The influence of hypoxia on the prostate cancer proteome.

Prostate cancer accounts for around 15% of male deaths in Western Europe and is the second leading cause of cancer death in men after lung cancer. Mounting evidence suggests that prostate cancer deposits exist within a hypoxic environment and this contributes to radio-resistance thus hampering one of the major therapies for this cancer. Recent reports have shown that nitric oxide (NO) donating non-steroidal anti-inflammatory drugs (NSAIDs) reduced tumour hypoxia as well as maintaining a radio-sensitising/therapeutic effect on prostate cancer cells. The aim of this study was to evaluate the impact of hypoxia on the proteome of the prostate and to establish whether NO-NSAID treatment reverted the protein profiles back to their normoxic status. To this end an established hormone insensitive prostate cancer cell line, PC-3, was cultured under hypoxic and normoxic conditions before and following exposure to NO-NSAID in combination with selected other common prostate cancer treatment types. The extracted proteins were analysed by ion mobility-assisted data independent acquisition mass spectrometry (MS), combined with multivariate statistical analyses, to measure hypoxia-induced alterations in the proteome of these cells. The analyses demonstrated that under hypoxic conditions there were well-defined, significantly regulated/differentially expressed proteins primarily involved with structural and binding processes including, for example, TUBB4A, CIRP and PLOD1. Additionally, the exposure of hypoxic cells to NSAID and NO-NSAID agents, resulted in some of these proteins being differentially expressed; for example, both PCNA and HNRNPA1L were down-regulated, corresponding with disruption in the nucleocytoplasmic shuttling process.

Synthesis and biological evaluation of nitric oxide-donating analogues of sulindac for prostate cancer treatment.

A series of analogues of the non-steroidal anti-inflammatory drug (NSAID) sulindac 1 were synthesised tethered to nitric oxide (NO) donating functional groups. Sulindac shows antiproliterative effects against immortal PC3 cell lines. It was previously demonstrated that the effect can be enhanced when tethered to NO releasing groups such as nitrate esters, furoxans and sydnonimines. To explore this approach further, a total of fifty-six sulindac-NO analogues were prepared and they were evaluated as NO-releasing cytotoxic agents against prostate cancer (PCa) cell lines. Compounds 1k and 1n exhibited significant cytotoxic with IC50 values of 6.1±4.1 and 12.1±3.2µM, respectively, coupled with observed nitric oxide release.

The relevance of a hypoxic tumour microenvironment in prostate cancer.

Research into the hypoxic tumour microenvironment is accelerating and the reversal of hypoxia is increasingly being suggested as a mechanism for improving cancer treatment. Recent studies have suggested that hypoxia is also a feature in prostate cancer and is associated with a poor prognosis. Hypoxia has been shown to cause radio-resistance and hence hamper one of the major treatments for prostate cancer. However, unlike other solid tumours, such as cervical and head-and-neck cancer, there are inconsistencies and unanswered questions about the relevance of hypoxia in prostate cancer. This review outlines the role of low-oxygen conditions in prostate cancer and the areas where further studies are required.

NO-sulindac inhibits the hypoxia response of PC-3 prostate cancer cells via the Akt signalling pathway.

Nitric oxide-donating non-steroidal anti-inflammatory drugs are safer than traditional NSAIDs and inhibit the growth of prostate cancer cells with greater potency than NSAIDs. In vivo, prostate cancer deposits are found in a hypoxic environment which induces resistance to chemotherapy. The aim of this study was to assess the effects and mechanism of action of a NO-NSAID called NO-sulindac on the PC-3 prostate cancer cell line under hypoxic conditions. NO-sulindac was found to have pro-apoptotic, cytotoxic, and anti-invasive effect on PC-3 cells under normoxia and hypoxia. NO-sulindac was significantly more cytotoxic than sulindac at all oxygen levels. The sulindac/linker and NO-releasing subunits both contributed to the cytotoxic effects of NO-sulindac. Resistance of PC-3 cells to NO-sulindac was induced as the oxygen concentration declined. Hypoxia-induced chemoresistance was reversed by knocking-down hypoxia-inducible factor-1alpha (HIF-1alpha) mRNA using RNAi. Nuclear HIF-1alpha levels were upregulated at 0.2% oxygen but reduced by treatment with NO-sulindac, as was Akt phosphorylation. NO-sulindac treatment of hypoxic PC-3 cells transfected with a reporter construct, downregulated activation of the hypoxia response element (HRE) promoter. Co-transfection of PC-3 cells with the HRE promoter reporter construct and myr-Akt (constitutively active Akt) plasmids reversed the NO-sulindac induced reduction in HRE activation. Real-time polymerase chain reaction analysis of hypoxic, NO-sulindac treated PC-3 cells showed downregulation of lysyl oxidase and carbonic anhydrase IX mRNA expression. Collectively, these novel findings demonstrate that NO-sulindac directly inhibits the hypoxia response of PC-3 prostate cancer cells by inhibiting HIF-1alpha translation via the Akt signalling pathway. The ability of NO-sulindac to inhibit tumour adaption to hypoxia has considerable relevance to the future management of prostate cancer with the same cellular properties as PC-3.

Analysis of hypoxia-associated gene expression in prostate cancer: lysyl oxidase and glucose transporter-1 expression correlate with Gleason score.

Prostate cancer cells exist under hypoxic conditions. Hypoxia has a detrimental effect on the efficacy of treatment and final outcome in patients with prostate cancer. There have been a large number of endogenous markers of hypoxia described previously across a range of cancer types, both in vitro and in vivo. The aim of this study was to evaluate the expression of a range of hypoxia-associated genes within benign prostatic hypertrophy (BPH) and prostate cancer tissue. Messenger RNA was extracted from primary prostate tissue obtained from 67 men with benign prostatic hypertrophy or prostate cancer (Gleason score 5 to 10). Real-time polymerase chain reaction was performed to quantify the expression levels of 12 hypoxia-associated genes in these tissues. Expression of lysyl oxidase (LOX) and glucose transporter-1 (GLUT-1) genes were significantly higher in prostate cancer compared with BPH tissue (P<0.05) and correlated with Gleason score (LOX: R=0.297, P=0.015; GLUT-1: R=0.274, P=0.026). HIF-2alpha had a negative correlation with Gleason score (R= -0.309, P=0.012). The remaining hypoxia-associated genes did not show any specific pattern of expression in prostate tissue. Numerous molecules have been proposed as endogenous markers of hypoxia. The findings of this study illustrate that not all hypoxia-associated molecules are relevant to prostate cancer in vivo. However, LOX and GLUT-1 are candidate markers of hypoxia in prostate cancer and may prove useful in identifying patients with hypoxic prostate cancer. Not all hypoxia-associated molecules are relevant in prostate cancer in vivo.

The insulin-like growth factor type 1 receptor and colorectal neoplasia: insights into invasion.

This study examines the expression of the insulin-like growth factor type 1 receptor (IGF-1R) in colorectal neoplasia. Previous studies have shown that the IGF-1R is expressed at high levels in normal embryonic stem cells and in many cancer phenotypes. However, lower IGF-1R levels are expressed in some advanced cancer phenotypes. The timing of and the reasons for these changes in expression during the evolution of a cancer are not understood. Here, we examine IGF-1R expression in the evolution of colorectal cancer by means of Northern blotting and immunohistochemistry validated by tissue and reagent controls and Western blotting. We show for the first time that (1) in normal colorectal crypts, epithelial stem cells in the basal crypt region express high IGF-1R levels, which decrease to low levels when these cells migrate to and differentiate in the mid and upper crypt regions; (2) in tumor initiation in aberrant crypt foci, all of the transformed cells express high levels of the IGF-1R at stem cell levels throughout the crypt axis; (3) in tumor progression in adenomatous and cancerous crypts, tumor cells of an epithelial type morphology express high levels of the IGF-1R; (4) in advanced cancers, low levels of the IGF-1R are expressed in invasive foci where cancer cells dedifferentiate to a mesenchymal-type morphology and show a loss of cell adhesion. Interestingly, these cells can form an alternating pattern with mesenchymal type cells that show cell adhesion and high levels of IGF-1R expression. In summary, this study shows that high-level IGF-1R expression in colorectal neoplasia is initiated by an abnormality of stem cell programmed differentiation in the aberrant crypt focus. However, low-level IGF-1R expression is found in some invasive cancers where it is consequent to cancer cell dedifferentiation to a mesenchymal type morphology with loss of cell adhesion.

Dynamic instrumented palpation - a new method for soft tissue quality assessment: application to prostate disease diagnosis.

The objective is to establish the feasibility of using dynamic instrumented palpation, a novel technique of low-frequency mechanical testing, applied here to diagnose soft tissue condition. The technique is applied, in vitro, to samples of excised prostate gland affected by benign prostate hyperplasia and/or prostate cancer. Particular attention is paid to the relationship between the histological structure of the tissue and the dynamic mechanical properties in an attempt to separate patient-specific aspects from histopathological condition (i.e. prostate cancer or benign prostate hyperplasia). The technique is of clinical interest because it is potentially deployable in vivo. Prostate samples were obtained from a total of 36 patients who had undergone transurethral resection of the prostate to relieve prostatic obstruction and 4 patients who had undergone radical cystoprostatectomy for bladder cancer. Specimens (chips) recovered from transurethral resection of the prostate were of nominal size 5 mm × 8 mm and thicknesses between 2 and 4 mm, whereas those from the cystoprostatectomy were in the form of transverse slices of thickness approximately 6 mm. Specimens were mechanically tested by a controlled strain cyclic compression technique, and the resulting dynamic mechanical properties expressed as the amplitude ratio and phase difference between the cyclic stress and cyclic strain. After mechanical testing, the percentage areas of glandular and smooth muscle were measured at each probe point. Good contrast between the dynamic modulus of chips from benign prostate hyperplasia and prostate cancer patients was demonstrated, and absolute values similar to those published by other authors are reported. For the slices, modulus values were considerably higher than for chips, and good in-patient mechanical contrast was revealed for predominantly nodular and predominantly stromal areas. Extending this classification between patients required pattern recognition techniques. Overall, the study has demonstrated that dynamic mechanical properties can potentially be used for diagnosis of prostate condition using in vivo measurements.

The loss of 5alpha-reductase type I and type II mRNA expression in metastatic prostate cancer to bone and lymph node metastasis.

PURPOSE: Considerable evidence has accumulated demonstrating that the 5alpha-reduction of testosterone to dihydrotestosterone occurs more efficiently in the normal and benign hyperplastic prostate than in prostate cancer tissues. Efforts have also been channeled into investigating the distribution of 5alpha-reductase isoenzymes in primary prostate tissues and in "in vitro" cell models of the human prostate. However, no one has, thus far, examined the expression of these isoenzymes in prostate cancer metastasis, although such studies might shed some light on the mechanism(s) responsible for the loss of hormone sensitivity in those tumors. The present report addresses this issue in the hope that this might help to identify the steps leading to the development of prostate cancer metastasis. EXPERIMENTAL DESIGN: In the present study we used in situ mRNA hybridization of sections from archival paraffin-embedded material to investigate the expression of 5alpha-reductase type I (5alphaR-I) and type II (5alphaR-II) mRNAs in prostate cancer bony (n = 9) and lymph node (n = 13) metastasis, and compared the mRNA distributions with those observed in sections from primary prostate tumors (n = 12). In parallel, sections were investigated for androgen receptor (AR) mRNA expression, and immunostained for AR and prostate-specific antigen. RESULTS: Neither 5alphaR-I nor 5alphaR-II mRNA expression was detected in any of the prostate metastatic lesions, although the same metastatic sites expressed AR mRNA, and stained for cytoplasmic prostate-specific antigen and nuclear AR. In contrast, primary prostate tumors displayed intense staining for 5alphaR-I and 5alphaR-II. CONCLUSION: These findings suggest that the loss of 5alpha-reductase mRNA expression in bone and lymph node metastasis may be associated, in part, with the progression of these tumors to androgen insensitivity.

CYP7B generates a selective estrogen receptor beta agonist in human prostate.

In human prostate, dehydroepiandrosterone (DHEA) is a substrate for two major metabolic pathways that produce functionally opposing sex steroids. In one pathway, DHEA is converted into potent androgens such as testosterone and 5alpha-dihydrotestosterone. In the other, DHEA is metabolized to 7alpha-hydroxy-DHEA (7HD). Recently, CYP7B, a novel P450 enzyme originally characterized in mouse brain and expressed in rodent prostate, has been found to be responsible for all extrahepatic 7alpha-hydroxylase activity. In this study, we have investigated the expression and function of this novel enzyme in human prostate. We have used reverse transcription combined with PCR and mRNA in situ hybridization to determine and localize the expression of CYP7B mRNA in human benign prostatic hyperplasia. High levels of CYP7B mRNA were localized in the epithelial cells together with estrogen receptor beta (ERbeta). 7alpha-Hydroxylation was the major metabolic fate of DHEA in human prostate. Furthermore, we have shown that human prostate epithelial cells in primary culture maintain a high level of 7alpha-hydroxylase activity, which was enhanced by coculture with stroma cells. To investigate the functional relevance of CYP7B expression to sex-steroid action in prostate, we used transient transfections and ligand binding assay to determine the ability of 7HD to bind and activate the sex-steroid receptors: androgen receptor, ERalpha, and ERbeta. 7HD specifically activates ERbeta-mediated transcription, mimicking the effects of 17beta-estradiol, but has no impact on ERalpha and androgen receptor. Given that DHEA, and its sulfate, circulate at micromolar concentrations, there is a clear possibility that CYP7B generates sufficient 7HD to activate ERbeta over and above that achieved with very low concentrations of intraprostatic 17beta-estradiol. In conclusion, our study suggests that CYP7B catalyzes oxysterol 7alpha-hydroxylation within the human prostate epithelium. By this reaction, an ERbeta-specific agonist, 7HD, is produced. Therefore, CYP7B may be a novel regulator of the androgens/estrogenic balance within the prostate.

Estrogen and androgen signaling in the pathogenesis of BPH.

Estrogens and androgens have both been implicated as causes of benign prostatic hyperplasia (BPH). Although epidemiological data on an association between serum androgen concentrations and BPH are inconsistent, it is generally accepted that androgens play a permissive role in BPH pathogenesis. In clinical practice, inhibitors of 5α-reductase (which converts testosterone to the more potent androgen dihydrotestosterone) have proven effective in the management of BPH, confirming an essential role for androgens in BPH pathophysiology. To date, multiple lines of evidence support a role for estrogens in BPH pathogenesis. Studies of the two estrogen receptor (ER) subtypes have shed light on their differential functions in the human prostate; ERα and ERß have proliferative and antiproliferative effects on prostate cells, respectively. Effects of estrogens on the prostate are associated with multiple mechanisms including apoptosis, aromatase expression and paracrine regulation via prostaglandin E2. Selective estrogen receptor modulators or other agents that can influence intraprostatic estrogen levels might conceivably be potential therapeutic targets for the treatment of BPH.

DNA strand breaks and hypoxia response inhibition mediate the radiosensitisation effect of nitric oxide donors on prostate cancer under varying oxygen conditions.

Prostate cancer cells can exist in a hypoxic microenvironment, causing radioresistance. Nitric oxide (NO) is a radiosensitiser of mammalian cells. NO-NSAIDs are a potential means of delivering NO to prostate cancer cells. This study aimed to determine the effect and mechanism of action of NO-sulindac and radiation, on prostate cancer cells and stroma, under normoxia (21% oxygen) and chronic hypoxia (0.2% oxygen). Using clonogenic assays, at a surviving fraction of 10% the sensitisation enhancement ratios of radiation plus NO-sulindac over radiation alone on PC-3 cells were 1.22 and 1.42 under normoxia and hypoxia, respectively. 3D culture of PC-3 cells revealed significantly reduced sphere diameter in irradiated spheres treated with NO-sulindac. Neither NO-sulindac nor sulindac radiosensitised prostate stromal cells under normoxia or hypoxia. HIF-1α protein levels were reduced by NO-sulindac exposure and radiation at 21 and 0.2% oxygen. Alkaline Comet assay analysis suggested an increased rate of single strand DNA breaks and slower repair of these lesions in PC-3 cells treated with NO-sulindac prior to irradiation. There was a higher level of γ-H2AX production and hence double strand DNA breaks following irradiation of NO-sulindac treated PC-3 cells. At all radiation doses and oxygen levels tested, treatment of 2D and 3D cultures of PC-3 cells with NO-sulindac prior to irradiation radiosensitised PC-3, with minimal effect on stromal cells. Hypoxia response inhibition and increased DNA double strand breaks are potential mechanisms of action. Neoadjuvent and concurrent use of NO-NSAIDs have the potential to improve radiotherapy treatment of prostate cancer under normoxia and hypoxia.

Oestrogen and benign prostatic hyperplasia: effects on stromal cell proliferation and local formation from androgen.

Oestrogens have been implicated as a cause of benign prostatic hyperplasia (BPH). Previous animal studies led to the hypothesis that oestrogens can stimulate prostate growth, resulting in hyperplasia of the gland. In humans, the precise role of oestrogens in BPH pathogenesis is currently unclear. We investigated the direct effects of oestradiol on the proliferation of BPH-derived prostate cells in culture. Oestradiol (10(-7) and 10(-6) M) moderately increased the proliferation of stromal cells in culture; this stimulation was antagonised by anti-oestrogen ICI 182 780, indicating an oestrogen receptor (ER)-mediated mechanism. By contrast, oestradiol had no effects on the proliferation of epithelial cells in culture. Parameters that can determine the response of stromal cells to oestrogens, including expression of the two ER subtypes and aromatase activity, were investigated. ER beta expression in stromal cells in culture was demonstrated by immunohistochemistry and western blot analysis, and was confirmed by semi-quantitative RT-PCR showing higher expression of ER beta than ER alpha mRNA in stromal cells. Aromatase, the enzyme that converts androgen precursors to oestrogens, was also examined. Aromatase mRNA and activity were detected in stromal, but not epithelial cells in culture, suggesting a mechanism whereby oestrogen concentrations can be regulated in the BPH stroma. Taken together, these findings support the hypothesis that oestrogens play a role in the pathogenesis of BPH, a disease characterised predominantly by stromal overgrowth.

Dermcidin expression confers a survival advantage in prostate cancer cells subjected to oxidative stress or hypoxia.

BACKGROUND: Dermcidin (DCD) is a candidate survival gene in breast cancer. DCD gene expression has been identified in prostate cancer cell lines and primary prostate cancer tissue. The DCD protein is composed of proteolysis-inducing factor-core peptide (PIF-CP) and the skin antimicrobial DCD-1. The aim of this work was to: (i) establish if the DCD gene confers resistance of prostate cancer cells to hypoxia and oxidative stress; (ii) identify the component of the gene transcript responsible for this effect. METHODS: Site-directed mutagenesis was used to create mutant DCD vectors. PC-3M prostate cancer cells were stably transfected with pcDNA3.1+ vectors encoding the entire DCD cDNA, mutant DCD vectors, or a control empty vector. Oxidative stress was produced using menadione, glucose oxidase, or hydrogen peroxide. Cell hypoxia was induced by incubation at 0.2% oxygen. RESULTS: Comparison of cell growth showed a 54.5% relative-proliferative advantage for the DCD-transfected PC-3M cells compared with sham-transfected cells after 8 days of cell growth (P = 0.03). Overexpression of DCD provided upto 36% absolute survival advantage over sham-transfected cells following induction of oxidative stress or hypoxia (P = 0.004). On exposure to hypoxia or oxidative stress PC-3M cells overexpressing the entire DCD gene had upto 42% survival advantage over those transfectants lacking the PIF-CP sequence (P = 0.004). CONCLUSIONS: DCD and PIF-CP are proliferation and survival factors in prostate cancer cells subjected to stressors found in the prostate cancer microenvironment. Thus, DCD and specifically PIF-CP are potential targets for the treatment of prostate cancer.

Polymorphic forms of prostate specific antigen and their interaction with androgen receptor trinucleotide repeats in prostate cancer.

BACKGROUND: Recent data has suggested that polymorphisms in the prostate specific antigen (PSA) may increase prostate cancer (PC) risk. The PSA gene contains a G/A substitution in the androgen response element (ARE) 1 region. The androgen receptor (AR) gene has polymorphic regions containing variable length glutamine and glycine repeats and these are believed to be associated with PC risk. The effect on PC risks from PSA polymorphisms alone and synergistically with the AR gene was examined in this report. METHODS: One hundred PC patients and an age matched cohort of 79 benign prostate hyperplasia and 67 population controls were entered in this study. DNA was extracted from blood and PSA/ARE promoter region amplified by PCR. PCR products were cut with Nhe 1 restriction enzyme to distinguish G/A alleles. AR/CAG and GGC repeat length was detected by automated fluorescence from PCR products. RESULTS: We found a significantly higher PSA/GG distribution in PC (30%) than either benign prostatic hyperplasia (BPH) (18%) or population controls (16%) (P = 0.025). Furthermore the GG distribution within cases was even greater in younger men (< 65 years; 42%; P = 0.012). Additionally, when PSA genotype was cross classified with CAG repeat, significantly more cases than both BPH and population controls were observed to have a short (< 22) CAG/GG genotype (P = 0.006). CONCLUSIONS: Our results indicate that the PSA/ARE GG genotype confers an increased risk of PC especially among younger men. Moreover, we confirm previous results that a short glutamine repeat in conjunction with GG genotype significantly increases the risk of malignant disease.

Serenoa repens (Permixon) inhibits the 5alpha-reductase activity of human prostate cancer cell lines without interfering with PSA expression.

The phytotherapeutic agent Serenoa repens is an effective dual inhibitor of 5alpha-reductase isoenzyme activity in the prostate. Unlike other 5alpha-reductase inhibitors, Serenoa repens induces its effects without interfering with the cellular capacity to secrete PSA. Here, we focussed on the possible pathways that might differentiate the action of Permixon from that of synthetic 5alpha-reductase inhibitors. We demonstrate that Serenoa repens, unlike other 5alpha-reductase inhibitors, does not inhibit binding between activated AR and the steroid receptor-binding consensus in the promoter region of the PSA gene. This was shown by a combination of techniques: assessment of the effect of Permixon on androgen action in the LNCaP prostate cancer cell line revealed no suppression of AR and maintenance of PSA protein expression at control levels. This was consistent with reporter gene experiments showing that Permixon failed to interfere with AR-mediated transcriptional activation of PSA and that both testosterone and DHT were equally effective at maintaining this activity. Our results demonstrate that despite Serenoa repens effective inhibition of 5alpha-reductase activity in the prostate, it did not suppress PSA secretion. Therefore, we confirm the therapeutic advantage of Serenoa repens over other 5alpha-reductase inhibitors as treatment with the phytotherapeutic agent will permit the continuous use of PSA measurements as a useful biomarker for prostate cancer screening and for evaluating tumour progression.

Quantitative morphometric analysis of individual resected prostatic tissue specimens, using immunohistochemical staining and colour-image analysis.

OBJECTIVE: To develop a method for obtaining morphometric measurements representative of individual chips from transurethral resection of the prostate (TURP). MATERIALS AND METHODS: In all, 232 sections were cut in pairs from 25 TURP chips, collected from four patients undergoing TURP for benign prostatic hyperplasia. Individual tissue chips were processed, embedded in paraffin wax and pairs of neighbouring sections cut from the specimens at intervals of 300 microm throughout the thickness of the specimen. Of each pair, the epithelial tissue (ET) of one and the smooth muscle (SM) of the other section were stained immunohistochemically with anti-prostate-specific antigen and anti-SM myosin, respectively. Proportions of ET and SM within the sections were measured with colour-image analysis and calculated within the TURP chips using all pairs of sections cut from the specimen, and the first pair of sections only. The differences between the sets of results were analysed using descriptive statistics. RESULTS: From each TURP chip, 3-7 pairs of sections were cut; for both ET and SM within each chip the differences between the results calculated using data from all pairs of sections and the first pair alone were small, as were the distributions of these differences within each prostate. CONCLUSIONS: Morphometric measurements from one section from a processed TURP chip, as opposed to serial sections, can be used to reliably assess the morphology of tissue within that specimen. This permits a considerable saving of resources when undertaking morphometric image analysis of resected prostatic tissue specimens.

Nitric oxide donating nonsteroidal anti-inflammatory drugs induce apoptosis in human prostate cancer cell systems and human prostatic stroma via caspase-3.

PURPOSE: New nitric oxide (NO) donating nonsteroidal anti-inflammatory drugs (NSAIDs) have been synthesized to counteract the side effects of conventional NSAIDs. Mounting evidence suggests that NSAIDs may have a possible chemopreventative/therapeutic role in prostate cancer. NO is a powerful biological messenger with multiple cellular effects. We established the effects of 2 of these new drugs in prostate cell systems. MATERIALS AND METHODS: We studied the effects of NO-ibuprofen (NCX 2111) and NO-aspirin (NCX 4060) on hormone sensitive (LNCap) and insensitive (PC3) prostate cancer epithelial cell lines as well as primary cultures of prostatic stroma. Proliferation was measured using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazalium bromide) assay to examine proliferation. Subsequently flow cytometry, cell cycle analysis and TUNEL staining were used to look for apoptosis. Caspase-3 expression was also examined in treated cell types. RESULTS: NCX 2111 and NCX 4060 were found to be potent inhibitors of proliferation in a dose dependent fashion. The 2 drugs induced apoptosis, as seen by flow cytometry, cell cycle analysis and TUNEL staining, at doses between 10 and 100 microM. These NO-NSAIDs increased caspase-3 expression. NCX 4060 was more effective at lower concentrations (10 microM) but each compound was much more potent than conventional ibuprofen and aspirin at inducing apoptosis and inhibiting proliferation. CONCLUSIONS: NO-NSAIDs are potent antiproliferative pro-apoptotic compounds in prostate cell systems. This pro-apoptotic effect is mediated via caspase-3 and it is independent of the type of prostate cell used. These findings have ramifications for the use of these new drugs in prostate cancer chemoprevention or treatment.

Androgen receptor protein expression in prostatic tissues in Black and Caucasian men.

BACKGROUND: CaP has a higher incidence and mortality in Black men. We hypothesized that subpopulation differences in AR expression may contribute to this phenomenon. METHOD: AR immunostaining was compared in epithelium and PES of normal, BPH, and CaP tissues from Black African men and UK Caucasian men. RESULTS: AR expression was similar in normal prostatic epithelium of both groups, but was higher in BPH and CaP epithelium of Black than Caucasian men (P