-
Asian Journal of Surgery Jun 2023
Topics: Humans; Male; Neoplasm Grading; Overdiagnosis; Prostate-Specific Antigen; Overtreatment
PubMed: 36624005
DOI: 10.1016/j.asjsur.2022.12.147 -
Tumour Biology : the Journal of the... Mar 2019Prostate cancer represents a major cause of cancer death in men worldwide. Novel non-invasive methods are still required for differentiation of non-aggressive from...
Investigation on core-fucosylated prostate-specific antigen as a refined biomarker for differentiation of benign prostate hyperplasia and prostate cancer of different aggressiveness.
Prostate cancer represents a major cause of cancer death in men worldwide. Novel non-invasive methods are still required for differentiation of non-aggressive from aggressive tumors. Recently, changes in prostate-specific antigen glycosylation pattern, such as core-fucosylation, have been described in prostate cancer. The objective of this study was to evaluate whether the core-fucosylation determinant of serum prostate-specific antigen may serve as refined marker for differentiation between benign prostate hyperplasia and prostate cancer or identification of aggressive prostate cancer. A previously developed liquid chromatography-mass spectrometry/mass spectrometry-based strategy was used for multiplex analysis of core-fucosylated prostate-specific antigen (fuc-PSA) and total prostate-specific antigen levels in sera from 50 benign prostate hyperplasia and 100 prostate cancer patients of different aggressiveness (Gleason scores, 5-10) covering the critical gray area (2-10 ng/mL). For identification of aggressive prostate cancer, the ratio of fuc-PSA to total prostate-specific antigen (%-fuc-PSA) yielded a 5%-8% increase in the area under the curve (0.60) compared to the currently used total prostate-specific antigen (area under the curve = 0.52) and %-free prostate-specific antigen (area under the curve = 0.55) tests. However, our data showed that aggressive prostate cancer (Gleason score > 6) and non-aggressive prostate cancer (Gleason score ≤ 6) could not significantly (p-value = 0.08) be differentiated by usage of %-fuc-PSA. In addition, both non-standardized fuc-PSA and standardized %-fuc-PSA had no diagnostic value for differentiation of benign prostate hyperplasia from prostate cancer. The %-fuc-PSA serum levels could not improve the differentiation of non-aggressive and aggressive prostate cancer compared to conventional diagnostic prostate cancer markers. Still, it is unclear whether these limitations come from the biomarker, the used patient cohort, or the imprecision of the applied method itself. Therefore, %-fuc-PSA should be further investigated, especially by more precise methods whether it could be clinically used in prostate cancer diagnosis.
Topics: Aged; Aged, 80 and over; Biomarkers, Tumor; Chromatography, Liquid; Diagnosis, Differential; Glycosylation; Humans; Male; Middle Aged; Neoplasm Grading; Prostate; Prostate-Specific Antigen; Prostatic Hyperplasia; Prostatic Neoplasms; Tandem Mass Spectrometry
PubMed: 30907281
DOI: 10.1177/1010428319827223 -
Journal of Immunological Methods Jun 2011Total levels of circulating prostate-specific antigen (tPSA) are strongly associated with prostate cancer (PCa) risk and outcome but benign prostate disease is the most...
Immunoassay for the discrimination of free prostate-specific antigen (fPSA) forms with internal cleavages at Lys(₁₄₅) or Lys(₁₄₆) from fPSA without internal cleavages at Lys(₁₄₅) or Lys(₁₄₆).
Total levels of circulating prostate-specific antigen (tPSA) are strongly associated with prostate cancer (PCa) risk and outcome but benign prostate disease is the most frequent cause of a moderately elevated PSA level. Free PSA (fPSA) forms are independently associated with PCa risk and contribute modest diagnostic enhancements above and beyond tPSA alone. We developed an immunoassay for fPSA subfractions containing internal cleavages at Lys(145) or Lys(146) (fPSA-N). The assay was based on blocking intact single-chain fPSA (fPSA-I) with antibody 4D4 which does not detect PSA containing internal cleavages at Lys(145) or Lys(146). We also measured fPSA-N in blood from healthy volunteers and in anti-coagulated plasma from 76 men with or without evidence of PCa at biopsy. The analytical and functional detection limits of this assay were 0.016 ng/mL and 0.10 ng/mL, respectively. The median recovery of male fPSA-N from female plasma was 95.0%. All 12 female samples (average age 28 years) had fPSA-N concentrations at or below the analytical detection limit. The median fPSA-N concentration (0.050 ng/mL) in 9 healthy male volunteers (age<40 years) was below the functional detection limit, 0.420 ng/mL in 27 patients with benign prostate conditions and 0.239 ng/mL in 49 patients with PCa. Deming regression analysis of the patient samples showed that the measured fPSA-N concentrations were generally 23% lower than the previously calculated (fPSA minus fPSA-I) concentrations, likely due to differences in the antibody combinations used. In conclusion, we have developed a sensitive, specific and direct immunoassay for fPSA-N which can be used to study the clinical relevance of this PSA isoform.
Topics: Adult; Antibodies, Monoclonal; Female; Humans; Immunoassay; Male; Prostate-Specific Antigen; Sensitivity and Specificity
PubMed: 21554885
DOI: 10.1016/j.jim.2011.04.006 -
PloS One 2013Prostate-specific membrane antigen (PSMA) is a type-II membrane glycoprotein that was initially identified in LNCaP cells. It is expressed at elevated levels in prostate...
Prostate-specific membrane antigen (PSMA) is a type-II membrane glycoprotein that was initially identified in LNCaP cells. It is expressed at elevated levels in prostate cancer. In view of the correlation between the expression levels of PSMA and disease grade and stage, PSMA is considered to be one of the most promising biomarkers in the diagnosis and treatment of prostate cancer. In LNCaP cells PSMA undergoes internalization via clathrin-coated pits followed by accumulation in the endosomes. PSMA associates with different types of detergent-resistant membranes (DRMs) along the secretory pathway. Its mature form is mainly insoluble in Lubrol WX, but does not associate with Triton X-100-DRMs. To understand the mechanism of PSMA internalization we investigated its association during internalization with DRMs. For this purpose, internalization was induced by antibody cross-linking. We demonstrate at the biochemical and cell biological levels that: [i] exclusively homodimers of PSMA are associated with Lubrol WX-DRMs, [ii] antibody-induced cross-linking of PSMA molecules results in a time-dependent partitioning into another DRMs type, namely Triton X-100-DRMs, and [iii] concomitant with its association with Triton-X-100-DRMs internalization of PSMA occurs along tubulin filaments. In a previous work (Colombatti et al. (2009) PLoS One 4: e4608) we demonstrated that the small GTPases RAS and RAC1 and the MAPKs p38 and ERK1/2 are activated during antibody cross-linking. As downstream effects of this activation we observed a strong induction of NF-kB associated with an increased expression of IL-6 and CCL5 genes and that IL-6 and CCL5 enhanced the proliferative potential of LNCaP cells synergistically. These observations together with findings reported here hypothesize a fundamental role of DRMs during activation of PSMA as platforms for trafficking, endocytosis and signalling. Understanding these mechanisms constitutes an essential prerequisite for utilization of PSMA as a therapeutically suitable target in prostate cancer.
Topics: Cell Line, Tumor; Cell Membrane; Cell Proliferation; Cross-Linking Reagents; Detergents; Endocytosis; Gene Expression Regulation, Neoplastic; Humans; MAP Kinase Signaling System; Male; Octoxynol; Polyethylene Glycols; Prostate-Specific Antigen; Prostatic Neoplasms; Protein Multimerization
PubMed: 23840421
DOI: 10.1371/journal.pone.0066193 -
Biochimica Et Biophysica Acta Aug 2000The serine proteinase prostate-specific antigen (PSA), and its complex with the serine proteinase inhibitor alpha(1)-antichymotrypsin (ACT), have been used as markers...
The serine proteinase prostate-specific antigen (PSA), and its complex with the serine proteinase inhibitor alpha(1)-antichymotrypsin (ACT), have been used as markers for the diagnosis of prostate cancer. PSA prepared from seminal fluid is typically contaminated with the trypsin-like glandular kallikrein (hK2). Here we describe a convenient and reproducible preparation of catalytically active recombinant PSA (rPSA) and demonstrate an overall similarity in the properties of cloned and refolded rPSA to PSA purified from seminal fluid. We also present results that are relevant for increasing the sensitivity of assays of PSA activity in biological fluids, for the putative role of PSA activity in physiologically important processes, including prostate cancer metastasis, and for the design of PSA inhibitors. Specifically, we find that added salts, in particular NaCl, give rise to dramatic increases in rPSA catalytic activity, as does added glycerol. On the other hand, Zn(2+), spermine, and spermidine, each a major component of seminal and prostatic fluid, strongly inhibit rPSA activity, with Zn(2+) being a non-competitive inhibitor while spermine is a competitive inhibitor. Citrate, also a major component of seminal and prostatic fluid, spermine, and spermidine each protect rPSA from Zn(2+) inhibition, presumably via Zn(2+) sequestration. Finally, rPSA efficiently proteolyzes several protein substrates.
Topics: Caseins; Catalysis; Cations, Divalent; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Fibronectins; Glycerol; Humans; Insulin; Kinetics; Molecular Weight; Oligopeptides; Prostate-Specific Antigen; Protein Folding; Protein Precursors; Recombinant Proteins; Sodium Chloride; Spermine; Zinc; alpha 1-Antichymotrypsin
PubMed: 10962094
DOI: 10.1016/s0167-4838(00)00116-3 -
Breast Cancer Research : BCR 2001Since its identification, much information has been obtained about prostate-specific antigen (PSA, or human glandular kallikrein 3 [hK3]), a kallikrein-like serine... (Review)
Review
Since its identification, much information has been obtained about prostate-specific antigen (PSA, or human glandular kallikrein 3 [hK3]), a kallikrein-like serine protease that is the most valuable tumour marker for the screening, diagnosis and management of human prostate carcinoma. Recently, it has become widely accepted that PSA is also present in many nonprostatic sources, casting doubts about the specificity of its tissue expression. Here we summarize the findings on the biomolecular expression of PSA in breast secretions, cells and tissues of healthy and diseased females. Although several studies have strongly suggested that the molecular forms of PSA seem to represent a potential tool for the risk assessment of breast cancer, recent reports have yielded conflicting results. Although several studies have suggested new biological function(s) for PSA in breast physiopathology, more studies are needed to enlist PSA unequivocally as an additional weapon in the anticancer armoury in breast cancer diagnostics.
Topics: Biomarkers, Tumor; Breast; Breast Neoplasms; Female; Fibrocystic Breast Disease; Humans; Immunoassay; Inhalation; Male; Nipples; Prognosis; Prostate-Specific Antigen; Prostatic Neoplasms; Sensitivity and Specificity
PubMed: 11434875
DOI: 10.1186/bcr302 -
TheScientificWorldJournal Oct 2010The discovery of prostate-specific antigen (PSA) as a biomarker represented a major discovery in the early diagnosis and monitoring of prostate cancer. However, the use... (Review)
Review
The discovery of prostate-specific antigen (PSA) as a biomarker represented a major discovery in the early diagnosis and monitoring of prostate cancer. However, the use of PSA is limited by the lack of specificity and an inability to differentiate indolent from life-threatening disease reliably at the time of diagnosis. A multitude of studies have aimed to improve the performance of PSA as well as identify additional biomarkers. The purpose of this study is to review available data on prostate cancer biomarkers for prostate cancer screening and prognostication, including prostatic acid phosphatase, PSA, PSA derivatives (PSA density, free PSA, pro PSA, and PSA kinetics), PCA3, GSTP1, AMACR, and other newly emerging molecular and genetic markers.
Topics: Biomarkers, Tumor; Forecasting; Genetic Predisposition to Disease; Genome-Wide Association Study; Humans; Male; Polymorphism, Single Nucleotide; Prostate-Specific Antigen; Prostatic Neoplasms; Sensitivity and Specificity
PubMed: 20890581
DOI: 10.1100/tsw.2010.182 -
Journal of Andrology 2006Semenogelins I and II are major coagulum-forming proteins in semen, and they are secreted mainly by the seminal vesicles. These proteins bind Zn(2+) and act as...
Semenogelins I and II are major coagulum-forming proteins in semen, and they are secreted mainly by the seminal vesicles. These proteins bind Zn(2+) and act as substrates for prostate-specific antigen and transglutaminase. A variant semenogelin I lacking 60 amino acids has been described that occurs in different populations with an allele frequency of 1%-3%. To better understand the function of the semenogelins in vivo, our aim was to characterize the properties of the variant form and compare with the wild type. Recombinant proteins were synthesized in insect cells. Binding of Zn(2+) was studied by titration of metal ions in the presence of a zinc (II) fluorophore chelator. SDS-PAGE was used to visualize the results of cleavage by prostate-specific antigen and cross-linking with transglutaminase. We found that the truncated and wild-type semenogelin molecules had similar Zn(2+)-binding properties (ie, a stoichiometry of at least 9-10 mol per mol of protein and an average dissociation constant of 5 mumol/L per site), and they showed also similar susceptibility for degradation by prostate-specific antigen. Furthermore, like the wild-type form, the truncated semenogelin I was able to serve as a substrate for transglutaminase. These findings imply that the studied characteristics do not depend on a well-defined tertiary structure, or that the deletion has no major effect on the structure responsible for these features.
Topics: Electrophoresis, Polyacrylamide Gel; Humans; Male; Mass Spectrometry; Peptide Fragments; Prostate-Specific Antigen; Recombinant Proteins; Seminal Vesicle Secretory Proteins; Zinc
PubMed: 16582407
DOI: 10.2164/jandrol.05188 -
The Prostate May 2010Prostate-specific antigen (PSA) is a serine protease secreted as a zymogen. Previously, cell-free biochemical studies have identified various kallikreins (KLK) as...
BACKGROUND
Prostate-specific antigen (PSA) is a serine protease secreted as a zymogen. Previously, cell-free biochemical studies have identified various kallikreins (KLK) as candidate activating proteases. In this study, KLK2-mediated activation of PSA in cell-based in vitro, xenograft, and transgenic models was evaluated.
METHODS
Du145-derived PSA- or KLK2-expressing clones were coincubated in vitro and in vivo to evaluate KLK2-induced PSA activity. While mice possess orthologs of KLK4-15, they do not have functional orthologs of PSA or KLK2. Therefore, transgenic animals expressing PSA or both PSA and KLK2 were generated to assess orthotopic PSA activation.
RESULTS
PSA is activated by KLK2 when the cells are physically in contact, and through co-conditioned media. In vivo, the free (inactive PSA) to total (active + inactive PSA) ratio in the blood is decreased when PSA and KLK2-expressing cells are co-inoculated subcutaneously, suggesting increased active PSA. Additionally, double-transgenic mice expressing both genes in the prostate produce more active PSA compared to single transgenic animals. A longitudinal evaluation over a 2-year period demonstrated no morphologic changes (i.e., no PIN or prostate cancer) due to PSA or PSA/KLK2 double transgene expression relative to non-transgenic mice.
CONCLUSIONS
These data demonstrate, with biologically relevant models, that KLK2 is the protease responsible for activating PSA. While PSA is involved in the processing and release of a number of important growth factors, our results suggest that active PSA is not sufficient to induce the development of prostate cancer or prostate cancer precursors in aging PSA transgenic mice.
Topics: Animals; Blotting, Western; Cells, Cultured; Immunohistochemistry; Male; Mice; Mice, Transgenic; Neoplasm Transplantation; Prostate; Prostate-Specific Antigen; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; Tissue Kallikreins
PubMed: 20058238
DOI: 10.1002/pros.21111 -
Urology Jan 1998To study the rates of elimination of total prostate-specific antigen (PSA-T), free PSA (PSA-F), and PSA complexed to alpha 1-antichymotrypsin (PSA-ACT) from blood after... (Comparative Study)
Comparative Study
OBJECTIVES
To study the rates of elimination of total prostate-specific antigen (PSA-T), free PSA (PSA-F), and PSA complexed to alpha 1-antichymotrypsin (PSA-ACT) from blood after radical retropubic prostatectomy (RRP).
METHODS
We obtained venous blood from 10 patients with prostate cancer who were undergoing RRP. We analyzed PSA-F and PSA-ACT and equimolar detection of both of these forms together (PSA-T) by using immunofluorometric assays. An attempt was made to fit the serum concentrations of PSA-F, PSA-ACT, and PSA-T for each patient to exponential curves by applying one- and two-compartment models for pharmacokinetic analysis.
RESULTS
Manipulation of the prostate during RRP resulted in a 3- to 28-fold increase in PSA-F concentrations in serum. Removal of the prostate resulted in a rapid, biexponential elimination of PSA-F from serum, corresponding to a mean initial (alpha) half-life of 0.81 hours and a mean terminal (beta) half-life of 13.9 hours. Serum PSA-ACT concentrations decreased by 20% to 40% immediately after removal of the gland; the elimination after surgery was slow and nonexponential, corresponding to a mean rate of 0.8 ng/mL/day. The elimination of PSA-T reflects a combination of the elimination patterns for PSA-F and PSA-ACT.
CONCLUSIONS
The main proportion of PSA-F is rapidly eliminated from serum, possibly by glomerular filtration. PSA-F released during surgery did not form complexes with ACT, as suggested by the lack of PSA-ACT elevation in serum. The size (approximately 90 kDa) and the extensive in vitro stability of the PSA-ACT complex prevents renal clearance. The nonexponential elimination of the PSA-ACT complex is evidence of a capacity-limited process (e.g., metabolic transformation).
Topics: Aged; Humans; Middle Aged; Prostate-Specific Antigen; Prostatectomy; Time Factors; alpha 1-Antichymotrypsin
PubMed: 9457289
DOI: 10.1016/s0090-4295(97)00572-4