair, and tumorigenesis. Secretoglobin family 2A member 1 (Scgb2a1) is a component of prostatein, a major androgen-binding protein secreted by the rat prostate. Using a rat model for developmental reprogramming of susceptibility to prostate carcinogenesis, we identified, by RNA-seq, that Scgb2a1 is significantly upregulated (>100-fold) in the prostate of adult rats neonatally exposed to bisphenol A (BPA), with increased gene expression confirmed by quantitative RT-PCR and chromatin immunoprecipitation for histone H3 lysine 9 acetylation. Bisulfite analysis of both CpG islands located within 10 kb of the Scgb2a1 promoter identified significant hypomethylation of the CpG island upstream of the transcription start site of this gene in the reprogrammed prostate. These data suggest that expression of Scgb2a1 in the adult prostate could be epigenetically reprogrammed by BPA exposure during prostate development, with potential implications for cancer risk and response to chemotherapeutics associated with prostatein binding.

MSMB variation and prostate cancer risk: clues towards a possible fungal etiology

BACKGROUND. With recent advances in high-throughput sequencing technologies, many prostate cancer risk loci have been identified, including rs10993994, a single nucleotide polymorphism (SNP) located near the MSMB gene. Variant allele (T) carriers of this SNP produce less prostate secretory protein 94 (PSP94), the protein product of MSMB, and have an increased risk of prostate cancer (approximately 25% per T allele), suggesting that PSP94 plays a protective role in prostate carcinogenesis, although the mechanisms for such protection are unclear. METHODS. We reviewed the literature on possible mechanisms for PSP94 protection for prostate cancer. RESULTS. One possible mechanism is tumor suppression, as PSP94 has been observed to inhibit cell or tumor growth in in vitro and in vivo models. Another novel mechanism, which we propose in this review article, is that PSP94 may protect against prostate cancer by preventing or limiting an intracellular fungal infection in the prostate. This mechanism is based on the recent discovery of PSP94's fungicidal activity in low-calcium environments (such as the cytosol of epithelial cells), and accumulating evidence suggesting a role for inflammation in prostate carcinogenesis. We provide further details of our proposed mechanism in this review article. CONCLUSIONS. To explore this mechanism, future studies should consider screening prostate specimens for fungi using the rapidly expanding number of molecular techniques capable of identifying infectious agents from the entire tree of life.

L-selenomethionine does not protect against testosterone plus 17β-estradiol-induced oxidative stress and preneoplastic lesions in the prostate of NBL rats

Previous animal studies examining dietary selenium effects on prostatic carcinogenesis did not show preventive benefit, including 1 study in a rat model involving testosterone (T) and estradiol (E2)-induced prostatic oxidative stress. Here, we examined modulation of T + E2-induced prostatic oxidative stress, dysplasia, and inflammation by L-selenomethionine at 1.5 or 3.0 mg selenium/kg in NIH-07 diet in Noble (Nbl)/Crl rats treated with T + E2 for 16 wk. Hormone treatment increased immunohistochemical staining for 8-hydroxydeoxyguanosine (8-OHdG) in the prostatic sites of T + E2-induced preneoplasia (P < 0.05), but selenomethionine did not attenuate 8-OHdG staining and dysplasia in the lateral prostate. Glutathione-peroxidase activity (P < 0.05) and mRNA expression were induced by T + E2 (P < 0.0001) but not changed by selenomethionine. Selenomethionine did not cause significant responses in expression and activity of glutathione-peroxidase and MnSOD, except for a reduction of MnSOD protein expression in the lateral prostate (P < 0.01). The absence of reduction of oxidative stress and dysplasia and the minimal effects on antioxidant enzymes caused by selenomethionine are consistent with the null effects observed in selenium supplementation animal studies and clinical trials. Significant (P < 0.01) opposite apoptosis/cell proliferation balance responses to selenomethionine and to T + E2 occurred in the lateral and dorsal prostate, explaining why T + E2 induces lesions selectively in the lateral lobe of NBL rats.

Tumor models for prostate cancer exemplified by fibroblast growth factor 8-induced tumorigenesis and tumor progression

Prostate cancer is a very common malignancy among Western males. Although most tumors are indolent and grow slowly, some grow and metastasize aggressively. Because prostate cancer growth is usually androgen-dependent, androgen ablation offers a therapeutic option to treat post-resection tumor recurrence or primarily metastasized prostate cancer. However, patients often relapse after the primary response to androgen ablation therapy, and there is no effective cure for cases of castration-resistant prostate cancer (CRPC). The mechanisms of tumor growth in CRPC are poorly understood. Although the androgen receptors (ARs) remain functional in CRPC, other mechanisms are clearly activated (e.g., disturbed growth factor signaling). Results from our laboratory and others have shown that dysregulation of fibroblast growth factor (FGF) signaling, including FGF receptor 1 (FGFR1) activation and FGF8b overexpression, has an important role in prostate cancer growth and progression. Several experimental models have been developed for prostate tumorigenesis and various stages of tumor progression. These models include genetically engineered mice and rats, as well as induced tumors and xenografts in immunodeficient mice. The latter was created using parental and genetically modified cell lines. All of these models greatly helped to elucidate the roles of different genes in prostate carcinogenesis and tumor progression. Recently, patient-derived xenografts have been studied for possible use in testing individual, specific responses of tumor tissue to different treatment options. Feasible and functional CRPC models for drug responsiveness analysis and the development of effective therapies targeting the FGF signaling pathway and other pathways in prostate cancer are being actively investigated.

A new proposed rodent model of chemically induced prostate carcinogenesis: distinct time-course prostate cancer progression in the dorsolateral and ventral lobes

BACKGROUND

Characterization of novel rodent models for prostate cancer studies requires evaluation of either spontaneous and carcinogen-induced tumors as well as tumor incidence in different prostatic lobes. We propose a new short-term rodent model of chemically induced prostate carcinogenesis in which prostate cancer progression occurs differentially in the dorsolateral and ventral lobes.

METHODS

Adult gerbils were treated with MNU alone or associated with testosterone for 3 or 6 months of treatment. Tumor incidence, latency, localization, and immunohistochemistry (AR, PCNA, smooth muscle α-actin, p63, MGMT, and E-cadherin) were studied in both lobes.

RESULTS

Comparisons between both lobes revealed that lesions developed first in the DL while the VL presented longer tumor latency. However, after 6 months, there was a dramatic increase in tumor multiplicity in the VL, mainly in MNU-treated groups. Lesions clearly progressed from a premalignant to a malignant phenotype over time and tumor latency was decreased by MNU + testosterone administration. Three-dimensional reconstruction of the prostatic complex showed that the DL developed tumors exclusively in the periurethral area and showed intense AR, PCNA, and MGMT immunostaining. Moreover, VL lesions emerged throughout the entire lobe. MNU-induced lesions presented markers indicative of an aggressive phenotype: lack of basal cells, rupture of the smooth muscle cell layer, loss of E-cadherin, and high MGMT staining.

CONCLUSIONS

There are distinct pathways involved in tumor progression in gerbil prostate lobes. This animal provides a good model for prostate cancer since it allows the investigation of advanced steps of carcinogenesis with shorter latency periods in both lobes.

Alcohol exposure in utero increases susceptibility to prostate tumorigenesis in rat offspring

BACKGROUND

Prenatal alcohol exposure has been shown to increase offspring susceptibility to some chemical carcinogens. Whether prenatal exposure to alcohol makes the offspring more susceptible to the development of prostate cancer is not known. Therefore, we determined whether any functional abnormalities and increased cancer susceptibility exist in the prostate of fetal alcohol-exposed male rats during the adult period.

METHODS

Pregnant rats were fed with a liquid diet containing alcohol (alcohol-fed [AF]), or pair-fed with isocaloric liquid diet (PF) or ad libitum fed with rat chow (ad lib-fed). Male offspring of these rats were given N-Nitroso-N-methylurea and testosterone to induce prostate neoplasia or left untreated. Around 6 to 8 months of age, the prostates of these animals were processed for determination of biochemical changes and histopathologies.

RESULTS

Prostates of noncarcinogen treated animals that were alcohol exposed during the prenatal period demonstrated inflammatory cell infiltration and epithelial atypia and increased number of proliferative cells in the ventral lobe of this gland, but the prostate of control animal showed normal cytoarchitecture. In addition, prenatal alcohol-exposed rats showed decreased levels of cell-cell adhesion marker and increased estrogenic activity in the ventral prostate. Prenatally ethanol (EtOH)-exposed rats, when treated with carcinogen and testosterone, showed histological evidence for high-grade prostatic intraepithelial neoplasia (PIN) primarily in the ventral prostate, whereas control animals showed only low-grade PIN. Prenatally EtOH-exposed rats treated with carcinogen and testosterone also showed increased number of proliferative cells and androgen receptor with concomitant decreased levels of tumor suppressor proteins in the ventral prostate.

CONCLUSIONS

These results suggest for the first time that prenatal EtOH exposures induce histophysiological changes in the prostate as well as it increases the susceptibility of the prostate to develop neoplasia during adulthood.

Histological inflammation and risk of subsequent prostate cancer among men with initially elevated serum prostate-specific antigen (PSA) concentration in the Finnish prostate cancer screening trial

OBJECTIVE

To assess whether histological signs of inflammation are associated with an increased risk of subsequent prostate cancer (PCa) in men with elevated serum prostate-specific antigen (PSA) concentrations and benign initial biopsy.

MATERIALS AND METHODS

Study subjects were men aged 54-67 years with an elevated PSA (≥4 ng/mL or 3-4 ng/mL and free to total PSA ratio ≤0.16 or positive digital rectal examination), but a benign biopsy result within the Finnish population-based randomised screening trial for PCa, which started in 1996. A total of 293 prostate biopsies without PCa or suspicion of malignancy from the first screening round in the Tampere centre were re-evaluated by a uropathologist to assess histological inflammation. Results of the subsequent screening rounds were obtained from the trial database and PCa diagnoses made outside the screening were obtained from the Finnish Cancer Registry. The median length of follow-up was 10.5 years. Cox regression analysis was used to assess PCa risk after the initial benign biopsy.

RESULTS

Histological inflammation was found in 66% of the biopsies. Subjects with inflammation at the biopsy had a slightly lower PCa risk in the second screening round (18 vs 27%, rate ratio 0.69, 95% confidence interval [CI] 0.35-1.34) relative to men without inflammation. In further follow-up, the PCa risk remained nonsignificantly lower (hazard ratio [HR] 0.71, CI 0.46-1.10; P = 0.13). The risk was not appreciably affected by adjustment for age, PSA, prostate volume and family history of PCa (HR 0.67, CI 0.42-1.07; P = 0.092).

CONCLUSIONS

Histological inflammation in a prostate biopsy among men with an initial false-positive screening test was not associated with an increased risk of subsequent PCa, but instead with a decreased risk which was of borderline significance. Inflammation in prostate biopsy is not a useful risk indicator in PCa screening.

Opposing roles of ERα and ERβ in the genesis and progression of adenocarcinoma in the rat ventral prostate

BACKGROUND

Prostate cancer is a common malignancy in men and although hormone ablation therapy is effective, men develop hormone resistance. There is need for therapies applicable earlier, such as treatment of prostatic intraepithelial neoplasia (PIN). Estrogens besides androgens play a role in prostate cancer pathogenesis via two receptors ERα and ERβ and both receptors are thought to play different, opposing, roles with ERα having proliferative properties and ERβ having anti-proliferative properties. To differentiate between the roles both receptors play in prostate cancer an ERα and an ERβ agonist, ERA-45 and ERB-26, have been tested in a rodent model for prostate carcinogenesis.

METHODS

The influence of ERα on prostate cancer progression was studied in intact male rats treated with testosterone in combination with the ERα agonist, ERA-45 for either a long-term (20-week) period or a shorter term (6-week) period. The ERβ agonist was tested in the shorter term model in intact male rats treated with testosterone in combination with the ERα agonist, ERA-45, followed by administration of the ERβ agonist, ERB-26, during the last 2 weeks.

RESULTS

Treatment of rats with testosterone in combination with ERA-45 induced mild PIN lesions at 6 weeks and severe precancerous PIN lesions at 20 weeks. The ERβ agonist prevented the onset of PIN lesions at 6 weeks. Moreover, prostate epithelial cell apoptosis was increased and proliferation was decreased.

CONCLUSION

These findings confirm the opposing roles ERα and ERβ play in prostate carcinogenesis and suggest a therapeutic opportunity of ERβ for treating precancerous PIN lesions.

Estrogens and prostate cancer: etiology, mediators, prevention, and management

The mainstay targets for hormonal prostate cancer (PCa) therapies are based on negating androgen action. Recent epidemiologic and experimental data have pinpointed the key roles of estrogens in PCa development and progression. Racial and geographic differences, as well as age-associated changes, in estrogen synthesis and metabolism contribute significantly to the etiology. This article summarizes how different estrogens/antiestrogens/estrogen mimics contribute to prostate carcinogenesis, the roles of the different mediators of estrogen in the process, and the potentials of new estrogenic/antiestrogenic compounds for prevention and treatment of PCa.

Loss of NADPH quinone oxidoreductase in the prostate and enhanced serum levels of cytokine-induced neutrophil chemoattractant 2alpha in hormone-stimulated noble rats: potential role in prostatic intraepithelial neoplasia development

The Noble rat is an established model for studying hormone-induced development of prostatic intraepithelial neoplasia and prostatic adenocarcinoma. It is known that for a period, hormones in the prostate generate reactive molecules that have the capacity to overwhelm intracellular defenses, damage macromolecules, and modulate redox-regulated signaling pathways leading to increased oxidative stress. Such hormone-induced imbalance in the oxidative stress/antioxidant defense enzymes may lead to neoplastic transformation of the prostate. We investigated alteration in the expression of critical antioxidant defense enzymes, a redox-regulated transcription factor nuclear factor kappaB (NFkappaB) and its downstream target inflammation-associated cyclooxygenase 2 (Cox-2) in the prostate from hormone-stimulated Noble rats using immunohistochemistry. Further, we also analyzed serum levels of cytokines and chemokines associated with inflammation using multiplex immunoassay. Our results show that there was no significant change in the expression of glutathione peroxidase, glutathione S-transferase pi, superoxide dismutase, or catalase. However, the level of NADPH quinone oxidoreductase decreased in hormone-stimulated animals compared with their unstimulated counterparts. Further, the prostate from hormone-stimulated rats showed very strong expressions of p65, Cox-2, and NFkappaB DNA binding activity. In addition, the cytokine-induced neutrophil chemoattractant 2alpha was significantly upregulated by more than 10-fold (P = .001) in serum from animals stimulated with hormones. Although further studies are required, we speculate that activation of NFkappaB/cytokine-induced neutrophil chemoattractant 2alpha/Cox-2 along with modulation of antioxidant defense mechanisms may create a proinflammatory environment suitable for tumor growth and survival.

Serum bisphenol A pharmacokinetics and prostate neoplastic responses following oral and subcutaneous exposures in neonatal Sprague-Dawley rats

The present study examines BPA pharmacokinetics in neonatal rats following s.c. injection or oral delivery of 10 μg BPA/kg BW and compares susceptibility to estrogen-induced prostate intraepithelial neoplasia (PIN) following either exposure route. Serum BPA in PND3 rats was measured using HPLC-MS-MS. Free and total BPA at C(max) were 1.77 and 2.0 ng/ml, respectively following injection and 0.26 and 1.02 ng/ml, respectively following oral exposure. The AUC(0-2) for free and total BPA was 4.1-fold and 1.8-fold greater, respectively, in s.c. vs. oral delivery. While exposure route affected BPA metabolism, internal dosimetry following s.c. injection of 10 μg BPA/kg BW is similar to BPA levels observed in humans. Prostates from aged rats given s.c. or oral BPA neonatally and T+E implants as adults exhibited nearly identical, heightened susceptibility to PIN incidence and score as compared to neonatal oil-controls. These findings on prostate health are directly relevant to humans at current BPA exposure levels.

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.

Estrogens and bladder outlet obstruction

Increasing evidence indicates a direct interrelationship between benign prostatic hyperplasia and chronic non-bacterial prostatic inflammation in the development of human voiding dysfunction in aging male, which gradually transforms to bladder outlet obstruction (BOO). Increased prevalence of BOO along with the aging process further suggests that estrogen or more precisely decreased androgen to estrogen ratio in serum is involved in the pathogenesis of BOO. In this review, we will analyze the hormonal causes, clinical relevance, and biologically relevant estrogen-modulated animal models potential for BOO study. In light of the data presented in this review, it becomes apparent that direct inhibition of estrogen action may provide important pharmaceutical treatment of the BOO.

Selenomethionine and alpha-tocopherol do not inhibit prostate carcinogenesis in the testosterone plus estradiol-treated NBL rat model

Previous studies with selenium and/or vitamin E in prostate carcinogenesis animal models have been negative, but these models may not involve oxidative stress mechanisms. In this study, we examined the potential of selenomethionine and alpha-tocopherol to modulate prostate cancer development in the testosterone plus estradiol-treated NBL rat, a model that does involve sex hormone-induced oxidative stress mechanisms and prostatic inflammation. One week following the implantation with hormone-filled Silastic implants, rats were fed diets containing l-selenomethionine (1.5 or 3.0 mg/kg), DL-alpha-tocopherol acetate (2,000 or 4,000 mg/kg), or a natural ingredient control diet (NIH-07). The development of prostate carcinomas was not affected by dietary treatment with either agent. Food intake, body weight, and mortality were also not affected. The high dose of selenomethionine reduced the severity of epithelial dysplasia in the lateral prostate that was not associated with inflammation, and alpha-tocopherol reduced in a dose-related fashion the incidence of marked inflammation and marked epithelial dysplasia in the lateral prostate, regardless of whether these lesions were associated with inflammation. alpha-Tocopherol significantly increased the incidence of adenocarcinomas of the mammary glands at both dietary concentrations. Collectively, our findings suggest that selenomethionine and alpha-tocopherol supplementation does not prevent prostate cancer in rats fed diets with nutritionally adequate levels of selenium and vitamin E. Importantly, the results of the current animal studies and those reported previously were fully predictive of the outcome of the Selenium and Vitamin E Cancer Prevention Trial.

Inflammation and epithelial alterations in rat prostate: impact of the androgen to oestrogen ratio

Chronic non-bacterial prostatitis may offer new insights into the pathogenesis of human benign prostatic hyperplasia and prostate cancer and the strategies for their treatment and prevention. The potential significance of androgen replacement therapy in terms of the reversal of oestradiol (E(2))-induced inflammatory reaction was studied in the dorsolateral prostate (DLP) of the Noble rat. Castrated Noble rats were treated with E(2) and different doses of androgens [dihydrotestosterone (DHT) and testosterone (T)] to achieve an elevated concentration of E(2) and a wide range of the androgen-to-oestradiol ratios in serum. After the 3-week treatment, inflammatory changes in the DLP were classified and counted. Oestrogen receptor alpha (ER alpha), progesterone receptor (PR), fos-related antigen-2 (Fra2), Ki-67 and P63 were immunocytochemically stained. T, E(2) and prolactin concentrations in serum were measured and the relative weights of the seminal vesicles and pituitary glands and microscopic structures of the DLP and seminal vesicle ducts were determined. Hypoandrogenic doses of DHT (judged on the basis of seminal vesicle weight gain), dose-dependently increased the number of perivascular and stromal inflammatory infiltrates. T and DHT were anti-inflammatory at the doses which normalized or over stimulated the growth of the seminal vesicles. As signs of anti-oestrogenicity, androgens dose-dependently decreased the number and distribution of the ER alpha and PR-positive cells at proinflammatory concentrations. Anti-inflammatory concentrations were needed to reduce the expression of Fra2, E(2)-increased prolactin concentration in serum and pituitary weight. The androgen concentrations required to prevent proinflammatory and epithelial responses to E(2) in the presence of elevated E(2) concentrations may subject the accessory sex glands to more intense androgenic stimulation than is normal for the male. The androgen-resistant endpoints of oestrogen action (body weight reduction and hyperplasia of seminal vesicle ducts) further indicate limitations in the possible preventive effects of androgen-replacement therapy.