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Analytical Chemistry Apr 2018The concentration of prostate-specific antigen (PSA) in serum is used as an early detection method of prostate cancer (PCa); however, it shows low sensitivity,...
The concentration of prostate-specific antigen (PSA) in serum is used as an early detection method of prostate cancer (PCa); however, it shows low sensitivity, specificity, and a poor predictive value. Initial studies suggested the glycosylation of PSA to be a promising marker for a more specific yet noninvasive PCa diagnosis. Recent studies on the molecular features of PSA glycosylation (such as antenna modification and core fucosylation) were not successful in demonstrating its potential for an improved PCa diagnosis, probably due to the lack of analytical sensitivity and specificity of the applied assays. In this study, we established for the first time a high-performance PSA Glycomics Assay (PGA), allowing differentiation of α2,6- and α2,3-sialylated isomers, the latter one being suggested to be a hallmark of aggressive types of cancer. After affinity purification from urine and tryptic digestion, PSA samples were analyzed by CE-ESI-MS (capillary electrophoresis-electrospray ionization coupled to mass spectrometry). Based on positive controls, an average interday relative standard deviation of 14% for 41 N-glycopeptides was found. The assay was further verified by analyzing PSA captured from patients' urine samples. A total of 67 N-glycopeptides were identified from the PSA pooled from the patients. In summary, the first PGA successfully established in this study allows an in-depth relative quantitation of PSA glycoforms from urine. The PGA is a promising tool for the determination of potential glycomic biomarkers for the differentiation between aggressive PCa, indolent PCa, and benign prostate hyperplasia in larger cohort studies.
Topics: Aged; Aged, 80 and over; Glycosylation; Humans; Male; Middle Aged; Prostate-Specific Antigen; Prostatic Neoplasms
PubMed: 29502397
DOI: 10.1021/acs.analchem.7b04281 -
In Vivo (Athens, Greece) 2021Lack of interchangeability between prostate-specific antigen (PSA) assays could have a clinical impact. We compared PSA assays from different manufacturers and... (Comparative Study)
Comparative Study
BACKGROUND/AIM
Lack of interchangeability between prostate-specific antigen (PSA) assays could have a clinical impact. We compared PSA assays from different manufacturers and calibrations.
PATIENTS AND METHODS
A total of 233 men who underwent prostate biopsy (PSA: 2-10 ng/ml; Beckman Coulter Access Hybritech as reference) were enrolled. Total (tPSA) and free PSA (fPSA) were also measured using the Roche cobas and the Abbott Architect methods.
RESULTS
Roche tPSA values were ≈1% higher than Beckman, while Abbott values were ≈5% lower. Roche had the highest diagnostic sensitivity (92%) compared to Beckman Coulter (87%) and Abbott (85%). Roche fPSA was ≈3% lower and Abbott ≈17% higher than that of Beckman. For the percentage of fPSA, Roche had the highest sensitivity (98%).
CONCLUSION
Roche cobas and Beckman Coulter Access Hybritech tPSA were almost interchangeable. While the agreement was acceptable for tPSA, this did not happen with fPSA and greater efforts for harmonization are required.
Topics: Calibration; Humans; Male; Prostate-Specific Antigen; Prostatic Neoplasms; Reference Standards; World Health Organization
PubMed: 34697179
DOI: 10.21873/invivo.12643 -
The Journal of Urology May 2013Recent studies have identified genetic variants associated with increased serum prostate specific antigen concentrations and prostate cancer risk, raising the...
PURPOSE
Recent studies have identified genetic variants associated with increased serum prostate specific antigen concentrations and prostate cancer risk, raising the possibility of diagnostic bias. By correcting for the effects of these variants on prostate specific antigen, it may be possible to create a personalized prostate specific antigen cutoff to more accurately identify individuals for whom biopsy is recommended. Therefore, we determined how many men would continue to meet common biopsy criteria after genetic correction of their measured prostate specific antigen concentrations.
MATERIALS AND METHODS
The genotypes of 4 single nucleotide polymorphisms previously associated with serum prostate specific antigen levels (rs2736098, rs10788160, rs11067228 and rs17632542) were determined in 964 healthy Caucasian volunteers without prostate cancer. Genetic correction of prostate specific antigen was performed by dividing an individual's prostate specific antigen value by his combined genetic risk. Analyses were used to compare the percentage of men who would meet commonly used biopsy thresholds (2.5 ng/ml or greater, or 4.0 ng/ml or greater) before and after genetic correction.
RESULTS
Genetic correction of serum prostate specific antigen results was associated with a significantly decreased percentage of men meeting biopsy thresholds. Genetic correction could lead to a 15% or 20% relative reduction in the total number of biopsies using a biopsy threshold of 2.5 ng/ml or greater, or 4.0 ng/ml or greater, respectively. In addition, genetic correction could result in an 18% to 22% reduction in the number of potentially unnecessary biopsies and a 3% decrease in potentially delayed diagnoses.
CONCLUSIONS
Our results suggest that 4 single nucleotide polymorphisms can be used to adjust a man's measured prostate specific antigen concentration and potentially delay or prevent unnecessary prostate biopsies in Caucasian men.
Topics: Aged; Biopsy; Genetic Variation; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Precision Medicine; Prostate-Specific Antigen; Prostatic Neoplasms; Unnecessary Procedures
PubMed: 23246478
DOI: 10.1016/j.juro.2012.12.023 -
International Journal of Molecular... May 2013Prostate cancer (PCa) is a leading cause of cancer-related death of men globally. Since its introduction, there has been intense debate as to the effectiveness of the... (Review)
Review
Prostate cancer (PCa) is a leading cause of cancer-related death of men globally. Since its introduction, there has been intense debate as to the effectiveness of the prostate specific antigen (PSA) test as a screening tool for PCa. It is now evident that the PSA test produces unacceptably high rates of false positive results and is not prognostic. Here we review the current status of molecular biomarkers that promise to be prognostic and that might inform individual patient management. It highlights current efforts to identify biomarkers obtained by minimally invasive methods and discusses current knowledge with regard to gene fusions, mRNA and microRNAs, immunology, and cancer-associated microparticles.
Topics: Acid Phosphatase; Biomarkers, Tumor; Humans; Male; Prostate-Specific Antigen; Prostatic Neoplasms; Protein Tyrosine Phosphatases
PubMed: 23708103
DOI: 10.3390/ijms140611034 -
Journal of Proteome Research Jul 2020Elevated serum prostate-specific antigen (PSA) levels in body fluids may indicate prostate cancer (PCa), but it is noted that the clinical performance is rather poor....
Elevated serum prostate-specific antigen (PSA) levels in body fluids may indicate prostate cancer (PCa), but it is noted that the clinical performance is rather poor. Specificity and sensitivity values of 20 and 94% at a cutoff value of 4.1 ng/mL, respectively, result in overdiagnosis and unnecessary interventions. Previous exploratory studies have indicated that the glycosylation of PSA potentially leads to improved PCa diagnosis based on qualitative analyses. However, the applied methods are not suited for a quantitative evaluation or implementation in a medical laboratory. Therefore, in this proof-of-principle study, we have evaluated the use of hydrophilic interaction liquid chromatography (HILIC) in combination with targeted quantitative mass spectrometry for the sialic acid linkage-specific analysis of PSA glyco-proteoforms based on either trypsin or ArgC peptides. The efficiency of PSA proteolysis was optimized as well as the glycopeptide separation conditions (buffer type, strength, and pH). The HILIC-based analysis of PSA glyco-proteoforms presented here has the potential for the clinical validation of patient cohorts. The method shows the feasibility of the use of a HILIC stationary phase for the separation of isomeric glycopeptides to detect specific glyco-proteoforms. This is the first step toward the development and evaluation of PSA glyco-proteoforms for use in a clinical chemistry setting aiming for improved PCa diagnosis or screening.
Topics: Chromatography, Liquid; Glycopeptides; Humans; Hydrophobic and Hydrophilic Interactions; Male; Mass Spectrometry; Prostate-Specific Antigen
PubMed: 32142289
DOI: 10.1021/acs.jproteome.0c00050 -
Bioorganic & Medicinal Chemistry Dec 2017Emetine is a small molecule protein synthesis inhibitor that is toxic to all cell types and therefore suitable for complete killing of all types of heterogeneous cancer...
Anticancer activities of emetine prodrugs that are proteolytically activated by the prostate specific antigen (PSA) and evaluation of in vivo toxicity of emetine derivatives.
Emetine is a small molecule protein synthesis inhibitor that is toxic to all cell types and therefore suitable for complete killing of all types of heterogeneous cancer cells within a tumor. It becomes significantly inactive (non-toxic) when derivatized at its N-2' secondary amine. This provides a strategy for targeting emetine to cancerous tumor without killing normal cells. In this report, PSA activatable peptide prodrugs of emetine were synthesized. To overcome steric hindrances and enhance protease specific cleavage, a 2-stage prodrug activation process was needed to release emetine in cancer cells. In this 2-stage process, emetine prodrug intermediates are coupled to PSA peptide substrate (Ac-His-Ser-Ser-Lys-Leu-Gln) to obtain the full prodrug. Both prodrug intermediates 10 (Ala-Pro-PABC-Emetine) and 14 (Ser-Leu-PABC-Emetine) were evaluated for kinetics of hydrolysis to emetine and potency [Where PABC = p-aminobenzyloxycarbonyl]. While both intermediates quantitatively liberate emetine when incubated under appropriate conditions, upon coupling of PSA substrate to give the full prodrugs, only prodrug 16, the prodrug obtained from 14 was hydrolyzable by PSA. Cytotoxicity studies in PSA producing LNCaP and CWR22Rv1 confirm the activation of the prodrug by PSA with an IC of 75 nM and 59 nM respectively. The cytotoxicity of 16 is significantly reduced in cell lines that do not produce PSA. Further, in vivo toxicity studies are done on these prodrugs and other derivatives of emetine. The results show the significance of conformational modulation in obtaining safe emetine prodrugs.
Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Emetine; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Molecular Structure; Prodrugs; Prostate-Specific Antigen; Proteolysis; Software; Structure-Activity Relationship
PubMed: 29153549
DOI: 10.1016/j.bmc.2017.11.015 -
International Braz J Urol : Official... 2019
Topics: Humans; Male; Prognosis; Prostate-Specific Antigen; Prostatic Neoplasms
PubMed: 30912890
DOI: 10.1590/S1677-5538.IBJU.2018.0867 -
Disease Markers 2016Glycans of prostate-specific antigen (PSA) in prostate cancer were found to be different from that in benign disease. It is difficult to analyze heterogeneous PSA...
Glycans of prostate-specific antigen (PSA) in prostate cancer were found to be different from that in benign disease. It is difficult to analyze heterogeneous PSA glycoforms in each individual specimen because of low protein abundance and the limitation of detection sensitivity. We developed a method for prostate cancer diagnosis based on PSA glycoforms. Specific glycoforms were screened in each clinical sample based on liquid chromatography-tandem mass spectrometry with ion accumulation. To look for potential biomarkers, normalized abundance of each glycoform in benign prostate hyperplasia (BPH) and in prostate cancer was evaluated. The PSA glycoform, Hex5HexNAc4NeuAc1dHex1, and monosialylated, sialylated, and unfucosylated glycoforms differed significantly between the prostate cancer and BPH samples. The detection sensitivity (87.5%) and specificity (60%) for prostate cancer identification are higher than those of the serum PSA marker. As low as 100 amol PSA could be detected with the ion accumulation method which has not been reported before. The improved detection specificity can help reduce unnecessary examinations.
Topics: Aged; Aged, 80 and over; Chromatography, Liquid; Diagnosis, Differential; Glycopeptides; Glycosylation; Humans; Ions; Kallikreins; Male; Middle Aged; Prostate-Specific Antigen; Prostatic Hyperplasia; Prostatic Neoplasms; Sensitivity and Specificity; Tandem Mass Spectrometry
PubMed: 27065039
DOI: 10.1155/2016/8915809 -
The Analyst Feb 2016This study presents a proof-of-concept for the development of an impedimetric biosensor for ultra-sensitive glycoprofiling of prostate specific antigen (PSA). The...
This study presents a proof-of-concept for the development of an impedimetric biosensor for ultra-sensitive glycoprofiling of prostate specific antigen (PSA). The biosensor exhibits three unique characteristics: (1) analysis of PSA with limit of detection (LOD) down to 4 aM; (2) analysis of the glycan part of PSA with LOD down to 4 aM level and; (3) both assays (i.e., PSA quantification and PSA glycoprofiling) can be performed on the same interface due to label-free analysis.
Topics: Animals; Biosensing Techniques; Dielectric Spectroscopy; Humans; Limit of Detection; Plant Lectins; Polysaccharides; Prostate-Specific Antigen
PubMed: 26647853
DOI: 10.1039/c5an02322j -
Optics Express Jun 2016The detection of low-concentration biomarkers is expected to facilitate the early diagnosis of severe diseases, including malignant tumors. Using photonic crystal...
The detection of low-concentration biomarkers is expected to facilitate the early diagnosis of severe diseases, including malignant tumors. Using photonic crystal nanolaser sensors, we detected prostate-specific antigen (PSA) from a concentration of 1 fM, which is difficult to detect by conventional enzyme-linked immunosorbent assay. The signal intensity and stability were improved by using a surfactant (i.e., ethanolamine). Even when a contaminant such as bovine serum albumin was mixed into the PSA sample, thereby increasing the concentration of the contaminant ten billion times, it was still possible to maintain a high level of detection.
Topics: Enzyme-Linked Immunosorbent Assay; Humans; Lasers; Male; Nanotechnology; Optics and Photonics; Photons; Prostate-Specific Antigen; Serum Albumin, Bovine
PubMed: 27410308
DOI: 10.1364/OE.24.012886