Stromal expression of VEGF-A and VEGFR-2 in prostate tissue is associated with biochemical and clinical recurrence after radical prostatectomy

Evidence of the Link between Stroma Remodeling and Prostate Cancer Prognosis

Prostate cancer (PCa), the most commonly diagnosed cancer in men worldwide, is particularly challenging for oncologists when a precise prognosis needs to be established. Indeed, the entire clinical management in PCa has important drawbacks, generating an intense debate concerning the possibility to individuate molecular biomarkers able to avoid overtreatment in patients with pathological indolent cancers. To date, the paradigmatic change in the view of cancer pathogenesis prompts to look for prognostic biomarkers not only in cancer epithelial cells but also in the tumor microenvironment. PCa ecology has been defined with increasing details in the last few years, and a number of promising key markers associated with the reactive stroma are now available. Here, we provide an updated description of the most biologically significant and cited prognosis-oriented microenvironment biomarkers derived from the main reactive processes during PCa pathogenesis: tissue adaptations, inflammatory response and metabolic reprogramming. Proposed biomarkers include factors involved in stromal cell differentiation, cancer-normal cell crosstalk, angiogenesis, extracellular matrix remodeling and energy metabolism.

Development of a novel prostate Cancer-Stroma Sphere (CSS) model for In Vitro tumor microenvironment studies

Tumor employs non-cancerous cells to gain beneficial features that promote growth and survival of cancer cells. Despite intensive research in the area of tumor microenvironment, there is still a lack of reliable and reproducible in vitro model for tumor and tumor-microenvironment cell interaction studies. Herein we report the successful development of a heterogeneous cancer-stroma sphere (CSS) model composed of prostate adenocarcinoma PC3 cells and immortalized mesenchymal stem cells (MSC). The CSS model demonstrated a structured spatial layout of the cells, with stromal cells concentrated at the center of the spheres and tumor cells located on the periphery. Significant increase in the levels of VEGFA, IL-10, and IL1a has been detected in the conditioned media of CSS as compared to PC3 spheres. Single cell RNA sequencing data revealed that VEGFA was secreted by MSC cells within heterogeneous spheroids. Enhanced expression of extracellular membrane (ECM) proteins was also shown for CSS-derived MSCs. Furthermore, we demonstrated that the multicellular architecture altered cancer cell response to chemotherapeutic agents: the inhibition of sphere formation by topotecan was 74.92 ± 4.56 % for PC3 spheres and 45.95 ± 7.84 % for CSS spheres (p < 0.01), docetaxel showed 37,51± 20,88 % and 15,67± 14,08 % inhibition, respectively (p < 0.05). Thus, CSS present an effective in vitro model for examining the extracellular matrix composition and cell-to-cell interactions within the tumor, as well as for evaluating the antitumor activity of drugs.

Immunoexpression of CD44, p16 and VEGF in oral cancer

Objectives

The aim of the present study was to examine the immunoexpression of CD44, p16 and VEGF in oral squamous cell carcinoma (OSCC) and correlate them to clinicopathological parameters and survival outcomes in order to clarify their prognostic impact.

Material and Methods

A total of 68 individuals with OSCC recruited between 2011 and 2015 from two referral centres were enrolled in the study. The samples were placed on silanized glass slides and subjected to immunohistochemistry using anti-p16, anti-CD44 and anti-VEGF antibodies. The H Score was used for p16 and VEGF, while CD44 was scored according to the percentage of stained cells. Chi-square tests and Fisher's exact probability tests were used to compare clinicopathological characteristics according to the immunohistochemical expression, while overall survival and disease-free survival were estimated and compared using the Kaplan-Meier method and log-rank test, respectively. For all hypothesis tests, the level of significance was set at P ≤ 0.05.

Results

No correlation was observed between the expression of tumour VEGF, p16 and CD44, and the clinicopathological characteristics analysed. Patients with high stromal VEGF expression had better disease-free survival than patients with low VEGF expression (P = 0.023).

Conclusion

In summary, P16, CD44 and tumour VEGF did not prove to be good prognostic biomarkers. Stromal VEGF expression is suggested to be a good candidate prognostic biomarker, although additional studies are needed.

Overcoming Immune Resistance With Radiation Therapy in Prostate Cancer

Prostate cancer is the second most common cancer in men and represents a significant healthcare burden worldwide. Therapeutic options in the metastatic castration-resistant setting remain limited, despite advances in androgen deprivation therapy, precision medicine and targeted therapies. In this review, we summarize the role of immunotherapy in prostate cancer and offer perspectives on opportunities for future development, based on current knowledge of the immunosuppressive tumor microenvironment. Furthermore, we discuss the potential for synergistic therapeutic strategies with modern radiotherapy, through modulation of the tumor microenvironment. Emerging clinical and pre-clinical data suggest that radiation can convert immune desert tumors into an inflamed immunological hub, potentially sensitive to immunotherapy.

The natural compound atraric acid suppresses androgen-regulated neo-angiogenesis of castration-resistant prostate cancer through angiopoietin 2

Castration-resistant prostate cancer (CRPC) is an aggressive lethal form of prostate cancer (PCa). Atraric acid (AA) not only inhibits the wild-type androgen receptor (AR) but also those AR mutants that confer therapy resistance to other clinically used AR antagonists, indicating a different mode of AR antagonism. AA induces cellular senescence and inhibits CRPC tumour growth in in vivo xenograft mouse model associated with reduced neo-angiogenesis suggesting the repression of intratumoural neo-angiogenesis by AA. In line with this, the secretome of CRPC cells mediates neo-angiogenesis in an androgen-dependent manner, which is counteracted by AA. This was confirmed by two in vitro models using primary human endothelial cells. Transcriptome sequencing revealed upregulated angiogenic pathways by androgen, being however VEGF-independent, and pointing to the pro-angiogenic factor angiopoietin 2 (ANGPT2) as a key driver of neo-angiogenesis induced by androgens and repressed by AA. In agreement with this, AA treatment of native patient-derived PCa tumour samples ex vivo inhibits ANGPT2 expression. Mechanistically, in addition to AA, immune-depletion of ANGPT2 from secretome or blocking ANGPT2-receptors inhibits androgen-induced angiogenesis. Taken together, we reveal a VEGF-independent ANGPT2-mediated angiogenic pathway that is inhibited by AA leading to repression of androgen-regulated neo-angiogenesis.

Production and Conjugation of Truncated Recombinant Diphtheria Toxin to VEGFR-2 Specific Nanobody and Evaluation of its Cytotoxic Effect on PC-3 Cell Line

Immunotoxins have represented a great potency in targeted therapeutics to encounter tumors. They consist of a protein toxin conjugated to a targeting moiety, which recognizes a specific antigen on surface of cancer cells and accordingly induces cell death by toxin segment. The targeting part could be a nanobody, which is a group of antibodies composed of an only functional single variable heavy chain (VHH).Therefore, this study was done to produce an immunotoxin (VGRNb-DT) by chemical conjugation of a truncated diphtheria toxin moiety to an anti-vascular endothelial growth factor receptor 2(VEGFR-2) nanobody, and to identify effectiveness of immunotoxin in recognizing the VEGFR-2- positive cancer cells and inhibiting cell growth and survival. Diphtheria toxin was expressed and purified by nickel affinity chromatography, and accordingly, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis confirmed its expression. Function of heterobifunctional crosslinkers, Sulfo-SMCC (sulfosuccinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate), and SATP (N-succinimidyl-S- acetylthiopropionate) for bioconjugation purposes was acknowledged by cation exchange high-performance liquid chromatography (HPLC). Cytotoxicity of immunotoxin was evaluated on the VEGFR-2 positive PC-3 cell line by MTT assay. Overexpression of VEGFR-2 in the PC-3 cell line allowed immunotoxin to recognize them by anti-VEGFR-2 nanobodies. The concentrations above 5 μg/ml represented a significant decrease in cell survival rate in PC-3 cells compared to HEK293 cells (VEGFR-2 negative cells) as controls.VGRNb-DT demonstrated a successful bioconjugation; furthermore, variable concentrations were correlated with cell death in prostate cancer PC-3 cells.

Anti-Proliferative, Anti-Angiogenic and Safety Profiles of Novel HDAC Inhibitors for the Treatment of Metastatic Castration-Resistant Prostate Cancer

Metastatic castration-resistant prostate cancer (CRPC) has a five-year survival rate of 28%. As histone deacetylases (HDACs) are overexpressed in CRPC, the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) was trialled in CRPC patients but found to be toxic and inefficacious. Previously, we showed that novel HDAC inhibitors (Jazz90 (N1-hydroxy-N⁸-(4-(pyridine-2-carbothioamido)phenyl)octanediamide) and Jazz167 ([chlorido(η⁵-pentamethylcyclopentadieny[1–4](N1-hydroxy-N⁸-(4-(pyridine-2-carbothioamido-κ²N,S)phenyl)octanediamide)rhodium(III)] chloride) had a higher cancer-to-normal-cell selectivity and superior anti-angiogenic effects in CRPC (PC3) cells than SAHA. Thus, this study aimed to further investigate the efficacy and toxicity of these compounds. HUVEC tube formation assays revealed that Jazz90 and Jazz167 significantly reduced meshes and segment lengths in the range of 55–88 and 43–64%, respectively. However, Jazz90 and Jazz167 did not affect the expression of epithelial-to-mesenchymal transitioning markers E-cadherin and vimentin. Jazz90 and Jazz167 significantly inhibited the growth of PC3 and DU145 spheroids and reduced PC3 spheroid branching. Jazz90 and Jazz167 (25, 50 and 75 mg/kg/day orally for 21 days) were non-toxic in male BALB/c mice. The efficacy and safety of these compounds demonstrate their potential for further in vivo studies in CRPC models.

A Perspective on Withania somnifera Modulating Antitumor Immunity in Targeting Prostate Cancer

Medicinal plants serve as a lead source of bioactive compounds and have been an integral part of day-to-day life in treating various disease conditions since ancient times. Withaferin A (WFA), a bioactive ingredient of Withania somnifera, has been used for health and medicinal purposes for its adaptogenic, anti-inflammatory, and anticancer properties long before the published literature came into existence. Nearly 25% of pharmaceutical drugs are derived from medicinal plants, classified as dietary supplements. The bioactive compounds in these supplements may serve as chemotherapeutic substances competent to inhibit or reverse the process of carcinogenesis. The role of WFA is appreciated to polarize tumor-suppressive Th1-type immune response inducing natural killer cell activity and may provide an opportunity to manipulate the tumor microenvironment at an early stage to inhibit tumor progression. This article signifies the cumulative information about the role of WFA in modulating antitumor immunity and its potential in targeting prostate cancer.

Grading Evolution and Contemporary Prognostic Biomarkers of Clinically Significant Prostate Cancer

Simple Summary

Prostate cancer treatment decisions are based on clinical stage and histological diagnosis, including Gleason grading assessed by a pathologist, in biopsies. Prior to staging and grading, serum or blood prostate-specific antigen (PSA) levels are measured and often trigger diagnostic examinations. However, PSA is best suited as a marker of cancer relapse after initial treatment. In this review, we first narratively describe the evolution of histological grading, the current status of Gleason pattern-based diagnostics and glance into future methodology of risk assessment by histological examination. In the second part, we systematically review the biomarkers that have been shown, independent from clinical characteristics, to correlate with clinically relevant end-points, i.e., occurrence of metastases, disease-specific mortality and overall survival after initial treatment of localized prostate cancer.

Abstract

Gleason grading remains the strongest prognostic parameter in localized prostate adenocarcinoma. We have here outlined the evolution and contemporary practices in pathological evaluation of prostate tissue samples for Gleason score and Grade group. The state of more observer-independent grading methods with the aid of artificial intelligence is also reviewed. Additionally, we conducted a systematic review of biomarkers that hold promise in adding independent prognostic or predictive value on top of clinical parameters, Grade group and PSA. We especially focused on hard end points during the follow-up, i.e., occurrence of metastasis, disease-specific mortality and overall mortality. In peripheral blood, biopsy-detected prostate cancer or in surgical specimens, we can conclude that there are more than sixty biomarkers that have been shown to have independent prognostic significance when adjusted to conventional risk assessment or grouping. Our search brought up some known putative markers and panels, as expected. Also, the synthesis in the systematic review indicated markers that ought to be further studied as part of prospective trials and in well characterized patient cohorts in order to increase the resolution of the current clinico-pathological prognostic factors.

Omega-3 Eicosapentaenoic Acid Reduces Prostate Tumor Vascularity

The impact of omega (ω)-3 fatty acids on prostate cancer is controversial in epidemiological studies but experimental studies suggest a protective effect. However, little is known about the mechanism of action. Here, we studied the effects of purified fatty acid molecules on prostate tumor progression using the TRAMP-C2 syngeneic immunocompetent mouse model. Compared with ω-6 or ω-9-supplemented animals, we observed that late-stage prostate tumor growth was reduced with a monoacylglyceride (MAG)-conjugated form of eicosapentaenoic acid (EPA) supplementation, whereas docosahexanenoic acid (DHA) caused an early reduction. MAG-EPA significantly decreased tumor blood vessel diameter (P < 0.001). RNA sequencing analysis revealed that MAG-EPA downregulated angiogenesis- and vascular-related pathways in tumors. We also observed this tissue vascular phenotype in a clinical trial testing MAG-EPA versus a high oleic sunflower oil placebo. Using anti-CD31 IHC, we observed that MAG-EPA reduced blood vessel diameter in prostate tumor tissue (P = 0.03) but not in normal adjacent tissue. Finally, testing autocrine and paracrine effects in an avascular tumor spheroid growth assay, both exogenous MAG-EPA and endogenous ω3 reduced VEGF secretion and in vitro endothelial cell tube formation and blocked tumor spheroid growth, suggesting that ω3 molecules can directly hinder prostate cancer cell growth. Altogether, our results suggest that fatty acids regulate prostate cancer growth and that a tumor-specific microenvironment is required for the anti-vascular effect of MAG-EPA in patients with prostate cancer. IMPLICATIONS: Increasing the amount of ingested EPA omega-3 subtype for patients with prostate cancer might help to reduce prostate tumor progression by reducing tumor vascularization.

Emerging Players in Prostate Cancer-Bone Niche Communication

Patients with advanced prostate cancer (PCa) frequently develop skeletal metastases that are associated with fractures, disability, and increased mortality. Within the bone metastatic niche, mutual interactions between tumor cells and osteoblasts have been proposed as major contributors of osteotropism by PCa. Here, we highlight the emerging role of PCa-derived extracellular vesicles (EVs) in reprogramming osteoblasts and support of premetastatic niche formation. We also develop the concept of cancer-associated osteoblasts (CAOs) and outline the potential of PCa cells to acquire an osteoblastic phenotype, termed osteomimicry, as two strategies that PCa utilizes to create a favorable protected niche. Finally, we delineate future research that may help to deconstruct the complexity of PCa osteotropism.

Cediranib, an inhibitor of vascular endothelial growth factor receptor kinases, inhibits proliferation and invasion of prostate adenocarcinoma cells

Prostate Cancer is the second cause of cancer-related death in men and development of metastatic castration-resistant prostate cancer (mCRPC) is the major reason for its high mortality rate. Despite various treatments, all patients succumb to resistant disease, suggesting that there is a pressing need for novel and more efficacious treatments. Members of the vascular endothelial growth factor (VEGF) family play key roles in the tumorigenesis of mCRPC, indicating that VEGF-targeted therapies may have potential anti-tumor efficacy in this malignancy. However, due to compensatory activation of other family members, clinical trials with single-targeted VEGF inhibitors were discouraging. Here, we determined the anti-neoplastic activity of Cediranib, a pan-VEGF receptor inhibitor, in the mCRPC cell lines. Anti-growth effects of Cediranib were studied by MTT and BrdU cell proliferation assays and crystal violet staining. Annexin V/PI, radiation therapy and cell motility assays were carried out to examine the effects of Cediranib on apoptosis, radio-sensitivity and cell motility. Quantitative reverse transcription-PCR (qRT-PCR) and Western blot analyses were conducted to determine the molecular mechanisms underlying the anti-tumor activity of Cediranib. Cediranib decreased cell viability and induced apoptosis via inhibition of the anti-apoptotic proteins. Combination with Cediranib synergistically increased Docetaxel sensitivity and potentiated the effects of radiation therapy. Furthermore, Cediranib impaired cell motility via decrease in the expression of the epithelial-to-mesenchymal transition markers. These findings suggest that Cediranib may have anti-tumor activity in mCRPC cells and warrant further investigation on the therapeutic activity of this pan-VEGF receptor inhibitor in mCRPC.

Contrast-enhanced transrectal ultrasound can reduce collection of unnecessary biopsies when diagnosing prostate cancer and is predictive of biochemical recurrence following a radical prostatectomy in patients with localized prostate cancer

Background

To investigate the value of using contrast-enhanced transrectal ultrasound (CETRUS) to reduce unnecessary collection of biopsies during prostate cancer diagnosis and its utility in predicting biochemical recurrence in patients with localized prostate cancer.

Methods

This was a prospective study of suspected prostate cancer patients who were evaluated with CETRUS followed by a prostate biopsy. Prostate blood flow via CETRUS was graded using a 5-point scale. The relationship between CETRUS score and biopsy outcome was then analyzed for all patients; univariate and multi-variate analyses were used to determine the probable prognostic factors for biochemical recurrence in patients with localized prostate cancer that underwent a radical prostatectomy.

Results

A total of 347 patients were enrolled in the study. Prostate cancer was found in 164 patients. A significant positive correlation (r = 0.69, p < 0.001) was found between CETRUS scores and prostate cancer incidence. Using CETRUS scores ≥2 as the threshold for when to biopsy could have safely reduced the number of biopsies taken overall by 12.1% (42/347) and spared 23.0% (42/183) of patients from undergoing an unnecessary biopsy. 77 patients with localized prostate cancer underwent a radical prostatectomy. The median follow-up time was 30 months (range: 8–56 months) and 17 of these 77 patients exhibited biochemical recurrence during the follow-up period. 3-year biochemical recurrence-free survival rates were 86% for patients with low CETRUS scores (≤ 3) and 59% for patients with high scores (> 3; p = 0.015). Multivariate Cox regression analysis indicated that CETRUS score was an independent predictor of biochemical recurrence (HR: 7.02; 95% CI: 2.00–24.69; p = 0.002).

Conclusions

CETRUS scores may be a useful tool for reducing the collection unnecessary biopsy samples during prostate cancer diagnosis and are predictive of biochemical recurrence in patients with localized prostate cancer following a radical prostatectomy.

Expression of Angiogenic Proteins in Tumor and Stroma Affects Survival in Patients With Gastric Cancer

BACKGROUND

Gastric cancer is one of the most frequent malignancies worldwide. Angiogenic growth factors play a crucial role in mediating the crosstalk between cancer cells and the surrounding microenvironment. In this exploratory study, we investigate the impact of angiogenic proteins within the tumor cell or stroma compartment on survival of patients with gastric cancer.

MATERIALS AND METHODS

In 29 patients, tumor and stromal compartments were separated using laser capture microdissection. Angiogenic protein expression was measured using a bead-based immunoassay and correlated with tumor stage and overall survival.

RESULTS

Overall survival was significantly shorter in patients with a high stroma concentration of vascular endothelial growth factor (VEGF)-A (23.5 (±17.6) versus 33.6 (±21.0) mo; P = 0.009) and stem cell factor (22.2 (±18.5) versus 33.6 (±21.8) mo; P = 0.01) compared with patients with a low stroma concentration. High stromal VEGF-D showed a trend toward worse survival (26.8 (±22.0) versus 37.2 (±19.0) mo; P = 0.09). We did not observe any significant correlation between tumor-specific expression of angiogenic cytokines and survival.

CONCLUSIONS

This translational study highlights the difference in clinical impact between tumor and stromal expression of angiogenic proteins. Compartment-specific concentrations of VEGF-A and stem cell factor affect the clinical prognosis and help to identify the best therapy for patients with gastric cancer.

Development and evaluation of the MiCheck test for aggressive prostate cancer

BACKGROUND

A clinical need exists for a biomarker test to accurately delineate aggressive prostate cancer (AgCaP), and thus better assist clinicians and patients decision-making on whether to proceed to prostate biopsy.

OBJECTIVES

To develop a blood test for AgCaP and compare to PSA, %free PSA, proPSA, and prostate health index (PHI) tests.

DESIGN, SETTINGS AND PARTICIPANTS

Patient samples from the MiCheck-01 trial were used for development of the MiCheck test.

METHODS

Serum analyte concentrations for cellular growth factors were determined using a custom-made Luminex-based R&D Systems multianalyte kit.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Bayesian model averaging and random forest approaches were used to identify clinical factors and growth factors able to distinguish between men with AgCaP (Gleason Score [GS] ≥3+4) from those with non-AgCaP (GS 3+3). Logistic regression and Monte Carlo cross-validation identified variable combinations in order to able to maximize differentiation of AgCaP from non-AgCaP.

RESULTS

The MiCheck logistic regression model was developed and comprises the following variables: serum prostate-specific antigen (PSA), patient age, Digital Rectal Exam (DRE) status, Leptin, IL-7, vascular endothelial growth factor, and Glypican-1. The model differentiated AgCaP from non-AgCaP with an area under the curve of 0.83 and was superior to PSA, %free PSA and PHI in all patient groups, regardless of PSA range. Applying the MiCheck test to all evaluable biopsy patients from the MiCheck-01 study demonstrated that up to 30% of biopsies could be avoided while delaying diagnosis of only 6.8% of GS ≥3+4 cancers, 5% of GS ≥4+3 cancers and no cancers of GS 8 or higher.

CONCLUSIONS

The MiCheck test outperforms PSA, %free PSA and PHI tests in differentiating AgCaP vs. non-AgCaP patients. The MiCheck test could result in a significant number of biopsies being avoided with a low number of patients experiencing a delayed diagnosis.

miR-221-3p Regulates VEGFR2 Expression in High-Risk Prostate Cancer and Represents an Escape Mechanism from Sunitinib In Vitro

Downregulation of miR-221-3p expression in prostate cancer (PCa) predicted overall and cancer-specific survival of high-risk PCa patients. Apart from PCa, miR-221-3p expression levels predicted a response to tyrosine kinase inhibitors (TKI) in clear cell renal cell carcinoma (ccRCC) patients. Since this role of miR-221-3p was explained with a specific targeting of VEGFR2, we examined whether miR-221-3p regulated VEGFR2 in PCa. First, we confirmed VEGFR2/KDR as a target gene of miR-221-3p in PCa cells by applying Luciferase reporter assays and Western blotting experiments. Although VEGFR2 was mainly downregulated in the PCa cohort of the TCGA (The Cancer Genome Atlas) database, VEGFR2 was upregulated in our high-risk PCa cohort (n = 142) and predicted clinical progression. In vitro miR-221-3p acted as an escape mechanism from TKI in PC3 cells, as displayed by proliferation and apoptosis assays. Moreover, we confirmed that Sunitinib induced an interferon-related gene signature in PC3 cells by analyzing external microarray data and by demonstrating a significant upregulation of miR-221-3p/miR-222-3p after Sunitinib exposure. Our findings bear a clinical perspective for high-risk PCa patients with low miR-221-3p levels since this could predict a favorable TKI response. Apart from this therapeutic niche, we identified a partially oncogenic function of miR-221-3p as an escape mechanism from VEGFR2 inhibition.

Can epigenetic and inflammatory biomarkers identify clinically aggressive prostate cancer?

Prostate cancer (PCa) is a highly prevalent malignancy and constitutes a major cause of cancer-related morbidity and mortality. It emerges through the acquisition of genetic and epigenetic alterations. Epigenetic modifications include DNA methylation, histone modifications and microRNA deregulation. These generate heritable transformations in the expression of genes but do not change the DNA sequence. Alterations in DNA methylation (hypo and hypermethylation) are the most characterized in PCa. They lead to genomic instability and inadequate gene expression. Major and minor-specific modifications in chromatin recasting are involved in PCa, with signs suggesting a dysfunction of enzymes modified by histones. MicroRNA deregulation also contributes to the initiation of PCa, including involvement in androgen receptor signalization and apoptosis. The influence of inflammation on prostate tumor carcinogenesis is currently much better known. Recent discoveries about microbial species resident in the urinary tract suggest that these are the initiators of chronic inflammation, promoting prostate inflammatory atrophy and eventually leading to PCa. Complete characterization of the relationship between the urinary microbiome and prostatic chronic inflammation will be crucial to develop plans for the prevention of PCa. The prevalent nature of epigenetic and inflammatory alterations may provide potential biomarkers for PCa diagnosis, treatment decisions, evaluation of prognosis and posttreatment surveillance.

Phase 1b trial of docetaxel, prednisone, and pazopanib in men with metastatic castration-resistant prostate cancer

BACKGROUND

Docetaxel prednisone is a standard of care for men with metastatic castration-resistant prostate cancer (mCRPC), and plasma vascular endothelial growth factor (VEGF) levels are a poor prognostic factor in this population; therefore, we evaluated the combination of docetaxel prednisone with pazopanib, an oral VEGF receptor inhibitor, for safety and preliminary efficacy.

METHODS

This is a two-site phase 1b Department of Defense Prostate Cancer Clinical Trials Consortium trial of docetaxel, prednisone, and pazopanib once daily and ongoing androgen deprivation therapy and prophylactic pegfilgrastim in men with mCRPC. The primary endpoint was safety and the determination of a maximum tolerated dose (MTD) through a dose-escalation and expansion design; secondary endpoints included progression-free and overall survival (OS), prostate specific antigen (PSA) declines, radiographic responses, and pharmacokinetic and plasma angiokine biomarker analyses.

RESULTS

Twenty-five men were treated over six dose levels. Pegfilgrastim was added to the regimen after myelosuppression limited dose escalation. With pegfilgrastim, our target MTD of docetaxel 75 mg/m² q3 weeks; prednisone 10 mg daily; and pazopanib 800 mg daily was reached. Eleven additional patients were accrued at this dose level for a total of 36 patients. Dose-limiting toxicities included neutropenia, syncope, and hypertension. Three deaths attributed to study treatment occurred. The objective response rate was 31%; median PFS was 14.1 months (95% confidence interval [CI]: 7.1 and 22.2); and OS was 18.6 months (95% CI: 11.8 and 22.2).

CONCLUSIONS

The combination of docetaxel, prednisone, and pazopanib (with pegfilgrastim) was tolerable at full doses and demonstrated promising efficacy in a relatively poor risk patients with mCRPC. Further development of predictive biomarkers may enrich for patients who receive clinical benefit from this regimen.

MicroRNA 141 is associated to outcome and aggressive tumor characteristics in prostate cancer

A large number of miRNAs influence key cellular processes involved in prostate tumorigenesis. Previous studies have demonstrated high expression of miRNAs in human prostate cancer (PC) tissues and cell lines. In previous microarray data, we found miR-141 to be upregulated and miR-145 to be downregulated in PC. In this large PC cohort (n = 535), we explored the prognostic role of miR-141 and miR-145 in PC. Tumor epithelial (TE) and tumor stromal (TS) areas were evaluated separately and combined (TE + TS). In situ hybridization was used to evaluate the expression of the miRNAs. We found that miR-141 (TE) correlated significantly to Gleason score ≥8 (p = 0.040) and large tumor size (≥20 mm, p = 0.025) and miR-141 (TE + TS) to Gleason grade (p = 0.001). MiR-145 correlated to pT-stage (p = 0.038), tumor size (p = 0.025), Gleason grade (p = 0.051) and PSA (p = 0.032). In univariate analysis miR-141 (TE + TS) was significantly associated with biochemical failure-free survival (BFFS, p = 0.007) and clinical failure-free survival (CFFS, p = 0.021). For miR-145, there were no differences between patients with high versus low expression. In multivariate analysis overexpression of miR-141 in tumor epithelium and tumor stroma was significantly associated with BFFS (HR = 1.07 CI95% 1.00–1.14, p = 0.007). To conclude, high expression of miR-141 appears associated with increased risk of biochemical PC recurrence.

High miR-205 expression in normal epithelium is associated with biochemical failure - an argument for epithelial crosstalk in prostate cancer?

Due to insufficient prognostic tools, failure to predict aggressive prostate cancer (PC) has left patient selection for radical treatment an unsolved challenge. This has resulted in overtreatment with radical therapy. Better prognostic tools are urgently warranted. MicroRNAs (miRs) have emerged as important regulators of cellular pathways, resulting in altered gene expressions. miR-205 has previously been observed downregulated in PC, acting as tumor suppressor. Herein, the expression of miR-205 in prostate tissue was examined in a large, well-described cohort of 535 Norwegian prostatectomy patients. Using in situ hybridization, miR-205 expression was semiquantatively measured in normal and tumor tissues from radical prostatectomy specimens. Associations with clinicopathological data and PC relapse were calculated. Expression of miR-205 was lower in tumor epithelium compared to normal epithelium. No association was observed between miR-205 expression in primary tumor epithelium and cancer relapse. In contrast, high expression of miR-205 in normal epithelium was independently associated with biochemical relapse (HR = 1.64, p = 0.003). A prognostic importance of miR-205 expression was only found in the normal epithelium, raising the hypothesis of epithelial crosstalk between normal and tumor epithelium in PC. This finding supports the proposed novel hypothesis of an anti-cancerogenous function of normal epithelium in tumor tissue.

Evaluation of the proliferation marker Ki-67 in a large prostatectomy cohort

The tumor proliferation index marker Ki-67 is strongly associated with tumor cell proliferation, growth and progression, and is widely used in routine clinicopathological investigation. Prostate cancer is a complex multifaceted and biologically heterogeneous disease, and overtreatment of localized, low volume indolent tumors, is evident. Here, we aimed to assess Ki-67 expression and related outcomes of 535 patients treated with radical prostatectomy. The percentage of tumor epithelial cells expressing Ki-67 was determined by immunohistochemical assay, both digital image analysis and visual scoring by light microscope were used for quantification. The association of Ki-67 and prostate cancer was evaluated, as well as its prognostic value. There was a positive correlation between high expression of Ki-67 and Gleason score > 7 (p < 0.001) as well as tumor size (≥ 20 mm, p = 0.03). In univariate analyses, a high expression of Ki-67 in tumor epithelium was significantly associated with biochemical failure (BF) (digital scoring, p = 0.014) and (visual scoring, p = 0.004). In the multivariate analyses, a high level of Ki-67 was an independent poor prognostic factor for biochemical failure-free survival (BFFS) (Visual scoring, Ki67, p = 0.012, HR:1.50, CI95% 1.10–2.06). In conclusion, high Ki-67 expression is an independent negative prognostic marker for biochemical failure. Our findings support the role of Ki-67 as a significant, poor prognostic factor for in prostate cancer outcome.

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.

Asporin is a stromally expressed marker associated with prostate cancer progression

BACKGROUND

Prostate cancer shows considerable heterogeneity in disease progression and we propose that markers expressed in tumour stroma may be reliable predictors of aggressive tumour subtypes.

METHODS

We have used Kaplan-Meier, univariate and multivariate analysis to correlate the expression of Asporin (ASPN) mRNA and protein with prostate cancer progression in independent cohorts. We used immunohistochemistry and H scoring to document stromal localisation of ASPN in a tissue microarray and mouse prostate cancer model, and correlated expression with reactive stroma, defined using Masson Trichrome staining. We used cell cultures of primary prostate cancer fibroblasts treated with serum-free conditioned media from prostate cancer cell lines to examine regulation of ASPN mRNA in tumour stromal cells.

RESULTS

We observed increased expression of ASPN mRNA in a data set derived from benign vs tumour microdissected tissue, and a correlation with biochemical recurrence using Kaplan-Meier and Cox proportional hazard analysis. ASPN protein localised to tumour stroma and elevated expression of ASPN was correlated with decreased time to biochemical recurrence, in a cohort of 326 patients with a median follow up of 9.6 years. Univariate and multivariate analysis demonstrated that ASPN was correlated with progression, as were Gleason score, and clinical stage. Additionally, ASPN expression correlated with the presence of reactive stroma, suggesting that it may be a stromal marker expressed in response to the presence of tumour cells and particularly with aggressive tumour subtypes. We observed expression of ASPN in the stroma of tumours induced by p53 inhibition in a mouse model of prostate cancer, and correlation with neuroendocrine marker expression. Finally, we demonstrated that ASPN transcript expression in normal and cancer fibroblasts was regulated by conditioned media derived from the PC3, but not LNCaP, prostate cancer cell lines.

CONCLUSIONS

Our results suggest that ASPN is a stromally expressed biomarker that correlates with disease progression, and is observed in reactive stroma. ASPN expression in stroma may be part of a stromal response to aggressive tumour subtypes.

Prognostic Value of Endocan in Prostate Cancer: Clinicopathologic Association between Serum Endocan Levels and Biochemical Recurrence after Radical Prostatectomy

Purpose

To assess the diagnostic capability of serum endocan level in association with clinicopathologic features and its impact on biochemical progression-free survival in patients with prostate cancer (PCa).

Methods

A total of 86 patients with localized prostate cancer were treated with open radical prostatectomy (RP). The control group included 80 patients who were referred to the urology outpatient clinic with normal rectal examination and prostate-specific antigen (PSA) levels. The patients’ characteristics, baseline PSA value, and serum endocan levels were recorded. The patients were followed up with the measurement of PSA concentration every 3 months during the first year, thereafter every 6 months until 5 years, then yearly after surgery. The primary endpoint of follow-up was the time of biochemical recurrence.

Results

The median serum endocan levels were 3.14 ng/mL in the RP group and 2.98 ng/mL in the control group (p = 0.122). A total of 86 patients who underwent RP for PCa were divided into 2 groups based on a cutoff serum endocan level of 1.8 ng/mL. The distribution of Gleason score and biochemical failure rate were significantly higher in patients with serum endocan ≥1.8 ng/mL (p = 0.031 and p = 0.047). The biochemical recurrence-free time for endocan ≥1.8 ng/mL and <1.8 ng/mL were 38 and 56 months, respectively (p = 0.041). Spearman correlation analysis showed a linear relationship between endocan expression and Gleason score (p = 0.025, p = 0.511). Multivariate analysis revealed that elevated serum endocan level (≥1.8 ng/mL) was a significant predictor of biochemical progression-free survival (hazard ratio 2.44; 95% confidence interval 1.78-3.23; p = 0.001).

Conclusions

The current study indicates that endocan has a close relationship with tumor recurrence in PCa.

Microvascular density and immunohistochemical expression of VEGF, VEGFR-1 and VEGFR-2 in benign prostatic hyperplasia, high-grade prostate intraepithelial neoplasia and prostate cancer

INTRODUCTION

The aim of our study was to determine and compare angiogenesis in benign prostatic hyperplasia (BPH), high-grade prostate intraepithelial neoplasia (HGPIN) and prostate cancer (Pca). Moreover, we evaluated its role as a prognostic factor for Pca.

MATERIAL AND METHODS

We examined 39, 12 and 51 samples of BPH, HGPIN and Pca, respectively. Immunohistochemical methods were applied in order to evaluate the expression of VEGF and its receptors (VEGFR-1, VEGFR-2), while microvascular density (MVD) was determined using CD105. In Pca samples, we recorded stage, differentiation, perineural invasion, adjuvant radiotherapy and their correlation with angiogenesis.

RESULTS

225 The expression of VEGF, VEGFR-1 and VEGFR-2 was significantly higher in Pca than compared to BPH (p <0.001, p <0.001 and p <0.001, respectively) and HGPIN (p <0.001, p <0.001 and p = 0.04, respectively), while there was no difference between BPH and HGPIN. MVD was higher in Pca compared to BPH (p <0.001) and HGPIN (p <0.01), while there was no difference between BPH and HGPIN. VEGF expression and MVD were significantly greater in Pca samples with poor differentiation (p = 0.044 and p = 0.038, respectively) and perineural invasion (p <0.001 and p = 0.019, respectively), while overexpression of VEGF was associated with advanced pathological stage (p = 0.047).

CONCLUSIONS

Angiogenesis is more prominent in Pca than in BPH and HGPIN, while there is no difference between BPH and HGPIN. Pharmaceutical inhibition of angiogenesis could be a valuable therapeutic option for Pca in the near future.