Potential Biomarker For Prostate Cancer Research Articles

Role of YY1 in the pathogenesis of prostate cancer and correlation with bioinformatic data sets of gene expression.

Current treatments of various cancers include chemotherapy, radiation, surgery, immunotherapy, and combinations. However, there is a need to develop novel diagnostic and therapeutic treatments for unresponsive patients. These may be achieved by the identification of novel diagnostic and prognostic biomarkers which will help in the stratification of patients' initial responses to particular treatments and circumvent resistance, relapses, metastasis, and death. We have been investigating human prostate cancer as a model tumor. We have identified Yin Yang 1 (YY1), a dysregulated transcription factor, whose overexpression correlated with tumor progression as well as in the regulation of drug resistance and the development of EMT. YY1 expression is upregulated in human prostate cancer cell lines and tissues. We postulated that YY1 may be a potential biomarker in prostate cancer for patients' stratification as well as a novel target for therapeutic intervention. We used Bioinformatic gene RNA array datasets for the expression of YY1 in prostate tumor tissues as compared to normal tissues. Interestingly, variations on the expression levels of YY1 mRNA in prostate cancer were reported by different investigators. This mini review summarizes the current reported studies and Bioinformatic analyses on the role of YY1 in the pathogenesis of prostate cancer.

110 The expression profile of phosphatidylinositol in high resolution imaging mass spectrometry is a potential biomarker for prostate cancer

110 The expression profile of phosphatidylinositol in high resolution imaging mass spectrometry is a potential biomarker for prostate cancer

A pattern recognition system for prostate mass spectra discrimination based on the CUDA parallel programming model

The aim of the present study was to implement a pattern recognition system for the discrimination of healthy from malignant prostate tumors from proteomic Mass Spectroscopy (MS) samples and to identify m/z intervals of potential biomarkers associated with prostate cancer. One hundred and six MS-spectra were studied in total. Sixty three spectra corresponded to healthy cases (PSA < 1) and forty three spectra were cancerous (PSA > 10). The MS-spectra are publicly available from the NCI Clinical Proteomics Database. The pre-processing comprised the steps: denoising, normalization, peak extraction and peak alignment. Due to the enormous number of features that rose from MS-spectra as informative peaks, and in order to secure optimum system design, the classification task was performed by programming in parallel the multiprocessors of an nVIDIA GPU card, using the CUDA framework. The proposed system achieved 98.1% accuracy. The identified m/z intervals displayed significant statistical differences between the two classes and were found to possess adequate discriminatory power in characterizing prostate samples, when employed in the design of the classification system. Those intervals should be further investigated since they might lead to the identification of potential new biomarkers for prostate cancer.

The Expression Profile of Phosphatidylinositol in High Spatial Resolution Imaging Mass Spectrometry as a Potential Biomarker for Prostate Cancer

High-resolution matrix-assisted laser desorption/ionization imaging mass spectrometry (HR-MALDI-IMS) is an emerging application for the comprehensive and detailed analysis of the spatial distribution of ionized molecules in situ on tissue slides. HR-MALDI-IMS in negative mode in a mass range of m/z 500–1000 was performed on optimal cutting temperature (OCT) compound-embedded human prostate tissue samples obtained from patients with prostate cancer at the time of radical prostatectomy. HR-MALDI-IMS analysis of the 14 samples in the discovery set identified 26 molecules as highly expressed in the prostate. Tandem mass spectrometry (MS/MS) showed that these molecules included 14 phosphatidylinositols (PIs), 3 phosphatidylethanolamines (PEs) and 3 phosphatidic acids (PAs). Among the PIs, the expression of PI(18:0/18:1), PI(18:0/20:3) and PI(18:0/20:2) were significantly higher in cancer tissue than in benign epithelium. A biomarker algorithm for prostate cancer was formulated by analyzing the expression profiles of PIs in cancer tissue and benign epithelium of the discovery set using orthogonal partial least squares discriminant analysis (OPLS-DA). The sensitivity and specificity of this algorithm for prostate cancer diagnosis in the 24 validation set samples were 87.5 and 91.7%, respectively. In conclusion, HR-MALDI-IMS identified several PIs as being more highly expressed in prostate cancer than benign prostate epithelium. These differences in PI expression profiles may serve as a novel diagnostic tool for prostate cancer.

ERG Rearrangement Is Associated with Prostate Cancer-Related Death in Chinese Prostate Cancer Patients

Recently, ETS-related gene (ERG) gene rearrangements, phosphatase tensin homologue (PTEN) deletions and EGFR family aberrations were characterized as potential biomarkers for prostate cancer (PCa) patient management. Although ERG gene rearrangement has been identified in approximately 50% of localized prostate cancers in western countries, the prognostic significance of this critical molecular event remains unknown in Chinese patients. Using fluorescence in situ hybridization (FISH) and immunohistochemistry, we evaluated ERG, PTEN and EGFR family aberrations in a cohort of 224 Chinese prostate cancer patients diagnosed in transurethral resection of the prostate (TUR-P). Overall, ERG rearrangement was detected in 23.2% (44/190) cases, of which 54.5% (24/44) showed deletion of the 5′end of ERG. PTEN deletion was identified in 10.8% (19/176) cases. Amplification of EGFR and HER2 genes was present in 1.1% (2/178) and 5.8% (10/173) of cases, respectively. Significant correlation between ERG rearrangement and PTEN deletion was identified in this cohort. EGFR and HER2 aberrations occurred more frequently in PCas without ERG rearrangement than in those with ERG rearrangement, although this did not reach statistical significance. Overall, ERG rearrangement was associated with pre-operative PSA values (P = 0.038) and cancer-related death (P = 0.02), but not with the age, clinical T stage, Gleason score, or Ki-67 labeling index (LI). Notably, multivariate analysis including known prognostic markers revealed ERG rearrangement was an independent prognostic factor (P = 0.022). Additionally, ERG rearrangement status was helpful to identify patients with poor prognosis from PCa group with low Ki-67 LI. In summary, we reported that ERG rearrangement was associated with cancer-related death in Chinese PCa patients. Determination of ERG rearrangement status allows stratification of PCa patients into different survival categories.

Carbon ion irradiation of the human prostate cancer cell line PC3: A whole genome microarray study

Hadrontherapy is a form of external radiation therapy, which uses beams of charged particles such as carbon ions. Compared to conventional radiotherapy with photons, the main advantage of carbon ion therapy is the precise dose localization along with an increased biological effectiveness. The first results obtained from prostate cancer patients treated with carbon ion therapy showed good local tumor control and survival rates. In view of this advanced treatment modality we investigated the effects of irradiation with different beam qualities on gene expression changes in the PC3 prostate adenocarcinoma cell line. For this purpose, PC3 cells were irradiated with various doses (0.0, 0.5 and 2.0 Gy) of carbon ions (LET=33.7 keV/μm) at the beam of the Grand Accélérateur National d’Ions Lourds (Caen, France). Comparative experiments with X-rays were performed at the Belgian Nuclear Research Centre. Genome-wide gene expression was analyzed using microarrays. Our results show a downregulation in many genes involved in cell cycle and cell organization processes after 2.0 Gy irradiation. This effect was more pronounced after carbon ion irradiation compared with X-rays. Furthermore, we found a significant downregulation of many genes related to cell motility. Several of these changes were confirmed using qPCR. In addition, recurrence-free survival analysis of prostate cancer patients based on one of these motility genes (FN1) revealed that patients with low expression levels had a prolonged recurrence-free survival time, indicating that this gene may be a potential prognostic biomarker for prostate cancer. Understanding how different radiation qualities affect the cellular behavior of prostate cancer cells is important to improve the clinical outcome of cancer radiation therapy.

CC chemokine ligand 18 and IGF-binding protein 6 as potential serum biomarkers for prostate cancer.

Prostate cancer (PCa) is the second leading cause of cancer-related death in men globally. However, there are few sensitive biomarkers for PCa, especially those which can distinguish PCa and benign prostate hyperplasia (BPH). Antibody microarrays allow for high-throughput and high-sensitivity detection of multiple proteins simultaneously, providing a powerful tool for biomarker screening. Here, we selected 46 patients with PCa and 42 controls with BPH, and compared the serum levels of different cytokines in PCa and BPH patients using antibody microarrays. The results indicated that serum levels of macrophage colony-stimulating factor (M-CSF) and CC chemokine ligand 18 (CCL-18) were remarkably higher in PCa patients than those in BPH patients, while serum levels of insulin-like growth factor-binding protein 6 (IGFBP-6) and Fas receptor (Fas), also called tumor necrosis factor receptor superfamily member 6 (TNFRSF6), were significantly lower. M-CSF and Fas/TNFRSF6 have been reported to be associated with PCa pathogenesis, and thus were used as positive controls in the present study. CCL-18 is a chemokine primarily involved in recruitment of the adaptive immune system, while IGFBP-6 has been reported to inhibit proliferation of PCa cells. Serum levels of these four cytokines could distinguish PCa from BPH with high sensitivity and high specificity. Furthermore, the area under the ROC curve (AUC) was above 0.925 and 0.835 for CCL-18 and IGFBP-6, respectively, implying their high diagnostic value. In conclusion, we have identified CCL-18 and IGFBP-6 as new potential serum biomarkers for PCa.

CXCL12 Modulates Prostate Cancer Cell Adhesion by Altering the Levels or Activities of β1-Containing Integrins.

The mechanisms by which prostate cancer (PCa) cell adhesion and migration are controlled during metastasis are not well understood. Here, we studied the effect of CXCL12 in PCa cell adhesion and spreading in DU145 and PC3 cell lines using as substrates collagen I, fibronectin (FN), and their recombinant fragments. CXCL12 treatment increased β1 integrin-dependent PC3 cell adhesion on FN which correlated with increased focal adhesion kinase activation. However neither α5β1 nor α4β1 subunits were involved in this adhesion. By contrast, CXCL12 decreased DU145 adhesion and spreading on FN by downregulating α5 and β1 integrin expression. To demonstrate the clinical relevance of CXCL12 in PCa, we measured CXCL12 levels in plasma by using ELISA and found that the chemokine is elevated in PCa patients when compared to controls. The high concentration of CXCL12 in patients suffering from PCa in comparison to those with benign disease or healthy individuals implicates CXCL12 as a potential biomarker for PCa. In addition these data show that CXCL12 may be crucial in controlling PCa cell adhesion on fibronectin and collagen I, possibly via crosstalk with integrin receptors and/or altering the expression levels of integrin subunits.

Sensitive determination of the potential biomarker sarcosine for prostate cancer by LC-MS withN,N′-dicyclohexylcarbodiimide derivatization

Sarcosine, a potential biomarker of prostate cancer, has drawn great attention in recent years. However, controversial research keeps arising about its role as a biomarker that might come from the two isomers (α-alanine and β-alanine) of sarcosine due to their same molecular weight and similar properties, which could interfere with the accurate detection of sarcosine. In this study, a simple and sensitive method was developed for the detection of sarcosine and the two isomers by LC with ion-trap MS through a novel derivatization reagent N,N'-dicyclohexylcarbodiimide. N,N'-Dicyclohexylcarbodiimide is usually considered as a condensation reagent, however, it was directly used as a derivatization reagent through a rearrangement side reaction in this study. The proposed method not only improved the chromatographic retention behavior of sarcosine and its two isomers, which was a benefit to their separation, but also dramatically enhanced the detection sensitivity of sarcosine, which was more favorable for real sample analysis. The factors affecting the productivity of the derivatization reaction, such as reaction time and amount of derivatization reagent, were systematically optimized. The method shows good linearity (R(2) > 0.99), sensitivity with LODs of sarcosine as low as 1 ng/mL, and repeatability with the RSD < 6.07%. The developed method was applied to the analysis of urine.

PTRF/cavin-1 neutralizes non-caveolar caveolin-1 microdomains in prostate cancer.

Caveolin-1 has a complex role in prostate cancer and has been suggested to be a potential biomarker and therapeutic target. As mature caveolin-1 resides in caveolae, invaginated lipid raft domains at the plasma membrane, caveolae have been suggested as a tumor-promoting signaling platform in prostate cancer. However, caveola formation requires both caveolin-1 and cavin-1 (also known as PTRF; polymerase I and transcript release factor). Here, we examined the expression of cavin-1 in prostate epithelia and stroma using tissue microarray including normal, non-malignant and malignant prostate tissues. We found that caveolin-1 was induced without the presence of cavin-1 in advanced prostate carcinoma, an expression pattern mirrored in the PC-3 cell line. In contrast, normal prostate epithelia expressed neither caveolin-1 nor cavin-1, while prostate stroma highly expressed both caveolin-1 and cavin-1. Utilizing PC-3 cells as a suitable model for caveolin-1-positive advanced prostate cancer, we found that cavin-1 expression in PC-3 cells inhibits anchorage-independent growth, and reduces in vivo tumor growth and metastasis in an orthotopic prostate cancer xenograft mouse model. The expression of α-smooth muscle actin in stroma along with interleukin-6 (IL-6) in cancer cells was also decreased in tumors of mice bearing PC-3-cavin-1 tumor cells. To determine whether cavin-1 acts by neutralizing caveolin-1, we expressed cavin-1 in caveolin-1-negative prostate cancer LNCaP and 22Rv1 cells. Caveolin-1 but not cavin-1 expression increased anchorage-independent growth in LNCaP and 22Rv1 cells. Cavin-1 co-expression reversed caveolin-1 effects in caveolin-1-positive LNCaP cells. Taken together, these results suggest that caveolin-1 in advanced prostate cancer is present outside of caveolae, because of the lack of cavin-1 expression. Cavin-1 expression attenuates the effects of non-caveolar caveolin-1 microdomains partly via reduced IL-6 microenvironmental function. With circulating caveolin-1 as a potential biomarker for advanced prostate cancer, identification of the molecular pathways affected by cavin-1 could provide novel therapeutic targets.

Sarcosine as a Potential Prostate Cancer Biomarker—A Review

Prostate cancer (CaP) is the most common type of tumour disease in men. Early diagnosis of cancer of the prostate is very important, because the sooner the cancer is detected, the better it is treated. According to that fact, there is great interest in the finding of new markers including amino acids, proteins or nucleic acids. Prostate specific antigen (PSA) is commonly used and is the most important biomarker of CaP. This marker can only be detected in blood and its sensitivity is approximately 80%. Moreover, early stages cannot be diagnosed using this protein. Currently, there does not exist a test for diagnosis of early stages of prostate cancer. This fact motivates us to find markers sensitive to the early stages of CaP, which are easily detected in body fluids including urine. A potential is therefore attributed to the non-protein amino acid sarcosine, which is generated by glycine-N-methyltransferase in its biochemical cycle. In this review, we summarize analytical methods for quantification of sarcosine as a CaP marker. Moreover, pathways of the connection of synthesis of sarcosine and CaP development are discussed.

Circulating microRNAs as potential new biomarkers for prostate cancer

Since they were first described in the 1990s, circulating microRNAs (miRNAs) have provided an active and rapidly evolving area of current research that has the potential to transform cancer diagnostics and therapeutics. In particular, miRNAs could provide potential new biomarkers for prostate cancer, the most common cause of cancer in UK men. Current diagnostic tests for prostate cancer have low specificity and poor sensitivity. Further, although many prostate cancers are so slow growing as not to pose a major risk to health, there is currently no test to distinguish between these and cancers that will become aggressive and life threatening. Circulating miRNAs are highly stable and are both detectable and quantifiable in a range of accessible bio fluids, thus have the potential to be useful diagnostic, prognostic and predictive biomarkers. This review aims to summarise the current understanding of circulating miRNAs in prostate cancer patients and their potential role as biomarkers.

Abstract 7: Berg Interrogative Biology™ platform unravels novel biomarkers FLNB and LY9 in combination with PSA enhances specificity in serum of patients with prostate cancer.

Abstract Prostate Specific Antigen (PSA) test is the predominant screening test for prostate cancer. Utility is limited by the low predictive power to differentiate patients with indolent tumors from aggressive disease with potential for metastasis. Identification of potential biomarkers to increase prediction of patient population with propensity for progression to metastatic disease remains the overarching unmet need in prostate cancer screening. This study reports the identification of a panel of potential biomarkers using the Berg Interrogative Biology™ platform, a novel non-hypothesis driven approach to characterize disease specific molecular signatures for the identification of physiological drivers of disease etiology. Filamin B (FLNB) and lymphocyte antigen 9 (LY9) were two of several markers identified from a high confidence causal network of prostate cancer model using the Berg Interrogative Biology™ platform. Both FLNB and LY9 were validated in a small case-control retrospective study in human serum samples of patients with prostate cancer and age-matched normal controls. The utility of FLNB and LY9 as potential biomarkers in prostate cancer was determined by comparing the serum levels to that of PSA to establish benchmark comparison. Statistically significant elevation of the PSA, FLNB, and LY9 concentrations was detected in the prostate cancer group compared to the age-matched normal control group. Statistical analyses were performed to determine the sensitivity and specificity of the molecular markers by ROC curve analysis. The predictive power of FLNB or LY9 alone was comparable to that of the PSA test. The combination of FLNB and LY9 with PSA out-performed PSA alone with AUC=0.975 in the study. The study provides data in support of FLNB and LY9 as biomarkers with potential to improve screening outcomes when used in combination with PSA. Efforts are currently underway in large patient cohorts to validate the clinical utility of FLNB and LY9 as candidate biomarkers for use in the screening of prostate cancer with correlate to the Gleason score to enable more instructive data to the practitioner. Citation Format: Rangaprasad Sarangarajan, Joyce Chan, Eric Grund, Vivek K. Vishnudas, Shen Luan, Viatcheslav R. Akmaev, Niven R. Narain. Berg Interrogative Biology™ platform unravels novel biomarkers FLNB and LY9 in combination with PSA enhances specificity in serum of patients with prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 7. doi:10.1158/1538-7445.AM2013-7

2238 ERG AS A POTENTIAL BIOMARKER FOR PROSTATE CANCER MAY BENEFIT EUROPEAN AMERICAN MEN BUT NOT AFRICAN AMERICAN MEN

You have accessJournal of UrologyProstate Cancer: Markers (II)1 Apr 20132238 ERG AS A POTENTIAL BIOMARKER FOR PROSTATE CANCER MAY BENEFIT EUROPEAN AMERICAN MEN BUT NOT AFRICAN AMERICAN MEN Isaac Powell, Greg Dyson, and Aliccia Bollig-Fischer Isaac PowellIsaac Powell Detroit, MI More articles by this author , Greg DysonGreg Dyson Detroit, MI More articles by this author , and Aliccia Bollig-FischerAliccia Bollig-Fischer Detroit, MI More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2147AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES ERG (avian v-ets erythroblastosis virus E26 oncogene homolog) gene rearrangement and over-expression with potential functional consequences has been detected in 40-50% of men with prostate cancer. The utilization of ERG as an additional biomarker to prostate specific antigen (PSA) is being strongly considered. Evidence suggests that ERG expression is associated with disease progression. However, the evidence is controversial and primarily relies on studies including only European or European American men (EAM) as subjects. A relatively limited study in fact reports a low frequency percentage of ERG protein expression African American men (AAM). Here we are reporting on a larger diverse population of men with prostate cancer (PCa). METHODS Formalin-fixed paraffin-embedded archived tumor samples from radical prostatectomy were included in the study. An Illumina DASL bead array was used to measure ERG expression in 639 tumor-derived DNA samples (270 AAM, 369 EAM). RESULTS A t-test using the Satterthwaite approximation of degrees of freedom was then performed comparing ERG expression in AAM to EAM, which demonstrated that ERG was more highly expressed overall in the EAM population. Furthermore, density plots display two populations among AAM and EAM, one subpopulation demonstrating low ERG expression and another with significantly high-level expression. For EAM, 40% show high-level expression of ERG. However, among AAM only 14% show high levels of ERG expression. CONCLUSIONS The gene-level result from the current analysis showed that ERG expression was significantly greater in PCa from EAM compared to AAM; suggesting that the potential utility of ERG as a biomarker is limited, and may be specific to EAM. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e917-e918 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Isaac Powell Detroit, MI More articles by this author Greg Dyson Detroit, MI More articles by this author Aliccia Bollig-Fischer Detroit, MI More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

A strategy to decorate porous polymer monoliths with graphene oxide and graphene nanosheets

Graphene oxide (GO)/graphene (GN) nanosheets were coated onto the poly(glycidyl methacrylate-ethylene dimethacrylate) monolithic bed synthesized inside the capillary in order to prepare a promising polymer monolith microextraction (PMME) material (GO/GN@poly(GMA-EDMA)). Various techniques, including Fourier transform infrared spectroscopy, atomic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy, were employed to characterize the synthesized GO/GN@poly(GMA-EDMA) monoliths, confirming that GO/GN was effectively functionalized on the poly(GMA-EDMA) monolithic materials. Furthermore, a new method was developed for the analysis of sarcosine (identified as a potential prostate cancer biomarker) using PMME coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Under the preoptimized conditions, the monolithic column afforded satisfactory enhancement factor (32-fold) and low limits of detection (1.0 ng mL(-1)) were obtained. In comparison to several other commercialized solid phase extraction adsorbents, GN@poly(GMA-EDMA) monoliths exhibited excellent performance with recoveries of sarcosine approaching 93% with relative standard deviations less than 11.5%.

Identification of Differentially Expressed Proteins in Direct Expressed Prostatic Secretions of Men with Organ-confined Versus Extracapsular Prostate Cancer

Current protocols for the screening of prostate cancer cannot accurately discriminate clinically indolent tumors from more aggressive ones. One reliable indicator of outcome has been the determination of organ-confined versus nonorgan-confined disease but even this determination is often only made following prostatectomy. This underscores the need to explore alternate avenues to enhance outcome prediction of prostate cancer patients. Fluids that are proximal to the prostate, such as expressed prostatic secretions (EPS), are attractive sources of potential prostate cancer biomarkers as these fluids likely bathe the tumor. Direct-EPS samples from 16 individuals with extracapsular (n = 8) or organ-confined (n = 8) prostate cancer were used as a discovery cohort, and were analyzed in duplicate by a nine-step MudPIT on a LTQ-Orbitrap XL mass spectrometer. A total of 624 unique proteins were identified by at least two unique peptides with a 0.2% false discovery rate. A semiquantitative spectral counting algorithm identified 133 significantly differentially expressed proteins in the discovery cohort. Integrative data mining prioritized 14 candidates, including two known prostate cancer biomarkers: prostate-specific antigen and prostatic acid phosphatase, which were significantly elevated in the direct-EPS from the organ-confined cancer group. These and five other candidates (SFN, MME, PARK7, TIMP1, and TGM4) were verified by Western blotting in an independent set of direct-EPS from patients with biochemically recurrent disease (n = 5) versus patients with no evidence of recurrence upon follow-up (n = 10). Lastly, we performed proof-of-concept SRM-MS-based relative quantification of the five candidates using unpurified heavy isotope-labeled synthetic peptides spiked into pools of EPS-urines from men with extracapsular and organ-confined prostate tumors. This study represents the first efforts to define the direct-EPS proteome from two major subclasses of prostate cancer using shotgun proteomics and verification in EPS-urine by SRM-MS.

WS14-6 - Plasma Prosaposin: A New Potential Biomarker for Metastatic Prostate Cancer Regulated by Sphingosine Kinase 1

ABSTRACT Background Prosaposin is a neurotrophic secreted protein that stimulates specific G-coupled receptors and is involved in cancer progression, metastasis and chemoresistance through activation of the Raf-MAPK and uPA/uPAR pathways. Here we have investigated the crossregulation of prosaposin and sphingosine kinase 1 (SK1) pathways in hormone refractory prostate cancer (PCa) models. Methods and results Prosaposin knockout mice exhibited an involution of the prostate gland which correlated with a significant reduction of prostate SK1 activity. In PCa cell lines SK1 activity correlated with the amount of secreted, but not intracellular prosaposin, indicating a role for the prosaposin/GPCR signalling. The specific knockdown of prosaposin in PCa cells induced a significant decrease in SK1 activity and expression on mRNA and protein level. Additionally, a short prosaposin peptide TX14A enhanced SK1 activity and up-regulated SK1 mRNA expression via ERK1/2-mediated mechanism. Cytokine array showed that TX14A induced a significant upregulation of MIF and PAI-1 secretion, which was abrogated by pretreatment with psap- or SphK1-specific siRNA. Increased prosaposin secretion was detected in metastatic PCa cells lines and associated with increased cancer cell motility. Subsequently, SK1 activation was essential for prosaposin secretion and expression during serum deprivation. The effect was further amplified upon overexpression of SK1 and was drastically abrogated by specific knockdown or SK1 inhibitors, which could also abrogate prosaposin-induced cancer cell migration. Analysis of PCa patients plasma samples revealed increased levels of circulating prosaposin in comparison to cancer-free controls. Conclusions These data provide evidence that SK1-dependent prosaposin secretion promotes cancer cell migration and has potential diagnostic/prognostic and therapeutic value in PCa patients.

Genetic association of the KLK4 locus with risk of prostate cancer.

The Kallikrein-related peptidase, KLK4, has been shown to be significantly overexpressed in prostate tumours in numerous studies and is suggested to be a potential biomarker for prostate cancer. KLK4 may also play a role in prostate cancer progression through its involvement in epithelial-mesenchymal transition, a more aggressive phenotype, and metastases to bone. It is well known that genetic variation has the potential to affect gene expression and/or various protein characteristics and hence we sought to investigate the possible role of single nucleotide polymorphisms (SNPs) in the KLK4 gene in prostate cancer. Assessment of 61 SNPs in the KLK4 locus (±10 kb) in approximately 1300 prostate cancer cases and 1300 male controls for associations with prostate cancer risk and/or prostate tumour aggressiveness (Gleason score <7 versus ≥7) revealed 7 SNPs to be associated with a decreased risk of prostate cancer at the Ptrend<0.05 significance level. Three of these SNPs, rs268923, rs56112930 and the HapMap tagSNP rs7248321, are located several kb upstream of KLK4; rs1654551 encodes a non-synonymous serine to alanine substitution at position 22 of the long isoform of the KLK4 protein, and the remaining 3 risk-associated SNPs, rs1701927, rs1090649 and rs806019, are located downstream of KLK4 and are in high linkage disequilibrium with each other (r2≥0.98). Our findings provide suggestive evidence of a role for genetic variation in the KLK4 locus in prostate cancer predisposition.

Monitoring potential prostate cancer biomarkers in urine by capillary electrophoresis–tandem mass spectrometry

Current prostate cancer (PCa) diagnosis based on prostate-specific antigen (PSA) has been gradually losing its credibility over the last decade due to contradictory results in published literature and clinical practice. Recently, a group of potential PCa biomarkers in urine, particularly sarcosine, was found to increase significantly as the cancer progressed to metastasis. We report a simple, robust, and reproducible CE–ESI-MS/MS method for the determination of sarcosine and other representative potential biomarkers in pooled urine. The pooled urine was obtained from 20 healthy adult volunteers between the ages of 23–30 years old. A solid phase extraction (SPE) technique was optimized for maximum recovery of sarcosine. With no derivatization step, excellent resolution between sarcosine and its isomers (α-alanine and β-alanine) was achieved. A separate non-SPE method was also developed for quantitative determination of highly concentrated urinary metabolites. CE separation was performed on a positively-charged, polyethyleneimine (PEI)-coated capillary using 0.4–2% formic acid in 50% methanol. Precision for intra- and inter-day standard addition calibration of sarcosine were found to be within 15%, whereas intra-day precisions for the rest of the metabolites varied from 0.03 to 13.4%. Acceptable intra-day and inter-day accuracies, ranging from 80 to 124%, were obtained for sarcosine and the other metabolites.

Urinary engrailed‐2 (EN2) levels predict tumour volume in men undergoing radical prostatectomy for prostate cancer

What's known on the subject? and What does the study add? There are a lot of potential prostate cancer biomarkers being evaluated. All aim to improve on the sensitivity and specificity of PSA. EN2 was recently shown by our group to have better sensitivity and specificity than PSA. EN2 is a simple ELISA test and is not dependent on other parameters, even PSA, unlike all the other current biomarkers under evaluation. To date, no marker correlates with the amount of cancer present - the present study shows this positive correlation with EN2 in men undergoing prostatectomy. The potential utility of this work is that by knowing that the level of EN2 corresponds to the amount of cancer present, irrelevant of tumour grade and number of cancer foci, we can define an EN2 level corresponding to small cancers, which can then undergo surveillance. We are conducting a further study that is aimed at determining whether the levels of EN2 in urine can indicate 'significant' vs 'non-significant cancer' using the threshold of 0.5 mL cancer (after Epstein's work). To evaluate the relationship between levels of a recently described prostate cancer biomarker engrailed-2 (EN2) in urine and cancer volume in men who had undergone radical prostatectomy (RP) for prostate cancer. To date, prostate-specific antigen (PSA) levels have not reliably predicted prostate cancer volume. Reliable volume indicator biomarker(s) may aid management decisions, e.g. active treatment vs active surveillance. Archived patient samples from the Aarhus Prostate Cancer Project, Denmark, were assessed. Pre-treatment mid-stream urines, without preceding prostatic massage, were collected and stored at -80 °C. Urinary EN2 levels were measured by a recently published enzyme-linked immunosorbent assay. In all, 88 of the whole cohort of 125 men (70%) were positive for EN2 in their urine (>42.5 µg/L); 38/58 (65%) men where cancer volume data was available. There was no statistical relationship between urinary EN2 levels and serum PSA levels. PSA levels did not correlate with tumour stage, combined Gleason grade, total prostatic weight or cancer volume. There was a strong statistical relationship between urinary EN2 and prostate cancer volume by linear regression (P = 0.006). Higher EN2 levels correlated with tumour stage T1 vs T2 (P = 0.027). Pre-surgical urinary EN2 levels were associated with increasing tumour stage and closely reflected the volume of cancer in RP specimens. Given the ease of collection (no prostatic massage required) and the simplicity, low cost and robustness of the assay, EN2 may become a useful biomarker in not only identifying which patients have prostate cancer but may also facilitate risk stratification by indicating the burden of tumour volume.