Detection of Prostate Cancer and Predicting Progression

Established and emerging liquid biomarkers for prostate cancer detection: A review

Prostate cancer remains one of the most frequently diagnosed cancers among men in the world today. Since its introduction in 1987 and FDA approval in 1994, prostate specific antigen (PSA) has reduced prostate cancer specific mortality considerably. However, the positive and negative predictive value of PSA is less than ideal and can lead to the over-detection of clinically insignificant prostate cancer. In the search for better screening measures to identify this cohort, liquid biomarkers for prostate cancer have emerged. In this review we will explore the commonly used urine and blood based prostate cancer liquid biomarkers. We detail the mechanism of each test and the validation studies that underscore their efficacy. Additionally, we will examine each test's effect on shared decision making as well as their cost efficacy in clinical practice.

Curcumin encapsulation in functional PLGA nanoparticles: A promising strategy for cancer therapies

Nanoparticles have emerged as promising drug delivery systems for the treatment of several diseases. Novel cancer therapies have exploited these particles as alternative adjuvant therapies to overcome the traditional limitations of radio and chemotherapy. Curcumin is a natural bioactive compound found in turmeric, that has been reported to show anticancer activity against several types of tumors. Despite some biological limitations regarding its absorption in the human body, curcumin encapsulation in poly(lactic-co-glycolic acid) (PLGA), a non-toxic, biodegradable and biocompatible polymer, represents an effective strategy to deliver a drug to a tumor site. Furthermore, PLGA nanoparticles can be engineered with targeting moieties to reach specific cancer cells, thus enhancing the antitumor effects of curcumin. We herein aim to bring an up-to-date summary of the recently developed strategies for curcumin delivery to different types of cancer cells through encapsulation in PLGA nanoparticles, correlating their effects with those of curcumin on the biological capabilities acquired by cancer cells (cancer hallmarks). We discuss the targeting strategies proposed for advanced curcumin delivery and the respective improvements achieved for each cancer cell analyzed, in addition to exploring the encapsulation techniques employed. The conjugation of correct encapsulation techniques with tumor-oriented targeting design can result in curcumin-loaded PLGA nanoparticles that can successfully integrate the elaborate network of development of alternative cancer treatments along with traditional ones. Finally, the current challenges and future demands to launch these nanoparticles in oncology are comprehensively examined.

Interactions of Urea-Based Inhibitors with Prostate-Specific Membrane Antigen for Boron Neutron Capture Therapy

In this study, molecular interactions of prostate-specific membrane antigen (PSMA) with five chemically distinct urea-based boron-containing inhibitors have been investigated at the atomic level using molecular docking and molecular dynamics simulations. The PSMA-inhibitor complexations have been analyzed by comparing their binding modes, secondary structures, root-mean-square deviations, noncovalent interactions, principal components, and binding free energies. PSMA is a cell surface glycoprotein upregulated in cancerous cells and can be targeted by boron-labeled inhibitors for boron neutron capture therapy (BNCT). The effective BNCT requires the selective boron delivery to the tumor area and highly specific PSMA-mediated cellular uptake by tumor. Thus, a potent inhibitor must exhibit both high binding affinity and high boron density. The computational results suggest that the chemical nature of inhibitors affects the binding mode and their association with PSMA is primarily dominated by hydrogen bonding, salt bridge, electrostatic, and π-π interactions. The binding free energies (-28.0, -15.2, -43.9, -23.2, and -38.2 kcal/mol) calculated using λ-dynamics for all inhibitors (In1-5) predict preferential binding that is in accordance with experimental data. Among all inhibitors, In5 was found to be the best candidate for BNCT. The binding of this inhibitor to PSMA preserved its overall secondary structure. These results provide computational insights into the coordination flexibility of PSMA and its interaction with various inhibitors. They can be used for the design and synthesis of efficient BNCT agents with improved drug selectivity and high boron percentage.

Bi-parametric magnetic resonance imaging based radiomics for the identification of benign and malignant prostate lesions: cross-vendor validation

The purpose of this study was to develop Bi-parametric Magnetic Resonance Imaging (BP-MRI) based radiomics models for differentiation between benign and malignant prostate lesions, and to cross-vendor validate the generalization ability of the models. The prebiopsy BP-MRI data (T2-Weighted Image [T2WI] and the Apparent Diffusion Coefficient [ADC]) of 459 patients with clinical suspicion of prostate cancer were acquired using two scanners from different vendors. The prostate biopsies are the reference standard for diagnosing benign and malignant prostate lesions. The training set was 168 patients' data from Siemens (Vendor 1), and the inner test set was 70 patients' data from the same vendor. The external test set was 221 patients' data from GE (Vendor 2). The lesion Region of Interest (ROI) was manually delineated by experienced radiologists. A total of 851 radiomics features including shape, first-order statistical, texture, and wavelet features were extracted from ROI in T2WI and ADC, respectively. Two feature-ranking methods (Minimum Redundancy Maximum Relevance [MRMR] and Wilcoxon Rank-Sum Test [WRST]) and three classifiers (Random Forest [RF], Support Vector Machine [SVM], and the Least Absolute Shrinkage and Selection Operator [LASSO] regression) were investigated for their efficacy in building single-parametric radiomics signatures. A biparametric radiomics model was built by combining the optimal single-parametric radiomics signatures. A comprehensive diagnosis model was built by combining the biparametric radiomics model with age and Prostate Specific Antigen (PSA) value using multivariable logistic regression. All models were built in the training set and independently validated in the inner and external test sets, and the performances of models in the diagnosis of benign and malignant prostate lesions were quantified by the Area Under the Receiver Operating Characteristic Curve (AUC). The mean AUCs of the inner and external test sets were calculated for each model. The non-inferiority test was used to test if the AUC of model in external test was not inferior to the AUC of model in inner test. Combining MRMR and LASSO produced the best-performing single-parametric radiomics signatures with the highest mean AUC of 0.673 for T2WI (inner test AUC = 0.729 vs. external test AUC = 0.616, p = 0.569) and the highest mean AUC of 0.810 for ADC (inner test AUC = 0.822 vs. external test AUC = 0.797, p = 0.102). The biparametric radiomics model produced a mean AUC of 0.833 (inner test AUC = 0.867 vs. external test AUC = 0.798, p = 0.051). The comprehensive diagnosis model had an improved mean AUC of 0.911 (inner test AUC = 0.935 vs. external test AUC = 0.886, p = 0.010). The comprehensive diagnosis model for differentiating benign from malignant prostate lesions was accurate and generalizable.

Detection of TMPRSS2-ERG Fusion Transcript in Biopsy Specimen of Prostate Cancer Patients: A Single Centre Experience

INTRODUCTION

Prostate carcinoma is the most frequent malign neoplasm among men with an ever-growing incidence rate. TMPRSS2-ERG fusion transcript leads to the androgen induction of ERG proto-oncogenes expression, representing a high presence of oncogenes alteration among prostate tumour cells.

AIM

The aim of this research was to detect and evaluate theTMPRSS2-ERG fuse transcript in the tissues of patients with prostate cancer, and establish a base of material of these samples for further genetic examination.

MATERIALS AND METHODS

The research was a prospective clinical study that involved and focused on random sampling of 101 patients (62 with prostate cancer-study group and 39 with benign changes in the prostate-control group). Real time PCR analysis for detection of the TMPRSS2-ERG fusion transcript in prostate tissue was performed and also data from the histopathology results of tissues were used, as well as data for the level of PSA (prostate-specific antigen) in blood.

RESULTS

TMPRSS2-ERG fusion transcript was detected in 20 out of 62 (32.2%) patients with prostate carcinoma and among no patients with benign changes whatsoever. There were no significant differences between patients with/without detected TMPRSS2-ERG fusion related to Gleason score. Among 50%, in the study group this score was greater than 7 per/for Median IQR=7 (6-8). Significant difference was recognized, related to the average value of PSA in favour of significantly higher value of PSA in the study group with prostate cancer, but there was also no significant difference between samples with prostate cancer who were with/without detected TMPRSS2-ERG fusion transcript related to PSA level.

DISCUSSION

The results from this research are in accordance with the values and results from analyses done in several research centres and oncological institutes.

CONCLUSION

The positive findings in small scale studies encourage the implementation of larger scale studies that will be enriched with results of genetic transcript in blood and urine and will define the positive diagnostic meaning of the TMPRSS-ERG fusion transcript.

Gene expression analysis of human prostate cell lines with and without tumor metastasis suppressor CD82

BACKGROUND

Tetraspanin CD82 is a tumor metastasis suppressor that is known to down regulate in various metastatic cancers. However, the exact mechanism by which CD82 prevents cancer metastasis is unclear. This study aims to identify genes that are regulated by CD82 in human prostate cell lines.

METHODS

We used whole human genome microarray to obtain gene expression profiles in a normal prostate epithelial cell line that expressed CD82 (PrEC-31) and a metastatic prostate cell line that does not express CD82 (PC3). Then, siRNA silencing was used to knock down CD82 expression in PrEC-31 while CD82 was re-expressed in PC3 to acquire differentially-expressed genes in the respective cell line.

RESULTS

Differentially-expressed genes with a P < 0.05 were identified in 3 data sets: PrEC-31 (+CD82) vs PrEC-31(-CD82), PC3-57 (+CD82) vs. PC3-5 V (-CD82), and PC3-29 (+CD82) vs. PC3-5 V (-CD82). Top 25 gene lists did not show overlap within the data sets, except (CALB1) the calcium binding protein calbindin 1 which was significantly up-regulated (2.8 log fold change) in PrEC-31 and PC3-29 cells that expressed CD82. Other most significantly up-regulated genes included serine peptidase inhibitor kazal type 1 (SPINK1) and polypeptide N-acetyl galactosaminyl transferase 14 (GALNT14) and most down-regulated genes included C-X-C motif chemokine ligand 14 (CXCL14), urotensin 2 (UTS2D), and fibroblast growth factor 13 (FGF13). Pathways related with cell proliferation and angiogenesis, migration and invasion, cell death, cell cycle, signal transduction, and metabolism were highly enriched in cells that lack CD82 expression. Expression of two mutually inclusive genes in top 100 gene lists of all data sets, runt-related transcription factor (RUNX3) and trefoil factor 3 (TFF3), could be validated with qRT-PCR.

CONCLUSION

Identification of genes and pathways regulated by CD82 in this study may provide additional insights into the role that CD82 plays in prostate tumor progression and metastasis, as well as identify potential targets for therapeutic intervention.

Optimized Anti-Prostate-Specific Membrane Antigen Single-Chain Variable Fragment-Loaded Nanobubbles as a Novel Targeted Ultrasound Contrast Agent for the Diagnosis of Prostate Cancer

OBJECTIVES

To prepare optimized prostate-specific membrane antigen (PSMA) single-chain variable fragment (scFv)-loaded nanobubbles (NBs) as a novel targeted ultrasound (US) contrast agent for diagnosis and treatment of prostate cancer (PCa).

METHODS

Prostate-specific membrane antigen scFv-loaded NBs were prepared by membrane hydration and biotin-streptavidin conjugation. Flow cytometry was used to observe the binding rate of the targeted NBs to PSMA-expressing cells. Contrast-enhanced US was used to monitor targeted and nontargeted NBs administered to nude mice with 22RV1, LNCaP, and PC-3 xenograft tumors. The specific binding ability of the targeted NBs was further examined by fluorescence imaging of tumor cryosections.

RESULTS

Uniformly sized targeted NBs were successfully prepared (mean ± SD, 485.3 ± 28.4 nm). The NBs showed good stability and bound specifically to LNCaP and 22RV1 cells with high PSMA expression in vitro but did not bind to PC-3 cells without PSMA expression. The targeted NBs presented good US enhancement, and the results of the in vivo xenograft tumor nude mouse model showed that the peak contrast intensity in LNCaP and 22RV1 cells was significantly higher for the targeted NBs than the nontargeted NBs (P < .05), whereas there was no significant difference in PC-3 cells. Immunofluorescence results obtained from tumor sections confirmed that the targeted NBs were capable of targeting PSMA-expressing tumor cells.

CONCLUSIONS

These novel PSMA scFv-loaded NBs have proven to be an excellent US contrast agent for imaging PSMA-expressing PCa and have the potential to not only enable efficient and safe molecular imaging but also to serve as a delivery system for targeted PCa therapies.

Men With Inflammatory Bowel Disease: Sexual Function, Fertility, Medication Safety, and Prostate Cancer

Half of patients with inflammatory bowel disease (IBD) are men, yet less attention has been focused on their sexual issues despite higher rates of sexual dysfunction and infertility than the general population. Depression and IBD disease activity are the most consistently reported risk factor for sexual dysfunction among men with IBD. Methotrexate and sulfasalazine have been rarely associated with impotence. Sulfasalazine reversibly reduces male fertility. No other medications used in IBD significantly affect fertility in humans. There is no increase in adverse fetal outcomes among offspring of fathers with IBD. Patients with IBD seem to be at a higher risk for prostate cancer; therefore, screening as recommended for high-risk patients should be considered.

Post-SELEX Optimization and Characterization of a Prostate Cancer Cell-Specific Aptamer for Diagnosis

The RNA aptamer A4 binds specifically to tumor prostate cells. A4 was modified (mA4) by adding deoxyribonucleotides to its ends to remove the reactive 2' hydroxyl groups of RNA's sugar at the ends of the aptamer and to make it more stable to widespread RNase contamination in laboratories. Thus, mA4 would be more suitable to use in the clinical settings of prostate cancer (PCa). We aimed to characterize this optimized oligonucleotide to verify its potential as a diagnostic tool. The sequences and structures of A4 and mA4 were compared through in silico approaches to corroborate their similarity. Then, the degradation of mA4 was measured in appropriate media and human plasma for in vitro tests. In addition, the binding abilities of A4 to prostate cells were contrasted with those of mA4. The effects of mA4 were assessed on the viability, proliferation, and migration of human prostate cell lines RWPE-1 and PC-3 in three-dimensional (3D) cell cultures. mA4 showed configurational motifs similar to those of A4, displayed a half-life in plasma substantially higher than A4, and exhibited a comparable binding capacity to that of A4 and unaltered viability, proliferation, and migration of prostatic cells. Therefore, mA4 maintains the crucial 3D structures of A4 that would allow binding to its target, as suggested by in silico and binding analyses. mA4 may be a good PCa reporter as it does not change cellular parameters of prostate cells when incubated with it. Its additional deoxyribonucleotides make mA4 inherently more chemically stable than A4, avoiding its degradation and favoring its storage and handling for clinical applications. These characteristics support the potential of mA4 to be used in diagnostic systems for PCa.

Biomarker selection and imaging design in cancer: A link with biochemical pathways for imminent engineering

Malignant cells reprogram metabolic pathways to meet the demands of growth and proliferation. These altered manners of metabolism are now identified as hallmarks of cancer. Studies have revealed tumor cells alter specific pathways such as glycolysis, fatty acid synthesis and amino acid synthesis to support their proliferation. In this review, we provide a theoretical framework to understand metabolic reprogramming and the mechanisms accompanying distorted metabolism to tumor progression. How these alterations will be assisting in cancer diagnostics and advances in standard techniques in marker identification and imagining are also discussed.

Comparison of prostate-specific membrane antigen ligands in clinical translation research for diagnosis of prostate cancer

BACKGROUND

Prostate-specific membrane antigen (PSMA), overexpressed on prostate cancer (PCa), is a well-characterized cell surface protein to selectively diagnose PCa. PSMA's unique characteristics and its 1000-fold higher expression in PCa compared with other tissues renders it as a suitable biomarker for detection of PCa in its early stage. In this report, we critically analyze and recommend the requirements needed for the development of variety of PSMA-targeted molecular imaging agents based on antibodies, small molecule ligands, peptides, and aptamers. The targeting moieties are either conjugated to radionuclear isotopes or near-infrared agents for efficient diagnosis of PCa.

RECENT FINDINGS

From the analysis, it was found that several small molecule-derived PCa imaging agents are approved for clinical trials in Europe and the United States, and few are already in the clinical use for diagnosis of PCa. Even though ¹¹¹In-labeled capromab pendetide was approved by the Food and Drug Administration (FDA) and other engineered antibodies are available for detection of PCa, but high production cost, low shelf life (less than 1 month at 4°C), possibility of human immuno reactions, and low blood clearance rate necessitated a need for developing new imaging agents, which are serum stable, cost-effective, and possesses longer shelf life (6 months), have fast clearance rate from nontargeted tissues during the diagnosis process. It is found that small molecule ligand-derived imaging agents possesses most of the desired properties expected for an ideal diagnostic agent when compared with other targeting moieties.

CONCLUSION

This report discusses in detail the homing moieties used in the development of targeted diagnostic tools for detection of PCa. The merits and demerits of monoclonal antibodies, small molecule ligands, peptides, and aptamers for imaging of PCa and intraoperative guided surgery are extensively analyzed. Among all, urea-based ligands were found to be most successful in preclinical and clinical trials and show a major promise for future commercialization.

Obstacles in prostate cancer screening: Current issues and future solutions

Prostate cancer is the most common cancer in men and is associated with unacceptably high mortality rates, yet an accurate and acceptable screening programme that detects clinically significant prostate cancer remains elusive. Although there is good evidence that prostate-specific antigen (PSA)-based screening lowers prostate cancer-specific mortality, especially when conducted at high intensity, the harm caused by overinvestigation, overdiagnosis and overtreatment of clinically insignificant cases arguably outweighs these benefits. Several attempts have therefore been made to improve screening, enhancing the diagnostic value of PSA and identifying novel modalities for screening. Here, we provide a comprehensive review of the benefits and harms, and analyse which of these novel screening methods show most promise.

Level of evidence: 5, expert opinion

Cellular Refractive Index Comparison of Various Prostate Cancer and Noncancerous Cell Lines via Photonic-Crystal Biosensor

The current clinical standard for mass screening of prostate cancer are prostate-specific antigen (PSA) biomarker assays. Unfortunately, the low specificity of PSA's bioassays to prostate cancer leads to high false-positive rates, as such there is an urgent need for the development of a more specific detection system independent of PSA levels. In our previous research, we have successfully demonstrated, with the use of our Photonic-Crystal based biosensor in a Total-Internal-Reflection (PC-TIR) configuration, detection of prostate cancer (PC-3) cells against benign prostate hyperplasia (BPH-1) cells. The PC-TIR biosensor achieved detection of individual prostate cancer cells utilizing cellular refractive index (RI) as the only contrast parameter. To further study this methodology in vitro, we report a comprehensive study of the cellular RI's of various prostate cancer and noncancerous cell lines (i.e. RWPE-1, BPH-1, PC-3, DU-145, and LNCaP) via reflectance spectroscopy and single-cell RI imaging utilizing the PC-TIR biosensor. Our study shows promising clinical potential in utilizing the PC-TIR biosensor system for the detection of prostate cancer against noncancerous prostate epithelial cells.

PSCA expression is associated with favorable tumor features and reduced PSA recurrence in operated prostate cancer

Background

Prostate Stem Cell Antigen (PSCA) is frequently expressed in prostate cancer but its exact function is unclear.

Methods

To clarify contradictory findings on the prognostic role of PSCA expression, a tissue microarray containing 13,665 prostate cancers was analyzed by immunohistochemistry.

Results

PSCA staining was absent in normal epithelial and stromal cells of the prostate. Membranous and cytoplasmic PSCA staining was seen in 53.7% of 9642 interpretable tumors. Staining was weak in 22.4%, moderate in 24.5% and strong in 6.8% of tumors. PSCA expression was associated with favorable pathological and clinical tumor features: Early pathological tumor stage (p < 0.0001), low Gleason grade (p < 0.0001), absence of lymph node metastasis (p < 0.0001), low pre-operative PSA level (p = 0.0118), negative surgical margin (p < 0.0001) and reduced PSA recurrence (p < 0.0001). PSCA expression was an independent predictor of prognosis in multivariate analysis (hazard ratio 0.84, p < 0.0001).

Conclusions

The absence of statistical relationship to TMPRSS2:ERG fusion status, chromosomal deletion or high tumor cell proliferation argues against a major role of PSCA for regulation of cell cycle or genomic integrity. PSCA expression is linked to favorable prognosis. PSCA measurement is a candidate for inclusion in multi-parametric prognostic prostate cancer tests.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4547-7) contains supplementary material, which is available to authorized users.

Label-free in vitro prostate cancer cell detection via photonic-crystal biosensor

Prostate-specific antigen (PSA) biomarker assays are the current clinical method for mass screening of prostate cancer. However, high false-positive rates are often reported due to PSA's low specificity, leading to an urgent need for the development of a more specific detection system independent of PSA levels. In our previous research, we demonstrated the feasibility of using cellular refractive indices (RI) as a unique contrast parameter to accomplish label-free detection of prostate cancer cells via variance testing, but were unable to determine if a specific cell was cancerous or noncancerous. In this paper, we report the use of our Photonic-Crystal biosensor in a Total-Internal-Reflection (PC-TIR) configuration to construct a label-free imaging system, which allows for the detection of individual prostate cancer cells utilizing cellular RI as the only contrast parameter. Noncancerous prostate (BPH-1) cells and prostate cancer (PC-3) cells were mixed at varied ratios and measured concurrently. Additionally, we isolated and induced PC-3 cells to undergo epithelial-mesenchymal transition (EMT) by exposing these cells to soluble factors such as TGF-01. The biophysical characteristics of the cellular RI were quantified extensively in comparison to non-induced PC-3 cells as well as BPH-1 cells. EMT is a crucial mechanism for the invasion and metastasis of epithelial tumors characterized by the loss of cell-cell adhesion and increased cell mobility. Our study shows promising clinical potential in utilizing the PC-TIR biosensor imaging system to not only detect prostate cancer cells, but also evaluate prostate cancer progression.

Selection and characterization of DNA aptamer for metastatic prostate cancer recognition and tissue imaging

Prostate cancer (PCa) is the second leading cause of death and most prevalent cancer in men. The absence of curative options for castration-resistant metastatic prostate cancer and biomarkers able to discriminate between indolent and aggressive tumors contribute to these statistics. In this study, a DNA aptamer termed DML-7 was successfully selected against human PCa cell line DU145 by using the cell-based systematic evolution of ligands by exponential enrichment (SELEX) method. The selected aptamer DML-7 was found to internalize into target cells in a temperature-dependent manner and exhibit high binding affinity for target cells with dissociation constants in the nanomolar range. Binding analysis further revealed that DML-7 only binds to DU145 and PC-3 cells with metastatic potential, but not to LNCaP or 22Rv1 cells with low or nonmetastatic potential, demonstrating that DML-7 has excellent selectivity for the recognition of the metastatic PCa cells. Clinical tissue imaging further confirmed these results. Therefore, both high binding affinity and specificity to metastatic PCa cells and tissues afford DML-7 with the potential for development into a novel tool for diagnosis and targeted drug delivery against metastatic prostate cancer.

Adoptive T-Cell Therapy for Solid Tumors

Chimeric antigen receptor (CAR) T-cell therapy is an innovative form of immunotherapy wherein autologous T cells are genetically modified to express chimeric receptors encoding an antigen-specific single-chain variable fragment and various costimulatory molecules. Upon administration, these modified T cells traffic to, and recognize, cancer cells in an HLA-independent manner. CAR T-cell therapy has shown remarkable success in the treatment of CD-19-expressing B-cell acute lymphocytic leukemia. However, clinical gains to the same magnitude have not been reported in solid tumors. Several known obstacles to CAR T-cell therapy for solid tumors include target antigen identification, effective trafficking to the tumor, robust activation, proliferation, and in vivo cytotoxicity. Beyond these T-cell intrinsic properties, a complex and dynamic immunosuppressive tumor microenvironment in solid tumors hinders T-cell efficacy. Notable advancements in CAR design to include multiple costimulatory molecules, ligands, and soluble cytokines have shown promise in preclinical models, and some of these are currently in early-phase clinical trials. In this review, we discuss selected solid tumor malignancies and relevant preclinical data and highlight clinical trial results that are available. Furthermore, we outline some obstacles to CAR T-cell therapy for each tumor and propose strategies to overcome some of these limitations.

Adoptive T-Cell Therapy for Solid Tumors

Chimeric antigen receptor (CAR) T-cell therapy is an innovative form of immunotherapy wherein autologous T cells are genetically modified to express chimeric receptors encoding an antigen-specific single-chain variable fragment and various costimulatory molecules. Upon administration, these modified T cells traffic to, and recognize, cancer cells in an HLA-independent manner. CAR T-cell therapy has shown remarkable success in the treatment of CD-19-expressing B-cell acute lymphocytic leukemia. However, clinical gains to the same magnitude have not been reported in solid tumors. Several known obstacles to CAR T-cell therapy for solid tumors include target antigen identification, effective trafficking to the tumor, robust activation, proliferation, and in vivo cytotoxicity. Beyond these T-cell intrinsic properties, a complex and dynamic immunosuppressive tumor microenvironment in solid tumors hinders T-cell efficacy. Notable advancements in CAR design to include multiple costimulatory molecules, ligands, and soluble cytokines have shown promise in preclinical models, and some of these are currently in early-phase clinical trials. In this review, we discuss selected solid tumor malignancies and relevant preclinical data and highlight clinical trial results that are available. Furthermore, we outline some obstacles to CAR T-cell therapy for each tumor and propose strategies to overcome some of these limitations.

A bioinformatics-to-clinic sequential approach to analysis of prostate cancer biomarkers using TCGA datasets and clinical samples: a new method for precision oncology?

Biomarker-driven cancer therapy has met with significant clinical success. Identification of a biomarker implicated in a malignant phenotype and linked to poor clinical outcome is required if we are to develop these types of therapies. A subset of prostate adenocarcinoma (PACa) cases are treatment-resistant, making them an attractive target for such an approach. To identify target molecules implicated in shorter survival of patients with PACa, we established a bioinformatics-to-clinic sequential analysis approach, beginning with 2-step in silico analysis of a TCGA dataset for localized PACa. The effect of candidate genes identified by in silico analysis on survival was then assessed using biopsy specimens taken at the time of initial diagnosis of localized and metastatic PACa. We identified PEG10 as a candidate biomarker. Data from clinical samples suggested that increased expression of PEG10 at the time of initial diagnosis was linked to shorter survival time. Interestingly, PEG10 overexpression also correlated with expression of chromogranin A and synaptophysin, markers for neuroendocrine prostate cancer, a type of treatment-resistant prostate cancer. These results indicate that PEG10 is a novel biomarker for shorter survival of patients with PACa. Also, PEG10 expression at the time of initial diagnosis may predict focal neuroendocrine differentiation of PACa. Thus, PEG10 may be an attractive target for biomarker-driven cancer therapy. Thus, bioinformatics-to-clinic sequential analysis is a valid tool for identifying targets for precision oncology.

Downregulation of microRNA‑574 in cancer stem cells causes recurrence of prostate cancer via targeting REL

miR‑574‑5p has been reported involved in the pathogenesis of numerous human malignancies such as colorectal and lung cancer. In this study, we aimed to explore the roles of REL and miR‑574 in the recurrence of prostate cancer (PCa) and to identify the underlying molecular mechanisms. Our literature search found that miR‑574 is regulated in cancer stem cells (CSCs), and next we used the microRNA (miRNA) database (www.mirdb.org) to find REL as a target of miR‑574. Luciferase assay was performed to verify the miRNA/target relationship. Oligo-transfection, real‑time PCR and western blot analysis were used to support the conclusions. We validated REL to be the direct gene via luciferase reporter assay system, and real‑time PCR and western blot analysis were also conducted to study the mRNA and protein expression level of REL between different groups (recurrence and non‑recurrence) or cells treated with scramble control, miR‑574 mimics, REL siRNA and miR‑574 inhibitors, indicating the negative regulatory relationship between miR‑574 and REL. We also investigated the relative viability of prostate CSCs when transfected with scramble control, miR‑574 mimics, REL siRNA and miR‑574 inhibitors to validate miR‑574 to be positively interfering with the viability of prostate CSCs. We then investigated the relative apoptosis of prostate CSCs when transfected with scramble control, miR‑574 mimics, REL siRNA and miR‑574 inhibitors. The results showed miR‑574 inhibited apoptosis. In conclusion, miR‑574 might be a novel prognostic and therapeutic target in the management of PCa recurrence.

Selecting Targets for Tumor Imaging: An Overview of Cancer-Associated Membrane Proteins

Tumor targeting is a booming business: The global therapeutic monoclonal antibody market accounted for more than $78 billion in 2012 and is expanding exponentially. Tumors can be targeted with an extensive arsenal of monoclonal antibodies, ligand proteins, peptides, RNAs, and small molecules. In addition to therapeutic targeting, some of these compounds can also be applied for tumor visualization before or during surgery, after conjugation with radionuclides and/or near-infrared fluorescent dyes. The majority of these tumor-targeting compounds are directed against cell membrane-bound proteins. Various categories of targetable membrane-bound proteins, such as anchoring proteins, receptors, enzymes, and transporter proteins, exist. The functions and biological characteristics of these proteins determine their location and distribution on the cell membrane, making them more, or less, accessible, and therefore, it is important to understand these features. In this review, we evaluate the characteristics of cancer-associated membrane proteins and discuss their overall usability for cancer targeting, especially focusing on imaging applications.

Antibody response to BK polyomavirus as a prognostic biomarker and potential therapeutic target in prostate cancer

Infectious agents, including the BK polyomavirus (BKPyV), have been proposed as important inflammatory pathogens in prostate cancer. Here, we evaluated whether the preoperative antibody response to BKPyV large T antigen (LTag) and viral capsid protein 1 (VP1) was associated with the risk of biochemical recurrence in 226 patients undergoing radical prostatectomy for primary prostate cancer. Essentially, the multivariate Cox regression analysis revealed that preoperative seropositivity to BKPyV LTag significantly reduced the risk of biochemical recurrence, independently of established predictors of biochemical recurrence such as tumor stage, Gleason score and surgical margin status. The predictive accuracy of the regression model was denotatively increased by the inclusion of the BKPyV LTag serostatus. In contrast, the VP1 serostatus was of no prognostic value. Finally, the BKPyV LTag serostatus was associated with a peculiar cytokine gene expression profile upon assessment of the cellular immune response elicited by LTag. Taken together, our findings suggest that the BKPyV LTag serology may serve as a prognostic factor in prostate cancer. If validated in additional studies, this biomarker may allow for better treatment decisions after radical prostatectomy. Finally, the favorable outcome of LTag seropositive patients may provide a potential opportunity for novel therapeutic approaches targeting a viral antigen.

Biomarkers for evaluation of prostate cancer prognosis

Prostate cancer, with a lifetime prevalence of one in six men, is the second cause of malignancy-related death and the most prevalent cancer in men in many countries. Nowadays, prostate cancer diagnosis is often based on the use of biomarkers, especially prostate-specific antigen (PSA) which can result in enhanced detection at earlier stage and decreasing in the number of metastatic patients. However, because of the low specificity of PSA, unnecessary biopsies and mistaken diagnoses frequently occur. Prostate cancer has various features so prognosis following diagnosis is greatly variable. There is a requirement for new prognostic biomarkers, particularly to differentiate between inactive and aggressive forms of disease, to improve clinical management of prostate cancer. Research continues into finding additional markers that may allow this goal to be attained. We here selected a group of candidate biomarkers including PSA, PSA velocity, percentage free PSA, TGFβ1, AMACR, chromogranin A, IL-6, IGFBPs, PSCA, biomarkers related to cell cycle regulation, apoptosis, PTEN, androgen receptor, cellular adhesion and angiogenesis, and also prognostic biomarkers with Genomic tests for discussion. This provides an outline of biomarkers that are presently of prognostic interest in prostate cancer investigation.

Current early diagnostic biomarkers of prostate cancer

Prostate cancer (PCa) has become to have the highest incidence and the second mortality rate in western countries, affecting men's health to a large extent. Although prostate-specific antigen (PSA) was discovered to help diagnose the cancer in an early stage for decades, its specificity is relative low, resulting in unnecessary biopsy for healthy people and over-treatment for patients. Thus, it is imperative to identify more and more effective biomarkers for early diagnosis of PCa in order to distinguish patients from healthy populations, which helps guide an early treatment to lower disease-related mortality by noninvasive or minimal invasive approaches. This review generally describes the current early diagnostic biomarkers of PCa in addition to PSA and summarizes the advantages and disadvantages of these biomarkers.

Altered glycosylation in prostate cancer

Prostate cancer is annually the most common newly diagnosed cancer in men. The prostate functions as a major secretory gland for the production of glycoproteins critical to sperm activation and reproduction. Prostate-specific antigen (PSA), produced by the prostate, is one of the most commonly assayed glycoproteins in blood, serving as a biomarker for early detection and progression of prostate cancer. The single site of N-glycosylation on PSA has been the target of multiple glycan characterization studies. In this review, the extensive number of studies that have characterized the changes in O-linked and N-linked glycosylations associated with prostate cancer development and progression will be summarized. This includes analysis of the glycosylation of PSA, and other prostate glycoproteins, in tissues, clinical biofluids, and cell line models. Other studies are summarized in the context of understanding the complexities of these glycan changes in order to address the many confounding questions associated with prostate cancer, as well as efforts to improve prostate cancer biomarker assays using targeted glycomic-based strategies.

The PCA3 test for guiding repeat biopsy of prostate cancer and its cut-off score: a systematic review and meta-analysis

The specificity of prostate-specific antigen (PSA) for early intervention in repeat biopsy is unsatisfactory. Prostate cancer antigen 3 (PCA3) may be more accurate in outcome prediction than other methods for the early detection of prostate cancer (PCa). However, the results were inconsistent in repeated biopsies. Therefore, we performed a systematic review and meta-analysis to evaluate the role of PCA3 in outcome prediction. A systematic bibliographic search was conducted for articles published before April 2013, using PubMed, Medline, Web of Science, Embase and other databases from health technology assessment agencies. The quality of the studies was assessed on the basis of QUADAS criteria. Eleven studies of diagnostic tests with moderate to high quality were selected. A meta-analysis was carried out to synthesize the results. The results of the meta-analyses were heterogeneous among studies. We performed a subgroup analysis (with or without inclusion of high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical small acinar proliferation (ASAP)). Using a PCA3 cutoff of 20 or 35, in the two sub-groups, the global sensitivity values were 0.93 or 0.80 and 0.79 or 0.75, specificities were 0.65 or 0.44 and 0.78 or 0.70, positive likelihood ratios were 1.86 or 1.58 and 2.49 or 1.78, negative likelihood ratios were 0.81 or 0.43 and 0.91 or 0.82 and diagnostic odd ratios (ORs) were 5.73 or 3.45 and 7.13 or 4.11, respectively. The areas under the curve (AUCs) of the summary receiver operating characteristic curve were 0.85 or 0.72 and 0.81 or 0.69, respectively. PCA3 can be used for repeat biopsy of the prostate to improve accuracy of PCa detection. Unnecessary biopsies can be avoided by using a PCa cutoff score of 20.

Ectokinases as novel cancer markers and drug targets in cancer therapy

While small-molecule kinase inhibitors became the most prominent anticancer drugs, novel combinatorial strategies need to be developed as the fight against cancer is not yet won. We review emerging literature showing that the release of several ectokinases is significantly upregulated in body fluids from cancer patients and that they leave behind their unique signatures on extracellular matrix (ECM) proteins. Our analysis of proteomic data reveals that fibronectin is heavily phosphorylated in cancer tissues particularly within its growth factor binding sites and on domains that regulate fibrillogenesis. We are thus making the case that cancer is not only a disease of cells but also of the ECM. Targeting extracellular kinases or the extracellular signatures they leave behind might thus create novel opportunities in cancer diagnosis as well as new avenues to interfere with cancer progression and malignancy.

Array-based sensing of proteins and bacteria by using multiple luminescent nanodots as fluorescent probes

Luminescent nanodots for protein sensing and discrimination of bacteria: Luminescent nanodots are applied as novel fluorescent probes in a sensing array. The sensing strategy uses graphene oxide (GO) for protein recognition, with displacement of fluorescent probes to generate the output. This sensing platform is a powerful tool to detect protein targets and discriminate bacteria.

Anti-cancer activity of curcumin loaded nanoparticles in prostate cancer

Prostate cancer is the most commonly diagnosed cancer disease in men in the Unites States and its management remains a challenge in everyday oncology practice. Thus, advanced therapeutic strategies are required to treat prostate cancer patients. Curcumin (CUR) is a promising anticancer agent for various cancer types. The objective of this study was to evaluate therapeutic potential of novel poly(lactic-co-glycolic acid)- CUR nanoparticles (PLGA-CUR NPs) for prostate cancer treatment. Our results indicate that PLGA-CUR NPs efficiently internalize in prostate cancer cells and release biologically active CUR in cytosolic compartment of cells for effective therapeutic activity. Cell proliferation (MTS), clonogenic, and Western blot analyses reveal that PLGA-CUR NPs can effectively inhibit proliferation and colony formation ability of prostate cancer cells than free CUR. PLGA-CUR NPs showed superior tumor regression compared to CUR in xenograft mice. Further investigations reveal that PLGA-CUR NPs inhibit nuclear β-catenin and AR expression in cells and in tumor xenograft tissues. It also suppresses STAT3 and AKT phosphorylation and leads to apoptosis via inhibition of key anti-apoptotic proteins, Mcl-1, Bcl-xL and caused induction of PARP cleavage. Additionally, significant downregulation of oncogenic miR21 and up-regulation of miR-205 was observed with PLGA-CUR NPs treatment as determined by RT-PCR and in situ hybridization analyses. A superior anti-cancer potential was attained with PSMA antibody conjugated PLGA-CUR NPs in prostate cancer cells and a significant tumor targeting of (131)I labeled PSMA antibody was achieved with PLGA-CUR NPs in prostate cancer xenograft mice model. In conclusion, PLGA-CUR NPs can significantly accumulate and exhibit superior anticancer activity in prostate cancer.

Circulating nucleic acids as biomarkers of prostate cancer

Prostate cancer, the most common cancer of western men, requires new biomarkers, especially given that the benefits of PSA testing remain uncertain. Nucleic acids can now be accurately and sensitively detected in human blood. Over the last decade, investigations into utility of circulating cell-free miRNA, DNA and mRNA as novel biomarkers have expanded exponentially. In the near future, they may be routinely used to accurately diagnose cancers, stratify indolent from aggressive disease and inform treatment decisions. However, advancement of such tests into clinical settings is hampered by technical problems with assay specificity and sensitivity, and small study sizes. This review highlights the different forms of circulating nucleic acids and those that show the most potential as viable biomarkers for prostate cancer.

A Quest to Identify Prostate Cancer Circulating Biomarkers with a Bench-to-Bedside Potential

Prostate cancer (PCA) is a major health concern in current times. Ever since prostate specific antigen (PSA) was introduced in clinical practice almost three decades ago, the diagnosis and management of PCA have been revolutionized. With time, concerns arose as to the inherent shortcomings of this biomarker and alternatives were actively sought. Over the past decade new PCA biomarkers have been identified in tissue, blood, urine, and other body fluids that offer improved specificity and supplement our knowledge of disease progression. This review focuses on superiority of circulating biomarkers over tissue biomarkers due to the advantages of being more readily accessible, minimally invasive (blood) or noninvasive (urine), accessible for sampling on regular intervals, and easily utilized for follow-up after surgery or other treatment modalities. Some of the circulating biomarkers like PCA3, IL-6, and TMPRSS2-ERG are now detectable by commercially available kits while others like microRNAs (miR-21, -221, -141) and exosomes hold potential to become available as multiplexed assays. In this paper, we will review some of these potential candidate circulating biomarkers that either individually or in combination, once validated with large-scale trials, may eventually get utilized clinically for improved diagnosis, risk stratification, and treatment.

Expression of the Metastasis Suppressor KAI1 in Uveal Melanoma

Introduction. Uveal melanoma (UM) is an intraocular tumor that leads to metastatic disease in approximately 50% of afflicted patients. There is no efficacious treatment for metastatic disease in this cancer. Identification of markers that can offer prognostic and therapeutic value is a major focus in this field at present. KAI1 is a metastasis suppressor gene that has been reported to play a role in various human malignancies, although it has not previously been evaluated in UM. Purpose. To investigate the expression of KAI1 in UM and its potential value as a prognostic marker. Materials and Methods. 18 cases of human primary UM were collected and immunostained for KAI1 expression. A pathologist evaluated staining intensity and distribution semiquantitatively. Each case was categorized as group 1 (low staining) or group 2 (high staining). Results. In group 2, two of the 12 cases presented with metastasis. Conversely, in group 1, five out of 6 cases had metastasis. The mean follow-up of patients who did not develop metastasis was 81.81 months (median: 75 months) versus 42.14 months (median: 44 months) for patients with metastasis. Conclusions. KAI1 is a promising candidate marker that may offer prognostic value in UM; it may also represent a therapeutic target in metastatic disease.

On-chip screening for prostate cancer: an EIS microfluidic platform for contemporary detection of free and total PSA

Prostate cancer affects a large part of the western male population. The need for an early and accurate detection is thus a great challenge in common clinical practice, but the lack of specificity of the serum marker PSA (Prostate Specific Antigen) is a serious problem since its increased concentration can be related to several abnormalities. PSA, however, is found in serum in both a free and a complexed form with other proteins and the percentage amount of unbound PSA (the free-to-total PSA ratio) can be employed to distinguish prostate cancer from benign prostatic conditions, and also to predict the future risk of prostate cancer. To improve the operating characteristics of current PSA tests and to provide a clinical tool able to run label-free and sensitive analysis, we thus developed a biosensing platform based on Electrochemical Impedance Spectroscopy (EIS), which allows the contemporary detection of free and total PSA on a single biochip, enabling a quick screening for the risk of prostate cancer thanks to the presence of two different immobilized antibodies specific for the different antigens researched.

Variable metastatic potentials correlate with differential plectin and vimentin expression in syngeneic androgen independent prostate cancer cells

Prostate cancer is a clinically heterogeneous disease, ranging from indolent asymptomatic disease to very aggressive metastatic and life threatening forms of the disease. Distant metastasis represents the major lethal cause of prostate cancer. The most critical clinical challenge in the management of the patients is identifying those individuals at risk of developing metastatic disease. To understand the molecular mechanisms of prostate cancer metastasis and identify markers with metastatic potential, we have analyzed protein expression in two syngeneic prostate cancer cells lines PC3-N2 and PC3-ML2 using isobaric tags for relative and absolute quantitation labeling and multi-dimensional protein identification technology liquid chromatography matrix assisted laser desorption ionization tandem mass spectrometry. PC3-N2 is lowly metastatic while PC3-ML2 highly metastatic. A total of 1,756 proteins were identified in the analyses with 130 proteins showing different expression levels (p<0.01) in the two cell lines. Out of these, 68 proteins were found to be significantly up-regulated while 62 are significantly down-regulated in PC3-ML2 cells compared with PC3-N2 cells. The upregulation of plectin and vimentin which were the most significantly differentially expressed were validated by Western blot and their functional relevance with respect to invasion and migration was determined by siRNA gene silencing. To our knowledge, this study is the first to demonstrate that up-regulation of vimentin and plectin expression positively correlates with the invasion and metastasis of androgen-independent PCA.

Cell-free circulating plasma hTERT mRNA is a useful marker for prostate cancer diagnosis and is associated with poor prognosis tumor characteristics

Background

Serum prostate-specific antigen (PSA) is the most widely used marker for diagnosing prostate cancer (PCa). It lacks specificity and predictive value, resulting in inaccurate diagnoses and overtreatment of the disease. The aim of this study was to assess the usefulness of plasma telomerase reverse transcriptase (hTERT) mRNA as a diagnostic and prognostic tool for PCa and its association with clinicopathological parameters of tumors.

Principal Findings

Plasma hTERT mRNA levels were determined by qRT-PCR in 105 consecutive patients with elevated PSA levels and in 68 healthy volunteers. The diagnostic accuracy, the efficacy as a prognostic factor of biochemical recurrence and the association with tumor clinicopathological parameters of plasma hTERT mRNA and serum PSA tests were determined using univariate and multivariate analyses. The results show that plasma hTERT mRNA is a non-invasive biomarker for PCa diagnosis that shows higher sensitivity (85% vs. 83%), specificity (90% vs. 47%), positive predictive value (83% vs. 56%), and negative predictive value (92% vs. 77%) than serum PSA. Plasma hTERT mRNA is significantly associated with poor prognosis tumor clinicopathological parameters and is a significant independent predictor of PCa (p<0.0001). Univariate analysis identified plasma hTERT mRNA (but not serum PSA) as a significant prognostic factor of biochemical recurrence. Plasma hTERT mRNA Kaplan-Meier curves confirmed the significant differences between groups and patients with higher levels than the cut-off value showed diminished recurrence-free survival (p = 0.004), whereas no differences were observed with serum PSA (p = 0.38). Multivariate analysis indicated that plasma hTERT mRNA (but not serum PSA) and stage were significantly associated with biochemical recurrence.

Conclusions

Overall, these findings indicate that hTERT mRNA is a useful non-invasive tumor marker for the molecular diagnosis of PCa, affording a greater diagnostic and prognostic accuracy than the PSA assay and may be of relevance in the follow-up of the disease.

miRNAs as biomarkers in prostate cancer

Current prostate cancer (PCa) diagnosis is based in the serum prostate-specific antigen biomarker and digital rectal examination. However, these methods are limited by a low predictive value (24-37 %) and a high risk of mistaken results. During last years, new promising biomarkers such as Prostate Cancer Antigen 3 (PCA-3) and TMPRSS2-ETS fusion genes have been evaluated for their clinical use. However, the search of new biomarkers that could be used for PCa diagnosis and prognosis is still needed. Recent studies have demonstrated that the aberrant expression of microRNAs (miRNAs), small non-coding RNAs that negatively regulate gene expression, is related with the development of several cancers, including PCa. Since miRNAs serve as phenotypic signatures of different cancers, they appear as potential diagnostic, prognostic and therapeutic tools. Here, we review the current knowledge of miRNA expression patterns in PCa and their role in PCa prognosis and therapeutics.

A Review on the Clinical Utility of PSA in Cancer Prostate

Prostate cancer has come to share the oncological centrestage among male cancers. The availability of Serum Prostate Specific Antigen, PSA, as a marker has encouraged it's use to diagnose both cancer and cancer recurrence. Some clarity is required about its precise role in clinical practice. The available literature on Prostate Specific Antigen was reviewed; Articles were reviewed for content, applicability to the problem at hand, availability of data about sensitivity and specificity of values, refinements in measurements and finally for impact of screening programmes using these values on survival and quality of life. The data in the literature was critically re-evaluated and analysed to draw reasonable conclusions. Serum PSA measurements show variable reliability when it comes to diagnosis of Prostate cancer, given the dynamics of PSA physiology. Surrogate measures like PSA density, PSA velocity, free-to-complexed PSA ratio, percentage Pro-PSA, etc., have been used to improve the predictive utility of this assay for Prostate cancer. The ability of PSA to detect those cancers that will cost life, and thereby permit early curative treatment, is as yet unclear. It's most definitive role appears to be in diagnosing recurrences after adequate surgical treatment, and in evaluating response to treatment.

Plasma hTERT mRNA discriminates between clinically localized and locally advanced disease and is a predictor of recurrence in prostate cancer patients

INTRODUCTION

Since the introduction of prostate-specific antigen (PSA) testing, new prostate cancer (PCa) patients are diagnosed earlier and most have localized and locally advanced disease. Current diagnosis methods lack specificity and sensitivity, leading to overdiagnosis and overtreatment of patients with low-risk organ-confined localized disease. Therefore, new non-invasive molecular tools are needed to discriminate between localized and locally advanced disease.

METHODS

Plasma telomerase reverse transcriptase (hTERT) mRNA levels were determined by qRT-PCR in 49 patients with localized and locally advanced PCa. Diagnostic accuracy and efficacy as a prognostic factor of biochemical recurrence of plasma hTERT mRNA were determined using univariate and multivariate analyses and compared with conventional tumor markers.

RESULTS

Patients with locally advanced disease had significantly (p < 0.05) higher plasma hTERT mRNA and serum PSA levels than those with localized disease. Plasma hTERT mRNA test showed lower sensitivity (83% vs. 100%), higher specificity (73% vs. 43%), AUC ROC curve (0.911 vs. 0.757), and positive likelihood ratios (6.17 vs. 1.76) than the PSA assay in discriminating between localized and locally advanced disease. At multivariate analysis, plasma hTERT mRNA levels and age but not PSA showed a positive trend (p = 0.05) in the risk of locally advanced PCa. On univariate analysis, plasma hTERT mRNA and serum PSA were identified as significant prognostic factors of biochemical recurrence. Using ROC curves and the appropriate cutoff, both tests showed high sensitivity (85%) and specificity (72%). Kaplan-Meier curves confirmed the significant differences between the groups and patients with higher levels than the cutoff value showed diminished recurrence-free survival (p < 0.05). At multivariate analysis, Gleason score and PSA were the strongest factors associated with biochemical recurrence (p < 0.05), whereas hTERT mRNA did not reach statistical significance, although a positive trend was observed (p = 0.09).

CONCLUSION

Plasma hTERT mRNA quantification can be both a useful non-invasive tumor marker for discriminating between localized and locally advanced PCa, as well as a prognostic factor of recurrence at the molecular level.

Candidate serum biomarkers for prostate adenocarcinoma identified by mRNA differences in prostate tissue and verified with protein measurements in tissue and blood

BACKGROUND

Improved tests are needed for detection and management of prostate cancer. We hypothesized that differential gene expression in prostate tissue could help identify candidate blood biomarkers for prostate cancer and that blood from men with advanced prostate disease could be used to verify the biomarkers presence in circulation.

METHODS

We identified candidate markers using mRNA expression patterns from laser-capture microdissected prostate tissue and confirmed tissue expression using immunohistochemistry (IHC) for the subset of candidates having commercial antisera. We analyzed tissue extracts with tandem mass spectrometry (MS/MS) and measured blood concentrations using immunoassays and MS/MS of trypsin-digested, immunoextracted peptides.

RESULTS

We selected 35 novel candidate prostate adenocarcinoma biomarkers. For all 13 markers having commercial antisera for IHC, tissue expression was confirmed; 6 showed statistical discrimination between nondiseased and malignant tissue, and only 5 were detected in tissue extracts by MS/MS. Sixteen of the 35 candidate markers were successfully assayed in blood. Four of 8 biomarkers measured by ELISA and 3 of 10 measured by targeted MS showed statistically significant increases in blood concentrations of advanced prostate cancer cases, compared with controls.

CONCLUSIONS

Seven novel biomarkers identified by gene expression profiles in prostate tissue were shown to have statistically significant increased concentrations in blood from men with advanced prostate adenocarcinoma compared with controls: apolipoprotein C1, asporin, cartilage oligomeric matrix protein, chemokine (C-X-C motif) ligand 11 (CXCL11), CXCL9, coagulation factor V, and proprotein convertase subtilisin/kexin 6.

Low serum testosterone levels are predictive of prostate cancer

PURPOSE

Although hormones play fundamental roles in prostate growth, their clinical significance is not completely clear. Aims of present study were to assess whether testosterone and serum sex hormone levels are predictors of benign prostatic hyperplasia (BPH) or prostate cancer (PC) and to verify whether prostate cancer is associated with low testosterone levels, and to test association between testosterone levels and known prognostic factors in prostate cancer.

METHODS

In 206 consecutive patients with benign prostatic hyperplasia or prostate cancer testosterone, follicle-stimulating hormone, luteinizing hormone and prolactin levels were tested and correlated with disease. In patients with prostate cancer, hormone levels were also correlated with known prognostic factors. Predictive value was assessed for age, prostate-specific antigen (PSA), PSA ratio, PSA density, prostate volume and serum sex hormone levels using multiple logistic regression analysis and receiver operating characteristic curves.

RESULTS

Considering sex hormones, only testosterone levels were significantly lower in patients with prostate cancer than those with BPH; testosterone levels appear to be independent predictor of prostate cancer, enhancing predictive accuracy for BPH and PC. Testosterone levels do not seem to be associated with known clinical prognostic factors.

CONCLUSIONS

This study supports experimental findings that testosterone levels are predictor of prostate cancer and that prostate cancer is frequently associated with low testosterone levels. In the diagnostic work-up for prostate cancer, adding testosterone determination to PSA test may improve predictive accuracy.

IκB-Kinase-ε (IKKε/IKKi/IκBKε) expression and localization in prostate cancer tissues

BACKGROUND

Advanced prostate cancer (PCa) remains a one of the leading causes of cancer related death and is often due to the progression from a hormone sensitive (HS) to a castrate resistant (CR) state for which therapeutic alternatives remain palliative. Molecular events involved in the progression to CR-PCa remain largely unknown. A previous study reported significantly higher levels of Iκ-B kinase-epsilon (IKKε) expression in CR compared to androgen-responsive cell lines. In the present study, we evaluate IKKε expression in human prostate tissue.

METHODS

In order to evaluate the modulation of IKKε expression in PCa tissue IKKε immunostaining was performed on paraffin-embedded prostate tissue microarrays containing cores from normal tissues (n = 47), non-malignant tissues adjacent to the tumor (n = 53), prostatic intraepithelial neoplasia (PIN) (n = 28), HS (n = 62), and CR tumors (n = 31).

RESULTS

We found a low cytoplasmic expression of IKKε in non-malignant tissue. HS tumors showed a significant increase in cytoplasmic IKKε expression compared to non-malignant tissues. CR tissues presented the highest cytoplasmic IKKε expression levels. We also report, for the first time, the presence of a nuclear localization of IKKε in prostate epithelial cells, in particular we observed an increase of IKKε nuclear localization in HS malignant tissues. Finally, we found a strong link between an increase of IKKε cytoplasmic expression in PCa and metastatic progression.

CONCLUSION

This study strongly suggests the role of IKKε as a PCa oncogene that may be involved in the emergence of a CR state.

123I-MIP-1072, a small-molecule inhibitor of prostate-specific membrane antigen, is effective at monitoring tumor response to taxane therapy

Because traditional endpoints in oncology trials are not always applicable for metastatic prostate cancer, better ways of following response to treatment are needed. Prostate-specific membrane antigen (PSMA) is a transmembrane protein expressed in normal human prostate epithelium and is upregulated in prostate cancer. (S)-2-(3-((S)-1-carboxy-5-((4-(123)I-iodobenzyl)amino)pentyl)ureido)pentanedioic acid, (123)I-MIP-1072, targets PSMA and was evaluated for monitoring the growth of PSMA-positive LNCaP cells in vitro and as xenografts after paclitaxel therapy.

METHODS

LNCaP and 22Rv1 cells were treated with paclitaxel (0-100 nM) for 48 h, after which binding of (123)I-MIP-1072 was examined. Cell number was determined by MTS assay, and PSMA expression was analyzed by Western blotting. LNCaP xenograft-bearing mice were treated with paclitaxel (6.25 mg/kg) for 3.5 cycles of 5 d on and 2 d off. Tissue distribution of (123)I-MIP-1072 was determined on days 2 and 23 from the start of paclitaxel treatment.

RESULTS

Paclitaxel (10-100 nM) inhibited LNCaP and 22Rv1 cell growth after 48 h, and binding of (123)I-MIP-1072 was proportional to cell number. Western blot analysis verified there was no paclitaxel-dependent change in PSMA expression. Treatment of LNCaP xenografts with paclitaxel resulted in a decrease in tumor volume (-21%), compared with an increase in the untreated xenografts (+205%) by day 23. Tumor uptake of (123)I-MIP-1072 was proportional to changes in tumor mass: decreased by paclitaxel treatment and increased in untreated mice.

CONCLUSION

Treatment of LNCaP cells or xenograft tumors with paclitaxel resulted in growth inhibition, which was detected with (123)I-MIP-1072. The high specificity of (123)I-MIP-1072 for prostate cancer may allow monitoring of tumor progression in patients before, during, and after chemotherapy.

Metastasis suppressor KAI1/CD82 attenuates the matrix adhesion of human prostate cancer cells by suppressing fibronectin expression and β1 integrin activation

KAI1/CD82, a tetraspanin membrane protein functions as a metastasis suppressor in many types of human cancers and has been shown to regulate cell adhesion properties. In the present study, we investigated the underlying mechanism of KAI1/CD82-mediated changes in cell adhesion to the extracellular matrix using human prostate cancer cells. We found that high KAI1/CD82 expression attenuated short-term cell adhesion to uncoated- or fibronectin-coated plates. Moreover, high KAI1/CD82 expression generated an extracellular environment unfavorable for cell adhesion as compared to low KAI1/CD82 expression, suggesting KAI1/CD82-dependent regulation of extracellular matrix (ECM) molecule(s) expression and/or secretion. Among ECM components examined, fibronectin exhibited decreased expression and secretion in high KAI1/CD82-expressing cells. Furthermore, high KAI1/CD82 expression interfered with the activation of β (1) integrin at the cell surface while total β (1) integrin levels remained unchanged, concomitant with reduced formation of focal adhesion complex and decreased bundling of actin filaments. Finally, high KAI1/CD82 expression significantly retarded cell motility in a scratch wound assay. Taken together, our results strongly suggest that KAI1/CD82 attenuates the activation of β (1) integrin, and thereby down-regulates outside-in signaling of β (1) integrin, leading to the reduction of focal adhesion formation and fibronectin expression/secretion, which subsequently interferes with cell adhesion properties and motility.