Distribution of vascular endothelial growth factor (VEGF) in prostate disease

An integrated strategy for deciphering the action mechanism of emplastrum: Prescription analysis- component identification- virtual screening and affinity testing in the case of Yaoshen Gao

ETHNOPHARMACOLOGICAL RELEVANCE

Emplastrum has a long history of use in the clinical practice of traditional Chinese medicine (TCM), valued for its convenient external application and pronounced therapeutic effects. Traditionally, the emplastrum was composed of numerous herbal medicines. The elucidation of their mechanisms of action are of great importance. YaoShen Gao (YSG), as a traditional example of emplastrum, was composed of more than 20 medicinal herbs. Clinically, YSG has been used to treat benign prostatic hyperplasia (BPH). However, the active components and therapeutic targets of YSG remain unclear, requiring further investigation.

AIM OF THE STUDY

To establish an integrated strategy to uncover the mechanisms underlying the potential active ingredients and therapeutic targets in complex TCM emplastra, using YSG for BPH treatment as a case study.

MATERIALS AND METHODS

A BPH rat model was established via castration and testosterone propionate injections. The therapeutic efficacy of YSG was evaluated comprehensively through phenotypic, pathological, physiological, and biochemical analyses. Prescription analysis was conducted based on the principles of "monarch, minister, assistant, and courier," as well as clinical dosage and efficacy. Based on the strategy of representative compounds-single herbal medicine -YSG formulation, the chemical profile of YSG was performed using UPLC-Q Exactive Orbitrap- MS. Network pharmacology identified preliminary targets, while molecular docking and literature mining further narrowed these down. Finally, molecular dynamics simulations and Bio-Layer Interferometry (BLI) were used to validate binding affinities of active components to targets.

RESULTS

The efficacy indicators demonstrated that treatment of YSG significantly reduced prostate wet weight and prostate index in BPH rats, with notable improvements observed in glandular structure. Additionally, YSG inhibited the expression of inflammatory factors (TNF- α, IL- 8) and fibrosis-related proteins (VEGF, TGF-β). Twelve key herbal medicines were identified by prescription analysis from the 20 herbs in YSG, such as Cistanche deserticola, Epimedium sagittatum and so on. High-resolution mass spectrometry (HR-MS) characterized 125 chemical components, and Venn analysis identified 409 common targets between YSG components and BPH. Subsequently, GO and KEGG analyses revealed that these targets are predominantly involved in protein phosphorylation, cellular components, and key signaling pathways. Protein-protein interaction (PPI) analysis identified 10 key targets, suggesting that the therapeutic effects of YSG on BPH are mediated through 39 active compounds and 12 relevant signaling pathways. Molecular docking analysis identified 14 target-compound pairs, and literature supported their relevance in PI3K/AKT, VEGF, TNF, and TGF-β pathways. Molecular dynamics simulations and BLI further validated the strong interactions between representative target-small molecule pairs like AKT1 with bavachalcone (KD = 46.8 μM) and PIK3R1 with apigenin (KD = 47.9 μM).

CONCLUSIONS

A systematic strategy for identifying active ingredients and therapeutic targets in complex TCM emplastra was developed. YSG contains active components, including bavachalcone, apigenin, schisandrin C, liquiritigenin, 8-prenyldaidzein, estrone, isopimpinellin, 8-prenylkaempferol, which act on six key targets, such as AKT1 and PIK3R1, to regulate the AKT/PI3K, AGE-RAGE, AR, VEGF, TGF-β, TNF and others signaling pathways. These pathways further modulate cellular proliferation, fibrosis, inflammation, and angiogenesis, thereby effectively contributing to the treatment of BPH.

The Effects of Resveratrol on Prostate Cancer through Targeting the Tumor Microenvironment

Prostate cancer is one of the most common cancers diagnosed in men in the United States and the second leading cause of cancer-related deaths worldwide. Since over 60% of prostate cancer cases occur in men over 65 years of age, and this population will increase steadily in the coming years, prostate cancer will be a major cancer-related burden in the foreseeable future. Accumulating data from more recent research suggest that the tumor microenvironment (TME) plays a previously unrecognized role in every stage of cancer development, including initiation, proliferation, and metastasis. Prostate cancer is not only diagnosed in the late stages of life, but also progresses relatively slowly. This makes prostate cancer an ideal model system for exploring the potential of natural products as cancer prevention and/or treatment reagents because they usually act relatively slowly compared to most synthetic drugs. Resveratrol (RSV) is a naturally occurring stilbenoid and possesses strong anti-cancer properties with few adverse effects. Accumulating data from both in vitro and in vivo experiments indicate that RSV can interfere with prostate cancer initiation and progression by targeting the TME. Therefore, this review is aimed to summarize the recent advancement in RSV-inhibited prostate cancer initiation, proliferation, and metastasis as well as the underlying molecular mechanisms, with particular emphasis on the effect of RSV on TME. This will not only better our understanding of prostate cancer TMEs, but also pave the way for the development of RSV as a potential reagent for prostate cancer prevention and/or therapy.

Prostatic hyperplasia: Vascularization, hemodynamic and hormonal analysis of dogs treated with finasteride or orchiectomy

As a consequence of a hormonal imbalance, Prostatic Hyperplasia (PH) is characterized by increased prostate volume, along with higher local angiogenesis and vascularization. Orchiectomy is the common treatment for dogs, however it is not an option for breeding animals. Thus, finasteride arises as the drug of choice for stud dogs. Therefore, the aim of this study was to evaluate the effects of orchiectomy or finasteride therapies on hormonal and vascular dynamics of PH dogs. Fifteen dogs, aged 6–13 years were assigned to: Untreated Group (dogs diagnosed with PH—n = 5), Finasteride treated group (PH dogs treated with finasteride—n = 5) and Orchiectomy treated group (PH dogs submitted to orchiectomy–n = 5). Evaluations were performed in a monthly interval (first day of treatment; after 30 and 60 days). Doppler ultrasonography was performed to measure prostatic volume, vascularization and hemodynamic profile of prostatic artery. Dihydrotestosterone, estrogen and testosterone concentrations were measured. At day 60, prostatic biopsy was performed for histological, immunohistochemical and qPCR analysis for VEGF-A expression. At day 60, vascularization score was higher in untreated compared to treated groups (finasteride and orchiectomy). Furthermore, VEGF-A expression was lower in the Orchiectomy Treated Group, but VEGF-A was immunohistochemically lower in both treated groups (finasteride and orchiectomy) compared to the Untreated Group. The efficiency of finasteride treatment in reducing clinical signs, prostate volume and vascularization appears to be similar to orchiectomy. In conclusion, both PH medical and surgical therapy lead to reduction in prostate dimension and VEGF-A expression and, consequently, lower local vascularization. However, orchiectomy promotes marked hormonal changes, which ultimately lead to prostate atrophy.

Evaluation of recombinant human vascular endothelial growth factor VEGF121-loaded poly-l-lactide microparticles as a controlled release delivery system

Vascular endothelial growth factor A (VEGF-A) is an important growth factor that plays a major role in angiogenesis. With different isoforms distributed in various tissues, the shortest isoform of VEGF-A is VEGF121, one of the physiologically functional variants next to VEGF165. It is well known that VEGF has a shorter half-life, and the stability of the protein must be considered in therapeutic aspects. Poly-l-lactide (PLA) microparticles can release the encapsulated protein in a sustained release mode. In this study, the VEGF121 gene was cloned and expressed in a prokaryotic expression system (Escherichia coli). The recombinant VEGF121 was encapsulated with PLA microparticles and studied in vitro  and ex ovo  for the sustained release mechanism. The PLA-VEGF microparticles and the recombinant VEGF121 were explored for their bioactivity in human umbilical vein endothelial cells (HUVEC). VEGF released in vitro  from PLA microparticles on days 1, 20, and 30 showed remarkable biological activity compared to PBS-loaded PLA microparticles such as the ability of the cells to proliferate, migrate, and form tubes similar to recombinant VEGF121. Besides, PLA-VEGF microparticles and the recombinant VEGF121 were also tested for their proangiogenic action in embryonated eggs by chicken chorioallantoic membrane assay (CAM), and the effect was observed in both forms. This study suggests that PLA-loaded VEGF microparticles in a sustainable release format can be effectively used in proangiogenic therapy and reduce the adverse effects caused due to multiple dosages.

Inhibitory Effect of Thymoquinone on Testosterone-Induced Benign Prostatic Hyperplasia in Wistar Rats

This study addresses the possible protective effects of thymoquinone (TQ) against the development of experimentally-induced benign prostatic hyperplasia (BPH) in Wistar rats. Eighteen adult male rats were divided into three groups; the negative control group (n = 6) received vehicle, and two groups received subcutaneous testosterone injection (3 mg/kg). Animals receiving testosterone were randomized to untreated BPH group (n = 6) and BPH + TQ treated group (n = 6, 50 mg/kg orally for 14 days). Histological changes and the mRNA levels of transforming growth factor-β1 (TGF-β1 ) and vascular endothelial growth factor-A (VEGF-A) were analyzed. Additionally, dihydrotestosterone and interleukin-6 (IL-6) serum levels were determined. The presented research shows significant increases in prostate weight/body weight ratio, prostate epithelial thickness, serum IL-6 and dihydrotestosterone levels, and the prostatic expressions of TGF-β1 and VEGF-A in the untreated BPH rats. Histological examination of the prostate tissues in the BPH rats showed an elevated level of proliferation in the stromal area and glandular epithelia with abundant intraluminal papillary folds. However, a reduction in prostate weight/body weight ratio, epithelial hyperplasia, serum IL-6 levels, and the expressions of TGF-β1 and VEGF-A were observed in the BPH + TQ treated rats compared with the untreated BPH rats. The findings support TQ as a useful natural treatment for animal BPH model. Copyright © 2017 John Wiley & Sons, Ltd.

Evaluation of VEGF and PEDF in prostate cancer: A preliminary study in serum and biopsies

Vascular endothelial growth factor (VEGF) and the pigment epithelium-derived factor (PEDF) serve an important role in prostate cancer (PCa). The aim of the present study was to evaluate whether the levels of VEGF and PEDF in serum are associated with the severity of PCa, and whether they can differentiate from patients with benign prostatic hyperplasia (BPH). Two groups of patients were recruited, patients with PCa or BPH that were newly diagnosed without other comorbidities, and were compared with healthy individuals. The levels of VEGF and PEDF were measured by ELISA in serum, and by immunohistochemistry in biopsies. A correlation analysis was performed for the values in biopsies and serum, comparing the VEGF/PEDF ratio, total-prostate-specific antigen (t-PSA) levels and the status of each sample as acinar Ad (Gleason score) or as benign hyperplasia. The results demonstrated that serum levels of VEGF, PEDF, and t-PSA between PCa and BPH were similar to each other, but different to healthy individuals (P<0.05). The VEGF/PEDF ratio in serum had a significant difference between acinar Ad with Gleason score 8–10 and BPH groups (P<0.05). The VEGF and PEDF immunostaining intensities were correlated with its circulating levels in all cases of PCa, but not in BPH. These preliminary results suggest that VEGF and PEDF levels by themselves or in combination with t-PSA did not differentiate between malignant, and benign prostate diseases. However, there was a significant difference observed in the VEGF/PEDF ratio in serum between the groups, suggesting that it may be used as an index for diagnosis and prognosis in a personalized manner, although more studies are necessary.

PSMA, EpCAM, VEGF and GRPR as imaging targets in locally recurrent prostate cancer after radiotherapy

In this retrospective pilot study, the expression of the prostate-specific membrane antigen (PSMA), the epithelial cell adhesion molecule (EpCAM), the vascular endothelial growth factor (VEGF) and the gastrin-releasing peptide receptor (GRPR) in locally recurrent prostate cancer after brachytherapy or external beam radiotherapy (EBRT) was investigated, and their adequacy for targeted imaging was analyzed. Prostate cancer specimens were collected of 17 patients who underwent salvage prostatectomy because of locally recurrent prostate cancer after brachytherapy or EBRT. Immunohistochemistry was performed. A pathologist scored the immunoreactivity in prostate cancer and stroma. Staining for PSMA was seen in 100% (17/17), EpCAM in 82.3% (14/17), VEGF in 82.3% (14/17) and GRPR in 100% (17/17) of prostate cancer specimens. Staining for PSMA, EpCAM and VEGF was seen in 0% (0/17) and for GRPR in 100% (17/17) of the specimens’ stromal compartments. In 11.8% (2/17) of cases, the GRPR staining intensity of prostate cancer was higher than stroma, while in 88.2% (15/17), the staining was equal. Based on the absence of stromal staining, PSMA, EpCAM and VEGF show high tumor distinctiveness. Therefore, PSMA, EpCAM and VEGF can be used as targets for the bioimaging of recurrent prostate cancer after EBRT to exclude metastatic disease and/or to plan local salvage therapy.

An introduction to acinar pressures in BPH and prostate cancer

Intra-acinar and peri-acinar pressures in the prostate might be key factors in the evolution of its zonal morphology and the pathogenesis of BPH and cancer. Herein, I hypothesize that intra-acinar pressures lead to a decrease in apoptosis by distending or stretching acinar epithelium and its surrounding stroma. Increased prostatic smooth muscle content and tone might generate peri-acinar pressures, which could, in the long-term, counteract intra-acinar pressures and decrease epithelial stretch. Thus, it is proposed that BPH (characterized by increased prostatic smooth muscle and, therefore, raised peri-acinar pressures) might decrease the risk of prostate cancer progression by counteracting intra-acinar pressures. In the context of this theory, the transition zone might have evolved as a specialized region within the prostate that can mount a concerted stromal-epithelial response to increased urethral and intra-acinar pressures (BPH), and the urethral angulation, anterior stroma and the prostatic capsule have an adjunctive evolutionary role in this phenomenon.

Differential expression of VEGF ligands and receptors in prostate cancer

BACKGROUND

Prostate cancer disseminates to regional lymph nodes, however the molecular mechanisms responsible for lymph node metastasis are poorly understood. The vascular endothelial growth factor (VEGF) ligand and receptor family have been implicated in the growth and spread of prostate cancer via activation of the blood vasculature and lymphatic systems. The purpose of this study was to comprehensively examine the expression pattern of VEGF ligands and receptors in the glandular epithelium, stroma, lymphatic vasculature and blood vessels in prostate cancer.

METHODS

The localization of VEGF-A, VEGF-C, VEGF-D, VEGF receptor (VEGFR)-1, VEGFR-2, and VEGFR-3 was examined in cancerous and adjacent benign prostate tissue from 52 subjects representing various grades of prostate cancer.

RESULTS

Except for VEGFR-2, extensive staining was observed for all ligands and receptors in the prostate specimens. In epithelial cells, VEGF-A and VEGFR-1 expression was higher in tumor tissue compared to benign tissue. VEGF-D and VEGFR-3 expression was significantly higher in benign tissue compared to tumor in the stroma and the endothelium of lymphatic and blood vessels. In addition, the frequency of lymphatic vessels, but not blood vessels, was lower in tumor tissue compared with benign tissue.

CONCLUSIONS

These results suggest that activation of VEGFR-1 by VEGF-A within the carcinoma, and activation of lymphatic endothelial cell VEGFR-3 by VEGF-D within the adjacent benign stroma may be important signaling mechanisms involved in the progression and subsequent metastatic spread of prostate cancer. Thus inhibition of these pathways may contribute to therapeutic strategies for the management of prostate cancer.

Vascular endothelial growth factor (VEGF) expression in locally advanced prostate cancer: secondary analysis of radiation therapy oncology group (RTOG) 8610

Background

Angiogenesis is a key element in solid-tumor growth, invasion, and metastasis. VEGF is among the most potent angiogenic factor thus far detected. The aim of the present study is to explore the potential of VEGF (also known as VEGF-A) as a prognostic and predictive biomarker among men with locally advanced prostate cancer.

Methods

The analysis was performed using patients enrolled on RTOG 8610, a phase III randomized control trial of radiation therapy alone (Arm 1) versus short-term neoadjuvant and concurrent androgen deprivation and radiation therapy (Arm 2) in men with locally advanced prostate carcinoma. Tissue samples were obtained from the RTOG tissue repository. Hematoxylin and eosin slides were reviewed, and paraffin blocks were immunohistochemically stained for VEGF expression and graded by Intensity score (0–3). Cox or Fine and Gray’s proportional hazards models were used.

Results

Sufficient pathologic material was available from 103 (23%) of the 456 analyzable patients enrolled in the RTOG 8610 study. There were no statistically significant differences in the pre-treatment characteristics between the patient groups with and without VEGF intensity data. Median follow-up for all surviving patients with VEGF intensity data is 12.2 years. Univariate and multivariate analyses demonstrated no statistically significant correlation between the intensity of VEGF expression and overall survival, distant metastasis, local progression, disease-free survival, or biochemical failure. VEGF expression was also not statistically significantly associated with any of the endpoints when analyzed by treatment arm.

Conclusions

This study revealed no statistically significant prognostic or predictive value of VEGF expression for locally advanced prostate cancer. This analysis is among one of the largest sample bases with long-term follow-up in a well-characterized patient population. There is an urgent need to establish multidisciplinary initiatives for coordinating further research in the area of human prostate cancer biomarkers.

Cigarette smoke induces nuclear translocation of heme oxygenase 1 (HO-1) in prostate cancer cells: nuclear HO-1 promotes vascular endothelial growth factor secretion

Prostate cancer is the second leading cause of male-cancer related death in the United States. Despite a number of evidence-based studies which strongly suggest an association between cigarette smoking and prostate cancer, the underlying biological mechanism is largely unknown. Heme oxygenase 1 (HO-1) has been implicated in maintaining cellular homeostasis, but also in tumor angiogenesis. Nuclear HO-1 protein expression has been observed in various types of tumors including prostate cancer. These studies, however, were reported as clinical and pathological observations, and failed to investigate nuclear HO-1 at the molecular level in cancer. The present study explores the relationship between cigarette smoke and nuclear HO-1-modulated promotion of vascular endothelial growth factor (VEGF) secretion. We have demonstrated that cigarette smoke medium (SM)-induced HO-1 mRNA expression and upregulated HO-1 protein levels in the prostate cancer cell lines DU145 and PC3. We also observed that SM significantly induced nuclear expression of HO-1, and enhanced secretion of VEGF in cells. Nuclear-directed expression of HO-1 activated the transcriptional activity of VEGF and promoted VEGF secretion in prostate cancer cells. This study provides new insights into the molecular mechanism by which cigarette smoke-induced nuclear translocation of HO-1 promotes VEGF secretion in prostate cancer cells. Nuclear HO-1 may, therefore, constitute an attractive therapeutic target to inhibit angiogenesis and the progression of prostate cancer.

Prostate-specific membrane antigen can promote in vivo osseous metastasis of prostate cancer cells in mice

Reports remain insufficient on whether and how prostate-specific membrane antigen (PSMA) can influence in vivo osseous metastasis of prostate cancer (PCa). In the present study, the authors induced stable expression of PSMA in mouse PCa cell line RM-1. In vivo osseous metastasis was induced in 37 6-week-old female C57BL/6 mice weighing 22.45 ± 0.456 g. RM-1 cells were actively injected into the femoral bone cavity, leading to bilateral dissymmetry of bone density in the femoral bone. Tumor cells were also detected in bone tissue by pathological examination. The impact on bone density was demonstrated by the significant difference between animals injected with RM-PSMA cells (0.0738 ± 0.0185 g/cm²) and animals injected with RM-empty plasmid cells (0.0895 ± 0.0241 g/cm²). The lytic bone lesion of the RM-PSMA group (68.4%) was higher than that of the control group (27.8%). Immunohistochemistry showed that the expression of both vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) was distinctly higher in the RM-PSMA group than in the control group, while ELISA and Western blot assay indicated that VEGF and MMP-9 were higher in the RM-PSMA group compared to the control group (in vitro). Thus, the present study proposed and then confirmed for the first time that PSMA can promote in vivo osseous metastasis of PCa by increasing sclerotic destruction of PCa cells. Further analyses also suggested that PSMA functions positively on the invasive ability of RM-1 by increasing the expression of MMP-9 and VEGF by osseous metastases in vivo.

Prostate size correlates with fasting blood glucose in non-diabetic benign prostatic hyperplasia patients with normal testosterone levels

We evaluated the correlations between BMI, fasting glucose, insulin, testosterone level, insulin resistance, and prostate size in non-diabetic benign prostatic hyperplasia (BPH) patients with normal testosterone levels. Data from 212 non-diabetic BPH patients with normal testosterone levels, who underwent transurethral resection of the prostate (TURP) due to medical treatment failure, were evaluated retrospectively. Patients with prostate specific antigen (PSA) levels of ≥ 3 ng/mL underwent multicore transrectal prostate biopsy before TURP to rule out prostate cancer. Patients with diabetes mellitus (DM) or serum testosterone levels of < 3.50 ng/mL were excluded from analysis. Correlations between clinical and laboratory parameters were determined. Prostate size correlated positively with age (r = 0.227, P < 0.001), PSA (r = 0.510, P < 0.001), and fasting glucose level (r = 0.186, P = 0.007), but not with BMI, testosterone, insulin level, or insulin resistance (each P > 0.05). Testosterone level inversely correlated with BMI (r = -0.327, P < 0.001), insulin level (r = -0.207, P = 0.003), and insulin resistance (r = -0.221, P = 0.001), but not with age, prostate size, PSA, or fasting glucose level (each P > 0.05). Upon multiple adjusted linear regression analysis, prostate size correlated with elevated PSA (P < 0.001) and increased fasting glucose levels (P = 0.023). In non-DM BPH patients with normal testosterone levels, fasting glucose level is an independent risk factor for prostate hyperplasia.

Dynamic contrast-enhanced MR imaging in the evaluation of patients with prostate cancer

Prostate cancer is a common tumor among men, with increasing diagnosis at an earlier stage and a lower volume of disease because of screening with prostate-specific antigen (PSA). The need for imaging of the prostate stems from a desire to optimize treatment strategy on a patient and tumor-specific level. The major goals of prostate imaging are (1) staging of known cancer, (2) determination of tumor aggressiveness, (3) diagnosis of cancer in patients who have elevated PSA but a negative biopsy, (4) treatment planning, and (5) the evaluation of therapy response. This article concentrates on the role of dynamic contrast-enhanced MR imaging in the evaluation of patients who have prostate cancer and how it might be used to help achieve the above goals. Various dynamic contrast enhancement approaches (quantitative/semiquantitative/qualitative, high temporal versus high spatial resolution) are summarized with reference to the relevant strengths and compromises of each approach.

Lack of immunohistochemical detection of VEGF in prostate carcinoma

BACKGROUND

Vascular endothelial growth factor (VEGF) has been implicated in tumor angiogenesis and is a potential therapeutic target in prostatic adenocarcinoma (PrCa). Immunohistochemical (IHC) analysis has been used to demonstrate VEGF expression in PrCa, and in various other tumors including breast carcinoma, renal cell carcinoma, hepatocellular carcinoma, and gliomas. Prior studies have reported markedly varied VEGF expression in benign prostatic hyperplasia (0% to 100%) and PrCa (40% to 100%). The objective of this study was to measure VEGF expression in PrCa specimens, using IHC analysis with antibodies from different manufacturers and different antigen retrieval techniques.

DESIGN

Cases were identified from an ongoing study analyzing 1270 cases of PrCa diagnosed at various Veterans Health Administration hospitals in the New England region during 1991 to 1995. From this study population, 50 cases (including 40 biopsies, 8 transurethral resections of prostate, and 2 radical resections) were selected. In all cases, tissues were fixed in 10% formalin and embedded in paraffin. Four different antibodies were used for IHC using indirect peroxidase method. For each antibody, different dilutions and antigen retrieval methods (steam with ethylene diamine tetra-acetate, steam with low pH, water bath with target unmasking fluid, trypsin, proteinase K) were tested. EnVision+ system was used to overcome nonspecific staining. Appropriate positive and negative controls were used.

RESULTS

Using different antibodies, positive staining of varying intensity was seen in benign glands, malignant glands, endothelial cells, and fibromuscular stroma. Some cases showed cytoplasmic and granular staining in prostatic glands. However, the staining disappeared in all cases when EnVision+ system was used to block nonspecific staining except for focal and minimal staining in the endothelial cells.

CONCLUSIONS

Our results show that when nonspecific staining is blocked, no staining is found for VEGF within the prostate, in either benign or malignant glands. The reasons for the granular and nonspecific staining are unclear at present. Our study may help to explain variable results reported in previous studies, and suggests caution in interpreting VEGF expression in studies of PrCa and benign glands.

An illustration of the potential for mapping MRI/MRS parameters with genetic over-expression profiles in human prostate cancer

INTRODUCTION

Magnetic resonance imaging (MRI) and MR spectroscopy can probe a variety of physiological (e.g. blood vessel permeability) and metabolic characteristics of prostate cancer. However, little is known about the changes in gene expression that underlie the spectral and imaging features observed in prostate cancer. Tumor induced changes in vascular permeability and angiogenesis are thought to contribute to patterns of dynamic contrast enhanced (DCE) MRI images of prostate cancer even though the genetic basis of tumor vasculogenesis is complex and the specific mechanisms underlying these DCEMRI features have not yet been determined.

MATERIALS AND METHODS

In order to identify the changes in gene expression that correspond to MRS and DCEMRI patterns in human prostate cancers, we have utilized tissue print micropeel techniques to generate "whole mount" molecular maps of radical prostatectomy specimens that correspond to pre-surgical MRI/MRS studies. These molecular maps include RNA expression profiles from both Affymetrix GeneChip microarrays and quantitative reverse transcriptase PCR (qrt-PCR) analysis, as well as immunohistochemical studies.

RESULTS

Using these methods on patients with prostate cancer, we found robust over-expression of choline kinase a in the majority of primary tumors. We also observed overexpression of neuropeptide Y (NPY), a newly identified angiogenic factor, in a subset of prostate cancers, visualized on DCEMRI.

CONCLUSION

These studies set the stage for establishing MRI/MRS parameters as validated biomarkers for human prostate cancer.

Expression of vascular endothelial growth factor in Taiwanese benign and malignant prostate tissues

BACKGROUND

The expression of vascular endothelium growth factor (VEGF) has been correlated to the grading and stage of prostate cancers. However, data regarding Taiwanese prostate cancer patients are lacking. The aim of the present study was to examine VEGF expression in our radical prostatectomy specimens.

METHODS

Fifty-one radical prostatectomy specimens with prostate cancer (15 stage pT2N0, 25 pT3N0, 11 pT2-4 N1) were stained using goat anti-human VEGF polyclonal antibody (AB-293NA; R&D Systems Inc., Minneapolis, MN, USA). The VEGF expression in malignant and nonmalignant prostate tissues was compared. The correlations of VEGF immunoreactivity with Gleason scores and pathologic stages were examined. MannWhitney U test was used for comparison of preoperative prostate-specific antigen levels between patients with and without VEGF expression.

RESULTS

Positive VEGF staining was observed in 80.4% of malignant epithelia, 39.2% of peritumoral stroma, 68.6% of benign hyperplastic glands, and 25.5% of adjacent stroma. There was no difference in VEGF expression between malignant and nonmalignant areas. Advanced disease had significantly higher frequency of stroma but not epithelium VEGF staining as compared to organ-confined disease (p = 0.002 and p = 0.412, respectively). The Gleason 7 and higher tumors had significantly higher frequency of VEGF staining in stroma but not glandular epithelium (p = 0.041 and p = 0.353, respectively). Tumors with positive epithelium VEGF staining had significantly higher PSA levels (21.3 18.1 vs. 10.8 6.8 ng/mL; p = 0.013).

CONCLUSION

There was no difference in VEGF immunoreactivity between malignant and benign prostatic epithelium in Taiwanese. High Gleason grade tumors and advanced disease had significantly higher frequency of VEGF expression in stroma but not glandular epithelium. Tumors with positive epithelium VEGF staining had significantly higher PSA levels.

Microvessel density and regulators of angiogenesis in malignant and nonmalignant prostate tissue

The aim of this study was to investigate the relationship between microvessel density (MVD), positive and negative angiogenic factors, and established prognostic factors in prostate cancer (PC), and, to clarify the effect of angiogenic factors to angiogenesis. The vascularization of neoplastic, non-neoplastic prostate tissue was determined by CD34 immunostaining. Angiogenetic mediators VEGF, bFGF, TSP-1, and p53 were studied by immunohistochemistry. Neovascularization and p53, VEGF, and TSP-1 expressions of tumorous tissue were higher than non-tumorous tissue. The bFGF expression in these tissues was not different. The p53 expression was not correlated with the expressions of VEGF, bFGF, and TSP-1 in PC. Our results demonstrate a significant increase in MVD, VEGF, TSP-1, and p53 expressions in prostate tumorigenesis. The pretreatment sPSA was the only parameter demonstrating significant correlation with tumor grade and may have a value in the prediction of aggressive tumor behavior in PC.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Increased growth factor production in a human prostatic stromal cell culture model caused by hypoxia

BACKGROUND

Local hypoxia may be one of the triggers of embryonic reawakening of the stroma and subsequent hyperplastic growth in the prostate. Using a cell culture model of human prostatic stromal cells, we investigated the effects of hypoxia on activation of hypoxia-inducible factor 1 (HIF 1) and on the production of growth factors.

METHODS

Primary prostatic stromal cells were grown in normal and hypoxic (1% O(2)) atmosphere. Activation of HIF 1 was evaluated after different time intervals by Western blot. Induced secretion of growth factors VEGF, FGF-7, TGF-beta, IL 8, and FGF-2 were analyzed by ELISA. To confirm the in vitro findings we also performed immunohistochemistry of HIF 1alpha as well as pro-collagen I, collagens I, III, and IV in the benign tissue of radical prostatectomy specimens.

RESULTS

HIF 1 is activated in a time-dependent manner, already starting 1 hr after exposure of stromal cells to hypoxic conditions. Secretion of VEGF, FGF-7, TGF-beta, FGF-2, and IL 8 is increased under hypoxic in vitro conditions in comparison to normoxia. Levels of TGF-beta, VEGF, and IL 8 were rapidly and statistically significantly increased in the supernatant of hypoxic cells. Consistent with the in vitro findings, immunohistochemistry of HIF 1alpha in (benign prostatic hyperplasia) BPH tissue revealed strong HIF 1alpha nuclear staining in hyperplastic areas. No difference was observed in the collagen pattern between hyperplastic and normal prostate tissue.

CONCLUSIONS

Prostatic stromal cells respond to hypoxia by upregulation of secretion of several growth factors suggesting that hypoxia can trigger prostatic growth. Therefore, hypoxia might be a key factor contributing to the pathogenesis of BPH.