Vascular Endothelial Growth Factor (VEGF) Expression in Prostate Cancer and Benign Prostatic Hyperplasia

TempEasy 3D Hydrogel Coculture System Provides Mechanistic Insights into Prostate Cancer Bone Metastasis

Patients diagnosed with advanced prostate cancer (PCa) often experience incurable bone metastases; however, a lack of relevant experimental models has hampered the study of disease mechanisms and the development of therapeutic strategies. In this study, we employed the recently established Temperature-based Easy-separable (TempEasy) 3D cell coculture system to investigate PCa bone metastasis. Through coculturing PCa and bone cells for 7 days, our results showed a reduction in PCa cell proliferation, an increase in neovascularization, and an enhanced metastasis potential when cocultured with bone cells. Additionally, we observed increased cell proliferation, higher stemness, and decreased bone matrix protein expression in bone cells when cocultured with PCa cells. Furthermore, we demonstrated that the stiffness of the extracellular matrix had a negligible impact on molecular responses in both primary (PCa cells) and distant malignant (bone cells) sites. The TempEasy 3D hydrogel coculture system is an easy-to-use and versatile coculture system that provides valuable insights into the mechanisms of cell-cell communication and interaction in cancer metastasis.

The Labyrinthine Landscape of APP Processing: State of the Art and Possible Novel Soluble APP-Related Molecular Players in Traumatic Brain Injury and Neurodegeneration

Amyloid Precursor Protein (APP) and its cleavage processes have been widely investigated in the past, in particular in the context of Alzheimer’s Disease (AD). Evidence of an increased expression of APP and its amyloidogenic-related cleavage enzymes, β-secretase 1 (BACE1) and γ-secretase, at the hit axon terminals following Traumatic Brain Injury (TBI), firstly suggested a correlation between TBI and AD. Indeed, mild and severe TBI have been recognised as influential risk factors for different neurodegenerative diseases, including AD. In the present work, we describe the state of the art of APP proteolytic processing, underlining the different roles of its cleavage fragments in both physiological and pathological contexts. Considering the neuroprotective role of the soluble APP alpha (sAPPα) fragment, we hypothesised that sAPPα could modulate the expression of genes of interest for AD and TBI. Hence, we present preliminary experiments addressing sAPPα-mediated regulation of BACE1, Isthmin 2 (ISM2), Tetraspanin-3 (TSPAN3) and the Vascular Endothelial Growth Factor (VEGFA), each discussed from a biological and pharmacological point of view in AD and TBI. We finally propose a neuroprotective interaction network, in which the Receptor for Activated C Kinase 1 (RACK1) and the signalling cascade of PKCβII/nELAV/VEGF play hub roles, suggesting that vasculogenic-targeting therapies could be a feasible approach for vascular-related brain injuries typical of AD and TBI.

6-sialyllactose ameliorates dihydrotestosterone-induced benign prostatic hyperplasia through suppressing VEGF-mediated angiogenesis

Benign prostatic hyperplasia (BPH), a common disease in elderly males, is accompanied by non-malignant growth of prostate tissues, subsequently causing hypoxia and angiogenesis. Although VEGF-related angiogenesis is one of the therapeutic targets of prostate cancer, there is no previous study targeting angiogenesis for treatment of BPH. Dihydrotestosterone (DHT)-induced expressions of vascular endothelial growth factor (VEGF) in prostate epithelial RWPE-1 cells and human umbilical vascular endothelial cells (HUVECs). Conditioned media (CM) from DHT-treated RWPE-1 cells were transferred to HUVECs. Then, 6SL inhibited proliferation, VEGFR-2 activation, and tube formation of HUVECs transferred with CM from DHT-treated RWPE-1 cells. In the rat BPH model, 6SL reduced prostate weight, size, and thickness of the prostate tissue. Formation of vessels in prostatic tissues were also reduced with 6SL treatment. We found that 6SL has an ameliorative effect on in vitro and in vivo the BPH model via inhibition of VEGFR-2 activation and subsequent angiogenesis. These results suggest that 6SL might be a candidate for development of novel BPH drugs.

Association between vascular endothelial growth factor rs699947 polymorphism and the risk of three major urologic neoplasms (bladder cancer, prostate cancer, and renal cell carcinoma): A meta-analysis involving 11,204 subjects

BACKGROUND

The relationship between vascular endothelial growth factor (VEGF) gene variant rs699947 polymorphism and urologic neoplasms risk was studied extensively in recent years. The VEGF gene plays a key role in angiogenesis of urologic neoplasms, but some conclusions are still inconclusive. The aim of this study was to determine whether this polymorphism is a risk factor for susceptibility to urologic neoplasms by conducting a meta-analysis.

METHODS

We performed a meta-analysis of 15 different publications from the PubMed, Embase and Medline databases, to better assess the association between VEGF rs699947 polymorphism and urologic neoplasms risk. Odds ratios (ORs) and 95% confidence intervals (CIs) were evaluated using random or fixed effects models.

RESULTS

By pooling all eligible studies, we found that the VEGF rs699947 polymorphism was not associated with overall urologic neoplasms. However, subgroup analysis based on cancer types demonstrated that significantly increased association was found between VEGF rs699947 polymorphism and the risk of bladder cancer (BCa) under heterozygous genetic model (OR = 1.48, 95%CI = 1.17-1.89). And rs699947 polymorphism was also identified an increased risk of renal cell carcinoma (RCC) under dominant, recessive, homozygous, heterozygous and allelic contrast genetic models, while no association was observed in prostate cancer (PCa). In addition, in subgroup analysis by ethnicity, we found rs699947 polymorphism was associated with Asian population under dominant, homozygous, heterozygous and allelic contrast genetic models. No evidence of publication bias was found (Begg's test, P = 0.855; Egger's test, P = 0.590).

CONCLUSIONS

In summary, our study showed evidence that the VEGF rs699947 polymorphism was obviously associated with an increased risk of bladder cancer and renal cell carcinoma, particularly in Asian population, while no significant association was observed in overall urologic neoplasms. Future studies with larger sample sizes are warranted to further evaluate these associations in more details.

Cellular Constituents of the Prostate Stroma: Key Contributors to Prostate Cancer Progression and Therapy Resistance

Reciprocal signaling between prostate stroma and its epithelium are fundamental to organ development and homeostasis. Similarly, interactions between tumor cells and stromal constituents are central to key aspects of carcinogenesis and malignancy growth involving tumor cell invasion, dissemination, and growth in distant sites. The prostate stroma is complex with several distinct resident cell types, infiltrating nonresident cell types and an amalgam of structural matrix factors, matricellular proteins, metabolites, growth factors, and cytokines. Of importance, the stroma is dynamic with changes in composition as a cause or consequence of intrinsic and extrinsic factors. In the context of epithelial neoplasia, the prostate stroma undergoes phenotypic changes with a loss of well-differentiated smooth muscle cell population and the expansion of cancer-associated fibroblast populations. This reactive stroma further coevolves with tumor progression. Recent studies show the role of tumor microenvironment components in therapy resistance and highlight the importance of a thorough knowledge of cross talk between tumor cells and microenvironment niches to develop new therapeutic strategies.

A class of extracellular vesicles from breast cancer cells activates VEGF receptors and tumour angiogenesis

Non-classical secretory vesicles, collectively referred to as extracellular vesicles (EVs), have been implicated in different aspects of cancer cell survival and metastasis. Here, we describe how a specific class of EVs, called microvesicles (MVs), activates VEGF receptors and tumour angiogenesis through a unique 90 kDa form of VEGF (VEGF_90K). We show that VEGF_90K is generated by the crosslinking of VEGF₁₆₅, catalysed by the enzyme tissue transglutaminase, and associates with MVs through its interaction with the chaperone Hsp90. We further demonstrate that MV-associated VEGF_90K has a weakened affinity for Bevacizumab, causing Bevacizumab to be ineffective in blocking MV-dependent VEGF receptor activation. However, treatment with an Hsp90 inhibitor releases VEGF_90K from MVs, restoring the sensitivity of VEGF_90K to Bevacizumab. These findings reveal a novel mechanism by which cancer cell-derived MVs influence the tumour microenvironment and highlight the importance of recognizing their unique properties when considering drug treatment strategies.

Extracellular vesicles (EVs) contain VEGF and can contribute to tumour angiogenesis, although the mechanism remains unclear. Here, the authors find that a form of VEGF (VEGF90K) resistant to Bevacizumab but sensitive to HSP90 inhibitors, associates with EVs through its interaction with Hsp90.

Endocrine Gland-Derived Vascular Endothelial Growth Factor/Prokineticin-1 in Cancer Development and Tumor Angiogenesis

A lot of data suggests endocrine gland-derived vascular endothelial growth factor (EG-VEGF) to be restricted to endocrine glands and to some endocrine-dependent organs. Many evidences show that EG-VEGF stimulates angiogenesis and cell proliferation, although it is not a member of the VEGF family. At the time, a lot of data regarding the role of this growth factor in normal development are available. However, controversial results have been published in the case of pathological conditions and particularly in malignant tumors. Thus, our present paper has been focused on the role of EG-VEGF in normal tissues and various malignant tumors and their angiogenic processes.

Serenoa repens, selenium and lycopene to manage lower urinary tract symptoms suggestive for benign prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) is a disease affecting most of the elderly male. α1-blockers and 5-alpha reductase inhibitors are currently used to target lower urinary tract symptoms (LUTS). Moreover phytotherapeutic agents, including Serenoa Repens (SeR), have shown to have a role in ameliorating BPH/LUTS alone or in combination of other elements like Selenium (Se) and Lycopene (Ly). Areas covered: A literature review was performed using data from articles assessing the role of of SeR+Se+Ly in the management of LUTS secondary to BPH. Diverging evidence on SeR's efficacy is available. On one hand several studies have shown SeR efficacy in treating BPH/LUTS. SeR is effective in reducing prostate size, urinary frequency, dysuria, nocturia and in improving maximum urine flow-rate. On the other hand two long-term trials reported that SeR did not improve prostate size or urinary flow. SeR+Se+Ly in combination with tamsulosin is more effective than single therapies in improving IPSS and increasing maximal urinary flow-rate in patients affected by LUTS/BPH. Expert opinion: Despite great amount of preclinical and clinical studies, the use of SeR in BPH/LUTS is not sustained by clear evidence for a therapeutic efficacy but current data hint higher efficacy of of SeR+Se+Ly compared to SeR alone.

Genetic variation: effect on prostate cancer

The crucial role of androgens in the development of prostate cancer is well established. The aim of this review is to examine the role of constitutional (germline) and tumor-specific (somatic) polymorphisms within important regulatory genes of prostate cancer. These include genes encoding enzymes of the androgen biosynthetic pathway, the androgen receptor gene, genes that encode proteins of the signal transduction pathways that may have a role in disease progression and survival, and genes involved in prostate cancer angiogenesis. Characterization of deregulated pathways critical to cancer cell growth have lead to the development of new treatments, including the CYP17 inhibitor abiraterone and clinical trials using novel drugs that are ongoing or recently completed [1]. The pharmacogenetics of the drugs used to treat prostate cancer will also be addressed. This review will define how germline polymorphisms are known affect a multitude of pathways, and therefore phenotypes, in prostate cancer etiology, progression, and treatment.

Immunohistochemical Expression of Angiogenic Factors by Neoplastic Epithelial Cells Is Associated With Canine Prostatic Carcinogenesis

The dog is the only species, other than humans, in which spontaneous prostatic cancer occurs; therefore, dogs are a valuable model for the study of factors that regulate tumor progression. Angiogenesis is important in the development and spread of a variety of cancers, including prostate cancer. To better define the role of cancer epithelial cells in prostate cancer neovascularization, immunohistochemical staining for angiogenic factors (vascular endothelial growth factor [VEGF], platelet endothelial cell adhesion molecule–1 [PECAM-1], Tie-2, and fibroblast growth factor–2 [FGF-2]) was performed on formalin-fixed, paraffin-embedded tissues from 10 normal prostates, 15 hyperplastic prostates, and 11 prostatic carcinomas from dogs. Normal and hyperplastic epithelial cells were negative for PECAM-1, VEGF, and Tie-2, while the same markers were expressed with a variable intensity of cytoplasmic staining by neoplastic cells. Mild to moderate FGF-2 staining was detected in all normal prostates with less than 10% of positive cells, mainly distributed in the basal layer. The percentage of FGF-2–positive hyperplastic cells was variable, with both basal and secretory cells exhibiting a perinuclear to diffuse cytoplasmic staining. The mean number of positive cells and the intensity of staining were higher in prostatic carcinomas than normal and hyperplastic prostates. Moreover, microvessel density analyzed on PECAM-1–stained slides was increased in prostate cancer compared with normal and hyperplastic prostates. Therefore, prostatic neoplastic cells are capable of simultaneous expression of various angiogenic factors and may increase tumor proliferation and angiogenesis in a paracrine and autocrine fashion.

Vascular Endothelial Growth Factor -460 C/T BstUI Gene Polymorphism is associated with Primary Open Angle Glaucoma

Background

Hypoxia and nitric oxide (NO) play important roles in the onset and progression of glaucoma. Vascular endothelial growth factor (VEGF) is one of the main factors responsive to hypoxia and NO. In this study, we investigated the association between the BstUI C/T VEGF gene polymorphism and primary open angle glaucoma (POAG).

Methods

60 POAG patients and 78 healthy volunteers were enrolled in this study. The most frequently observed polymorphism in the VEGF gene is BstUI C/T, which was located 460 nucleotides upstream of the gene. The polymorphism was observed using polymerase chain reaction-based restriction analysis.

Results

Significant differences were observed in the distribution of the polymorphism between control subjects and POAG patients (p = 0.003). C/C homozygotes are absent in the control group; therefore, this genotype represents a suitable genetic maker for POAG.

Conclusions

Hypoxia and NO may be involved in the pathway whereby the VEGF-460 polymorphism regulates POAG. Furthermore, homozygous C/C VEGF genotype is a useful maker for Chinese POAG.

Background

Hypoxia and nitric oxide (NO) play important roles in the onset and progression of glaucoma. Vascular endothelial growth factor (VEGF) is one of the main factors responsive to hypoxia and NO. In this study, we investigated the association between the BstUI C/T VEGF gene polymorphism and primary open angle glaucoma (POAG).

Methods

60 POAG patients and 78 healthy volunteers were enrolled in this study. The most frequently observed polymorphism in the VEGF gene is BstUI C/T, which was located 460 nucleotides upstream of the gene. The polymorphism was observed using polymerase chain reaction-based restriction analysis.

Results

Significant differences were observed in the distribution of the polymorphism between control subjects and POAG patients (p = 0.003). C/C homozygotes are absent in the control group; therefore, this genotype represents a suitable genetic maker for POAG

Conclusions

Hypoxia and NO may be involved in the pathway whereby the VEGF-460 polymorphism regulates POAG. Furthermore, homozygous C/C VEGF genotype is a useful maker for Chinese POAG.

Associations of nm23H1, VEGF-C, and VEGF-3 receptor in human prostate cancer

We studied the expression of the non-metastatic clone 23 type 1 (nm23H1) gene, vascular endothelial growth factor (VEGF)-C, and its receptor VEGFR-3 using an in situ hybridization technique and immunohistochemical analyses with prostate cancer tissues and adjacent benign tissues of 52 human archival cases. The association between VEGF-C expression, microlymphatic count (MLC), and staining intensity for nm23H1 and VEGFR-3 was used to evaluate tumor metastasis and survival rate. MLC values were significantly higher in tumorous tissue than in non-cancerous tissue. VEGF-C mRNA, VEGFR-3, and nm23H1 were highly expressed in tumorous tissue. VEGFR-3 expression was greater in VEGF-C mRNA-positive tumors than in VEGF-C mRNA-negative tumors. The association of VEGFR-3 expression with VEGF-C mRNA and MLC suggested that the poor prognosis and tumor metastasis associated with VEGFR-3 expression may be due, in part, to its role in promoting angiogenesis. VEGF-C expression was significantly associated with tumor lymphangiogenesis, angiogenesis, and immune response as a potent multifunctional stimulating factor in prostate cancer. Expression of nm23H1 was significantly inversely correlated with lymph node metastasis. Furthermore, there was a strong negative correlation between the expression of nm23H1, VEGF-C mRNA, and MLC. These findings provide important information for prophylactic, diagnostic, and therapeutic strategies for prostate cancer.

Association of the serum vascular endothelial growth factor levels with benign prostate hyperplasia and prostate malignancies

Background:

Recently, the development of new biomarkers as prognostic and predictive markers in prostate cancer has been crucial.

Objectives:

This study was aimed to determine whether serum vascular endothelial growth factor (VEGF) levels would be a prognostic marker or risk assessment factor in patients with prostate cancer and to investigate whether it could differentiate cancerous tissue from benign prostate hyperplasia (BPH).

Patients and Methods:

We enrolled 44 patients with prostate cancer, 57 patients with BPH, and 57 healthy individuals. Serum VEGF levels was measured by ELISA and was compared among all groups; then, its correlation with PSA and Gleason score in cancerous group was assessed. In addition, by using receiver operating characteristic (ROC) curve and area under curve (AUC), we determined the sensitivity and specificity of VEGF as well as combined variable of VEGF and PSA as a diagnostic marker of prostate cancer.

Results:

Serum VEGF level was significantly higher in patients with prostate cancer in comparison to the other groups (P value < 0.001); however, it was not different between BPH and control groups. Only in cancerous group a significant correlation between VEGF and PSA was found (r = 0.425, P = 0.004). Assessing the risk of prostate cancer, we found a powerful correlation between the VEGF alone as well as the combination of VEGF and PSA with prostate cancer.

Conclusions:

VEGF may be a diagnostic biomarker of prostate cancer. In addition, it may differentiate the cancerous tissue from BPH. We suggest that VEGF combined with PSA may be used as a screening test of prostate cancer.

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.

Prostate angiogenesis in development and inflammation

BACKGROUND

Prostatic inflammation is an important factor in development and progression of BPH/LUTS. This study was performed to characterize the normal development and vascular anatomy of the mouse prostate and then examine, for the first time, the effects of prostatic inflammation on the prostate vasculature.

METHODS

Adult mice were perfused with India ink to visualize the prostatic vascular anatomy. Immunostaining was performed on the E16.5 UGS and the P5, P20, and adult prostate to characterize vascular development. Uropathogenic E. coli 1677 was instilled transurethrally into adult male mice to induce prostate inflammation. RT-PCR and BrdU labeling was performed to assay anigogenic factor expression and endothelial proliferation, respectively.

RESULTS

An artery on the ventral surface of the bladder trifurcates near the bladder neck to supply the prostate lobes and seminal vesicle. Development of the prostatic vascular system is associated with endothelial proliferation and robust expression of pro-angiogenic factors Pecam1, Tie1, Tek, Angpt1, Angpt2, Fgf2, Vegfa, Vegfc, and Figf. Bacterial-induced prostatic inflammation induced endothelial cell proliferation and increased vascular density but surprisingly decreased pro-angiogenic factor expression.

CONCLUSIONS

The striking decrease in pro-angiogenic factor mRNA expression associated with endothelial proliferation and increased vascular density during inflammation suggests that endothelial response to injury is not a recapitulation of normal development and may be initiated and regulated by different regulatory mechanisms.

Mechanisms of synergism between antagonists of growth hormone-releasing hormone and antagonists of luteinizing hormone-releasing hormone in shrinking experimental benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) affects aging men. Combined therapy with antagonists of growth hormone-releasing hormone (GHRH) and of luteinizing hormone-releasing hormone (LHRH or GnRH) induces prostate shrinkage in rat models. We investigated the mechanisms of action of this combination on cell cycle traverse and expression of prostatic genes.

METHODS

Effects of GHRH antagonist, JMR-132 (40 µg/day), the LHRH antagonist, cetrorelix (0.625 mg/kg), and their combination were evaluated on testosterone-induced benign prostatic hyperplasia in male Wistar rats. Influence of JMR-132, cetrorelix, and their combinations on cell viability was assessed by MTS assay in BPH-1 human prostate epithelial cells and WPMY-1 normal prostate stromal cells. Cell cycle was analyzed by laser flow cytometry. Real-time PCR arrays were performed.

RESULTS

The combination of antagonists caused marked shrinkage of rat prostate (29.5%). In vitro, JMR-132 plus cetrorelix (both 5µM) produced synergistic (57.4%) inhibition of growth of BPH-1 cells, but a lesser inhibition (46%) of WPMY-1 cells. Co-treatment of with JMR-132 plus cetrorelix induced a significant increase of BPH-1 cells blocked in S-phase plus cells with lower G0 /G1 and G2 /M DNA content. Significant changes in expression of >40 gene transcripts related to growth factors, inflammatory cytokines, and signal transduction were identified.

CONCLUSIONS

GHRH antagonist and LHRH antagonist combination potentiates rat prostate weight reduction and synergistically inhibits of growth of BPH-1 leading to cell cycle arrest in S-phase. These effects were lesser in normal stromal prostate cell line, WPMY-1. Our findings suggest that GHRH antagonists could be useful for BPH therapy, possibly in combination with LHRH antagonists.

Osteopontin and MMP9: Associations with VEGF Expression/Secretion and Angiogenesis in PC3 Prostate Cancer Cells

Osteopontin and MMP9 are implicated in angiogenesis and cancer progression. The objective of this study is to gain insight into the molecular mechanisms underlying angiogenesis, and to elucidate the role of osteopontin in this process. We report here that osteopontin/αvβ3 signaling pathway which involves ERK1/2 phosphorylation regulates the expression of VEGF. An inhibitor to MEK or curcumin significantly suppressed the phosphorylation of ERK1/2 and expression of VEGF. MMP9 knockdown reduces the secretion but not the expression of VEGF. Moreover, MMP9 knockdown increases the release of angiostatin, a key protein that suppresses angiogenesis. Conditioned media from PC3 cells treated with curcumin or MEK inhibitor inhibited tube formation in vitro in human microvascular endothelial cells. Similar inhibitory effect on tube formation was found with conditioned media collected from PC3 cells expressing mutant-osteopontin at integrin-binding site and knockdown of osteopontin or MMP9. We conclude that MMP9 activation is associated with angiogenesis via regulation of secretion of VEGF and angiostatin in PC3 cells. Curcumin is thus a potential drug for cancer treatment because it demonstrated anti-angiogenic and anti-invasive properties.

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.

Effects of flavocoxid, a dual inhibitor of COX and 5-lipoxygenase enzymes, on benign prostatic hyperplasia

BACKGROUND AND PURPOSE

Inflammation plays a key role in the development of benign prostatic hyperplasia (BPH). Eicosanoids derived from the COX and 5-lipoxygenase (5-LOX) pathways are elevated in the enlarging prostate. Flavocoxid is a novel flavonoid-based 'dual inhibitor' of the COX and 5-LOX enzymes. This study evaluated the effects of flavocoxid in experimental BPH.

EXPERIMENTAL APPROACH

Rats were treated daily with testosterone propionate (3 mg·kg(-1)  s.c.) or its vehicle for 14 days to induce BPH. Animals receiving testosterone were randomized to receive vehicle (1 mL·kg(-1) , i.p.) or flavocoxid (20 mg·kg(-1) , i.p.) for 14 days. Histological changes, eicosanoid content and mRNA and protein levels for apoptosis-related proteins and growth factors were assayed in prostate tissue. The effects of flavocoxid were also tested on human prostate carcinoma PC3 cells.

KEY RESULTS

Flavocoxid reduced prostate weight and hyperplasia, blunted inducible expression of COX-2 and 5-LOX as well as the increased production of PGE(2) and leukotriene B(4) (LTB(4) ), enhanced pro-apoptotic Bax and caspase-9 and decreased the anti-apoptotic Bcl-2 mRNA. Flavocoxid also reduced EGF and VEGF expression. In PC3 cells, flavocoxid stimulated apoptosis and inhibited growth factor expression. Flavocoxid-mediated induction of apoptosis was inhibited by the pan-caspase inhibitor, Z-VAD-FMK, in PC3 cells, suggesting an essential role of caspases in flavocoxid-mediated apoptosis during prostatic growth.

CONCLUSION AND IMPLICATIONS

Our results show that a 'dual inhibitor' of the COX and 5-LOX enzymes, such as flavocoxid, might represent a rational approach to reduce BPH through modulation of eicosanoid production and a caspase-induced apoptotic mechanism.

Identification of ZNF217, hnRNP-K, VEGF-A and IPO7 as targets for microRNAs that are downregulated in prostate carcinoma

In primary prostate cancer (PCa), a major cause of cancer-related death in men, the expression of various microRNAs (miRNAs) is deregulated. We previously detected several miRNAs, for example, miR-24 and miR-22, as significantly downregulated in PCa (Szczyrba et al., Mol Cancer Res 2010;8:529-38). An in silico search predicted that zinc finger protein 217 (ZNF217) and importin 7 (IPO7) were potential target genes of these miRNAs. Additionally, for two genes that are deregulated in PCa (heterogeneous nuclear ribonucleoprotein K, hnRNP-K, and vascular endothelial growth factor A, VEGF-A), we identified two regulatory miRNAs, miR-205 and miR-29b. The regulation of the 3'-untranslated regions of the four genes by their respective miRNAs was confirmed by luciferase assays. As expected, the upregulation of ZNF217, hnRNP-K, VEGF-A and IPO7 could be verified at the protein level in the PCa cell lines LNCaP and DU145. ZNF217 and IPO7, which had not yet been studied in PCa, were analyzed in more detail. ZNF217 mRNA is overexpressed in primary PCa samples, and this overexpression translates to an elevated protein level. However, IPO7 was upregulated at the protein level alone. The inhibition of ZNF217 and IPO7 by siRNA resulted in reduced proliferation of the PCa cell lines. ZNF217 could thus be identified as an oncogene that is overexpressed in PCa and affects the growth of PCa cell lines, whereas the function of IPO7 remains to be elucidated in greater detail.

The prognostic value of expression of HIF1α, EGFR and VEGF-A, in localized prostate cancer for intermediate- and high-risk patients treated with radiation therapy with or without androgen deprivation therapy

Purpose

Androgens stimulate the production of hypoxia-inducible factor (HIF1α) and ultimately vascular endothelial growth factor (VEGF-A). Additionally, epithelial growth factor (EGF) mediates HIF1α production. Carbonic anhydrase IX (CAIX) expression is associated with tumor cell hypoxia in a variety of malignancies. This study assesses the prognostic relation between HIF1α, VEGF-A, EGF Receptor and CAIX expression by immunochemistry in diagnostic samples of patients with intermediate- and high-risk localized prostate cancer treated with radiation therapy, with or without androgen deprivation therapy (ADT).

Materials and methods

Between 1994 and 2004, 103 prostate cancer patients (mean age, 68.7 ± 6.2), with prostate cancer (mean PSA, 13.3 ± 3.7), were treated with radiation therapy (RT, median dose, 74 Gy). Fifty seven (55.3%) patients received ADT (median duration, 6 months; range, 0 – 24). Median follow-up was 97.6 months (range, 5.9 – 206.8).

Results

Higher EGFR expression was significantly (p = 0.04) correlated with higher Gleason scores. On univariate analysis, HIF1α nuclear expression was a significant (p = 0.02) prognostic factor for biological progression-free survival (bPFS). A trend towards significance (p = 0.05) was observed with EGFR expression and bPFS. On multivariate analysis, low HIF1α nuclear (p = 0.01) and high EGFR (p = 0.04) expression remained significant adverse prognostic factors.

Conclusions

Our study suggests that high nuclear expression of HIF1α and low EGFR expression in diagnostic biopsies of prostate cancer patients treated with RT ± ADT is associated with a good prognosis.

The angiogenic switch for vascular endothelial growth factor-A and cyclooxygenase-2 in prostate carcinoma: correlation with microvessel density, androgen receptor content and Gleason grade

OBJECTIVE

Angiogenesis is essential for tumor growth and metastasis; however, angiogenic factors are not uniformly expressed in prostate carcinoma. Our aim was to determine the expression of vascular endothelial growth factor-A (VEGF-A) and cyclooxygenase-2 (COX-2) in prostate carcinomas in relation to intratumoral microvessel density (MVD), tumor grade and androgen receptor (AR) status.

MATERIALS AND METHODS

The expression of AR, VEGF-A and COX-2 was immunohistochemically evaluated in 24 benign prostatic hyperplasia (BPH) and 139 prostate carcinoma cases. MVD was evaluated by CD34 immunostaining.

RESULTS

Nuclear AR expression was inversely related to tumor grade (p < 0.001). MVD was strongly related to tumor grade, VEGF-A and COX-2 (p < 0.001 in all comparisons). VEGF-A expression increased with tumor grade (p < 0.01) and was inversely related to stromal AR expression. COX-2 was present in both BPH and prostate carcinoma, but its expression increased with tumor grade (p < 0.01). High-grade neoplasms presented low-to-moderate VEGF staining intensity compared to strong COX-2 expression.

CONCLUSIONS

Both VEGF-A and COX-2 expression is positively correlated with tumor grade and MVD. However, in Gleason 8-10 tumors, VEGF expression is moderate while COX-2 immunostaining is intense, suggesting a possible switch in the role of these two angiogenic factors in poorly differentiated neoplasms.

Effects of TRPM8 on the proliferation and angiogenesis of prostate cancer PC-3 cells in vivo

Prostate cancer is a significant health concern. In the early stages, prostate cancer cells depend on androgens for growth and survival, hence androgen-ablation therapy at this time may be effective in causing tumor regression. However, treatment options for advanced hormone-refractory prostate cancers are still relatively inefficient. This study aimed to investigate the possible effects of TRPM8 on the proliferation and angiogenesis of androgen-independent cancer PC-3 cells in vivo. Thirty male nude mice were divided into three groups: the PC-3, PC-3-vector and PC-3-TRPM8 groups. PC-3, PC-3-vector and PC-3-TRPM8 cells were respectively inoculated in the right flank to establish a transplanted tumor model. The mice were treated daily for four weeks and each group was examined by histology and immunohistochemical staining for CD34, FAK and PCNA. A CD34 marked microvascular density (MVD) test was performed. Western blot analysis was used to detect the VEGF protein expression level. Compared to the PC-3 and PC-3-vector groups, the PC-3-TRPM8 group revealed a decrease in tumor volume (P=0.000 and P=0.000, respectively), MVD (P=0.045 and P=0.041, respectively), VEGF (P=0.000 and P=0.000, respectively), FAK and PCNA. The correlation between MVD and VEGF was positive (r=0.419; P=0.021). These data show that the overexpression of TRPM8 had a negative effect on the proliferation and angiogenesis progression of PC-3 cells in vivo.

Targeting non-malignant disorders with tyrosine kinase inhibitors

Receptor and non-receptor tyrosine kinases are involved in multiple proliferative signalling pathways. Imatinib, one of the first tyrosine kinase inhibitors (TKIs) to be approved, revolutionized the treatment of chronic myelogenous leukaemia, and other TKIs with different spectra of kinase inhibition are used to treat renal cell carcinoma, non-small-cell lung cancer and colon cancer. Studies also support the potential use of TKIs as anti-proliferative agents in non-malignant disorders such as cardiac hypertrophy, and in benign-proliferative disorders including pulmonary hypertension, lung fibrosis, rheumatoid disorders, atherosclerosis, in-stent restenosis and glomerulonephritis. In this Review, we provide an overview of the most recent developments--both experimental as well as clinical--regarding the therapeutic potential of TKIs in non-malignant disorders.

Polyethylenimine/small interfering RNA-mediated knockdown of vascular endothelial growth factor in vivo exerts anti-tumor effects synergistically with Bevacizumab

BACKGROUND

RNA interference is a powerful method for the knockdown of pathologically relevant genes. The in vivo delivery of siRNAs, preferably through systemic, nonviral administration, poses the major challenge in the therapeutic application of RNAi. Small interfering RNA (siRNA) complexation with polyethylenimines (PEI) may represent a promising strategy for siRNA-based therapies and, recently, the novel branched PEI F25-LMW has been introduced in vitro. Vascular endothelial growth factor (VEGF) is frequently overexpressed in tumors and promotes tumor growth, angiogenesis and metastasis and thus represents an attractive target gene in tumor therapy.

METHODS

In subcutaneous tumor xenograft mouse models, we established the therapeutic efficacy and safety of PEI F25-LMW/siRNA-mediated knockdown of VEGF. In biodistribution and siRNA quantification studies, we optimized administration strategies and, employing chemically modified siRNAs, compared the anti-tumorigenic efficacies of: (i) PEI/siRNA-mediated VEGF targeting; (ii) treatment with the monoclonal anti-VEGF antibody Bevacizumab (Avastin); and (iii) a combination of both.

RESULTS

Efficient siRNA delivery is observed upon systemic administration, with the biodistribution being dependent on the mode of injection. Toxicity studies reveal no hepatotoxicity, proinflammatory cytokine induction or other side-effects of PEI F25-LMW/siRNA complexes or polyethylenimine, and tumor analyses show efficient VEGF knockdown upon siRNA delivery, leading to reduced tumor cell proliferation and angiogenesis. The determination of anti-tumor effects reveals that, in pancreas carcinoma xenografts, single treatment with PEI/siRNA complexes or Bevacizumab is already highly efficacious, whereas, in prostate carcinoma, synergistic effects of both treatments are observed.

CONCLUSIONS

PEI F25-LMW/siRNA complexes, which can be stored frozen as opposed to many other carriers, represent an efficient, safe and promising avenue in anti-tumor therapy, and PEI/siRNA-mediated, therapeutic VEGF knockdown exerts anti-tumor effects.

Angiogenesis as a strategic target for prostate cancer therapy

It is becoming increasingly clear that angiogenesis plays a crucial role in prostate cancer (CaP) survival, progression, and metastasis. Tumor angiogenesis is a hallmark of advanced cancers and an attractive treatment target in multiple solid tumors. By understanding the molecular basis of resistance to androgen withdrawal and chemotherapy in CaP, the rational design of targeted therapeutics is possible. This review summarizes the recent advancements that have improved our understanding of the role of angiogenesis in CaP metastasis and the potential therapeutic efficacy of inhibiting angiogenesis in this disease. Current therapeutic options for patients with metastatic hormone-refractory CaP are very limited. Targeting vasculature is a developing area, which shows promise for the control of late stage and recurrent CaP disease and for overcoming drug resistance. We discuss angiogenesis and its postulated mechanisms and focus on the regulation of angiogenesis in CaP progression and the therapeutic beneficial effects associated with targeting of the CaP vasculature to overcome the resistance to current treatments and CaP recurrence.

[CT and MRI imaging in tumoral angiogenesis]

Angiogenesis is the process of activating dormant endothelial cells to form new vessels, after stimulation and it is essential in tumor growth. In many types of cancer, angiogenesis results from the activation of oncogenes that stimulate the production of Vascular Endothelial Growth Factor (VEGF). However, these newly formed vessels have a great number of abnormalities: increased density of fragile and hyper-permeable microvessels, arterial-venous shunts, caliber abnormalities and flow instabilities susceptible to flow direction inversion according to interstitial pressure. Anti-angiogenic treatments inhibit VEGF activity, perceived as structural and functional normalization of the microvascular pattern, such as reduced density of microvessels and restored morphology of the remaining ones. Conventional imaging techniques are not sensible to these changes, at best they show tumor size stabilization, hence the need of new techniques. Microvascularization imaging can be achieved by detecting functional disturbances to blood flow and not by showing the microvasculature per se. These techniques are based in quantifying the enhancement in tumor due to the passage of contrast agent after injection or protons labeled by a magnetic field. Through these measurements, one can derive interstitial and blood volumes as well as the tissue perfusion and capillary wall permeability. Microvascular imaging has greatly benefited from the improvements seen in CT and MRI equipment allowing large volume coverage with high spatial and temporal resolutions as from the evolutions in the methods to calculate, present and compare maps of the microcirculation and it's heterogeneity. However, software to analyze microvascularization are still rare, limiting the technique's application and validation in large scale. Nevertheless, imaging of the microcirculation is useful throughout the care of the oncological patient: it can reinforce the suspicious nature of a lesion, suggest anti-angiogenic treatment efficacy in hypervascular lesions, and show early treatment response before morphological changes as in RECIST criteria.

Multidisciplinary functional MR imaging for prostate cancer

Various functional magnetic resonance (MR) imaging techniques are used for evaluating prostate cancer including diffusion-weighted imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy. These techniques provide unique information that is helpful to differentiate prostate cancer from non-cancerous tissue and have been proven to improve the diagnostic performance of MRI not only for cancer detection, but also for staging, post-treatment monitoring, and guiding prostate biopsies. However, each functional MR imaging technique also has inherent challenges. Therefore, in order to make accurate diagnoses, it is important to comprehensively understand their advantages and limitations, histologic background related with image findings, and their clinical relevance for evaluating prostate cancer. This article will review the basic principles and clinical significance of functional MR imaging for evaluating prostate cancer.

VEGF -460C>T polymorphism and cancer risk: a meta-analysis

Vascular endothelial growth factor (VEGF) is a major driver of physiological and pathological angiogenesis and plays important roles in the etiology and metastasis of cancers. The -460C>T polymorphism in VEGF gene region has been implicated in cancer risk and related to VEGF expression. However, published data remain conflicting. To derive a more precise estimation, a meta-analysis of 5,863 cases and 5,276 controls from 14 published case-control studies was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. VEGF -460T represented a risk factor for cancers in Asians (OR=1.69, 95% CI: 1.09-2.62) but not in Europeans (OR=0.92, 95% CI: 0.78-1.08). Our meta-analysis showed the evidence that VEGF -460T was associated with increased cancer risk in Asians. Further prospective researches with larger numbers of worldwide participants are expected to validate this result.

Vascular endothelial growth factor in serum indicates cardiovascular risk in urology patients

OBJECTIVE

We hypothesized that a high serum concentration of vascular endothelial growth factor (VEGF), a cytokine involved in prostate growth which is also upregulated in chronic ischemia, indicates an increased risk of cardiovascular disease and death in urology patients.

MATERIAL AND METHODS

The serum VEGF concentration was measured in 219 males (mean age 72 years) who sought medical attention because of lower urinary tract symptoms. Data on cardiovascular events and survival were obtained from the hospital registry of Stockholm County and the Death Registry over a period of up to 10 years (mean 6.2 years).

RESULTS

After adjusting for the effects of age and smoking, patients with a serum VEGF level in the upper 20% of the cohort (>500 pg/ml) had an increased risk of developing cardiovascular disease (hazard ratio 2.18; 95% CI 1.04-4.60), including acute myocardial infarction (3.36; 1.35-8.41) and stroke (3.98; 1.61-9.86). They also had an increased risk of death (1.74; 1.01-3.00). These differences from patients with a lower serum VEGF concentration (<300 pg/ml) were manifested 2-5 years after the blood sample was taken.

CONCLUSION

An elevated VEGF level in peripheral blood was a risk factor for subsequent development of cardiovascular disease.

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.

Growth factors in benign prostatic hyperplasia: basic science implications

Benign prostatic hyperplasia (BPH) is the most common proliferative disease of the prostate of men in the United States. The histopathology of BPH strongly implicates local paracrine and autocrine growth factors and inflammatory cytokines in its pathogenesis. A complex milieu of growth-regulatory proteins includes members of the fibroblast, insulin-like, and transforming growth factor families. It appears that these proteins and downstream effector molecules, in addition to a variety of interleukins, are overexpressed in BPH and, working together, create a landscape of increased stromal and epithelial growth and mesenchymal transdifferentiation that leads to disease progression. Inflammation, commonly present in BPH, may contribute to tissue injury, and cytokines produced by inflammatory cells may serve to drive local growth factor production and angiogenesis in the tissues as a "wound healing" response. As we begin to unravel the precise mechanisms involved, new treatments for BPH aimed at these interacting pathways may emerge.

Diffusion and perfusion MR imaging of the prostate

Conventional anatomic MR imaging has evolved to a superior modality in the evaluation of prostate carcinoma and is now a widely established technique in the detection and staging of this disease, aiding in clinical decision making on treatment and therapy evaluation. Recent improvements in functional MR techniques, such as diffusion-weighted MR imaging and dynamic contrast-enhanced MR imaging, have greatly increased the impact of MR imaging in prostate cancer. The combination of T2-weighted imaging, diffusion-weighted MR imaging, and dynamic contrast-enhanced MR imaging may overcome the limitations of conventional T2-weighted MR imaging of the prostate and may be able accurately to detect, localize, stage, and grade prostate carcinoma and guide biopsies.

Contrast-enhanced transrectal ultrasound for assessing vascularization of hypoechoic BPH nodules in the transition and peripheral zones: comparison with pathological examination

The purpose of this study was to investigate the vascularization of zonal location of hypoechoic benign prostatic hyperplasia (BPH) nodules and to evaluate the clinical value of contrast-enhanced transrectal ultrasound (CETRUS) for assessing vascularity of hypoechoic BPH nodules. Sixty-two patients with hypoechoic biopsy-proven BPH nodules in transition zone (TZ) (32 patients) or peripheral zone (PZ) (30 patients) of the prostate gland underwent CETRUS examination between January 2006 and September 2006. The enhancement characteristics of hypoechoic BPH nodules were observed and time to enhancement (AT), time to peak intensity (TTP) and peak intensity (PI) were measured with ACQ time-intensity curve analysis software. In addition, microvessel density (MVD) and vascular endothelial growth factor (VEGF) immunoreactivity were determined in the biopsy specimens. Microvessels were identified by immunohistochemical staining of endothelial cells for CD34. Findings were compared between hypoechoic BPH nodules located in PZ and TZ. The most common enhancement characteristic of hypoechoic BPH nodules in PZ was nonenhanced area inside (21/30), while most of hypoechoic BPH nodules in TZ appeared homogeneous enhancement (28/32). The average AT and TTP were significantly longer, the average PI was significantly lower in hypoechoic BPH nodules located in PZ than TZ (p < 0.01). The VEGF expression and MVD were significantly higher in hypoechoic BPH nodules located in TZ than PZ (p < 0.01). PI was found to be an important parameter strongly correlated with degree of vascularity of hypoechoic BPH nodules. Hypoechoic BPH nodules located in PZ and TZ showed significant difference in vascularization, which indirectly verified our finding that BPH nodule could occur in the peripheral zone. CETRUS could afford information on the vascularity of hypoechoic BPH nodules in a noninvasive manner and this could be used to improve selection of nodules for biopsy.

Targeting vasculature in urologic tumors: mechanistic and therapeutic significance

Recent advances toward understanding the molecular mechanisms regulating cancer initiation and progression provide new insights into the therapeutic value of targeting tumor vascularity by interfering with angiogenic signaling pathways. The functional contribution of key angiogenic factors toward increased vascularity characterizing metastatic tumors and their therapeutic exploitation is considered in three major urologic malignancies, renal, bladder, and prostate cancer. With the realization that the success of the therapeutic efficacy of the various anti-angiogenic approaches for the treatment of urologic tumors has yet to be proven clinically, the challenge remains to select critical angiogenesis pathways that can be targeted for an individual tumor. Here we discuss the major mechanisms that support formation of vasculature in renal, bladder, and prostate tumors and the current results of targeting of specific molecules/regulators for therapeutic intervention against metastastic disease.

The endogenous anti-angiogenic VEGF isoform, VEGF165b inhibits human tumour growth in mice

Vascular endothelial growth factor-A is widely regarded as the principal stimulator of angiogenesis required for tumour growth. VEGF is generated as multiple isoforms of two families, the pro-angiogenic family generated by proximal splice site selection in the terminal exon, termed VEGFxxx, and the anti-angiogenic family formed by distal splice site selection in the terminal exon, termed VEGFxxxb, where xxx is the amino acid number. The most studied isoforms, VEGF165 and VEGF165b have been shown to be present in tumour and normal tissues respectively. VEGF165b has been shown to inhibit VEGF- and hypoxia-induced angiogenesis, and VEGF-induced cell migration and proliferation in vitro. Here we show that overexpression of VEGF165b by tumour cells inhibits the growth of prostate carcinoma, Ewing's sarcoma and renal cell carcinoma in xenografted mouse tumour models. Moreover, VEGF165b overexpression inhibited tumour cell-mediated migration and proliferation of endothelial cells. These data show that overexpression of VEGF165b can inhibit growth of multiple tumour types in vivo indicating that VEGF165b has potential as an anti-angiogenic, anti-tumour strategy in a number of different tumour types, either by control of VEGF165b expression by regulation of splicing, overexpression of VEGF165b, or therapeutic delivery of VEGF165b to tumours.

Differential efficacy of combined therapy with radiation and AEE788 in high and low EGFR-expressing androgen-independent prostate tumor models

PURPOSE

To determine the efficacy of combining radiation (XRT) with a dual epidermal growth factor receptor (EGFR)/vascular endothelial growth factor receptor inhibitor, AEE788, in prostate cancer models with different levels of EGFR expression.

METHODS AND MATERIALS

Immunoblotting was performed for EGFR, phosphorylated-EGFR, and phosphorylated-AKT in prostate cancer cells. Clonogenic assays were performed on DU145, PC-3, and human umbilical vein endothelial cells treated with XRT +/- AEE788. Tumor xenografts were established for DU145 and PC-3 on hind limbs of athymic nude mice assigned to four treatment groups: (1) control, (2) AEE788, (3) XRT, and (4) AEE788 + XRT. Tumor blood flow and growth measurements were performed using immunohistochemistry and imaging.

RESULTS

AEE788 effectively decreased phosphorylated-EGFR and phosphorylated-AKT levels in DU145 and PC-3 cells. Clonogenic assays showed no radiosensitization for DU145 and PC-3 colonies treated with AEE788 + XRT. However, AEE788 caused decreased proliferation in DU145 cells. AEE788 showed a radiosensitization effect in human umbilical vein endothelial cells and increased apoptosis susceptibility. Concurrent AEE788 + XRT compared with either alone led to significant tumor growth delay in DU145 tumors. Conversely, PC-3 tumors derived no added benefit from combined-modality therapy. In DU145 tumors, a significant decrease in tumor blood flow with combination therapy was shown by using power Doppler sonography and tumor blood vessel destruction on immunohistochemistry. Maldi-spectrometry (MS) imaging showed that AEE788 is bioavailable and heterogeneously distributed in DU145 tumors undergoing therapy.

CONCLUSIONS

AEE788 + XRT showed efficacy in vitro/in vivo with DU145-based cell models, whereas PC-3-based models were adequately treated with XRT alone without added benefit from combination therapy. These findings correlated with differences in EGFR expression and showed effects on both tumor cell proliferation and vascular destruction.

Chronic administration of valproic acid inhibits PC3 cell growth by suppressing tumor angiogenesis in vivo

AIM

Chromatin remodeling agents such as histone deacetylase inhibitors have been shown to modulate gene expression in tumor cells and inhibit tumor growth and angiogenesis. We investigated the mechanisms of chronic valproic acid (VPA) inhibiting PC3 cell growth in the study.

METHODS

We established tumor xenografts of the PC3 cell line and investigated the effect of VPA chronic administration on tumor growth. Apoptosis in tumor tissue was measured using the TUNEL Detection Kit. We detected the effect of VPA chronic administration on histone acetylation; p21CIP1/WAF1 gene expression; vascular endothelial growth factor (VEGF) expression by reverse-transcription Polymerase Chain Reaction (PCR) analysis; immunohistochemistry; and Western Blotting.

RESULT

In mouse models with established subcutaneous prostate (PC3), VPA treatment induced 70% inhibition of tumor growth without overt toxicity. Our result showed that chronic administration of VPA has an effect on tumor growth arrest and the effect was associated with increased histone acetylation, p21CIP1/WAF1 up-regulation, and VEGF down-regulation.

CONCLUSION

We conclude that chronic VPA results in profound decreases in the proliferation of PC3 cells, not only by increasing histone H3 acetylation and up-regulating p21CIP1/WAF1 expression, but also by down-regulating VEGF.

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.

Hypoxia-inducible factor-1alpha (HIF-1alpha) gene polymorphisms, circulating insulin-like growth factor binding protein (IGFBP)-3 levels and prostate cancer

BACKGROUND

The Hypoxia-inducible factor-1 (HIF-1) plays an important role in regulating angiogenesis in response to hypoxia. Two non-synonymous polymorphisms (P582S C-->T and A588T G-->A) in the coding region of the subunit 1alpha (HIF-1alpha) gene have been associated with enhanced stability of the protein and androgen-independent prostate cancer (CaP). Insulin-like growth factor binding protein (IGFBP)-3 mRNA is more abundantly expressed in hypoxia-related inflammatory angiogenesis and recent in vivo data suggest that IGFBP-3 has direct, IGF-independent inhibitory effects on angiogenesis.

METHODS

We examined the association of these polymorphisms with CaP among 1,072 incident cases and 1,271 controls, and further explored their joint associations with various prediagnostic plasma vascular endothelial growth factor (VEGF), IGF-I, and IGFBP-3 levels.

RESULTS

Neither the P582S nor the A588T polymorphism was associated with risk of overall or metastatic/fatal CaP. However, we found that, among men with the homozygous CC wild-type (but not CT/TT) of the HIF-1alpha P582S, higher IGFBP-3 levels (>/= vs. <median) were associated with a 28% (95% CI, 0.55-0.95; P(interaction) = 0.01) lower risk of overall CaP and a 53% (0.25-0.88; P(interaction) = 0.11) lower risk of metastatic and fatal CaP. The A588T polymorphism was too rare to assess interactions.

CONCLUSIONS

The two HIF-1alpha gene polymorphisms were not directly associated with CaP, but the interaction between the P582S polymorphism and IGFBP-3 merits further evaluation in mechanistic studies.

Dynamic contrast enhanced MRI in prostate cancer

Angiogenesis is an integral part of benign prostatic hyperplasia (BPH), is associated with prostatic intraepithelial neoplasia (PIN) and is key to the growth and for metastasis of prostate cancer. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) using small molecular weight gadolinium chelates enables non-invasive imaging characterization of tissue vascularity. Depending on the technique used, data reflecting tissue perfusion, microvessel permeability surface area product, and extracellular leakage space can be obtained. Two dynamic MRI techniques (T2*-weighted or susceptibility based and T1-weighted or relaxivity enhanced methods) for prostate gland evaluations are discussed in this review with reference to biological basis of observations, data acquisition and analysis methods, technical limitations and validation. Established clinical roles of T1-weighted imaging evaluations will be discussed including lesion detection and localisation, for tumour staging and for the detection of suspected tumour recurrence. Limitations include inadequate lesion characterisation particularly differentiating prostatitis from cancer, and in distinguishing between BPH and central gland tumours.

Androgen-dependent gene expression of prostate-specific antigen is enhanced synergistically by hypoxia in human prostate cancer cells

The androgen receptor (AR) is implicated in prostate cancer growth, progression, and angiogenesis. Hypoxia-inducible factor-1 (HIF-1), which transcriptionally regulates hypoxia-inducible angiogenic factors, is up-regulated in prostate cancers compared with adjacent normal tissues. HIF-1 may be involved in prostate cancer as well as the AR, but the involvement of HIF-1 in prostate cancer angiogenesis and progression has not been fully elucidated. In the present study, we found that in prostate cancer LNCaP cells dihydrotestosterone enhanced the expression of GLUT-1, one of the HIF-1 target genes, and also that hypoxia enhanced the expression of prostate-specific antigen (PSA) that is one of the AR target genes and is involved in tumor invasion. Small interfering RNA that specifically inhibits HIF-1 reduced the expression levels of PSA as well as GLUT-1. Reporter gene analysis showed that dihydrotestosterone activated the HIF-1-mediated gene expression and hypoxia enhanced the AR-induced promoter activity of human PSA gene. Deletion and site-directed mutation of the 5'-flanking region of human PSA gene revealed that the sequence ACGTG between -3951 and -3947 was essential in the response to hypoxia. Furthermore, chromatin immunoprecipitation assay indicated that HIF-1 interacts with the AR on the human PSA gene promoter. These results indicated that in prostate cancers, HIF-1 might cooperate with the AR to activate the expression of several genes related to tumor angiogenesis, invasion, and progression.

No association between polymorphism in the vascular endothelial growth factor gene at position -460 and sporadic prostate cancer in the Turkish population

The development and progression of prostate cancer (PCa) has biologically and genetically remained a mystery. A man's risk of developing PCa is influenced by both genetic and environmental factors. Angiogenic cytokines like vascular endothelial growth factor (VEGF) play a pivotal role in tumor angiogenesis. Single nucleotide polymorphisms in angiogenesis-dependent genes affect the sensibility of cancer development and progression. Therefore, we hypothesized a potential association between DNA sequence variations in VEGF -460 gene region and sporadic PCa patients in the Turkish population. 133 sporadic PCa patients and 157 healthy controls were studied. Genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. The distribution of genotype and allele frequencies of the polymorphism did not yield a statistically significant difference between patients and controls (P>0.05). Furthermore, classification of patients by tumor-lymph nodes-metastasis (TNM), Gleason Scores (GS) and serum prostate-specific antigen (PSA) levels did not show significant differences among the VEGF -460 C>T genotypes (P>0.05). This is the first demonstration showing that the VEGF -460 C>T polymorphism in men is not associated with sporadic PCa in the Turkish population.

Global analysis of differentially expressed genes in androgen-independent prostate cancer

Progression to androgen independent (AI) is the main cause of death in prostate cancer, and the mechanism is still unclear. By reviewing the expression profiles of 26 prostate cancer samples in a holistic view, we found a group of genes differentially expressed in AI compared with androgen-dependent groups (P-value<0.01, t-test). Focusing on apoptosis, proliferation, hormone and angiogenesis, we found a group of genes such as thioredoxin domain containing 5 , tumor necrosis factor receptor superfamily, member 10a , ribosomal protein S19 and Janus kinase 2 upregulated in AI prostate cancer, could play important roles in the transition from AD to AI and could be biomarkers of prognosis.